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Need some EFI help guys?

G

gwstang

Member
Ok, so far I have the EFI running (speed density) after having some injector issues with two of them not squirting. Picked up a cheap stethoscope from our Chinese buddies at harbor freight. Worked great and got the injectors (replaced those two) all working now. Got everything running pretty good except for one issue. There is a small stumble when I step on the gas pedal. It is just for a second at low rpm and quickly goes away as it revs up. What is interesting if this is the same stumble that was present when I still had the edelb. carb on there. I had a 2.5" exhaust and midlength headers put on when the carb was still on and the stumbles was there and a little worse back then. This is a mystery? I replaced the tps/iac and adjusted the tps a little and that did not remove it. Running 12 btdc timing. Any ideas here?
 
I'm going to run a compression test and change out the plugs while in there. I am hoping this might turn up something...I am not sure what to specifically look for with the test though? I'll get back next week after trying this. One thing, I took a 40 mile round-trip ride today to pick up the plugs and some other stuff and damn! This thing really woke up with the efi. The old edelbrock 4 barrel never had this much punch. I just barely pushed down on the pedal and it left a long black streak! AOD + 3.50 gears = :thum Oh Hell Yeah!

It just has that little stumble and sputter when I first press down. :dun
 
I am far from an expert when it comes to efi, but assuming you are running a Ford SEFI speed density system I was told setting the throttle position sensor was very important. I don't remember the details but you check the voltage at the sensor when the the throttle is closed. There is a parameter for it to be in, and the two screws on top allow for it to be adjusted. Maybe you did this, but that is all that comes to mind.

You did check for codes?
 
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