Cargirl Posted July 29, 2015 Share Posted July 29, 2015 I know there's another thread right now but I did not want to steal it. When I first bought my '91 it had an intermittent E041. I replaced the Cam Sensor and it was fixed. Today i drove it and now I have a constant E041. I removed the sensor, cleaned the connections and replaced the sensor. Still the light remains on. Of course, perhaps with parts being so cheap these days the sensor could have failed. One possibility. Instead of spending the $20 to replace a sensor i did 8 months ago I was going to inspect the magnet. I know you can remove the plug wires and play wheel of fortune or remove the plugs and turn the harmonic balancer However, in my '91 there is a chassis part in the way. I am not sure what it is, do I need to remove it to get the the harmonic balancer bolt? Is there another easier way to turn the crank so I can inspect the magnet? Thanks! Link to comment Share on other sites More sharing options...
padgett Posted July 29, 2015 Share Posted July 29, 2015 Sorry, I've never had a '91. You might be able to turn with the alternator bolt if you have not removed the belt. Link to comment Share on other sites More sharing options...
Cargirl Posted July 29, 2015 Author Share Posted July 29, 2015 Just for the record Padgett, here is the obstruction in a '91. Link to comment Share on other sites More sharing options...
Guest Rp1967 Posted July 29, 2015 Share Posted July 29, 2015 The inspection cover on the trans bell housing can be removed and using a large flat screwdriver you can slowly turn the engine by engaging the ring gear teeth Link to comment Share on other sites More sharing options...
Machiner 55 Posted July 29, 2015 Share Posted July 29, 2015 (edited) CG, I believe that it's possible to access the HB bolt by jacking up the right front of the car (use jack stand and wheel chocks for safety) and removing the wheel and the splash guards that separate the wheel well from the engine compartment. This should allow you to put a wrench on the HB bolt to turn the engine over allowing you to line up the cam-mag with the "window". Make sure the ignition is off (key in pocket) and or remove the negative battery cable. John F. Edited July 29, 2015 by Machiner 55 (see edit history) Link to comment Share on other sites More sharing options...
Cargirl Posted August 1, 2015 Author Share Posted August 1, 2015 (edited) It appears the magnet interrupter is intact and looks decent. I am going to try a new cam sensor first, it was replaced 8 months ago but perhaps failed. Wish me luck!One side note and this comes under believe it or not----when I went to inspect the magnet and was prepared to turn the engine over to find it, it was lined up after I took off the sensor. This is a true story, maybe I should buy a lottery ticket!! Edited August 1, 2015 by Cargirl (see edit history) Link to comment Share on other sites More sharing options...
Ronnie Posted August 1, 2015 Share Posted August 1, 2015 I would install a new cam position sensor to eliminate that as the problem. That might be all you will need to do. When I enlarge your photo it appears the magnet may be damaged. The interrupter (magnet) is actually made up of 4 small rod magnets inside a plastic case. If they get damaged it can degrade the strength of the magnetic field that the sensor needs to operate properly. Link to comment Share on other sites More sharing options...
Machiner 55 Posted August 1, 2015 Share Posted August 1, 2015 CG, Do me a favor. When you get the new sensor, compare them side by side to see if there are any obvious differences in their physical appearance. If there are, maybe you could post a shot of them side by side showing the diff. I'm especially interested in the way they look from a side-on perspective. If they are identical, or nearly so , no need to post pics. John F. Link to comment Share on other sites More sharing options...
Cargirl Posted August 1, 2015 Author Share Posted August 1, 2015 Will do John but just keep this in mind, I mentioned in my post that I did already replace the sensor 6 months ago so I will be viewing two replacement sensors, not a new one and the original one that came with the car. I fear Ronnie may be right, if you click on the image of the cam magnet interrupter I posted it expands and you can see that perhaps it is damaged. Like two of the pins are missing. We shall see soon.... Link to comment Share on other sites More sharing options...
Machiner 55 Posted August 2, 2015 Share Posted August 2, 2015 CG, That's fine. I'm wanting to see if the body of the installed sensor (not magnet) is bent in any way. If the body of the sensor were bent during installation, its possible that the distance between the head of the magnet and the face of the sensor is too great to send a steady and reliable signal which then, intermittently, throws a code which over time, while driving, seems to correct itself. It may be easy to check that all four magnet rods are in place by using a small screwdriver, a paperclip or something like a small finish nail to check that all four corners of the magnet head pull on the metal as you bring it near each corner. John F. Link to comment Share on other sites More sharing options...
Guest my3buicks Posted August 2, 2015 Share Posted August 2, 2015 Brenda, the magnet does look iffy - if you are that far as easy it is to replace it, I would not hesitate. Link to comment Share on other sites More sharing options...
Cargirl Posted August 4, 2015 Author Share Posted August 4, 2015 The new sensor did not work. OK, so if I knock out the old interrupter and plasitic bits fall into the engine block, where does the debris go? Do I need to change the oil after I knock the old one out? Help! Link to comment Share on other sites More sharing options...
Ronnie Posted August 4, 2015 Share Posted August 4, 2015 The parts of the magnet should fall down through the timing chain cover into the oil pan, hopefully without lodging in the chain or chain tensioner. If it were me I would turn the engine over by hand before starting it for the first time just to give any debris on the chain a chance to fall into the oil pan. I would change the oil afterwards. The magnet debris must not hurt the engine because they tend to fall out with age. I guess you have seen Padgett's excellent tutorial for replacing the magnet? Take care not to install the magnet backwards. Link to comment Share on other sites More sharing options...
Machiner 55 Posted August 4, 2015 Share Posted August 4, 2015 In this recent pan drop, This is what I found.I believe these are the remnants of the cam-mag sans magnets.God only knows where and what the magnets are stuck to.Don't plan on tearing the engine down to find out. John F. 1 Link to comment Share on other sites More sharing options...
Guest my3buicks Posted August 4, 2015 Share Posted August 4, 2015 Brenda, I used a mouse sander turned upside down on my lap to sand away the lip/brim of the new magnet - held the magnet even with the sandpaper and worked it until the lip was gone - it made for a perfectly clean smooth removal Link to comment Share on other sites More sharing options...
Cargirl Posted August 6, 2015 Author Share Posted August 6, 2015 (edited) OK, after the test drive the other day with no success, I bought the new interrupter today. When I removed the sensor the magnet was lined up right in the window just where I left it even though i drove the car. Am I going crazy or just terribly lucky? When you start the car the interrupter MUST spin around, right? I just can't calcuate the odds on it being lined up again? What exactly is the interrupter mounted too? I can't find any pictures in my service manual. Edit-I just found a blow up (in the service manual) and the magnet is located on the camshaft sprocket so it has to turn when started. Again, what are the chances of it being lined up both times?? Sorry for the rant tonight. Edited August 6, 2015 by Cargirl (see edit history) Link to comment Share on other sites More sharing options...
Cargirl Posted August 10, 2015 Author Share Posted August 10, 2015 Mission accomplished, SES light off, all is well in Gold Canyon, AZ. Thank you Reatta forum for being the best friend of Reatta owner 's everywhere. One last thanks to Padgett for his tutorial and short cut procedure for curing an ill interrupter. Brilliant! Link to comment Share on other sites More sharing options...
Guest Flacko9091 Posted August 16, 2015 Share Posted August 16, 2015 Cargirl,How many miles on your '91? Just curious. Also, how often does the magnet go bad and fall out or fall a part? Is it more of an age thing or miles? Link to comment Share on other sites More sharing options...
Cargirl Posted August 16, 2015 Author Share Posted August 16, 2015 It's definitely and age thing. As Donald Trump would say, the engineers that designed the interrupter are stupid! If you have not seen one, it is a powerful magnet that is held in place by a cheap plastic housing. The type of plastic that gets brittle with age and deteriorates in time. Since the interrupter never actually touches anything, the only way it fails is if the plastic gets so weak with age the magnet, being drawn to the cam sprocket, actually breaks itself loose from the housing by the power of the magnet. Yep, it's one of those items that they knew would fail with age but designed it that way anyway. If the housing was a non-conductive metal this part would never, ever fail. Link to comment Share on other sites More sharing options...
Guest Flacko9091 Posted August 16, 2015 Share Posted August 16, 2015 Does the computer go into some kind if limp home default timing if the magnet falls out, or are you stranded? Link to comment Share on other sites More sharing options...
Guest Flacko9091 Posted August 16, 2015 Share Posted August 16, 2015 (edited) I would also think heat cycles from running the engine would also contribute to the plastic aging, so I would think a low mileage car would tend to have a younger looking plastic magnet holder.Plus, as long as the plastic made it to the end of the warranty period, the engineers have done their job as far as the company is concerned. Engineered obsolecence so to speak.GM isn't too concerned about collectors of 24 year-old cars.. Edited August 16, 2015 by Flacko9091 (see edit history) Link to comment Share on other sites More sharing options...
Cargirl Posted August 16, 2015 Author Share Posted August 16, 2015 Actually the car runs very good with a bad interrupter. The cam sensor sets the timing for the sequential fuel injection. It sends a pulse to the ECM. If it is not working properly, it will still spray gas but not sequentially but all at once. It leads to a rougher idle and slightly reduced mileage. The worst part of it for me is the service engine light will be illuminated while you drive the car which ruins the fun of driving the car. Perhaps it's OCD but when that light is on my blood pressure raises 30 points, drive me crazy! Link to comment Share on other sites More sharing options...
Guest Flacko9091 Posted August 16, 2015 Share Posted August 16, 2015 (edited) I had a 2001 Yukon that would always throw a knock sensor code even though it seemed to run fine. I changed plugs, coils, wires, knock sensor, cleaned intake and I still had the code. It would never set code around town but would set it about 80% of the time once I drove more than 5 miles on the highway. I finally took the instrument cluster out and removed the light. I was tired of the stupid light staring me in the face!I find after a while on these old cars that I'm more of an evaluator than a driver. I don't mind troubleshooting things as long as it's not the same thing over and over. On one of the Allante forums a few years ago, I was actually elevated to a technical advisor since I had become familiar with most of the common problems on the car. I've parted a few Allantes over the years.Most of the fun though is interacting with other owners trying to improve each others cars. I owned a 2002 Tbird convertible for 3 years but I got bored with it cause there wasn't enough to tweak...yet.I always try to leave my cars better than I found them when I send them on to new homes. Edited August 16, 2015 by Flacko9091 (see edit history) Link to comment Share on other sites More sharing options...
Cargirl Posted August 16, 2015 Author Share Posted August 16, 2015 That's so funny, I do the same thing. I just posted an ad on CL to sell my 1983 Hurst/Olds. I really went through this car and now it's perfect, nothing left to do so, off to a new owner http://phoenix.craigslist.org/evl/cto/5167325514.html Link to comment Share on other sites More sharing options...
Machiner 55 Posted August 17, 2015 Share Posted August 17, 2015 (edited) Does the computer go into some kind if limp home default timing if the magnet falls out, or are you stranded? Yes, Someone can explain this better but "limp home mode" works just as well and No, you won't be stranded, the engine just doesn't perform as it should and may experience stalling issues. CG, I've often wondered the same thing with regard to the magnet holder. But engineers usually do what seems like a dumb thing for a very good reason. What reason could that be? Well, the "proper" procedure for replacing the magnet would require removing the timing cover. While it's off, it would be a really good time to check the condition of the sprockets, slop in the chain and the condition of the tensioner.Otherwise that stuff would never get looked at until possibly the chain or tensioner broke. Then you're sitting on the side of the road in the desert in 100 degree heat a hundred miles from nowhere wondering what that grinding noise was just before the engine stopped.I'm probably wrong (usually am) but it's the best thought on the subject I can come up with at the moment. John F. Edited August 17, 2015 by Machiner 55 (see edit history) 1 Link to comment Share on other sites More sharing options...
Guest Flacko9091 Posted August 17, 2015 Share Posted August 17, 2015 That's a good point John. My Mercedes 560 has nylon timing chain guides that normally are due for inspection or replacement at 100k miles. When I got my 560 it had 115k miles on it. I had lots of records but couldn't find anything that said the guides had been changed. I decided to remove the valve covers to inspect them and I'm glad I did. One of the guides had cracked around a pin and was waiting to drop into the path of the chain and trash the engine. I replaced the guides and installed a new tensioner.Point is things like the guides on my 560 or the magnet on the 3800 do force you to look under the timing chain covers periodically. Link to comment Share on other sites More sharing options...
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