Special Thanks & Weird -25% LTFT

**GTPpower** · 08-02-2013

Originally Posted by rperry435

Yes I have a fender well intake and I'm sure the position of the Maf is not stock, I will adjust the table. I've had LTFT's within 5% by adjusting the maf table (before the new intake, 3.6mps,104s and 10.5zzp wires...) so not sure how in the hell it's swinging -25%. I put then injectors back to normal stock IFR table for now. Pretty much starting from scratch to start dialing in the fuel trims again.

Also I see in the starting hpt thread it says something about timing not being over 40° in the cruising portion of the table and its something I haven't adjusted but it shows 45-47 in a few sections is this okay?

Anyone have a tuned Compg bin file? Just curious to see differences I know every vehicle is different.

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Yeah, that timing is fine. I have a the files from my comp G, but they aren't that much different than stock.

**darkhorizon** · 08-02-2013

Originally Posted by GTPpower

What injectors did you swap to?

They looked stock to me.. He has a 100% stock tune on it, and I started to attempt to lean it out just to see...The more I leaned it out the richer it ended up.

The strangest thing was when he first brought it to me... I saw the mass negitive stuff and was like well ****, I set it back to stock and forced open loop.. saw it was about 6% rich overall... figured hmm that makes sense I guess... so I pulled 6% out of the injectors, it worked perfectly for about a 3 miles, then it suddenly just started running 20-30% rich, all the time in open loop. (04s even do this weird thing in open loop where it adds a -12.5LTFT randomly which for testing reasons I just disable with realtime controls, and it was still rich) Maf freq's were in the 5500-6400 range at cruise 55mph-70mph, which I found to be overly abnormal.

Can you "maf tune" this car? Sure but holy christ i would feel weird doing it mostly due to how frigging random everything was.

And in the response to the "if you change the maf setup you have to tune it" guys... I agree to some point, but 999/1000 times the maf is never that far off in its "new location. Either way you are able to adjust for maf changes in the IFR table MUCH easier than trying to fiddle with a giant pile of maf numbers that are nowhere near linear.

**BillBoost37** · 08-02-2013

This is a great discussion on a couple approaches as it gives us info about what gets done and why.

**rperry435** · 08-02-2013

I was simply reading and learning trying to follow what write ups people have done to give me a good starting point since I'm no where near a pro on tuning. But she kept doing weird stuff I couldn't figure out and was seriously going insane.. but at least I wasn't doing anything wrong persay it's just acting bazaar.

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**GTPpower** · 08-02-2013

Originally Posted by darkhorizon

They looked stock to me.. He has a 100% stock tune on it, and I started to attempt to lean it out just to see...The more I leaned it out the richer it ended up.

The strangest thing was when he first brought it to me... I saw the mass negitive stuff and was like well ****, I set it back to stock and forced open loop.. saw it was about 6% rich overall... figured hmm that makes sense I guess... so I pulled 6% out of the injectors, it worked perfectly for about a 3 miles, then it suddenly just started running 20-30% rich, all the time in open loop. (04s even do this weird thing in open loop where it adds a -12.5LTFT randomly which for testing reasons I just disable with realtime controls, and it was still rich) Maf freq's were in the 5500-6400 range at cruise 55mph-70mph, which I found to be overly abnormal.

Can you "maf tune" this car? Sure but holy christ i would feel weird doing it mostly due to how frigging random everything was.

And in the response to the "if you change the maf setup you have to tune it" guys... I agree to some point, but 999/1000 times the maf is never that far off in its "new location. Either way you are able to adjust for maf changes in the IFR table MUCH easier than trying to fiddle with a giant pile of maf numbers that are nowhere near linear.

....that is goofy. Something else has to be going on.

**rperry435** · 08-02-2013

lol I'm going to try and dial them in later on tonight and through the weekend. Not sure what else I can do.

Would too much fuel pressure cause this? Like a bad fpr?

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**GTPpower** · 08-02-2013

As long as it's staying constant, it should be ok. 04+ should stick around 60psi no matter what you do with the gas pedal.

**rperry435** · 08-02-2013

Does an 04 has an actual fuel pressure reading? I don't think there's a port and the fpr is in the tank

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**GTPpower** · 08-02-2013

You should have a schrader valve on the front side of the rail.

**rperry435** · 08-02-2013

Apparently I'm a retard and didn't see that right in front of my face.

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**rperry435** · 08-02-2013

60psi. So that's not an issue

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**GTPpower** · 08-02-2013

Could you post a picture of your injectors? Just get a close-up of one, if you can.

**rperry435** · 08-02-2013

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**GTPpower** · 08-02-2013

Yup, you guys are right. Those are stock.

Hmmmmmmm.....

**Kyne** · 08-02-2013

Grand Prix GTP BIN Files For You 1997-2005

didnt realize there was another page, this is in response to asking for a compg bin.

**rperry435** · 08-02-2013

Yes I've seen that page and I have a stock bin, just curious too see what else what changed on someone who's compg was already tuned. Thanks though

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**Kyne** · 08-02-2013

Originally Posted by darkhorizon

They looked stock to me.. He has a 100% stock tune on it, and I started to attempt to lean it out just to see...The more I leaned it out the richer it ended up.

The strangest thing was when he first brought it to me... I saw the mass negitive stuff and was like well ****, I set it back to stock and forced open loop.. saw it was about 6% rich overall... figured hmm that makes sense I guess... so I pulled 6% out of the injectors, it worked perfectly for about a 3 miles, then it suddenly just started running 20-30% rich, all the time in open loop. (04s even do this weird thing in open loop where it adds a -12.5LTFT randomly which for testing reasons I just disable with realtime controls, and it was still rich) Maf freq's were in the 5500-6400 range at cruise 55mph-70mph, which I found to be overly abnormal.

Can you "maf tune" this car? Sure but holy christ i would feel weird doing it mostly due to how frigging random everything was.

And in the response to the "if you change the maf setup you have to tune it" guys... I agree to some point, but 999/1000 times the maf is never that far off in its "new location. Either way you are able to adjust for maf changes in the IFR table MUCH easier than trying to fiddle with a giant pile of maf numbers that are nowhere near linear.

Yeah the ecotech engines do weird tests that adjust the fueling. PITA most of the time to get those spot on when it kicks in.

His problem sounds like the MAF is reading at a higher freq and therefore reading more airflow. I've never had an issue with MAF tuning. I don't like fudging the IFR or PE to make up for an airflow error. Again the injector size doesn't change even if the fueling is off. The computer calculates the airflow from the MAF and using a known injector size adds the correct fueling. I've never done it that way but how does the fueling change from closed loop to PE? Do you get what you command in both?

**rperry435** · 08-02-2013

Id have to check. I know that scan I posted should show what's commanded and actual

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**Kyne** · 08-02-2013

That was more a question for dark horizon.

**darkhorizon** · 08-02-2013

Originally Posted by Kyne

Yeah the ecotech engines do weird tests that adjust the fueling. PITA most of the time to get those spot on when it kicks in.

His problem sounds like the MAF is reading at a higher freq and therefore reading more airflow. I've never had an issue with MAF tuning. I don't like fudging the IFR or PE to make up for an airflow error. Again the injector size doesn't change even if the fueling is off. The computer calculates the airflow from the MAF and using a known injector size adds the correct fueling. I've never done it that way but how does the fueling change from closed loop to PE? Do you get what you command in both?

yep. The commanded air fuel is the end all, then the closed loop system gets (usually) locked in at whatever the last value it was reporting to make a flat adjustment to that to then smash that against the maf frequency x injector constant to determine what pulse width to throw at the injectors.