[jkellam]

I'll start with the facts:
94 gt built for NASA road race series
It has the original high mileage block (150+)
GT40 heads with about 70k on them, they were disassembled, hot dipped and cleaned, new freeze plugs and Crane springs installed
E303 cam, new timing chain, new balancer (FR stock replacement)
Stock MAF w/ BBK Intake (elbow cut off to locate filter in engine bay)
bbk shorties to bbk h pipe
Stock injectors (new orings and caps, and cleaned)
stock throttle body, 94-95 cobra intake
the wiring harness from computer to engine bay (and CCM) was untouched, everything else was completely gutted and rewired. The grounds are good
I know i doesn't mean anything, but other new parts include:
Dist
coil
TPS
fuel pump

A local shop did some of the work and the tuning for me. The timing was set at 16 btdc (with spout out) and about 28 at 3000rpm, fuel pressure is reading about 35 psi

I just got the car back from the shop early this week and looked over everything they did, it looked good. I ran the car yesterday on a short 1/2 mile road at my house. I ran it up to 6000 in both 2nd and 3rd with no problem at all. I did this about 6 times. Loaded it up and dropped it off at the dyno shop. I was not there today when they did the pulls, but here is what I was told (I did get the dyno graph): 4th gear pulls
first run (wtr temp about 180) 250hp / 285 tq - graph looks nice and smooth - reves up quickly - A/F 16:1 (high...)
2nd run (185) 159 / 200 - started cutting out as soon as they got in the gas
A/F 20:1 WTF??

Killed car - checked under hood to make sure nothing came loose, everything was fine

Restarted car
3rd pull - 254 / 287 - A/F 15:1
4th pull 170 / 205 A/F 20:1

Just so you know, I'm not trying to make crazy power. Again this is a regulated road race series. 260 / 310 are the optimum numbers. And before I forget to mention, NO COMPUTER TUNING ALLOWED.

I'm guessing that because it isn't a constant problem, it has to be something self adjusting (computer). So either the computer isn't working right, or it is not recieving the correct signals from the sensors (HEGO, MAF...) As stated before, the grounds are good. The grounds from the computer and MAF are grounded directly to neg post on battery. Fuel pressure holds steady at 35 psi during all pulls. So now it is a process of elimination, and who ever finds the problem in the fewest steps wins. So... any ideas???

Given the fact that I can't tune the computer, would it be a benefit to retro a A9L (Fox) computer?? If so, what all is involved?? The fan is not an issue as it no longer exist.

Not sure if I left anything out or forgot to ask any questions, just looking for input

Thanks

[Racinjason81]

the A9L/A9P is a good idea since they adapt to cam changes much better than the 94-95 gt computer.you should datalog with a scanner during the dyno pull and go from there

[Trick Tuners]

set the FP to 40 psi like stock.