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emtcee1973
07-20-2007, 05:11 PM
i have a 67 camaro with a fuel injected 383 stroker.the fuel injection is controlled by acell dfi gen7...i have my lm1 setup along with the dfi to control air fuel ratio...about 2 weeks ago i was driving and the car started to have a real bad lean backfire...i confirmed this by hooking up my laptop and sure enough it was showing lean...anyway i went ahead and changed the fuel pressure regulator thinking that was it to no evail...now its real rich at idle and when i step on the gas in neutral it still goes real lean....does anyone have any suggestions as to what could be the problem??i was thinking of changing the fuel filter...also i checked the ohms on the injectors and they are all fine...one other thing when i start the car from a dead cold the fuel pressure stays steady but after it warms up the needle on my guage begins to jump around...just for the record i changed nothing in any of my maps in the dfi...again,any ideas or suggestions are welcomed...
mike

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MrForce
07-21-2007, 09:06 PM
If fuel pressure is sagging, it is most likely the fuel pump. If the pump has gotten noisy, or in some cases noisier, it is probably on it's way out. check fuel pressure under load and see if it drops at the same time you are getting the lean condition.

rob

MonzaRacer
07-22-2007, 10:51 AM
You could change the filter as it could be stopped up but I would bet the pump is going south.
If you know someone with a low amps probe you can scope the power circuit and watch the electrical signature of the pump and it should run in the 5 to 7 amp range power draw wise.

emtcee1973
07-22-2007, 02:41 PM
thanks for the replys guys...i think your both right...i did notice today that the pump is louder than normal and its definatly making an odd noise as its energized...i just ordered a new pump from summit so i will keep ya posted thanks again for the help..
mike

emtcee1973
07-26-2007, 04:02 PM
well i changed the fuel pump today and it is still lean...and the fuel pressure still drops when i stab the throttle in neutral...how would i know if the injectors are bad???also let me know if i set the fuel pressure right...with the key on and engine off i set it to 42lbs,is that the way to do it??is it possible that the computer itself went bad somehow???any ideas would be appreciated....
mike