LTFT and o2's

[justbob]

Well i just replaced my bank 1 rear o2 to only have it also register 0 on my datalog, just the same as the old one, so I traced the wires back to pin 96 on the ECM and sure enough, I had 1.5 volts, just the same as pin 95 (bank 2 rear). So what gives??? This car has never once given me a cel. But it still cuts out while in WOT.

Also noticed that the LTFT bank 2 was reading 98.xxxx and the LTFT bank 1 is only 5.xxxx???? What is that even and where should it be?

The car runs 100% perfect in every way untill you hit the go pedal. Still has ALOT of power but in and out like a plugged carb. You can see this on the datalog also, because it will hang out at the exact RPM for up to eight or so counts on the timer before moving VERY quickly another hundred or two RPM'S where it hangs up again.

The fuel pump volt AB also reads MANY zero's and jump to 8 then down to 0 back up to 15.9 all across the RPM's. COMPLETELY all over the place. But always at 49.xxx during pull and seemed to maintain good pressure all the way through. Does the ECM give a constant volt or is it adjusted as needed?

I have a new fuel pump that i'm gonna put in soon, because when this gets fixed, if ever, I would like to finally get my dyno since I haven't got around to it in the last two years being S/C.

I'm about to crack here.:mad2:

[babbage]

Sound like a wired electrical issue. How are the GROUND wires from the battery to the block? Add another ground from the neg terminal to the frame. Then see.

Clean, clean, clean = Vroom.

Were your Cats plugged before? Are you sure?

[justbob]

Yes, but only partially. My A/F dropped from 15.2 average to 14.9 average and you can feel quite a bit of more pep.

[LeoVampire]

They should constantly be fluctuating up and down the scale once the car is warmed up and off of the preset running cycle.

Did you check the throttle possition sensor to see if it is operating correctly?

[FordNut]

How are the front O2 sensors reading?

[justbob]

They should constantly be fluctuating up and down the scale once the car is warmed up and off of the preset running cycle.

Did you check the throttle possition sensor to see if it is operating correctly?
Thats exactly what the other three are doing. I have not checked the TPS in the datalog. I really didn't know what to test, so I just started with a handfull of things.

How are the front O2 sensors reading?
Perfectly near 1 volt and fluctuating properly.

[LeoVampire]

Thats exactly what the other three are doing. I have not checked the TPS in the datalog. I really didn't know what to test, so I just started with a handfull of things.

Perfectly near 1 volt and fluctuating properly.

I goofed with an o2 sensor got a universal direct fit one instead of the proper possition one and had a problem with code's being set and other than normal running.

There are numbers for before the cat's and after the cat's o2 sensors and do call for heated one's.

[FordNut]

Just for S&G's swap the rear O2 sensors L-R. The wires may reach so you don't even have to unscrew them. See if the problem switches sides.

[justbob]

Yeah, I noticed that before I bought the new one.

The only thing I can think that I may have done but I really believe this started before that, is that I snipped the wires off the MAF and I hooked up the IAT 2 upgrade. Would having higher temps than what it once was have a big effect on the ECM? I don't remember noticing any changes at all after I did that at the end of summer getting her ready for a dyno tune. But the older I get the more I am forgetting...

[justbob]

Just for S&G's swap the rear O2 sensors L-R. The wires may reach so you don't even have to unscrew them. See if the problem switches sides.
Thanks Brian, give me a couple minutes, I'll try that.

[FordNut]

Yeah, I noticed that before I bought the new one.

The only thing I can think that I may have done but I really believe this started before that, is that I snipped the wires off the MAF and I hooked up the IAT 2 upgrade. Would having higher temps than what it once was have a big effect on the ECM? I don't remember noticing any changes at all after I did that at the end of summer getting her ready for a dyno tune. But the older I get the more I am forgetting...

You did cut the outer two wires, right?

A vacuum leak could cause the LTFT issues. A fuel injector could do it also. The fuel trims should be close to the same from Bank1-Bank2. Maybe the intake gasket or the gasket/silicone between the blower discharge plate and the lower manifold has a leak?

It's possible there are 2 unrelated issues. Normally the rear O2 sensors don't have any effect whatsoever on how the car runs.

[justbob]

Well, swapped them out to no prevail. Data came back still 0 signal at bank 1 rear.

Yes, the outer wires were the ones I cut. I'll spray some carb cleaner around and see if I can find anything leaking, although that doesn't allways do the trick. I'm sure I still have more than one issue here and I'm starting to think the issue with the o2 is a communication issue with the livelink, a bad ECM, or chip. Because I did verify .15 volts going into the ECM like there should be and no codes present. Thanks guys.

[justbob]

Any idea with those LTFT numbers which side to look at?

[LeoVampire]

Well, swapped them out to no prevail. Data came back still 0 signal at bank 1 rear.

Yes, the outer wires were the ones I cut. I'll spray some carb cleaner around and see if I can find anything leaking, although that doesn't allways do the trick. I'm sure I still have more than one issue here and I'm starting to think the issue with the o2 is a communication issue with the livelink, a bad ECM, or chip. Because I did verify .15 volts going into the ECM like there should be and no codes present. Thanks guys.

Use throttle body safe cleaner or one of those small propane tanks with the end on it unlit with the valve slightly open to see about a vacume leak okay?!

[justbob]

Really? propane? Must say I've never heard of that one before? Carb cleaner no good for the injectors?

[FordNut]

Sorry, I can't help with pointing out which bank may be a problem. Did you have the fuel injectors out? Once upon a time I had a vacuum leak due to fuel injectors being pushed over to the side by ill-fitting aftermarket fuel rails.

[LeoVampire]

Really? propane? Must say I've never heard of that one before? Carb cleaner no good for the injectors?

I just don't like the idea of using the carb clean on these newer engines better safe than sorry I always say.

[justbob]

They've been out a couple times now. Starting to wonder about the O-rings. I know from working on my escort, MANY owners have been plaqued by bad o-rings leaking unmetered air and yet not leak a drip of fuel. Huge problem with many of them.

[LeoVampire]

They've been out a couple times now. Starting to wonder about the O-rings. I know from working on my escort, MANY owners have been plaqued by bad o-rings leaking unmetered air and yet not leak a drip of fuel. Huge problem with many of them.


I always put a little dielctric greese on the o-rings for the injectors so they will slide in easily and not cause any damage to them and make's a great water and air tight seal plus keeps them from rolling.

[FordNut]

They've been out a couple times now. Starting to wonder about the O-rings. I know from working on my escort, MANY owners have been plaqued by bad o-rings leaking unmetered air and yet not leak a drip of fuel. Huge problem with many of them.

Certainly worth looking at. Maybe get a propane torch and direct the flow around the base of the injectors to pinpoint which one(s) is/are leaking. Might as well check for intake manifold gasket leaks while you're at it.

[justbob]

I'll keep that in mind! Thanks Leo. Well, time to head back out to the garage...:alone: But I'll take you guys with and set you on the tool box:D

[LeoVampire]

I'll keep that in mind! Thanks Leo. Well, time to head back out to the garage...:alone: But I'll take you guys with and set you on the tool box:D

I hope you find the problem! I wish I was there to help you out with idea's.

[justbob]

Well I took four or five laps around the intake, injectors, and all vacumm lines. Not a single leak. Just purrs like a kitten! Oh well, I'll be around if anything else pops up in your heads. Thanks again.

[LeoVampire]

Well I took four or five laps around the intake, injectors, and all vacumm lines. Not a single leak. Just purrs like a kitten! Oh well, I'll be around if anything else pops up in your heads. Thanks again.

If your short on Propane or throttle body cleaner you can use a squirt bottle with water in it.

Are you sure about fuel pressure being okay?

And again check the TPS for the wide open throttle problem.

[justbob]

I'll take her for a run tonight and check the TPS. I noticed there were AD counts and something else. I'll just check them all and make sure nothing falls off.

I'll also recheck the pressure at the rails and the pump again.

BTW, i'm a plumber, I have plenty of map gas:D

I'll report back later.

[LeoVampire]

Differnt vehicles simular problems.

In most cases they pointed to the MAF sensor being dirty or a problem with the PCM reading the FRONT o2 sensors properly and sugested a change out of them both.

Then reconect the battery and drive it around and the problem should be solved.

Also they said to look for a break in the closed to WOT and close cycle of the throttle possition sensor.

Went through a lot of stuff and that was all I could find.

[justbob]

Thanks man, that was really cool of ya! This site is awesome! I've taken that MAF apart a few times for cleaning, but never once looked into the TPS. Can't lie, I am kinda liking the garage time here lately, good music, PC, and no KIDS! HAHA Anyways, it is getting old chasing this ghost however. Really really old.

[LeoVampire]

Thanks man, that was really cool of ya! This site is awesome! I've taken that MAF apart a few times for cleaning, but never once looked into the TPS. Can't lie, I am kinda liking the garage time here lately, good music, PC, and no KIDS! HAHA Anyways, it is getting old chasing this ghost however. Really really old.

And to be honest I was curious about the situation incase I ever have to deal with it on a friends car or mine.

But yes piece and quiet and tinkering with the car is relaxing wih a few tune's playing.


On a dual exhaust system, the banks stay 1 and 2 all the way back. For example, on the same truck with dual exhaust ... Bank 1, Sensor 1 is in the left manifold; Bank 2, Sensor 1 is at the right manifold; Bank 1, Sensor 2 is behind the driver's side converter; and Bank 2, Sensor 2 is behind the passenger side converter. If automotive engineers decide to add more O2 sensors, they will continue the numbering in this fashion.
Did you know the O2 sensors behind the catalytic converters have nothing to do with fuel delivery? Their only function is to tell the powertrain control module (PCM) how efficiently the converters are working. The PCM can set a service engine light to warn the driver of a low efficiency problem. A good catalytic converter can store a lot of oxygen. Since oxygen sensors read low voltage when they sense oxygen, and high voltage when there is a lack of oxygen, you should see a high number on the rear or post catalytic O2 sensors with a good converter because it has used up the oxygen cleaning the exhaust.

[LeoVampire]

http://www.fordfuelinjection.com/?p=30

All the info you need is right there.

[justbob]

Looks to be all better now. I installed a new fuel pump that I had bought for the dyno i'm wanting to set up, I really didn't figure this would help me any, but I nailed it atleast ten times at different speeds and so far not a single sputter! I had called Lidio this morning and once he found out that one of the o2's were on and the LTFT's were also, he told me that my chip had been touched by someone else and gave me some basic things to look at, but I had allready covered all them.

I had some time on my hands, so I went ahead and did the pump, still running WAY rich according to the A/F, but doesn't seem to be jumping all over like it had been, mostly staying in the low 10's-11. I'm just hoping this is something that can be adjusted in the tune and not a waisted expensive trip.

Thanks to all who offered up advice, this house is awesome. I just hope this did fix it, time and mileage will tell.

[musclemerc]

Looks like you showed that Merc who's boss Bob! Great Job..

[FordNut]

Looks to be all better now. I installed a new fuel pump that I had bought for the dyno i'm wanting to set up, I really didn't figure this would help me any, but I nailed it atleast ten times at different speeds and so far not a single sputter! I had called Lidio this morning and once he found out that one of the o2's were on and the LTFT's were also, he told me that my chip had been touched by someone else and gave me some basic things to look at, but I had allready covered all them.

I had some time on my hands, so I went ahead and did the pump, still running WAY rich according to the A/F, but doesn't seem to be jumping all over like it had been, mostly staying in the low 10's-11. I'm just hoping this is something that can be adjusted in the tune and not a waisted expensive trip.

Thanks to all who offered up advice, this house is awesome. I just hope this did fix it, time and mileage will tell.


Thanks for posting the info on what fixed it. That's a good one to file in the back of the memory banks.