2000 GT Strong exhaust smell possibly really rich but no codes

79pace

something stupid will fall out of my mouth
Founding Member
Jul 21, 2000
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Tulsa, OK
Some background. We did an engine swap on this car. It had a locked up motor so we put one from a 2002 in it. We used most all of the wiring and sensors off the 2000 and we do have the orange top injectors on it not the pink ones (the 2002 had orange). We did have to use the MAF from the 2002 since the 2000 did not have one with it when we got it. We put new chains and tensioners on it but otherwise we dropped it in stock. We added a off road X pipe to it which could be a contributor to our issue.

I am still hearing a small ticking on the passenger side bank almost like a clunking sound from what seems like inside the motor but so far it has not gotten any worse and I did put some seafaom in the oil to make sure a lifter wasnt sticking or anything like that. However the car seems rich, takes an extra crank to fire like its struggling to hit and the exhaust smell is bad. Like make your clothes stink bag and you can see the white smoke out of both sides of the back. It has zero codes being pulled and yes I have a code scanner. I am getting nothing. I have a blue tooth OBDII adapter I use in my truck with the Torque pro App but iit really does not pull much data out of this car. My old truck (2006) would pull data for each COP and have tones of sensor tests. This one does not give me much and fails a couple of them but does not say what they are. Is the computer just not new enough or do we have a bigger problem? I am suspecting the Fuel Pressure regulator may be bad but I dont want to just throw parts at it. I had another TPS so we threw it on and nothing changed. I was able to look at the O/2 data on the Torque app and all 4 looked basically the same with a curve that was going up and then back down over and over. No idea what that means but I assume they are working since it was at least getting data from them. What should we check next? I looked around and did not see any vacuum leaks and everything was plugged in and when I pulled the one off the FPR it had good vacuum at that port. Just looking for things to check or to do some self diagnosis before we buy parts. Just odd that it has no codes and runs descent when you drive it. No real symptoms of a problem over all. Once it did stumble and puff a lot of white smoke and barely re started but 30 minutes later it ran fine again. Oh and all the injectors sound good on the stethascope. All clicking like they should
 
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Let me ask you. What color injectors originally came with your 2000 GT? In my 2000 GT the injectors are YELLOW.

To me it's not a surprise that your 2000 GT is running rich when larger injectors that what the PCM is expecting have been used without a tune.

While it's true that a 2000 PCM doesn't have as many PID's as what a latter model year PCM would have, I can tell you from personal experience that a 2000 PCM will most certainly report:
  • MAF flow
  • Fuel Pressure
  • Long term fuel trims (LTFT) and short term fuel trims (STFT).
  • misfire data from the ODB2 mode6 data.
  • O2 sensor output.
 
Yellow is orange. They are 19# stock injectors from this car. They are not larger injectors. Orange tops are stock on 2000GT. If you had yellow they were just a lighter shade of orange but they were 19# injectors. A guy locally has another FPR and MAF we are going to try on it to see if it changes anything.
 
Any more ideas from anyone? We replaced the MAF with one from another 2000gt and also the FPR. I have a EGR controller and MAP also laying around we can try. Car seems to mostly run fine. I feel like it struggles on startup slightly and this is what it looks like idling. Just really strong exhaust smell. Could the catless X pipe be the issue? We do not have a tuner for this car so the rear O2's are functioning however we do not have any codes or check engine lights.
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We replaced the MAF with one from another 2000gt and also the FPR.
There really are a ton of "possible" items that could cause a rich condition. One that also comes to mind is an exhaust leak.

But instead of replacing parts consider testing more. Do you know if:
  • the O2 sensors are switching rich and lean?
  • what are LTFT and STFT doing.
  • is fuel pressure stable?
  • how many misfires?
  • If monitoring the O2 sensors do they respond IF brake clean is sprayed into the intake air stream do the O2 sensors respond by going rich? If an air leak is created to the O2 sensors respond by going lean?
 
  • Agree
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