I think I have a bad MAFT check the log and info

[myblack98gst]

I have been fighting an issue for awhile where the car magically leans out up top very quickly after messing with it alot I have come to the conclusion the MAFT must be messed up!

check this log I put into notepad.

rpms - INJD - KNCK - O2 - TIMA - MAFS
4562 - 37.5 - 0 ---- 80 - 18* -- 1874.4
4656 - 38.2 - 0 ---- 80 - 18* -- 1962.4
4781 - 40.6 - 0 ---- 80 - 18* -- 2050.4
5000 - 44.5 - 0 ---- 80 - 18* -- 2239.8
5093 - 44.5 - 0 ---- 80 - 19* -- 2251.8
5343 - 46.0 - 0 ---- 78 - 21* -- 2427.8 - peaks then falls
5437 - 43.7 - 2 ---- 78 - 22* -- 2214.0
5562 - 43.7 - 2 ---- 78 - 21* -- 2201.4
5812 - 42.1 - 1 ---- 76 - 21* -- 2063.0
5937 - 42.9 - 1 ---- 74 - 21* -- 2075.6
6062 - 42.1 - 1 ---- 74 - 21* -- 2138.4
6218 - 44.5 - 0 ---- 72 - 21* -- 2214.0
6375 - 46.0 - 0 ---- 70 - 20* -- 2302.0
6500 - 46.8 - 0 ---- 68 - 20* -- 2365.0
6750 - 50.0 - 0 ---- 70 - 19* -- 2453.0 - finally gets back up
6843 - 50.7 - 0 ---- 68 - 19* -- 2465.6
7062 - 52.3 - 7 ---- 70 - 15* -- 2515.8


this log was with +20 - 30% correction starting at 5,500 on up and in the negatives before that.. Before the corrections the counts were MUCH lower and the car would lean into the 15:1 area within a couple hundred rpms after being 10.5:1

also the car has a 8k rpm limiter but it cuts out bad again once the numbers get high at 7k!

no not fuel cut

this is 17-18psi on a sc61 - magnus manifold - fp2x cams - full race manifold - 1000cc's - bla bla.

 

[myblack98gst]

any ideas??

 

[turborebel]

Could there be a weak link in your fuel system that you may have not addressed?

 

[talonalex92]

With the car running, tap the maf with a small hammer or screw driver lightly. If it stalls the maf is bad. Best way to test them GM Mafs.

 

[turboglenn]

Have you rewired your fuel pump? I have a 255 and it wasn't hard wired and i was running really lean up top, it would start to fall off around 5500 and continue on. I wired the pump and it's been pig rich everywhere since. I've tuned the car back out, but man did that big wire to the pump make a huge difference. And i didn't even run it into the tank, just spliced it at the connector, then used the original wire to activate a relay i zip tied to the fuel lines while i was under there.

 

[myblack98gst]

it is a 255hp pump 10 gauge power wire going directly to the pump literally. all of the hose from pump forward is 3/8 i.d. injection hose with a 6-an fitting adapted into the rail for connection on the return side I have a aeromotive a-1000 afpr . oh yeah and PTE 1000cc injectors.

fuel system


and besides the fuel system would have nothing to do with the actual MAF readings dropping off like they do.