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Service Engine Soon warning lite

8

86targa

Guest
My 'Service Engine' lite came on for the first time last week. Turned out the distributor took a dump from heat. Also the bad distributor took out the ECM. Got both replaced. The car ran like total crap when the lite originally came on. Now it seems to run fine. The problem now is on the first startup in the morning, the check lite comes on and stays on till its shut off. On restarting, it runs fine and no lite? No codes show up. Anybody got any idea or just ignore it?
 

Edmond

Well-known member
Joined
Aug 1, 2001
Messages
5,218
Location
Louisiana
Corvette
2003 Z06
Hmmm, my intuition tells me not to ignore something like this. I was told that when that light comes on, it's most likely an electrical problem.

Did you scan it yourself or take it to the shop?
 

Bob86ZZ4

Well-known member
Joined
Apr 24, 2002
Messages
49
Location
St. Paul, MN, USA
Corvette
'86 Coupe
I wonder if you got the code cleared out completely. You need to either remove the ecm fuse or disconnect the battery for a few minutes. Then hook up the scan tool and turn the key on but don't start the motor. The scan tool should show no codes. I think something is wrong if you get the check engine light and you can't find any codes. What kind of scan tool are you using?
 
8

86targa

Guest
shop installed them both. I assume they disconnected the battery because all my displays in dash were reset. The car does seem to run right all the time lite or not. Read codes by connecting terminals in link, only got test '12'. Someone told me that a defective factory security system can set the service lite if its defective, and I know mine dont work right, had to take out the courtesty lites bulbs so they wouldnt stay on. I think one or both of the key switches in door handle are bad.
 
B

boblx2a

Guest
You didn't say (or I missed it) what code it was setting. My '86 used to regularly set the EGR code when the lite came on. It would usually come on while I was crusing down a rode and started uphill. It would stay on until I restarted the car after it sat for a few hours. i.e., coming out from work, etc. It would always have the EGR code set. This happened every couple of days, I don't recall it ever going longer then a week without occuring.

Finally I had the heads rebuilt, just because they needed it. Nothing to do with the EGR problem. The valve guides were leaking so we pulled the heads, rebuilt them and cleaned the pistons, etc.
Never set another EGR code after that. I left out that I totally replaced every component in the EGR area, long before I rebuilt the heads, with no results. I can't determine any connection between the two jobs. All I can think is that we must have inadvertantly fixed a bad connection somewhere.
 

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