LB7: What is limiting my fuel?

[JustinD]

Been chasing this problem for over a year found other things broken and had them fixed ( trans) ,swapped ECM, TCM , and swapped the engine harness, something is still limiting my fuel? It comes and goes one time the truck feels great next time you roll it feels like shit????? Any suggestions???

 

[chevyburnout1]

After I installed my 366 I would randomly drop power, log showed mm3 dropping drastically (not fuel pressure). No codes setting up until a hard full throttle run. Set a MAP sensor high voltage code. Would only set it one out of ten times I would get defuel. Disabled it with EFI Live and was golden.

 

[blk smoke lb7]

Dam I thought you had that demon whiped.Good luck buddy, I cant think of anything.

 

[JustinD]

I need to log it and post it here, feels great light throttle but sometimes if you get on it it will buck and have a very small burst power and then cuts out......

 

[GMC_2002_Dmax]

Did you ever update to the 2002/15186006 OS ?

 

[messejme]

Are you running stock y bridge? If so The elbow can pop out under high boost.

 

[blk smoke lb7]

Are you running stock y bridge? If so The elbow can pop out under high boost.

He would have seen that he has been fighting this for over a year.

 

[blk smoke lb7]

have you tried a differant FICM justin?

 

[Evan@InglewoodTrans]

Are you running stock y bridge? If so The elbow can pop out under high boost.

Nothing to pop out in the y bridge on his 01.

 

[JoshH]

You sure it isn't tuning related?

 

[SSchmi5519]

What is it limiting?? Have you logged it before?

 

[blk smoke lb7]

I believe he has posted logs on here before on a differant thread.

 

[SSchmi5519]

Is it limiting rail? pulse? mm3?

 

[Duramax racer 8]

It's limiting mm3 randomly

 

[SSchmi5519]

Have a log? or screenshot? Hard limit?

 

[Duramax racer 8]

He has many. What do you mean by hard limit?

 

[SSchmi5519]

limiting it to an exact mm3 value every time or is it softly pulling command mm3 down?

 

[Duramax racer 8]

I think around 89mm3 but its been a while since I've seen the logs

 

[JustinD]

Did you ever update to the 2002/15186006 OS ?

Yes I did Tony, it did the same thing....?

have you tried a differant FICM justin?

No, that is one thing I haven't changed....

You sure it isn't tuning related?

I tried my Toman tunes, I even bought a tune from Trent to rule that out.

What is it limiting?? Have you logged it before?

Is it limiting rail? pulse? mm3?

limits mm3, pulsewidth, and timing all together?????

Have a log? or screenshot? Hard limit?

I'll log it and post it here, it's snowing here so a few days before I can....

limiting it to an exact mm3 value every time or is it softly pulling command mm3 down?

Not consistent.....




Thanks for all the help guys, I hope someone will have insight on this, I did just get a fresh trans back, I had a trans issue along with theis defuel so it was horrible. Seems to be worlds better now, felt like it was applying 2 clutches before....... Do the 01's do queer stuff when learning???? It has been about 3 days maybe 200 miles since we installed it, got alot better shifting but still seems like its not right.......

 

[blk smoke lb7]

You got a good ficm to try if not i can send you a known good 1 to try.