85 Check Engine Light HELP
Thread Starter
Pro
Joined: Dec 2000
Posts: 534
Likes: 32
From: Farmington NY
85 Check Engine Light HELP
On the highway after driving about 20 miles (not local traffic) I get a check engine light. When I turn it off and restart of course it is gone. My dilemna is that whenever I check for codes, it says there are none stored!!! Now I've kept my AutoXray scanner in the car and before I shut it down and the light is still on, the scanner says no stored codes! What do I do and where do I begin to look for the problem? Seems to run okay with the light on but I know it's not a good situation. Engine is stock, has no modifications.
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
See if you can get it to spit one out by disconnecting the TPS with it idling. And to make sure it isn't your Auto X-ray, see if it will give you the code by grounding the Diagnostic Link. If not, suspect the ECM.
Advanced
Joined: Oct 2003
Posts: 67
Likes: 1
From: Renton Wa.
Can't say this will help but I had this similar experience while messing with the egr system. I disconnected the egr looking for performance gains, I would drive for miles with no problems but when I would get into a long mid throttle cruise situation the 'check eng' light would come on until I moved the throttle slightly, then light would go out. It never set a code, so I connected the scan software with laptop and recorded the data at the time check light came on, found O2 rich, caused by disconnected egr valve. Re-connecting everything fixed problem and also confirmed what I have read elsewhere, egr system is not a bad thing, only works at mid throttle cruise never when you get on the gas or at idle. You can also program in the bin when it comes on. Can you scan/record with tunerpro or similar software when light is on?
Hope this helps
Hope this helps
