EFI help fast!
03-09-2006, 11:47 PM
#1
3rd Gear Member
Thread Starter
Join Date: Aug 2005
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Posts: 519
EFI help fast!
Ok, Its not a mustang but I think you guys might be able to help.
The car is a 1989 Pontiac Grand Am with a TBI/CFI setup, and it runs EXTREMELY rich and pretty rough too. Ive spent a few hours trouble shooting, and I still cant find anything (yeah yeah im a crappy mechanic) Ive checked the MAP sensor, it tested fine, but I shotgunned it anyway, no change, so I can rule that out. I also did some investigating for vacuum leaks with a can of carb cleaner, nothing there. Its got spark on all 4 cylinders (btw) and I did a leakdown & compression test, and its all in speck, no burned valves or anything like that.
I *think* the problem might be the injector itself, because Im looking in the bowl when it is "running", and it doesnt look like a fine mist, as it should, it seems to "rain" in a small area of the stream. Heres what gets me... despite this, it still runs rich and rough, not lean like its not getting enough fuel which I would have thought. Is it possible there is high fuel pressure AND a clogged injector? I dont have a way to check fuel pressure, its an odd size line and the guage Im using doesnt have any adapter for it(and theres no schrader valve). I wouldnt think this is the case, as it hasnt seen much fuel... less than 55k on the odometer. What do you guys think? Im getting ready to just get a new injector for it, but If I install it and find that its not the problem, I just wasted a good, what, 80$? Of course, I dont have the special Injector testing tool GM says I need to use either. I checked the resistence of the injector, and it is in Spec with what Alldata is telling me.
What do you guys think? I need some opinions!
Thanks Alot!
Jim
The car is a 1989 Pontiac Grand Am with a TBI/CFI setup, and it runs EXTREMELY rich and pretty rough too. Ive spent a few hours trouble shooting, and I still cant find anything (yeah yeah im a crappy mechanic) Ive checked the MAP sensor, it tested fine, but I shotgunned it anyway, no change, so I can rule that out. I also did some investigating for vacuum leaks with a can of carb cleaner, nothing there. Its got spark on all 4 cylinders (btw) and I did a leakdown & compression test, and its all in speck, no burned valves or anything like that.
I *think* the problem might be the injector itself, because Im looking in the bowl when it is "running", and it doesnt look like a fine mist, as it should, it seems to "rain" in a small area of the stream. Heres what gets me... despite this, it still runs rich and rough, not lean like its not getting enough fuel which I would have thought. Is it possible there is high fuel pressure AND a clogged injector? I dont have a way to check fuel pressure, its an odd size line and the guage Im using doesnt have any adapter for it(and theres no schrader valve). I wouldnt think this is the case, as it hasnt seen much fuel... less than 55k on the odometer. What do you guys think? Im getting ready to just get a new injector for it, but If I install it and find that its not the problem, I just wasted a good, what, 80$? Of course, I dont have the special Injector testing tool GM says I need to use either. I checked the resistence of the injector, and it is in Spec with what Alldata is telling me.
What do you guys think? I need some opinions!
Thanks Alot!
Jim
03-10-2006, 12:38 AM
#2
5th Gear Member
Join Date: Apr 2005
Location:
Posts: 3,062
RE: EFI help fast!
Well a dirty injector doesn't necessarily mean "less flow lean mix".. it might just mean it's causing a dirty puddling flow & not a fine clean mist like you said you saw..
how bout running a can of injector cleaner thru the thing before buying a new injector?
how bout running a can of injector cleaner thru the thing before buying a new injector?
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