computer chip
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computer chip
Been having some start up issues with my '89. Had it scanned recently and there wasen't anything seriously wrong with the exception of the pulse rate(think this is right) within the injectors being off. Mine was high along with a "coking" showing up in the scan.
My question is: had the top end done 3 1/2 years ago and went with a 24 lb Bosch injector set up and recently replaced the throttle body with an after market 52 mm. Is this enough change from stock to affect idle, start up, etc. Seems the car wants to start up cold with an eratic idle even in warm Fl weather. Average fuel mieage is up and down from low 13's to around 19.2.
Any suggestions on what to do with the stock chip or which after market chip might work better? Can my stock be re-programmed? Generally, suggestions on which way to go. The injectors and throttle body are the only mods to this stocker. Never know what to expect.
Thanks
My question is: had the top end done 3 1/2 years ago and went with a 24 lb Bosch injector set up and recently replaced the throttle body with an after market 52 mm. Is this enough change from stock to affect idle, start up, etc. Seems the car wants to start up cold with an eratic idle even in warm Fl weather. Average fuel mieage is up and down from low 13's to around 19.2.
Any suggestions on what to do with the stock chip or which after market chip might work better? Can my stock be re-programmed? Generally, suggestions on which way to go. The injectors and throttle body are the only mods to this stocker. Never know what to expect.
Thanks
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You know , I didn't really look over my techs shoulder on this one. I know he couldn't get the idle down to 400 rpms to make the necessary adjustments for the iac. The throttle body is back to the stop and wouldn't idle down any more.The tps is right on the money. I just thought the 24 lb injectors might be creating the problems, enough to make it run rich. The tech is not a Vette expert and is using a SnapOn scanner but he claims all looks good, except for the reading of about 70 on (I thought the injector pulse rate?) and was supossed to be between 20-40. I might be wrong on this.This along with the "coking" that also showed on the scanner. Any suggestions on where to go on this?
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Thanks a lot. Although I have had these Bosch 111's for over 3 years with no problems, the scan didn't lie. The new throttle body has been on for less than 8 months but the indication of a coking problem bothers me. Should I remove and clean?Had a MAF sensor problem last year and it was replaced. Guess I can't correct the rich mixture without re-programming or injector replacement? Which way would you go from here?
Thanks again
JIm
Thanks again
JIm
Le Mans Master
Joined: May 1999
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From: Windermere FL
Jim,
My understanding is that computer can automatically adjust the AF ratio to a limited extent. I think it is like 5% (but I could be wrong). So in theory, if you put in larger or smaller injectors the ECM can learn a new pulse duration to get you to the right AF ratio. Now if you put in bigger injectors that gets you over that limit then you will have problems.
So perhaps your O2 sensor needs to be replaced? But if you said the scan is saying the computer knows it is running rich I don't understand why it does not correct it. The O2 sensor lasts about 50K miles. If it is off, then the ECM is going to have it using the wrong AF ratio.
24lb Bosche injectors should work fine. Your car will run rough after you disconnect the battery until the ECM learns and corrects the AF ratio.
My understanding is that computer can automatically adjust the AF ratio to a limited extent. I think it is like 5% (but I could be wrong). So in theory, if you put in larger or smaller injectors the ECM can learn a new pulse duration to get you to the right AF ratio. Now if you put in bigger injectors that gets you over that limit then you will have problems.
So perhaps your O2 sensor needs to be replaced? But if you said the scan is saying the computer knows it is running rich I don't understand why it does not correct it. The O2 sensor lasts about 50K miles. If it is off, then the ECM is going to have it using the wrong AF ratio.
24lb Bosche injectors should work fine. Your car will run rough after you disconnect the battery until the ECM learns and corrects the AF ratio.
Drifting
Joined: Aug 2010
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i think you have to retune your 165 ,enter a correct 24lb/h as injectors flow rate in the $6E mask using Tunerpro RT and a chip burner to write a new chip ,changing this costant your rich condition would disapear.Are you running new heads or stock heads with these 24 ish?
P.S I've done the swap to 24ish ford racing,my 85' become rich and smell incredibly...even if stock are 22lb/h,my 870 ecm has'nt a injectors flow rate costant,so retune an 85' for injectors swap is a PITA you have to go deeper into the tune map.
P.S I've done the swap to 24ish ford racing,my 85' become rich and smell incredibly...even if stock are 22lb/h,my 870 ecm has'nt a injectors flow rate costant,so retune an 85' for injectors swap is a PITA you have to go deeper into the tune map.
Last edited by tunedport85inject; Oct 15, 2011 at 03:19 AM.
