GM crap flash fuel trims - Tuning Forum

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GM crap flash fuel trims
Wednesday, September 12, 2012 8:55 AM
Just wondering what everyone's fuel trims look like on the crap flash?

My long term is almost always stuck on -15. It goes to 0 upon WOT I assume this is PE? Its also usually low upon coasting or decel.
My short term is -7 to 7 some days -3 to 3 some days and always 0 upon WOT and some times will peak up to -10 after wot for a quick second. It usually goes to 0 pretty quick or it the 7s on decel it will sometimes hit -10 for a split second on decel as well.

Is it normal for my long term to almost always be around -15? I am throwing a random p0172 code, but that usually happens when my short term climbs up to -10 with high engine load. Its usually when I have to hit the gas going slow in traffic going up a hill. My car likes to buck slightly in this situation too. I am try to to troubleshoot this code just wondering what everyone sees as normal.

Re: GM crap flash fuel trims
Wednesday, September 12, 2012 10:12 AM
Usually sort tem and long term by themselves should be no higher than 10 %. so STFT no higher or lower than 10 and LTFT no more than +/- 10.

Remember that negative trims mean the computer is pulling fuel....



Re: GM crap flash fuel trims
Wednesday, September 12, 2012 11:04 AM
Are you running the crapflash? Is that what you are seeing? I just want to know what is normal for the flash itself. I realize what is normal for most cars.
Re: GM crap flash fuel trims
Wednesday, September 12, 2012 11:35 AM
No I teach driveability on a national level and fuel trims are part of it. lol.



Re: GM crap flash fuel trims
Wednesday, September 12, 2012 11:57 AM
Mr. Newb, I am just going to say that what you are experiancing isnt abnormal for a car with the stock setup on it like your profile says you have. Especially not intercooled.

I would check a few things.

fuel filter, air filter, make sure you have no boost or vaccum leaks ANYWHERE, make sure your header to downpipe connection is good and solid and not leaking. just double check the car. I wouldnt worry about what you CANT change right now IE: the tune, and look for the littlest things that you can fix....



Re: GM crap flash fuel trims
Wednesday, September 12, 2012 12:13 PM
Thanks for the tips guys. Evo so you have seen / see fuel trims similar to mine?

Fuel filter was replaced 4 months ago. They said it was really bad have no clue when it was last changed as I did not own the car then.

Vacuum looks good on my map sensor and boost / vac gauge. Wouldn't a vac leak cause a lean condition?

Pretty sure it is not a boost leak as the issue does not occur during boost. Pretty sure it not an exhaust leak as that would cause a lean condition as well wouldn't it?
I don't smell or see any exhaust in the engine bay either.

I'm definitely going inter cooled soon I have the pump and brackets just need the heat exchanger.
Re: GM crap flash fuel trims
Wednesday, September 12, 2012 12:16 PM
My map does read about 2 hg less than my boost / vac guage does at times, but I have chalked it up to my boost guage being off. ex when car is warming up started: 19.3 hg vac on map 21 hg on guage.
Re: GM crap flash fuel trims
Wednesday, September 12, 2012 1:12 PM
I have not, but i know that it runs rich already, so there are things that can contribute to it being even richer. faulty injectors and all that kinda stuff. so just double check everything, and report back.



Re: GM crap flash fuel trims
Wednesday, September 12, 2012 1:17 PM
FYI..

Negative means pulling fuel.... he has a rich condition. What is the PID data?



Re: GM crap flash fuel trims
Wednesday, September 12, 2012 1:33 PM
You mean the freeze frame for the code?

Engine Load = 77.647 %
Engine Coolant Temperature = 88 C
Fuel Trim Bank 1 Short Term = -14.844 %
Fuel Trim Bank 1 Long Term = -7.812 %
Intake Manifold Pressure = 75.00 kPa ~ -7 Hg vac
Engine RPM = 1,494.5 rpm
Speed (OBD) = 39 miles/h
Timing Advance = 14.5
Intake Air Temperature = 46 C
Throttle Position(Manifold) = 18.431 %
Re: GM crap flash fuel trims
Wednesday, September 12, 2012 1:39 PM
Which is confusing because according to GM service manual the p0172 code shouldn't trigger unless the fuel trim index (I assume long term + short term?) is 42+/- Do you know how the index is calculated?

Re: GM crap flash fuel trims
Wednesday, September 12, 2012 1:40 PM
Are you running a wideband?



Re: GM crap flash fuel trims
Wednesday, September 12, 2012 1:45 PM
err -46% rather
Re: GM crap flash fuel trims
Wednesday, September 12, 2012 1:46 PM
No wideband unfortunately. I was holding off on one until I upgraded from the crap flash.
Re: GM crap flash fuel trims
Wednesday, September 12, 2012 1:51 PM
-46 is a huge deal....

I was trying to see if this was a crapflash rich condition, but at this trim I would start looking for fueling components that would cause this, FPR, injectors. Typically a thourogh fuel test will accomplish this, static, dead head and fuel volume and bleed down.



Re: GM crap flash fuel trims
Wednesday, September 12, 2012 1:59 PM
Yeah thats the thing the manual says:

Conditions for Running the DTC

DTCs P0106, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0125 , P0131, P0132, P0133, P0134, P0201-P0204, P0300, P0301-P0304, P0325, P0341, P0446, P0502, P0503, P0506, P0507, P0601, P0602, P1133, or P1441 are not set.
The engine coolant temperature (ECT) is 60-115C (140-239F).
The intake air temperature (IAT) is -25 to +115C (-13 to +239F).
The manifold absolute pressure (MAP) is above 28 kPa (4 psi).
The vehicle speed is less than 132 km/h (82 mph).
The engine speed is between 550-3,600 RPM.
The barometric pressure (BARO) is more than 72 kPa (10.3 psi).
The fuel ethanol composition is less than 88 percent.
The fuel level is more than 9.8 percent.
Conditions for Setting the DTC

The Fuel Trim Index is below -46 percent.
The diagnostics have determined that a rich condition was not due to excessive vapor.

But my index trims aren't below -46%... unless they are using some weird calculations....

I got a fuel pressure guage coming in tomorrow. I'm going to check my pressure. My injectors are brand new I was throwing this code almost every trip before I replaced them. One thing I thought of I am running those billet injector plugs you sold me. Since they are metal as opposed to the plastic do you think they would heat up more and cause the injectors to over heat?
Re: GM crap flash fuel trims
Friday, September 14, 2012 12:56 PM
Going to do some extensive troubleshooting this weekend. I placed an order for an aem Uego wideband as well to help troubleshoot.
Re: GM crap flash fuel trims
Friday, September 14, 2012 1:22 PM
No, there have to be 25-30 people on here running them, myself included, and they will not cause a rich condition, unless the o-rings were not seated correctly, and a stock injector cup would do that also.

You really need a scan tool that will do Mode 6 ($06)



Re: GM crap flash fuel trims
Friday, September 14, 2012 2:14 PM
What is mode 6 do exactly? I have a bluetooth obdII adapter and scanxl pro software on my laptop. I believe the software supports mode 6...
Re: GM crap flash fuel trims
Friday, September 14, 2012 2:37 PM
The torque app does give you results of system tests like:
Evap test pass/fail
02 test pass/fail
Cat efficiency test pass/fail
Misfire test pass/fail
ect.

According to the app all these systems pass. Is this is what you were getting at with mode 6?
Re: GM crap flash fuel trims
Monday, September 17, 2012 9:04 AM
They will pass,

Mode 6 lets you look at the high and low limits set, however sometimes it will pass the test but near high or low limit, like the fords with misfires.




Re: GM crap flash fuel trims
Tuesday, September 25, 2012 10:33 AM
Well I think I found the problem. In the past I have had a bad stumble on start and the car would throw a p0203 and p0303 code. It would always clear up after I drove it a while and was pretty random it hadn't even happened for 3 months or so. Well this weekend I decided to move my ecm into the cabin so I could install my strut bar. Well I must have broken the wire the rest of the way so its no longer an intermittent short because all it wants to do is misfire like hell on cylinder 3 and its throwing a p0300 and p0203 code. Hopefully once I find the short my rich condition will be fixed. We will see.
Re: GM crap flash fuel trims
Tuesday, September 25, 2012 10:36 AM
Wow, really?



Re: GM crap flash fuel trims
Tuesday, September 25, 2012 12:01 PM
Yep I have great luck.
Re: GM crap flash fuel trims
Tuesday, September 25, 2012 2:50 PM
Well turns out the ecm driver crapped out. Time to swap my old ecm in there and head up to gm for the reflash grrrrrrr.
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