2003 Mustang Gt Runaway STFT

[95Gturbo]

Like the title states. I have never ran into this before. Procharged car, 80lb/hr injectors, tuned like I have several others. Even forced OL and o2's unplugged, it will idle at 1.00 lambda for about 30 seconds, and then the STFT's will start hammering it with fuel. The log attached shows +99% STFT. No matter what I do in the Oxygen sensor tab, or the Closed/Open Loop tab, the car does the same. Log attached shows unplugged sensors. Sensors plugged in read around 0.750v at idle before it starts slamming fuel in it. You can see that target lambda changes as well. Any ideas would be greatly apprecitated.2v Runaway STFT.hpl
Procharger 2v V1.hpt

[mstang_man]

More than likely it the Injector data. What brand injectors are your 80's?

[95Gturbo]

Ford racing LU80's. And the injector data wouldn't cause it, because fueling is dead on 1.00 lambda at idle, and then it slams fuel into it. Also the voltage stays the same the entire time, so it isn't offsets either. The fuel trims activate, even when the pcm shows in the log that Open Loop is active and closed loop is not active. Injector data does not cause stft to take the car from 1.00 lambda, clear to .650 lambda when it quits.

[mstang_man]

Ford racing LU80's. And the injector data wouldn't cause it, because fueling is dead on 1.00 lambda at idle, and then it slams fuel into it. Also the voltage stays the same the entire time, so it isn't offsets either. The fuel trims activate, even when the pcm shows in the log that Open Loop is active and closed loop is not active. Injector data does not cause stft to take the car from 1.00 lambda, clear to .650 lambda when it quits.

there are none issues with the 80lb injector on older mustangs. The low injector pulsewidth can cause stability issues and create bank to bank differences in STFT's. you try to make small changes and your get wild swings.. FRPP's own acknowledgement, the 80s do not tolerate pulsewidths below 2ms. They go non-linear. Also, Ford Racing 80's have a really high min PW value which causes issues. Basically it's hitting that min PW and it's clipping the injector there, and it's too much fuel for your application, been there with a procharged Mach 1. A known "cheat" is to load the min PW value from the 60 lb value file, that will lower the clipping point and allow you to properly tune the MAF and see it respond to your changes.

[95Gturbo]

Min pw is set low. It idles fine at 1.00 lambda until those short terms take over. The car isn't rich and requires less fuel, the fueling is dead on, qnd then when the fuel trims start adding fuel, they keep adding fuel until it kills the car. Injector pw goes from 1.2ms clear to like 10ms and then the car dies

[mstang_man]

Min pw is set low. It idles fine at 1.00 lambda until those short terms take over. The car isn't rich and requires less fuel, the fueling is dead on, qnd then when the fuel trims start adding fuel, they keep adding fuel until it kills the car. Injector pw goes from 1.2ms clear to like 10ms and then the car dies

Sounds like you may have a restriction, When the fuel injector flow becomes restricted or blocked the engine controller will attempt to increase the fuel flow by opening the injector for a longer period of time,by increasing the injector pulse width. if all you data is correct than i look to the physical.

[murfie]

Try setting the DTCs for senors 1's, to "DTC on MIL off".
P0130-P0135
P0150-P0155
On the older GMs with HPT, If you set the code to no error you can't fail the sensor. Possible the O2's dont actually egister as failed, and it uses what they report which is extrememly lean.
Every one I know with these older cars has gone LS swap and holley unfortunately.

[95Gturbo]

Thanks, Murfie. I'll give it a shot, sir. Your advice is, as always, much appreciated.

[decipha]

You've corrupted almost every function you've changed. Amazing it even start much less idles.

Short term fuel trims are lambse they are supposed to move in open loop as its a piece of the commanded fuel.

On any vehicle you should never disable fault codes ALWAYS set them to a non-mil but still allow the code.

But yeah she's going ape shit cuz of everything you corrupted.

curious, you have engine size set to 5.4L

[95Gturbo]

Some of what I have done was to try to stop it from running away with fuel trims. I multiplied the cid by .45 to get around the injector clip, as well as the maf clip. I'm not sure how it is 5.4, because the value is smaller than what the stock tune was when I pulled the file. On a zero vacuum rev, load shows 90%. I did that trying to check load against what it should be.

[95Gturbo]

Stock file is here. I'm starting over completely on it and leaving closed loop enabled.


03 Gt Stk.hpt