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1988 Olds Eighty-Eight High HC, CO, Code 41

Hello gang. My mother has a 1988 model Olds Delta 88 with over 150,000 miles that is having a problem passing the emissions test for its yearly state inspection. The car has the VIN#C 3800 engine. The test results were:

(1) HC(PPM) Standard-152, (Current Reading-359 Fail High and Low RPM) (2) CO% Standard-0.97, (Current Reading-9.87 Fail High and Low RPM) (3) CO2% (Current Reading-8.3) (4) NOx Passed Well at 80 PPM (5) O2% is 0.4 (6) Dilution% Standard-Less Than 6, (Current Reading-18.2) (7) Gas Cap Integrity Passed

After it failed she brought the car to me and I pulled the dipstick and smelled strong gas in the oil and the computer had a hard code 41 (cam sensor). I checked the following concerning the gas in the oil and code 41:

Fuel Filter Fuel Pressure and Flow Fuel Pressure Regulator Diaphram For Leaks Vapor Canister (Couldn't Tell Much Though) Injector Leak Down Test Cleaned Throttle Body and Tested the IAC Checked the Type 1 DIS ( All Six Firing Blue) Changed Oil and Filter Twice Changed Cam Sensor and Felt Magnet On Pole (SES went out for a few hours then came back on) Added Fuel Injector Cleaner and Drove A Few Days With 93 Octane Gas

Other things replaced in the past 6 months: Plugs, Plug Wires, Coil Pack, Fuel Filter.

The second test result which I just saw didn't change. The tech said she might try replacing the O2 Sensor which I just did (After the second test). The tip of the O2 Sensor was very black with HC contamination. The SES light was on again, (hard code 41) during the test.

Concerning the Code 41 (Cam Sensor), I have replaced the Cam Sensor three times in the last 6 to 8 months. The SES light will stay out for a week or so and come right back on and stay on until I replace the sensor again, then it will do the same thing, last a week or so, and go bad again.

There seems to be a slight tip-in hesitation and my mother said it stalled backing out one time.

I have come up with this possible cause:

I think the timing chain is loose causing the high HC and CO readings and the code 41 is caused by the magnet being out of adjustment due to the loose chain changing the valve timing and/or the magnet although it is in place, may also be to weak to fire the cam sensor due to age.

I think I should replace the tensioner, chain, gears, magnet, and crank sensor as well because it works with the cam sensor too.

What do you guys think? Has anyone had a problem like this where the cam sensor will work for a while then quit?

I'm sorry for the long post and I appreciate the help. The man said he'd test it one more time for free. This is making me pull my hair out. My MT2599 Snap-On scanner was stolen so I dont have real time Block Learn or Intergrator info. I had to use the paper clip trick to get the codes.

Thanks again. Ed

Reply to
Glen Cooper
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Sounds like you need a new cam magnet. No way to adjust it , it presses in from behind the timing upper sprocket. As long as the ECN isn't receiving the impulse signal from the cam sensor your SES light will be set and won't pass the emissions test

Save yourself some $$$ and don't replace the timing chain & 2 spockets. These are solid steel parts that don't seem to wear out. When I took Bnneville's timing cover off in the May ( with 280,000 miles ) there was no wear in the sprocket's teeth or in the chain.

Just remove the timing sprocket and install a new magnet ( about a $ 9 part ).

I'd recommend replacing the nylon tensioner that rides against the side of the timing chain. Its does get a wear groove worn in it rubbing against the timing chain.

========= Harryface =========

1991 Pontiac Bonneville LE 3800 V6 ( C ), Black/Slate Grey _~_~_~297,525 miles_~_~_

~_~_~_~_U.S.A._~_~_~_~_~_

~~~The Former Fleet ~~~

89 Cavalier Z 24 convertible 78 Holiday 88 coupe 68 LeSabre convertible 73 Impala sedan
Reply to
Harry Face

Yea I guess I'll dig into it. Nice way to spend a holiday weekend LOL!

Thanks Harryface

Reply to
Glen Cooper

Forgot to mention--->>> Remove the cam sensor and bump the ignition a few times till the cam magnet in the timing sprocket cos into view. You'll need a mirror & strong flash light to see inside the hole.

If there are no parentheses ( ) shaped prongs you can see or feel, then the magnets have broken off. The magnets are in the prongs. Aother way to test is to stick about a 3/4 round piece of steel through the hole and see if it gets grabbed by the magnet.

Its only a $9 part but a lot of effort involved to replace it.

Good Luck.

========= Harryface =========

1991 Pontiac Bonneville LE 3800 V6 ( C ), Black/Slate Grey _~_~_~297,525 miles_~_~_

~_~_~_~_U.S.A._~_~_~_~_~_

~~~The Former Fleet ~~~

89 Cavalier Z 24 convertible 78 Holiday 88 coupe 68 LeSabre convertible 73 Impala sedan
Reply to
Harry Face

I wanted to bump this one up to let everyone know I got it to pass inspection. That magnet woolybuger for the cam sensor was bad but what I did was replace the O2 sensor and that brought the HC and CO into specs. That O2 Sensor was contaminated big time with the gas that got into the oil due to two cylinders not sparking the injected gas for a while last year. I talked the man into inspecting it even though the SES light still read Code

41 due to the bad magnet. After all it is an 88 model.

Maybe this will help others.

Thanks for the help everyone. Ed

Reply to
Glen Cooper

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