1987 buick lesabre cam sensor and interruptor magnet

[chupie]

need your help, on my 1987 buick lesabre it just one day did not start. will crank but will not start, check for spark and there was none at the ignition modular, read on line that it may be the crank sensor so i replaced it $43.00 and still no spark, took a chance and changed the ignition modular $130.00 and still no spark. removed the cam sensor and cleaned it and still no spark so I gave up and had it towed to local garage. they called and said that the problem was the cam sensor and it will cost $300.00 labor and $200.00 in parts and diagnostic $500.00 total, so I told him why so much in labor and he said that they have to remove the water pump and timing chain cover and will take a long time and it's a big job and i said but i removed the cam sensor and i didn't have to remove any of those part and i did it in about15 min. then he said that another part that's bad is a part called the interruptor mannet and to replace it they needed to remove all those part mentioned.
well since the car doesn't run I couldn't just go pick it up so i went with the repair work, when I got it back it really doesn't look like it was dismantled in the area of the water pump and timing chain cover, all look the same as when i was working in the area. no signs of any anti freeze or movement of any water hoses I really think i got beat
my question is a bad cam sensor will cause a no spark no start but what about the interrupter, what are the signs of it being faulty will it still produce spark and what are the chances both parts failed at the same time, honestly now after looking at the car I really think the interrupter was never changed they are just no signs at all of all these parts removed, need your help
thanks in advance

[buickmastermind]

Okay, the easiest way to tell if that was the problem, check to see of he took apart the underside of the dash, and put a new computer in. That would have been my initial guess as to the problem, as the cam sensor signal is ignored by the computer until after the motor has warmed up. Until that point, the crank sensor is used to run the motor. The might run after it has warmed up on a bad cam sensor, but when you shut the motor off, until it cools back down, it will not start again. As for the interuptor magnet, it will not fall off the motor you have. It is bolted on.

If you are not getting any spark at the ignition module, remove the connector, connect a test light to a good ground, and put the other end into the different slots of the connector. Have someone crank the motor, or you can do it yourselve. Repeat this process for all twelve of the wires. This will point to the problem. Do you have the type one ignition coil (one entire unit) or the type two coil assambly (three separate coils)? Did the sevice engine soon light come one before the car stopped running? When you crank it, does it come on? Have you checked the codes on it? To check the codes, you have to look under the center of the dash, where there is a 1inch by 2 inch hole in the black part, directly under the ashtray. In the hole, you should be able to see a connector. This is the ALCL connector, and you have to put a paper clip into terminal 'a' and put the other end into terminal 'b'. Reletive to the prong on the bottom side of the connector, they are the last two on the left of the bottom row of slots. The service engine soon light will flash on for a second, and turn off. Using a series of flashes, it will read out the trouble codes that have been stored. It should start off by flashing once, a short pause, and flashing twice, followed by a long pause. That signifies code 12. It will flash each code three times. After it flashes code 12 three times, it will either flash a different code, or continue to flash code twelve. Let us know what you find out. Also, tell me the color of the cars computer, located under the bottom of the dashboard, just below the passenger side glove box. It has two connectors on it. I ask this because a new computer is not the same color as the original. Oh, and check to see if the gasket by the timing chain cover has been changed. That will tell if he even went under the hood. The interupter magnet is $10, and the gasket $5. The computer is $100, so he ripped you off, assuming he replaced anything. Next time, just ask to see the broken parts. If he can't show them, he didn't fix them.

[chupie]

thanks, for helping me out,
I checked under the dash like you said and I can’t tell if anyone was there before, all screws were tight and I cant see any signs of any thing resent like lost or missing screws or things that may have fallen on the floor moved dust and the like. I did remove the cover to see the computer and it’s stainless steel (no color)
it’s bolted on standing up with the connectors in from under. can’t tell if it was removed so I put the cover back on and you know you won’t be able to tell I was there, any way about the codes, I didn’t look for them when the car cranked but didn’t start and then I disconnected the battery to replace the crank sensor and when that didn’t work the codes were gone, so I took a chance changing the ignition module and that didn’t work so I removed the cam sensor and cleaned it and put it back on and still no start just crank so I had it towed to the garage, the ignition module is the type one ignition coil now I have a spare since the one I took off is nothing wrong with it. And I did request to get the bad parts back, I had requested that when they had called me. I didn’t know the interrupter was just a magnet at the time and he told me when he gave me the 2 parts that the interrupter was broken, but looking at it now there is nothing wrong with it that I can see
as far as the cam sensor it looked very dirty considering I had cleaned it the day before.

as far as the timing chain cover gasket, well i had looked in this area and did mention before this area was not touched at all, and there is no new gasket on the timing chain cover. I talked to my neighbor next door about this work that was preformed on the car and he was kind enough to come over and take a look and he said there is no way any of these parts were removed. he said i’m 100% certain water pump and timing chain cover were not removed, and even offered to go to the shop with me to argue the point.

anyway I am going right back to the shop to talk to the owner about this and work it out with him. you know I didn’t mind paying the money to fix the car but what got me is I expect to get what I paid for so when I open the hood I want to see proof that the work was done, if I would have saw that the timing cover gasket was new it will have ended right then and there. But not seeing proof that the work was preformed tells me I was ripped off.

Anyway still wondering what will have caused the no spark at the ignition module

I really do appreciate you posting info on my question please do get back to me on what else you think.

I did read a lot of your post on this forum, and i do think you are very intelligent and know your car stuff.

Have a good thanksgiving
Louis

[buickmastermind]

The ICM is controlled by the computer. The ICM gets a signal from the computer to tell it when to spark, and on which coil to spark. The computer bases it's spark timing when cold on the crank sensor. It isn't until after the car warms up, as indicated by the coolant temp senor, that the computer fully adjusts spark timing, SFI, and IAC valve by using the O2 sensor, cam sensor, MAP (MAT) sensor, MAS, and the TPS. It could have been a bad computer, but the stainless steel tells me that it wasn't touched, unless he got one out of a junker. Any replacement computer is supposed to be black or even gray. Silver is the way to tell if it is the original factory computer. If you want, you can switch the ignition coil you have to the type two. It is a significantly more efficient coil. I was able to.
You don't have to disconnect the battery when replacing a sensor on the older cars. Maybe on the newer ones, but not on anything before 1990.

About the interuptor, what does it look like, exactly? It may have been the crank sensor interuptor, or one not even from your car. I have never had a cam sensor magnet come off on the 231 v6. What kind of mileage does your car have?

You can see for yourself that the cam sensor doesn't play a role in starting. Just disconnect the wires, and try to start it. Actually, I would be very surprised if it prevented the car from starting, as mine will run just fine without it, until it warms up, and dies.

[chupie]

Hello,
thanks for the info you posted.
the car only has 67,000 orig miles and it's a 3.8 6 cly and the interrupter look like 3/4 inch by 2" and if you would like to see what it looks like go to www.partsamerica.com in the search line enter dr1504 and you will see a picture of it now remember this is what the interruptor that they gave me back look like. its just a magnet and it looks fine. I called the garage and I have an appointment to talk to the owner on tuesday at 2:00 pm to go over my dissatifaction of the cost of repair which in my mind wasn't the real problem to begin and also to show him that the part his shop claims they changed was not so.
I'm sure everything will work out at the end.
well I think this is all for now, I do thank you for the info provide it was and will be helpful when i meet up with the shop owner tommorrow,
i'll let you know the outcome. my e-mail address is [email protected]
thanks
L.C.

[arnstr]

I would suspect they replaced the crankshaft sensor, its behind the damper just below the water-pump, dont need to remove the timing chain cover,In canada i got quote for $45 parts and 1.1 hours labour-$131 total

[buickmastermind]

I was getting at that...in an insinuative sort of way.

Was the quote in canadian, or American currency?

[rustbucket]

Mastermind,
Concerning post #4,
I dont think the ECM does control the ICM spark when cranking. I did a test on my 87, by unplugging the ECM power connector, and I installed a timing light and cranked. Of course it did not start, but the timing light flashed, which proved the ICM was doing the spark control by itself.

[buickmastermind]

Okay, that is supposed to happen. The computer controls the timing of the spark, or when it happens, based on the outputs of the other sensors. There are 'relays' in the ICM that during cranking, the spark timing is controlled by the crank sensor. The crank sensor has two separate interuptors, which I think are for the 3 and 6 cylinders. When the computer is disconnected, you should alway see a correct spark timing on those two. The others may spark, because the interuptor on the crank sensor is about 2 inches long, giving the time variable needed to give a rough calculation of the other timings, but the timings will be off. With the computer connected, you should see a correct spark timing on the other cylinders as well. When the car is actually running, after it has warmed up, the ICM yeilds full spark control to the computer. If you were to run your test again, plug the computer back in, and disconnect the crank sensor. You shouldn't get any sparking at all.