i had an 81 trans am that did that. turned out it had blown head gaskets. that was the only thing i fixed and it worked! for you though def sounds like a fuel problem. i bet the walbro will help a lot.

 

check for low fuel pressure under load and maf could be bad. underestimating under load. sounds like fuel pump

 

Would a bad maf give a code? I did use the special cleaner but didn'd notice anything. I read a link on here where someone did the same setup as me and they said the maf was off by 300%. How do you verify this?

 

put a fuel pressure guage on it and see what's up

 

Gauge shows normal fuel pressure rising slightly and at 2 psi of boost it goes to zero.

 

The fuel pressure is fine until it goes to zero for split second.

 

If the car shuts the fuel system off will it throw codes. What else will shut it down? I am having this happen and it is exactly like the system is turned off for a second. Sorry for throwing question off a little.

 

I am coming to more of the idea that the fuel system is being turned off for a second when the boost hits over 2 psi. What would have to be going on for this to happen?

 

Is your battery loose? Never saw a 4th gen F body that didn't have a broken hold down. Saw plenty of loose batteries that fell backwards under acceleration and positive post momentarily touched ground causing the symptom you spoke of.

Bet you need a new overflow resevoir.

Oh yeah, how many threads regarding this problem are you going to start? Found at least 4 since november. Why can't you stick with one thread so we can understand what is going on?

Now I found a post that said it occured around 3 PSI of boost and if you removed the blower belt, it didn't occur. Is that correct?

These muliple posts with some information in one and not in the other has to go! You're too confusing.

 

Glad you pointed that out..... a whole bunch of people ask questions, offer suggestions, and then he starts all over again. Let's merge the threads. Otherwise the chances of ever sorting this out are near zero.

 

Sorry for the confusion. I have come up with ideas that i would like to run by you guys. I have tried all the valid ones and have not solved my problem. Here is currently where i am at. My fuel system is turning itself off at the start of boost. I believed the fuel pump was causing it but i don't think the lack of volume needed to run the sc would make it go from 45 to 0 in a split second. I then believed the computer was turning off the fuel system and have read a lot of comments on the internet about this being a very good possibility. Now i think the maf or someother computer monitoring device is the culprit. I didn't want to get everyone confused with all the old ideas but i will keep this one going for now.

 

It turned out to be the mfu was hooked up wrong. It was causing the incoming fuel to be restricted instead of the fuel being stopped from being returned to the tank. Feel stupid and relieved all at the same time. I took it out and it pulls like a S.O.B. Used shoebox's diagram to see the back of the intake and he had labeled the incoming fuel line and the return line. I thanks everyone for the help. Now off to the dyno

 

Way back in November, the third response to your ORIGINAL post asked if you had the FMU hooked up right. Your response indicates you had it correctly in the return line. How did you suddenly discover it was in the feed line?

You had the correct answer 3 pages and 8 weeks ago.

 

I saw the manifold back diagram (shoebox) and it labeled the lines. There instructions manual is the worst i have ever seen. My screw up but could have been explained beter. I feel like an idiot not catching this earlier. Many people said the fmu or the fpr was a good guess. I figured they were bad and was trying to fix them instead of looking at the install being wrong.