Service Engine Soon Light

My Service Engine soon light comes on after 15min of driving.....once engine is restarted (off/on) is disappears for 15 more min of driving....I do have symptons of poor gaz mileage, smell of excess exhaust...and wondering if this could be the oxygen sensor....problem must occur, and light must remain on if the computer has to be changed...Could it be a MAP sensor? ref: 3.3 V6 cutlass cruiser - Also, engine noise around the camshaft. - tried and replaced balancer, belt, alternator, water pump, tensioner (3-times as it gives distinctive clicks ) any ideas, suggestions to repair this noise.

Bring it to a place like AutoZone, they will read the code for free and let you know what caused it.

My Service Engine soon light comes on after 15min of driving.....once engine is restarted (off/on) is disappears for 15 more min of driving....I do have symptons of poor gaz mileage, smell of excess exhaust...and wondering if this could be the oxygen sensor....problem must occur, and light must remain on if the computer has to be changed...Could it be a MAP sensor? ref: 3.3 V6 cutlass cruiser - Also, engine noise around the camshaft. - tried and replaced balancer, belt, alternator, water pump, tensioner (3-times as it gives distinctive clicks ) any ideas, suggestions to repair this noise.
Just a guess. On my 91 Olds Cutlass Ciera;, I had exhaust smell and it had a code that read O2. Was a cracked exhaust manifold. Had that replaced and drove the car for another 100Km before scrapping it at 363,000Km.
Great engine, never used oil, ran well after the rest of the car was wearing out.

With out a proper scan you cant tell why or whats causing the SES light, guessing is very costly.

I would agree that the 3.3L (90deg V6) was a very good engine.

With out a proper scan you cant tell why or whats causing the SES light, guessing is very costly.

I would agree that the 3.3L (90deg V6) was a very good engine.
I'm not suggesting to change out the exhaust manifold without a scan. When the scan on my car called out the O2 sensor, the manual listed possible causes, and as it turned out, one of the possible causes (I think it was listed as first item) was the manifold. I had the servicing done at the GM dealer and he found and fixed the problem with the first fix. (Yes, it was expensive)!!!
Good luck!:)

A cracked exhauat manifold would be quite loud though.

Well herbnadler's profile says he lives in MONTRÉAL , so a free scan may not be an option up there... :dunno:

Keep us posted herbnadler..

AutoZone won't do jack for you. You have an OBD-1 car, there scanners (I hesitate to call them that) are OBD-II only. 94/95 was OBD1.5 which didn't use either scanner, and 96+ autozone can scan.

BUT! You can get trouble codes from this. If you look to the left of the ashtray bolted to the lower steering column cover you'll find the diagnostic connector. It has a little plastic cover on it covering the pins-pull it off. The two right most top pins you'll want to jump them together (key on, engine off.)

Connectors you want to jump:
ABCDEFIH
ZOIJWERM

You want to jump I to H. The cooling fan will come on, and the SES light will blink out codes. Count the number of times it blinks, if it blinks twice then pauses, then blinks four more times then a long pause that means the first code is 24. The first code it will display is 12 (ignore it), then any codes which remain will be displayed.

You can look up what the codes mean-or refer to a manual.

This method will work for just about any pre-obdII GM car, assuming it has a connector in a similar place. Most EFI computers have a method or procedure of getting codes out without a scantool (AMC excepted)

This is greatly appreciated! What is confusing (prior to performing this test) is that the Service Engine Soon comes on intermittently, perhaps when the engine warms up after 15 min. on the highway....then when you shut it down, it goes away, and may not come back for a good period of time. Must the Service Engine soon light be present when performing the test? or , is the code stored, until retreived? Then, how do we clear this code after changing whatever we need to?

The code doesn't have to be active at the time, the ECM will have stored the fault.

After you've fixed whatever the issue is, you can either drive it and I believe it will reset itself eventually-not sure on the requirement the ECM has for that-or you can disconnect the battery for 10-20minutes and it will be reset.

Thier is a ODB I & II trouble codes posted in the N-Body Trouble Codes (http://www.automotiveforums.com/vbulletin/showthread.php?t=525205) , top of the page.

I wasn't sure about those jumpers for the hybrid odb 1.5, which some ODB I scan tools will read these but not very many low end scan tools.

Good Luck herbnadler, and post your results if you have time.

I've got a website i've prepared with just the information you may be looking for, rather or not you have the OBD-I or OBD-II connector, so long as its an OBD-I system...your good...HOPE THIS HELPS!!

http://xgamesj6.tripod.com/gmcodes.htm

That's kinda redundant XGamesJ6, we have 95% of the ODB codes right here at AF with pics too......

sorry my fault, i've never really cruised the site before, only forums for info and tryin to help out others. but now i know, thanks!