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Closed loop rich issue.

gvr4ever

Well-known member
Joined
Aug 6, 2002
Messages
6,190
Location
central Indiana
I'm having trouble with my cars idle. It just runs too rich. A/F gage goes in the green, and I can just smell it. I sometimes get low RPM knock too.

I spent the last few days dialing in the idle to 750 and the timing to 5 degrees. I've done a full boost leak test.

Mods are EVO 560cc injectors, 3G maf, FMIC, 2.5" turbo back. Only controls are a AFPR and a keydiver chip. AFPR is set as low as it can go. Doesn't seem to want to go lower then 32psi.

I didn't reset the ECU after changing the idle and timing, but it should learn.

Do I need a SAFC or what? I don't know how to tune it any better with what I have.

02 sensor only has about 20K miles on it.

Thanks
 

gvr4ever

Well-known member
Joined
Aug 6, 2002
Messages
6,190
Location
central Indiana
I guess I should add, that if I wait long enough, the idle will come down normally, but it takes too long. If I get in to any boost and then stop at a light or sign, it idles too rich. It takes about 15-20 seconds to stop running so damn rich.
 

Quoting gvr4ever:
AFPR is set as low as it can go. Doesn't seem to want to go lower then 32psi.



Is that reading with the vacuum line ON or OFF? When you apply vacuum, does the fuel pressure drop 7-9 psi?
 

ktmrider

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Joined
Sep 10, 2007
Messages
3,128
Location
Tempe, AZ
How old is the stock O2 sensor?
I would log the O2 Hz output and temp sensor readings to see what they are reporting.
 

gvr4ever

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Joined
Aug 6, 2002
Messages
6,190
Location
central Indiana
Quoting keydiver:
Quoting gvr4ever:
AFPR is set as low as it can go. Doesn't seem to want to go lower then 32psi.



Is that reading with the vacuum line ON or OFF? When you apply vacuum, does the fuel pressure drop 7-9 psi?



I'm setting it with the vacuum line off and plugged with my finger. It seems to only drop about 10psi with the line back on though, so if it's suppose to only be 7-9psi I am running more then that.
 

10 psi is great, you must be pulling good vacuum at idle. /ubbthreads/images/graemlins/smile.gif
So, even if you set it for 32 psi, vacuum disconnected, and it drops to 22 psi when you apply vacuum, it is still too rich at idle?
Are you sure you have the good #482 3G MAS?
Do you have a logger to look at the fueltrims? Any tuning, or an AFC, is worthless without a logger. Everyone should have one.
 

gvr4ever

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Joined
Aug 6, 2002
Messages
6,190
Location
central Indiana
MAF is the right number. Got it from Iceman and the connector.

I have a logger. I'll have to read up some. I only checked WOT high RPM numbers to make sure I was safe.
 

gvr4ever

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Joined
Aug 6, 2002
Messages
6,190
Location
central Indiana
Man, I went out of town last minuet with the GVR4 without logging. This thing is getting bad. When I come to a stop, the AFG just goes green and the car stalls. I'm going to log tomorrow when I get a chance, but I got one Q:

WTF wouldn't I be getting a CEL if the 02 sensor is that bad? The car didn't run that bad with the original one and it threw a CEL.
 

You should email me your name so we can go over your chip settings, just to be sure. Otherwise, you really need to do some logging to help troubleshoot the issue.
 

gvr4ever

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Joined
Aug 6, 2002
Messages
6,190
Location
central Indiana
Think I found the problem.... Man, I've heard the temp gauge was useless, and you guys aren't kidding. Stock gauge shows about half, and the logger shows 170. I couldn't get it warmer then that.

Could be why it was running fine the other day when it was in the 40s and when it was in the teens, it drove like crap.

~edit~

Just confirmed, t-stat is stuck open. Man, if 170 is in the garage with no air going across the radiator, I'd hate to think what it was while driving in really cold temps at HWY speeds.

I thought the heater seemed weak. /ubbthreads/images/graemlins/rofl.gif

Oh and 02 sensor is fine. It sweeps between .01 and .09 just fine. It just has some hang time coming off of throttle. I'm pretty sure it's from the temps being way too low. Can't burn well.
 
Last edited:
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