Whipple running rich / fat

[Tomlouns]

Working with PBD on a remote tune...
They are saying the data fueling should be at 8% and I am at 30 % at idle. There is no E in the car and no octane booster either.... I am just running 93 . The car seems to run great... and no bad fuel smells. The pipes stay mostly clean (no black ).
I am not able to find any leaks. The only thing the car does wrong is sometimes not all the time... shortly after you start the car I am talking 1-2 seconds ... the rpms can drop to about 500 and then a second later everything is running like it should.

I have two questions...

1. what can I check or test? They say they can tune around it but it could lead to head aches down the road... ( 2. what head aches am I in for?)

Please let me know your thoughts.

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[ManBearPig]

Are you referring to your fuel trims at idle? If the trims are adding fuel (+30%) and the trims are normal off idle, that’s an almost sure sign of an intake vacuum leak somewhere. How the trims (short and long) look with regular driving?

 

[Tomlouns]

Please feel free to take a look at the log...

 

[ManBearPig]

I am no expert at reading logs, but I do immediately notice in the attached log that LTFT is at 1.0 the entire time, so they must have adaptive learning turned off for some reason. STFT is way off during the entire log. Both banks are hovering around -30%. You’re way rich at idle for sure. I would not have them tune around that, and I have no idea what would cause that.

 

[Tomlouns]

I am at a loss on why too... my hope is that someone has seen this before and knows what to do or what tests I can run...

 

[Mustang Mods]

New install? If so almost certain its a vacuum leak. The o-ring around the bypass?
Did you give correct injector info?
Fuel pressure?

 

[Tomlouns]

New install? If so almost certain its a vacuum leak. The o-ring around the bypass?
Did you give correct injector info?
Fuel pressure?

I double checked to oring and it is in the right spot... half way down not on top... also double checked the TB gasket too... any other thoughts ?

 

[Tomlouns]

I double checked to oring and it is in the right spot... half way down not on top... also double checked the TB gasket too... any other thoughts ?

Here are the logs for the fuel... I think they look right...

 

[Ruiner46]

A vacuum leak would make the car lean, not rich. Was the engine fully warmed up?

 

[Tommy V]

Yes the a vaccum leak would make the a/f lean but the short terms fuel trims would add the 30 percent he is talking about to correct the problem.U need to look at a/f short term trims and commanded a/f to get a full picture.Im at work now and cant look at the log but if your adding 30 percent short term trim then u probably have a big vaccum leak somewhere or u could check your maf sensor.

 

[stang17]

I had something similar happen to me. Ended up being the bottom side of the air inlet tube had a slight dent in it near the clamp/silicone sleeve, which was letting unmetered air in, throwing my trims off. Took a heat gun to the inlet tube, straightened it out, reflashed the whipple tune, and was good ever since.

 

[ugstang17]

What tune is this datalog from? Is it PBD's base tune you were logging? If you have the Whipple tune I would put it back in and datalog again with PBD's data config file and see if LTFT starts doing something. STFT's will fluctuate some but that is not normal there. Standard application is that LTFT corrects after PCM sees STFT's stay below or go above 1.0 for a given period of time. If the LTFT's go beyond a given value, CEL codes are generated IIRC.

AFR Lambda is running slightly rich (0.989 = 13.8x) which is why STFT are low to compensate. This would initially indicate that too much fuel is being commanded based on air. That could be either air table related or fuel table related. Verify your MAF is clean and that it is installed in the right direction just as a precautionary. "Working around the problem" is not my idea of good service. So I would be very cautious in accepting that is a quick fix.

Manbearpig I believe is on the right track. Reloading the default Whipple tune (if that is an option) would give you a clear window to the know if this has been created at the tuner's end or if it is an issue within the car.

 

[ManBearPig]

His trims are pulling 30%, not adding it.

 

[Tomlouns]

A vacuum leak would make the car lean, not rich. Was the engine fully warmed up?

yes it was

 

[Tomlouns]

What tune is this datalog from? Is it PBD's base tune you were logging? If you have the Whipple tune I would put it back in and datalog again with PBD's data config file and see if LTFT starts doing something. STFT's will fluctuate some but that is not normal there. Standard application is that LTFT corrects after PCM sees STFT's stay below or go above 1.0 for a given period of time. If the LTFT's go beyond a given value, CEL codes are generated IIRC.

AFR Lambda is running slightly rich (0.989 = 13.8x) which is why STFT are low to compensate. This would initially indicate that too much fuel is being commanded based on air. That could be either air table related or fuel table related. Verify your MAF is clean and that it is installed in the right direction just as a precautionary. "Working around the problem" is not my idea of good service. So I would be very cautious in accepting that is a quick fix.

Manbearpig I believe is on the right track. Reloading the default Whipple tune (if that is an option) would give you a clear window to the know if this has been created at the tuner's end or if it is an issue within the car.

I never had a whipple tune... this was part of a kit with Long tube headers and 95pound injectors... the datalog is from the sct tuner. I cleaned the MAF, and just to make sure it wasn't put in backwards... the metal side should be down right? I also didn't like the way the wire clips onto the tube for the MAF, it isn't a clean snap like the other wired connections, is that normal?...

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