Problem after plenum/tb install

[Black_Out]

I installed a highly P&P upper plenum and throttle body the other day.. car feels great, pulls harder and sounds better.

The only issue I'm having is that under less than 5-10% throttle, the car will sort of rev on it's own. Say I'm going 40 and I have my foot on the throttle just enough to maintain speed - the car will rev slightly up and down causing it to buck a little bit. It will actually make noise sometimes as well under the same conditions, very high pitched pulsing like nails on a chalkboard lol.

I've gone through and made sure everything is hooked up correctly. No vacuum leaks, everything seems to be good. No CEL's. However, I didn't use any gaskets with the install, as recommended by the shop I bought it from. I also did no adjusting of the TPS or new throttle body, I just bolted it up. Could this be the issue?

[Zack]

The factory o ring below the plenum is fine. Are you saying you didnt use a gasket between the TB and plenum?????? No silicone either? I surely hope not!

As for the TPS, it should be at .98 at rest....very important!

[Black_Out]

Yep there is no gasket between the TB and the plenum. The guy I bought it from said not to use it, that it was only recommended for stock setups. Should I slap a gasket on? How do you calibrate the TPS so I can make sure that's good as well?

[Zack]

Put a gasket on it...now!

You need to have the ignition on, then get your voltmeter and probe 2 of the 3 wires(definitely the one in the middle) and take the reading. Set it at .98

[Black_Out]

Gasket and silicone? Or just gasket. I'm gonna go do this in the rain lol :D

[Zack]

Gasket and silicone? Or just gasket. I'm gonna go do this in the rain lol :D

Id go make a gasket for future ease of removal.

[Black_Out]

I have a rubber gasket that came with the TB, but the guy who I bought the plenum from told me not to use it. I'll slap it on there and see how if anything changes. I'm also putting on a stack racing intake spacer so the EGR will line up better.

[justbob]

While you have the TPS backstabbed with your meter, (KOEO) slowly crack open the throttle all the way and look for consistent readings going up as you open the throttle. The ceiling number should be around 4.6xxx I can't remember the exact value, do a search if needed. Just make sure your getting a smooth increase in numbers as you open.

But i'm sure your fine as this started after your install.

[Blackened300a]

I installed a highly P&P upper plenum and throttle body the other day.. car feels great, pulls harder and sounds better.

The only issue I'm having is that under less than 5-10% throttle, the car will sort of rev on it's own. Say I'm going 40 and I have my foot on the throttle just enough to maintain speed - the car will rev slightly up and down causing it to buck a little bit. It will actually make noise sometimes as well under the same conditions, very high pitched pulsing like nails on a chalkboard lol.

I've gone through and made sure everything is hooked up correctly. No vacuum leaks, everything seems to be good. No CEL's. However, I didn't use any gaskets with the install, as recommended by the shop I bought it from. I also did no adjusting of the TPS or new throttle body, I just bolted it up. Could this be the issue?

The idle surge sounds like the TPS The voltage range is .97-1 volt at idle and its 4.90-5 volts at WOT. If you are lower or high then these ranges, it will cause the surge in idle. Sometimes you will have to notch the TPS to get it in range. Some members had to do this when we did the accufab throttlebody GB a few years back. A gasket is needed no matter what! That may also be contributing to the sound if it has a leak.

I have the high pitched sound like you describe since I installed the short runner intake. I have heard from a few guys who had all kinds of whistles after playing with the intake and they said that it will go away once you get some carbon and oil buildup in the intake or it could be a leak. I did the same as you, I checked all my vacume lines for leaks and made sure everything was tight. Ill have to wait and see.

[Black_Out]

Installed the intake spacer, gasket, and TB gasket, re flashed tune, no go... still surging.

I'm guessing it has to be something with the TPS. Gonna give it a shot after I eat some breakfast I am starving and soaking wet from doing this in the rain lol :(

I'll search for the voltage values but if anyone knows them or can find them please post em up!

[Black_Out]

I just tested the TPS.. I used a multimeter, DCV set at 20. It's reading :

4.05 at idle
.35 at WOT
No abnormal readings when slowly opening all the way up to WOT. Am I doing this wrong? I kept it plugged in, and probed the wires from the back. This is on the crown vic, in case that makes a difference.

[Black_Out]

Measured the wrong wire! It is actually reading

.93 at Idle
4.63 at WOT

So the TPS isn't working with the new tb/plenum, how do I adjust it to within range?

[justbob]

I believe that is well in range. Too adjust you could oval out the holes a tad and rotate, but I belive your close enough. Here is some info from my alldata.
http://www.alldatadiy.com/alldata/AFI~V19939535~C37591~R0~OD~N/0/89012112/94698271/94698276/94698278/34853741/34857029/34857030/34857663/123117138/145902129

EDIT: IIRC, you have to be within the .96-4.65 threshold for optimal performance, I thought I read somewhere awile back that that allready included the max + and -

[Black_Out]

So which is it, Zack is saying idle should be at .98. Could my .93 be causing this issue?

If not, what else should I be chasing down? It JUST started happening after the plenum/tb install.

[FordNut]

Maybe swap the TB back to stock? Figure it out by making one change at a time? Process of elimination, that's the easiest part to swap back...

[Black_Out]

Yeah I'm going to try and figure it out tomorrow... With the new throttle body, should I adjust the blade (that goes into the TPS) so that it is at the same angle the stock TB was at? I noticed they were at different angles when closed.

[FordNut]

Do you have an xcal2? Can you datalog?

When I changed to my Whipple setup I changed the throttle body as follows:
1. Adjust throttle stop so the butterfly/blade fully closes but doesn't stick. If it closes too far it will be sticky when you open it, really easy to tell.
2. Check the TPS sensor voltage to see that it is in an acceptable operating range. I drove it like this and it seemed ok, but I took it for a dyno tune and:
3. My tuner was datalogging and had me adjust the throttle stop setscrew to open the throttle a little until he got the IAC operating where he wanted it. Not sure what value he was looking for, I suppose I could datalog and see what it is now.

[Black_Out]

Yep I have an Xcal2. Not sure how to datalog if it's even capable.

[justbob]

Download livelink off of the SCT website and go from there.

[justbob]

Have you confirmed no vacuum leaks yet using propane? (Not lit LOL)Still sounds like a leak to me.

[RacerX]

Hopefully the set screw is stock from the factory. DO NOT change the set screw if you know for sure it's from the factory. I didn't notice if someone said this, but, you can adjust the tps voltage while it's at idle by having the two screws slightly loose and moving it gently.

[magindat]

Classic un-metered air issue. Find the leak.

[Black_Out]

Slapped the stock TB/Plenum on, the problem while driving is solved, but now....

At idle, only in park, if you blip the throttle to rev it, the rpm's will stay high for a few seconds then gradually die down. This has never happened before. This whole thing has become a headache lol.