Running rich problem
09-13-2005, 12:42 AM
#1
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Join Date: May 2004
Location: Illinois
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Running rich problem
Car is tuned for mods in sig but its running too rich. I can smell gas in oil and exhaust burns my eyes out. I already bought an adjustable fuel pressure regulator and turned it down to 37psi idle. If I swapped out 30lb inj. for smaller injectors would that help at all? I need some kind of fix so I can break in engine for a dyno tune.
09-16-2005, 05:20 PM
#7
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Re: Running rich problem
Got new o2's in and it didn't help any. How about going with smaller injectors would that help at all? I need to do something this is running so rich I can't even breath around the car.
09-16-2005, 11:00 PM
#8
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Re: Running rich problem
There's no reason it should not be able to run, tuned correctly, with a 30# injector. Something is telling the PCM to add fuel the engine doesn't need. Exhaust leaks can be a major cause, and also misfires. When you get the scanner on it, look for long term fuel corrections (BLM's) approaching 160. That will be a sure sign you've got a "false lean".
Adjusting the fuel pressure is not a good way to try and tune, and swapping the injectors will not cure the "false lean" problem, if that's what it turns out to be.
You can also see a rich condition if the coolant temp sensor is showing too low a temperature, causing cold start enrichment; or if the MAP sensor is showing a high pressure, indicating the engine is under load when it isn't.
Adjusting the fuel pressure is not a good way to try and tune, and swapping the injectors will not cure the "false lean" problem, if that's what it turns out to be.
You can also see a rich condition if the coolant temp sensor is showing too low a temperature, causing cold start enrichment; or if the MAP sensor is showing a high pressure, indicating the engine is under load when it isn't.
09-27-2005, 03:51 PM
#10
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Re: Running rich problem
Originally Posted by Injuneer
There's no reason it should not be able to run, tuned correctly, with a 30# injector. Something is telling the PCM to add fuel the engine doesn't need. Exhaust leaks can be a major cause, and also misfires. When you get the scanner on it, look for long term fuel corrections (BLM's) approaching 160. That will be a sure sign you've got a "false lean".
Adjusting the fuel pressure is not a good way to try and tune, and swapping the injectors will not cure the "false lean" problem, if that's what it turns out to be.
You can also see a rich condition if the coolant temp sensor is showing too low a temperature, causing cold start enrichment; or if the MAP sensor is showing a high pressure, indicating the engine is under load when it isn't.
Adjusting the fuel pressure is not a good way to try and tune, and swapping the injectors will not cure the "false lean" problem, if that's what it turns out to be.
You can also see a rich condition if the coolant temp sensor is showing too low a temperature, causing cold start enrichment; or if the MAP sensor is showing a high pressure, indicating the engine is under load when it isn't.
09-27-2005, 04:20 PM
#12
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Join Date: May 2004
Location: Illinois
Posts: 516
Re: Running rich problem
I am still stumped on this. I had the valves adjusted at the machine shop, the map sensor is new, and theres no exhaust leak. I do have a 160 stat and fans come on early so it only runs at 170-175 usually really cool. Would putting this car on a chassis dyno even help me fix this problem? Anybody around Kankakee County wanna come by with a scanner and help me?
10-05-2005, 09:42 AM
#14
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Join Date: Feb 2004
Location: Houston, TX
Posts: 123
Re: Running rich problem
I have pretty much the same scenario, including a PCM4less tune for my mods. Really running rich, with no exhaust leaks, brand new GM O2s and the (for now) original injectors.
So I'm gonna piggyback my deal on this thread as well, if you don't mind.
Regards,
Brian T
So I'm gonna piggyback my deal on this thread as well, if you don't mind.
Regards,
Brian T
10-05-2005, 02:13 PM
#15
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Join Date: Jun 2004
Posts: 156
Re: Running rich problem
Sounds similar to my problem. LT BLM's drop to 108 on left and about 111 on right at idle and deceleration. They gradually return to normal from idle to 1800 rpms. Fuel pressure drops to 0 over about 3 hours sitting time. Got new injectors on the way. If that doesn't fix it, I'm at a loss.