"Burning too Rich or AFPR" ?
Thread Starter
Drifting
Joined: Apr 2004
Posts: 1,453
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From: crystalriver Florida
"Burning too Rich or AFPR" ?
I've got an appointment with Norris Motorsports in Orlando next thursday morning for a custom tune/dyno/chipburn. The car is burning "Very" rich on gas. I just took the car back to the local shop to clean the sparkplugs-Tuesday, but just yesterday I was getting that misfire again, but when when the car is going at a fast pace down the road its fine and doesn't give alot of headache and gunfire noise in the exast, but you can here a slight noise from the engine. I just thought about it today, I have an AFPR, the shop said its adjusted properly, but is it possible I can adjust it to a leaner side, I don't wanna overdo or underdo the gas intake, but just enough to get the car running properly till next thursday. I'm not familar with adjusting the afpr nor how it works either--I do see the bolt adjuster on top, I had it installed along with superram and LOTs of other engine upgrades.
Team Owner
Joined: Dec 2000
Posts: 90,675
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From: SE NY
Cruise-In II Veteran
If it's a L98, with the key off, jumper the ALDL pins A&B (upper right) with a paper clip, start the engine and watch the SES flash rate.
After a minute or two, when the ECM enters closed loop mode, the flashes should slow from 2Hz to 1Hz and the On/Off durations should be of equal length. Then raise the idle to say 2,000rpm and watch the On/Off durations again.
The SES On duration indicates a rich condition and the Off duration indicates a lean condition. So, if you see a longer On duration simply back off the AFPR screw a turn or two and check the SES flash duration again. This is only a rough tuning technique but should be close enough till you get it checked.
After a minute or two, when the ECM enters closed loop mode, the flashes should slow from 2Hz to 1Hz and the On/Off durations should be of equal length. Then raise the idle to say 2,000rpm and watch the On/Off durations again.
The SES On duration indicates a rich condition and the Off duration indicates a lean condition. So, if you see a longer On duration simply back off the AFPR screw a turn or two and check the SES flash duration again. This is only a rough tuning technique but should be close enough till you get it checked.
Thread Starter
Drifting
Joined: Apr 2004
Posts: 1,453
Likes: 0
From: crystalriver Florida
when you say back off the screw, do you mean, turn it clockwise or counter ? I just put that key jumper in the upper right side of the diagnostic port under steeringwheel, nothing happened at all, no lights, I do have a service engine light on though--but thats from the engine mods, but no ses blinking lights or anything out of the ordinary...
Last edited by chillcat; Jul 15, 2005 at 11:42 AM.
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
Turning the AFPR screw CCW will back it out.
If you get no SES flashes even when you jumper ALDL pins A&B and turn on the ignition, either you do not have an OBD-I system or there is a problem with the ALDL to ECM interface.
If you get no SES flashes even when you jumper ALDL pins A&B and turn on the ignition, either you do not have an OBD-I system or there is a problem with the ALDL to ECM interface.
