strange fuel issure


New Member
Guys this one has me stumped
86 T
60lb inj
340 pump
adj reg.
212/212 cam
70mm TB /precision plenum/rjc pwr plate

I went thought the engine last fall car ran very well low boost only (breakin period).
Finally went to started turning up the car and noticed a small problem that poped up if u stab the throttle the car hesitated for just and instant before taking off checked all over everything seemed ok, but could not get the stumble out of it.
I had always wanted a stand alone in the car so i thought might be a good time to learn one ordered a XFI installed it started up like a charm slowly started tuning on the car and ran into this senario.
The injectors were runnin at 100% duty at 16 psi, but the AF ratio was only 12.5 thought hmm ok. SO whipped out the trusty fuel gauge under the wiper and found that the fuel pressure wasnt dropping. Thought hmm ok this is odd, maybe the pump blew the hose between the pump and factory line so took the tank down and removed the pump only to find the wire from the connector inside the tank to the fuelpump had completely burned the insolator off leaving only bare wire. Needless to say that scared me. Started checking to try and figure why the wire would have cooked but found no apparant problems. And what really bugged me is why if something had shorted out that the fuse in the hotwire kit didn't blow which is a 10amp by the way. Checked voltage to the connector at the tank and had 14.2v with the car at idle so that wasnt the problem. Checked everthing that i could think of including the ground from tank to frame (with a volt meter) couldnt find anything wrong thought ok maybe the pump is just going bad. Replaced the pump with a new one, still din fix it so i replaced the regulator and the fuel filter still no luck. I know its gota be something simple that im just overllooking you guys have any ideas?
First check to see what the target A/F ratio is.....just to be sure it is set right. However, looking at your combo I think you MAY be close to needing more injector and double pumpers, even at 16lbs of boost. I had 72s with a 66 BB turbo and double pumpers and would be at 85% or so duty cycle at 16-18 lbs of boost and that was just with ported irons. I know you are saying the fuel pressure isn't dropping but the safety of the double pumpers is nice with your combo. My guess is injectors with the way the heads and turbo are flowing if nothing else is wrong. Also make sure your fuel pressure is around 40lbs, if you start with the pressure too high the pressure looks good but doesn't flow as well as the pressure rises with boost. My bet is injectors.