Stalled out

[ridinclean]

So last night after being a little boost happy Im driving normally and as im cruising with my foot off the accelerator my car stalls out, cuts off. I had to stop, put it in park and restart the car. This happened 3 times. I dont know if its blower-related or what. Brought it up to the L/M dealer today (stalled once on the way there) and they said they believe its a fuel sensor. Weekend newbie mechanic wants another tech to verify thats the prob on monday. So I left her up there for the weekend. :depress: I was told this would be covered under the warranty. Then the service dept lady looked at me very suspiciously and asked..."You havent done any modifications to your car have you?" Thinking that the mechanic probably just told her it didnt quite look stock I didnt want to lie to her face. So I said "Well I've done just a little" :lol: She then said if the sensor prob is related to my mods then it wont be covered...oh well

[Smokie]

If your foot was off the throttle, it may be IAC they tend to stick, I'm not buying the fuel sensor thing, but that's just me...let us know what fixes it.

[Rick-n-Miami]

If your foot is off the pedal and your at or close to idle, I'd check the IAC. A simple replacement part works wonders for it.

[cyclopsram]

IAC you do yourself 2 bolts and a wire plug.. Instead of stopping, just slide it into neutral to restart...even at 50 mph....RAM

[ridinclean]

Yea i was searching through the forums this morning and saw how someone was having a similar problem and it was the IAC. Everytime it happens its when my foot is off the accelerator or when i take my foot off the brake from a stop.

[HwyCruiser]

The IAC is $59.79 + shipping from rockauto.com 3-day delivery.

I just replaced mine after the car would not hold an idle on startup about 50% of the time, I'd have to give it a little gas to keep it running. It did this to me a occasionally on hot startups last summer/fall but it progressed to cold startups and the idle started fluctuating. I finally put 2 and 2 together and decided to try the IAC since it has bothered a few supercharged cars now. I guess being in semi-hibernation over the winter finally did it in.

The bypass passage was pretty nasty even though the throttle body was spotless. I figure the IAC motor finally gave up after having to fight against a bunch of crud but I haven't bench tested it. This seems to have corrected the problem.

[Marauderjack]

These IAC's are a PITA...I have had three so far and the blower accentuates the unstable idle especially in neutral!!!:mad2:

If I make a run in "da boost" the inlet air temp rises and I feel like the EEC cannot cope with it and tells the IAC to run all over the place and it eventually stalls!!:argue:

I have not had it stall but once in gear and that was a long time ago....right after I bought it.:(

Our EEC's have something called "Adaptive Learning" and I sometimes wonder if the blower and associated hot air, etc. screws it up??:confused:

I doubt your dealer can even shed any light on this one!!??:shake:

Marauderjack:cool:

[DEFYANT]

You have heard about the IAC.


It could also be a vacuum leak. FYI

[Jerry Barnes]

Ridinclean,

The IAC and the Vacuum Leak are my opinions. I will ask Claude and Chuck to give you a call.

Jerry

[Tallboy]

Ridinclean,

The IAC and the Vacuum Leak are my opinions. I will ask Claude and Chuck to give you a call.

Jerry


We're on it, Boss...:up:

[shakes_26]

Funny you mention Adaptive learning, This should be turned off in your tune. With a custom tune (especially power adder), you dont want the computer re-doing what the tuner spent time adjusting on the dyno/street

Just paraphrasing a very well known/respected tuner. I know precious little about the vagries of tuning and electronic engine management.

In any case, my money is on the IAC.





These IAC's are a PITA...I have had three so far and the blower accentuates the unstable idle especially in neutral!!!:mad2:

If I make a run in "da boost" the inlet air temp rises and I feel like the EEC cannot cope with it and tells the IAC to run all over the place and it eventually stalls!!:argue:

I have not had it stall but once in gear and that was a long time ago....right after I bought it.:(

Our EEC's have something called "Adaptive Learning" and I sometimes wonder if the blower and associated hot air, etc. screws it up??:confused:

I doubt your dealer can even shed any light on this one!!??:shake:

Marauderjack:cool:

[Zack]

Funny you mention Adaptive learning, This should be turned off in your tune. With a custom tune (especially power adder), you dont want the computer re-doing what the tuner spent time adjusting on the dyno/street

Just paraphrasing a very well known/respected tuner. I know precious little about the vagries of tuning and electronic engine management.

In any case, my money is on the IAC.

Dude, what are you saying?
Adaptive learning gets shut off WHEN THE CAR IS GETTING TUNED.
It gets turned back on when the car leaves the dyno!

Blower cars are notorious for dying out. The problen is in the IAC functions in the software. A few changes and the problem is solved. It is highly unlikely that the IAC is bad.

[Marauderjack]

Zack...

What do I have to do to stop the idle searching and eventually dying?? Dave Lamberson of Injected Racing has made some changes and it is better but it ain't perfect yet....HELP!!:help:

Marauderjack:burnout:

[Jerry Barnes]

Dude, what are you saying?
Adaptive learning gets shut off WHEN THE CAR IS GETTING TUNED.
It gets turned back on when the car leaves the dyno!

Blower cars are notorious for dying out. The problen is in the IAC functions in the software. A few changes and the problem is solved. It is highly unlikely that the IAC is bad.

Zack,

Everytime I think you are knowledgeable you say something stupid! "Blower cars are notorious for dying". What type of blower cars are you talking about???? Not a Trilogy Blower car! If our cars stalled, we would not have sold 10 kits!

Maybe the blower car you have is "notorious" for stalling, but not ours! It's time you baught a new blower car.

Jerry

[2ndMDRebel]

I have been fighting this very problem since having the conversion done on my Vic. Since having it tuned by another SCT shop the bouncing idle is gone but it will still stall at low speeds and has a bad hesitation/stutter like the engine wants to stall out on initial acceleration from a stop. Sometimes when starting after a brief stop (like running in the 7-11) the rpms will shoot up to 1400-1800 or so and hang around there. If I try to put it in gear to move it immediately stalls right out. Restarting after it does that is hard (spins but won't fire up) and I have to hold the accelerator to get it going again then its a cat and mouse game with the rpms and the gear selector... sometimes stalling two or three times just trying to back up! Its just no fun driving the car when you dread coming to a stop because you don't know what the car is going to do when its time to go again.

Now where's that thread on regretting mods, I've got a whole sig full of 'em...

[Jerry Barnes]

We're on it, Boss...:up:

You go get'em Chuck! Thanks a bunch!!

[Zack]

Zack,

Everytime I think you are knowledgeable you say something stupid! "Blower cars are notorious for dying". What type of blower cars are you talking about???? Not a Trilogy Blower car! If our cars stalled, we would not have sold 10 kits!

Maybe the blower car you have is "notorious" for stalling, but not ours! It's time you baught a new blower car.

Jerry

.....
Read what I said. Blower cars are notorious for dying out. I didnt say Trilogy's only. If you were a tuner or a mechanic, you'd know that when you shove boost into an engine and the throttle blades close abruptly (when you let off the gas) the computer gets confused and compensates through the IAC. The IAC is adjusted in the software. Im sure Lidio incorporated some changes in the tune for this. I know any Cobra with minimal mods needs IAC adjustments. My Vortech died out for the longest time before I fine tuned the IAC function and remedied the problem.
Jerry, this aint the Darkside. Check that personality at the door, huh?

[SergntMac]

Funny you mention Adaptive learning, This should be turned off in your tune. With a custom tune (especially power adder), you dont want the computer re-doing what the tuner spent time adjusting on the dyno/street. I disagree. First, all things learned by adaptive learning are cleaned out when the EEC is flashed. The blackboard is erased and washed down. Secondly, what is collected after that aids the EEC in making decisions when you don't feel like it. After a flash tune, get out and hit it hard, WOT. That's the beginning of a fresh adaptive learning cycle, and it's the best thing you can do for your tune.

[ridinclean]

Somebody remind me to start doing this stuff on my own in the future. I ordered an IAC valve and went ahead and let the dealer put it on, took a whole 10 mins cost me $200 for the part and labor. I feel *****. Oh well so far so good, no stalling on the ride home. Time to go cruise some more to see if its cured.

[Marauderjack]

Mac....

I originally brought up the "Adaptive Learning" aspect of our EEC's and I can tell you that what you say is 100% true!!:beer:

I can change only one parameter with my Diablo tuner and I'm back to crazy idle swings and stalling for about three days...at which point it settles back down and acts civil!!:bows:

Right now it will stall 50% of the time when I put it in "Park" but I attribite this to the temperature swing we are currently in.....down 30* from what it has been??:shake: It presently has not stalled in gear...only when I go to Neutral or Park!!:mad:

I was hoping Zack would elaborate on what needs to be changed so I could get Dave to do it for me!!:cool:

ZACK????:help:

Marauderjack:burnout:

[Tallboy]

For what it's worth, I presently have both a Predator with a tune written "by a friend of ours :gangster: ", and the SCT chip that came with my kit. Never had a problem with either. When I change parameters with my Predator; In-Gear Idle RPM, Shift Pressures, Torque Modulation, etc. I notice no ill-affects at all. Never had it stall, or even stumble, and I played around with the idle a lot before I got it where I wanted it.

For what it's worth, I think the "stalling thing" may be more prevalent in the centrifugal cars, as these are the only ones with the throttle blade "under pressure". The roots blowers create pressure in the lower intake.

Note: I'm not a tuner, and won't pretend to be. These are simply my thoughts. I'm gonna go try and learn more about this "adaptive learning" thing on blower cars...

[O's Fan Rich]

I disagree. First, all things learned by adaptive learning are cleaned out when the EEC is flashed. The blackboard is erased and washed down. Secondly, what is collected after that aids the EEC in making decisions when you don't feel like it. After a flash tune, get out and hit it hard, WOT. That's the beginning of a fresh adaptive learning cycle, and it's the best thing you can do for your tune.
So, now that my new gears are broke in... I should reinstall the factory tune, then put the 4:10 tune back in and crank her up?

[HwyCruiser]

Just wondering out loud about what the controllable range of IAC is.

Would raising the neutral and in-gear idle, to say 1000 rpm, basically forcing the IAC to operate at a more "wide open" range, instead of trying to control to the factory setting of 600 rpm, allow the computer to catch a low idle fuctuation before a stall?

[Tallboy]

Just wondering out loud about what the controllable range of IAC is.

Would raising the neutral and in-gear idle, to say 1000 rpm, basically forcing the IAC to operate at a more "wide open" range, instead of trying to control to the factory setting of 600 rpm, allow the computer to catch a low idle fuctuation before a stall?

Good question, JD. I raised my in-gear idle by 150 RPM. Maybe that had something to do with it?

[Smokie]

Just recently I was trapped in stop and go traffic for about 1 hour, after about 45 minutes while coasting in drive with foot off gas pedal the engine died. I have also noticed that any prolonged idle in Drive the rpm's fluctuate up and down; if I turn the A/C on it idles much smoother, however any prolonged idle in drive is not perfectly smooth, however as soon as throttle is applied the engine runs perfectly smooth.

[Smokie]

Just wondering out loud about what the controllable range of IAC is.

Would raising the neutral and in-gear idle, to say 1000 rpm, basically forcing the IAC to operate at a more "wide open" range, instead of trying to control to the factory setting of 600 rpm, allow the computer to catch a low idle fuctuation before a stall?

Codes 415 and 416 describe the adaptive lower and upper limit of the IAC . However I don't know what the adjustable parameters are and I lack the software to perform the parameter changes.

[SergntMac]

Gents...IMHO...

Everyone please step back one square and remember that there is an adjustment screw on the throttle linkage that acts like a doorstop for the throttle body blade. It's range is limited, but it serves to fine tune the movement of the blade, which ultimately affects your idle engine speed.

Though the switch is called an "Idle Air Control" sensor, it's actual job is that of a sensor, and sensing throttle position, not controlling it.

The IAC does not turn the throttle blade, the linkage turns it. The IAC only reports the balde's position to the EEC, which makes adjustments in other areas accordingly. Both the IAC and this adjustment screw are attached to the throttle blade at it's axis, but at different ends of the same axis. One moves it, the other reports it's move.

Whether boost is built outside the TB and forced against it (centrifugal), or, it's built inside the intake manifold and sucking air through it, (with likewise force...Roots), a sudden and complete shut of the throttle has the same effect on the blade, thus, on the idle speed and IAC as well.

I'm not a tuner either Hell I'm not even a mechanic, wrench, or tech. But, IMHO, the problem here is that the throttle body blade is shutting too tight too soon, and everything else is a reaction to no air flow at all.

Find this screw and tweak it by 1/4 turns. Engine idle will die, or, rise up in RPMs, and you'll learn very quickly which way to turn the screw. It's hidden under the plastic shroud where the linkage connects to the TB, and it looks just like the idle screw on my last Holly 750 DP from back in the late '60s.

Y'all got nothing to lose looking at this tweaking, right?

[Smokie]

...Y'all got nothing to lose looking at this tweaking, right?

Worth a try, neutral rpm's will come up as well, mine are close to a grand already. If it fixes that annoing fluctuation it would be worth it, thanks for the tip.:)

[Tallboy]

Gents...IMHO...

Everyone please step back one square and remember that there is an adjustment screw on the throttle linkage that acts like a doorstop for the throttle body blade. It's range is limited, but it serves to fine tune the movement of the blade, which ultimately affects your idle engine speed.

Though the switch is called an "Idle Air Control" sensor, it's actual job is that of a sensor, and sensing throttle position, not controlling it.

The IAC does not turn the throttle blade, the linkage turns it. The IAC only reports the balde's position to the EEC, which makes adjustments in other areas accordingly. Both the IAC and this adjustment screw are attached to the throttle blade at it's axis, but at different ends of the same axis. One moves it, the other reports it's move.

Whether boost is built outside the TB and forced against it (centrifugal), or, it's built inside the intake manifold and sucking air through it, (with likewise force...Roots), a sudden and complete shut of the throttle has the same effect on the blade, thus, on the idle speed and IAC as well.

I'm not a tuner either Hell I'm not even a mechanic, wrench, or tech. But, IMHO, the problem here is that the throttle body blade is shutting too tight too soon, and everything else is a reaction to no air flow at all.

Find this screw and tweak it by 1/4 turns. Engine idle will die, or, rise up in RPMs, and you'll learn very quickly which way to turn the screw. It's hidden under the plastic shroud where the linkage connects to the TB, and it looks just like the idle screw on my last Holly 750 DP from back in the late '60s.

Y'all got nothing to lose looking at this tweaking, right?

Hmmm. OK, serious question here...

From the factory, our throttle body and all associated parts are designed/engineered to operate under vacuum, right? Do you think pressurizing components designed/engineered to operate under vacuum could make 'em act screwy? I'm trying to absorb this, but having a hard time getting it all sorted out.

A little :help: ?

[HwyCruiser]

Mac, I think you're talking about the throttle position sensor (TPS). The IAC has a motor that drives a plunger in and out of a byass passage around the closed throttle blade to control idle. I agree, adjusting the throttle stop should help out where a good IAC fails to hold an idle. That or drill a hole through the throttle blade like the old-school'ers do it.

Chuck, the throttle is pretty much open when in boost anyway. A bad or slow bypass valve would cause an issue on rapid decel from WOT, which I think is what Zack was going after. It seems like a lot of these issues seem to be during no-boost conditions with either a centrifugal or roots blower though which kinda points to the IAC. This seems to be a problem with other Ford motors with an IAC setup, we're just getting old enough for it to start catching up with us too.

[Tallboy]

Mac, I think you're talking about the throttle position sensor (TPS). The IAC has a motor that drives a plunger in and out of a byass passage around the closed throttle blade to control idle. I agree, adjusting the throttle stop should help out where a good IAC fails to hold an idle. That or drill a hole through the throttle blade like the old-school'ers do it.

Chuck, the throttle is pretty much open when in boost anyway. A bad or slow bypass valve would cause an issue on rapid decel from WOT, which I think is what Zack was going after. It seems like a lot of these issues seem to be during no-boost conditions with either a centrifugal or roots blower though which kinda points to the IAC. This seems to be a problem with other Ford motors with an IAC setup, we're just getting old enough for it to start catching up with us too.

Good points, all. Thanks, JD! I've been out in the garage playing around with some parameters on the Predator. I'm finding out a lot more about this tune I have. What a wonderful tool!!!:)

[TripleTransAm]

I guess it kind of makes sense... the IAC (Idle Air Control) valve is nothing but a PCM-controlled vacuum leak. So if the intake is under positive pressure, I guess it would be leaking that pressure out if it was in an open position. Maybe it's closed, and that's what ends up stalling the motors when the throttle blades crack shut again?

From what I've seen, the throttle position sensor (the sensor that SergntMac is referring to above) has a range in which the PCM considers the throttle completely closed (to account for variance in the sensor build quality and adjustment variances as well). I suppose it would be possible for the throttle blade minimum opening to be opened via the screw discussed such that the PCM would still think it was technically 'closed' but yet still allow more air into the engine.

The thing I don't get (and I hope someone with tuning experience will chime in here) is that most non-Ford PCMs I've snooped on will have the IAC opened up fully during any non-closed-throttle situations, exactly to account for the sudden-throttle-closing situation we're discussing here. So why are we even experiencing this on these cars? Did Ford completely neglect this situation on their base programming?

One other thing I just thought of: anytime one plays with the intake on any of the non-Fords I've played with, it's strongly recommended to follow a procedure to reset the IAC (in order for the PCM/ECM/whatever to know exactly at what position the IAC pintle is located at, to increase the accuracy of the PCM in ordering exactly how much air to bypass the closed throttles). Is there such a procedure for Ford motors?

[HwyCruiser]

Here's a pic of the IAC I swapped out:

http://www.mercurymarauder.net/showcase/files/1/5/9/4/IAC.JPG

The motor looks like it had to work against some carbon buildup on the shaft. I have 41k+ miles on it, about 6k with the blower.

I'd like to test it out to see if it's stuck closed but I haven't a clue as to the voltage or polarity. I'd assume its a switched 12 volts, but I don't want to guess and smoke it in the process of trying to test it. Anybody know how to test these do-hickeys?

[DEFYANT]

This has happend before and it was on a Trilogy car. It is the IAC and is no big deal.

BillyGmans A recent problem (http://www.mercurymarauder.net/forums/showthread.php?t=20700) thread in which we all went over this. Check it out.

[DEFYANT]

Oh, and for the record, the choice of supercharger has zilch zero nada effect on this. I had one go bad on the CVPI, symptoms were the same. It is simply a POS part.

[Mike M]

I have been replacing IACs for years; the Fords IACs are prone to failure electrically but even more mechanically. I have been reading some comments here and want to clear up a few things.

It probably isn't a vacuum leak making it stall out; usually a vacuum leak will make it idle higher then normal...this is not a carb, its fuel injection.

The IAC does not sense anything, it is a controlled vacuum leak...it is an output not an input!

One thing that should be checked assuming the throttle body is CLEAN and the IAC is CLEANED and working properly is the minimum idle speed. This is done by removing the electrical plug on the IAC and using the throttle blade screw to bring the idle to about 550 RPM in park, just enough to keep it running in the event the IAC is too slow to react or goes bad.

In my PROFFESIONAL opinion the Supercharger choice is irrelevant even though it appears some people would like it to be.

I also heard the BLACK Marauders stall out more then any other color.

[SergntMac]

My apoligies to all for confusing the IAC and TPS but hey, gotcha thinking, right?

In my PROFFESIONAL opinion the Supercharger choice is irrelevant even though it appears some people would like it to be.

I also heard the BLACK Marauders stall out more then any other color. I agree on both points.

Until (and unless) our throttle body nomenclature is disposed of, all of us (supercharged, turbocharged and N/A) eventually face dealing with this stalling problem. It develops over time and use, only the "trailer queens" can brag "not me", and just for the time being. Time/use will eventually catch up to them too.

The time/use tables get upset when power adders are involved in the mix because the "use" table is accelerated. More tinkering with OEM structures means more problems to address. Moreover, more hours on the clock means accelerated wear, and accelerated wear accelerates "when".

I agree that the style of supercharging is remotely indifferent here, but being supercharged over N/A is not. Chances are, if you add a power adder, this will happen to you sooner. This was Zack's point, all supercharged applications suffer this problem, and sooner.

Back in June of 2003, Zack, Mark (N40GL) and I drove my Kenny Brown #1x Vortech supercharged Marauder to the first ever Trilogy open house in Detroit, MI. This was the debut of the Trilogy Roots kit and it's release to the public as a product for the Marauder. After 4 hours on the highway, my #1x died in the parking lot.

Jerry Barnes and Steve Babcock took it for a test drive, and it died out again, several times as I understand it. We had no problems on the 4 hour drive home, but stalling was a problem the following week. I chalked it up to variance in octane OTR, and atmospheric conditions between Chicago and Detroit confusing the adaptive memory. However, Zack discovered something not otherwise considered at that time, and it was something I never expected to deal with.

Dirt.

The throttle body was coated in a black sauce I cannot further describe, and that taught me that maintaining a clean engine bay will be a forever component of a reliable motor vehicle. My 1x hasn't stalled since. So it seems that it's not true that one supercharger is superior over another, it's just dirt.

If you tinker under the hood, or, with the tune, you need to maintain that tinkering. If you do not touch anything at all, eventually you will have to clean/repair/replace something. Tweaking your custom tune does not clean the dirt, trust me on this.

I have recently supported this "dirt" theory with my experience with my #3 Marauder. 72K on the clock when I bought it, and zero maintenence under the hood. First tank of gas produced 16.4 MPG, and I started to tinker from there. I'm at 24 MPG now, still bone stock with a CRD1 SCT tune, and this experience continues to grow. Dirt...Deal with it.

I also agree that "black" MMs suffer this problem more that other colors, but only because statiscally speaking, black is numerically superior in the sample. There are more black MMs among us than optional colors, which means that when discussing common problems (such as this) black MMs seem to suffer more than other colors.

If 50 percent of the sample base is black, the time/use tables will indicate "don't buy a black Marauder, it will stall", which is a true statement, statistically speaking. Thus, adding up the user numbers among us, supercharged Marauders seem to outnumber N/A. I think we (we meaning posting membership here) have more supercharged owners talking to each other, than not.

Therefore, this IS a problem all supercharged Marauders will have to deal with eventually, statistically speaking. Again, Zack is right, and not because "it appears some people would like it to be".

I love stats. You can make them lie any way you want...

[MikesMerc]

This was Zack's point, all supercharged applications suffer this problem, and sooner.

This is simply a boat load of crap.

To say blower cars inherently stall more than non-blower cars is simply wrong. The ONLY thing that can be said about blower cars that stall is that they have a bad tune.

I'm now on my FOURTH blower car, and none of them had an inherent stalling problem. Then again, I'm careful about who I choose to tune my car.

Two of my mustangs were HIGH MILEAGE blower cars. Niether succumbed to stalling issues. One of them did exhibit idle searching after many miles that was quickly remedied by a cleaning of the IAC (a small shot of gumout worked nicely).

My blown Marauder has stalled one time in its entire existence. It did so the day after I changed to a nitrous tune and added 60lb injectors and the SCT 90mm mass air meter. It happened the day of the DreamCruise while idling in heavy traffic in fact. I wasn't shocked though as changing the MAS to anything over 80mm can be tricky. Lidio tweaked the tune in 5 minutes and it has not happened since.

To have folks on this board BSing that blower cars are more prone to stalling mechanically speaking is ridiculous. Sure, blower cars do stall more, generally speaking....but usually due to a bad tune. I see it all the time at the track. In my opinion this is completely unacceptable. If the TB and IAC is clean, and the IAC hasn't gone bad (a notoriously failiing part for Ford), then its simply a bad tune.

When it comes to hardware failure (IAC going bad) or maintenance(dirty IAC or TB) then it matters not whether your SC or not. There are far too many supercharged OEM that don't experience the issue....not to mention thousands of personal experiences by blower car owners that don't have the issue either.

I can see Jerry's sensitivity to the issue. For our forum *cough* leaders *cough* to come on here and say that blower cars just stall more is simply incorrect and misleading. No one should be lead to beleive that because you have a SC on your car your going to subject to poor driveability conditions like stalling. That's simply not the case if you have a well designed blower kit with the proper tuning.

[Tallboy]

I'm still trying to understand all this. I thought the IAC motors get gummed up due to the fumes in the engine when we shut it off? [Ever see that golden-brown on the lower intake?] Those fumes rise and get the back of the throttle plate dirty, and in turn, the IAC gets gummed up. Am I on the right track here?

[SergntMac]

I'm still trying to understand all this. I thought the IAC motors get gummed up due to the fumes in the engine when we shut it off? [Ever see that golden-brown on the lower intake?] Those fumes rise and get the back of the throttle plate dirty, and in turn, the IAC gets gummed up. Am I on the right track here? Sorry, Chuck...In a perfect world, you don't see the golden brown lower intake and nothing gets gummed up.

[Smokie]

This thread has yielded a lot of valuable information in the area of stalling when "off throttle" and when a person is able to read it without a personal bias they will see that those that made contributions; even if they are on "opposing sides" helped to increase the overall knowledge base we can draw from.

The unfortunate part is that due to past "clashes" some can be overly sensitive, I guess this is simply never going to go away. I am a happy Trilogy customer and personal friend of Jerry, who is a great guy that sells an excellent product....I have not found anything in writing here that insults Jerry or his fine product.

Macs dirt theory I happen to personally agree with.

Zacks statement that "blower cars" are more prone to stalling as opposed to N/A cars, generally speaking is a true statement "in my opinion",

Mike Mielnicki's statement about Fords IAC I find to be also a true statement.

All of the above can be true and coexist without conflict....it's us that can't get alone....not the statements.

[MikesMerc]

I'm still trying to understand all this. I thought the IAC motors get gummed up due to the fumes in the engine when we shut it off? [Ever see that golden-brown on the lower intake?] Those fumes rise and get the back of the throttle plate dirty, and in turn, the IAC gets gummed up. Am I on the right track here?

Yes, Chuck, you are on the right track indeed. In both OEM, and well designed blower kit applications, you're going to have some PCV emmissions routed back through the intake track (take note of the hose that runs from the driver's side cam cover to the underneath of the intake elbow). This is going to lead to some amount of residue being deposited in the intake track. This can do a few things. More commonly it can gum up IAC and it can sometimes lead to a build up in the throttle body (on or near the blade). Both can cause low rpm driveability issues. It also accounts for some of the "brown" deposits in the lower intake as well.

What's important to understand is that this happens regardless of whether the car is SC'd or not. A little maintenance in keeping the IAC and TB clean helps.

[Zack]

My blown Marauder has stalled one time in its entire existence. It did so the day after I changed to a nitrous tune and added 60lb injectors and the SCT 90mm mass air meter. It happened the day of the DreamCruise while idling in heavy traffic in fact. I wasn't shocked though as changing the MAS to anything over 80mm can be tricky. Lidio tweaked the tune in 5 minutes and it has not happened since.

My point exactly.

[MikesMerc]

Zacks statement that "blower cars" are more prone to stalling as opposed to N/A cars, generally speaking is a true statement "in my opinion",


But I think you have to ask yourself "why?"

Mechancially speaking, a well designed blower kit with the proper tune should not increase the occurence of stalling one iota. The Lightening guys aren't stalling from the factory. Niether are the Cobra guys. Search the forums on SVT or elsewhere and look for the problem. Aside from the occasional stall issue from a bad or dirty IAC (which occurs on NA cars just as much), the problem isn't there.

So, if that's the case, why do blower cars stall more often in general? ...tuning.

[Zack]

Here are the revised values for the IAC in the SCT Software.

Stock ISC Drive Idle Air
4095.9375 1.1499
950.0000 1.1499
820.0000 0.8799
650.0000 0.6001
602.0000 0.5400
521.0000 0.4199
485.0000 0.3999
0.0000 0.3999
0.0000 0.3999
0.0000 0.3999

Corrected ISC Drive Idle Air
4095.9375 1.3799
950.0000 1.3799
820.0000 1.0557
650.0000 0.7202
602.0000 0.6479
521.0000 0.5039
485.0000 0.4800
0.0000 0.4800
0.0000 0.4800
0.0000 0.4800

Stock ISC Neutral Idle Air
4095.9375 3.0000
2200.0000 1.6201
1820.0000 0.9600
1170.0000 0.8599
1020.0000 0.7300
870.0000 0.6099
670.0000 0.4800
550.0000 0.3999
0.0000 0.3599
0.0000 0.3599

Corrected ISC Neutral Idle Air
4095.9375 1.5596
1170.0000 1.0317
1020.0000 0.8760
870.0000 0.7319
670.0000 0.5762
550.0000 0.4800
510.0000 0.4800
430.0000 0.4321
0.0000 0.4321
0.0000 0.4321

[Zack]

So, if that's the case, why do blower cars stall more often in general? ...tuning.

Duh, thats what I was trying to tell everyone.
Look at my post above.
Lets see if Lidio will chime in here and tell us if he made any changes to those functions in his Trilogy Tune.
When I first got my blower, these values were still at stock.
I realized the problem through a little research and corrected it.

[MikesMerc]

My point exactly.

What point zack?

That TUNING is the usual suspect in blower cars that stall? If so, I fully agree.

However, the more important point, is that tuning adjustments can be made and there is never a need to live with a stalling blower car. The Trilogy based kits have done this as close to perfection as can be achieved. Stalling is simply not a commonly reported issue whatsoever. In fact, its rare. Therefore, the tune is no longer the usual suspect when stalling arises on a Trilogy car. We instead look at non blower related causes such as a dirty or failed IAC. Just as this thread was doing before it was sidetracked into being blower related.

[Zack]

We all made our points, valuable info was exchanged.
I think this is a done thread.

[MikesMerc]

I agree, the thread has run its course.

I would, however, like to take the opportunity to help everyone realize Jerry's sensitivity to this issue. He spent a lot of time and money getting the tune for the Trilogy kit well ironed out. Stalling is simply not an inherent issue with his kit and he obviously wants that to be heard loud and clear. I don't blame him for feeling a bit uncomfortable that it was suggested that a trilogy car was stalling "just because it was a blower car."

I would also like to apologize to Zack. I didn't mean to get into a pissing match only to find that we basically agree on things. He is indeed VERY knowledgable and I value his opinions. I just hope Zack might understand Jerry's point of view and sensitivity to the issue as well.

[Smokie]

...The unfortunate part is that due to past "clashes" some can be overly sensitive, I guess this is simply never going to go away. .

This is probably the only part I got right...it really is a shame it has to be this way.

[SergntMac]

And so it goes...

[Zack]

I never doubted the R&D of Jerry Barnes.
There a lot of folks here who have had their car's tune altered from the chip supplied with the kit. Some owners stalling problems could have stemmed from this .
I was trying shed light that the tuning has a big part in the idle/stalling of a blower car, Roots or other.

[Tallboy]

I never doubted the R&D of Jerry Barnes.
There a lot of folks here who have had their car's tune altered from the chip supplied with the kit. Some owners stalling problems could have stemmed from this .
I was trying shed light that the tuning has a big part in the idle/stalling of a blower car, Roots or other.

All true. I apologize if my part in these conversations can be misconstrued as pointing a finger at any particular product. This was not my intention, more of kinda wondering aloud.

My education continues...

[Marauderjack]

Zack,

I don't know if you ever answered me.....What did you change to clear up the stalling??

Mine never stalls in gear....only when I go to Neutral or Park....It runs the RPM's up to about 1300 and falls to ZERO....about 25% of the time??:argue:

My idle in gear and in Neutral is 700 RPM's (rock solid) and I wonder if this is just to high??

Marauderjack:burnout:

[ridinclean]

Now that the apologies are out of the way how about my car just stalled again for the first time since the IAC valve was replaced. And Ive been doing alot of driving, I went to daytona and back. The stalling occured when taking my foot off the break about to coast away from a complete stop.:help:

[MikesMerc]

Now that the apologies are out of the way how about my car just stalled again for the first time since the IAC valve was replaced. And Ive been doing alot of driving, I went to daytona and back. The stalling occured when taking my foot off the break about to coast away from a complete stop.:help:

Well, let's get back to what Zack brought up. Are you running the stock Trilogy kit and tune?

[Smokie]

It was suggested earlier to unplug the IAC and adjust TB screw so the engine idles at lowest possible rpm about 550. Make sure that it can run with IAC disconnected that would give you a margin of error in case EEC is slow to react to closed blade and does not allow the bypass air to feed engine fast enough.

[2ndMDRebel]

One of my techs gave me a spacer that fits between the IAC and the throttlebody, it has screws for adjusting the idle. After two days of use my car has not stalled once and the hesitation when accelerating from a stop seems to have been reduced. The Ford part # is F2PE-9F942-AA but I was told they may no longer be available.

What is a good idle rpm to aim for when in gear and in neutral/park?

[ridinclean]

Well, let's get back to what Zack brought up. Are you running the stock Trilogy kit and tune?
Yes and yes.

[Smokie]

Yes and yes.

If you disconnect the the plug (wires) going into the IAC does your car continue to run (in Park) or shuts off right away???

[Zack]

Do not ever adjust the throttle blade screw.
The idle is controlled strictly by the IAC. The blades should be completely closed at all times.
Another very important thing I forgot to mention is the adjustment of the power steering pressures. Is anyone's car dying out while turning a corner or just turning the wheel?
I had to adjust my car for this.

[Smokie]

Do not ever adjust the throttle blade screw.
The idle is controlled strictly by the IAC. The blades should be completely closed at all times.
Another very important thing I forgot to mention is the adjustment of the power steering pressures. Is anyone's car dying out while turning a corner or just turning the wheel?
I had to adjust my car for this.

Zack do you know why there is an adjustment screw for the throttle blade???

[Zack]

http://www.mercurymarauder.net/showcase/files/4/0/4/IdleScreen2.bmp

As you can see everyone, there are many factors that control the idle in the tune.

[Zack]

Zack do you know why there is an adjustment screw for the throttle blade???

Yes, it is there to prevent the throttle blades from spinning all the way around in the bore.

[Zack]

The car can also die out from the A/C compressor being engaged. There is an adjustment in the software for this as well.

[Smokie]

Do not ever adjust the throttle blade screw.
The idle is controlled strictly by the IAC. The blades should be completely closed at all times.
Another very important thing I forgot to mention is the adjustment of the power steering pressures. Is anyone's car dying out while turning a corner or just turning the wheel?
I had to adjust my car for this.

Is the reason you say this because when you change the position of the blade the voltage output from the TPS to the EEC is changed and it must be readjusted??

[Smokie]

Yes, it is there to prevent the throttle blades from spinning all the way around in the bore.

Well I'll be dipped in dog doo....I thought the bottom of the blade actually bumped against the bore preventing this.....:confused:

[Zack]

Is the reason you say this because when you change the position of the blade the voltage output from the TPS to the EEC is changed and it must be readjusted??

Yeah that too, here is a SCT screen showing the idle adjusnments for the A/C clutch being applied.
Stock values for A/C on in Drive is 16
Stock values for A/C on in Neutral is 0
http://www.mercurymarauder.net/showcase/files/4/0/4/ACIdleScreen.bmp