1987 Lesabre with no spark

Im in need of some help with this problem, my car would appear to have no spark all of a sudden. The car was running fine, I drove it home parked it in the garage and when I went to start it 2 days later, it wouldt start. I checked the codes and found them pointing to the coolant temp sensor and the oxygen sensor, I know these codes were there from a previous problem, but replaced them anyhow. No change. I checked the spark and there was none. I had some spare parts that I know work, and swapped them, this included the ECM, ignition module, and coils, I did each part individually testing after each one was replaced and that did nothing. I am all out of ideas, all I know is I need this car to start and dont know what to do. Also, is has a new MAF. Thanks!

I would first check to make sure you have a ground on the module connector (10-12pin)(you'll have to check your wiring diagram), also there are ground wires that bolt on the front clyinder head, check to make sure there ok.

I have run into this many times (Bad grounds), the plate that hold the igintion module is famous for oxidizing, when you have the ignition module removed you will see (3) copper squares, these hold the plate that holds the module in place, these are the grounds for the module, but don't forget there is also a wire in the connector that also supplys ground.

If these are all good you may have to start looking at things like the crank sensor or Ecm.

Good Luck

Mr.Rob

Thanks for the quick replay, I will check that out tomarrow and let you know what happens.

I went out there this morning and cleaned the contacts, The car did start after that, but I dont think that was the problem. After a few minutes of running, then check engine light came on, i shut it off, checked the codes, and its the same ones I got before, the coolant temp sensor and the O2 sensor. I just replaced those twice last week, it cant be those. I tried to start the car again and all it does is crank. Any ideas?

Ok, heres the interesting part, the other night, I tried to start it again and it wont start! Im completly out of ideas! It sounds to me like a wiring problem now more than anything. Does anyone have any suggestions?

The codes on the light won't clear until after 50 starts.

Check the crank sensor, see if it is working properly. You may just want to replace it. If it still doesn't start properly, I would imagine that the computer is dying. At any rate, be sure that you check the crank sensor.

how much of a pain is it to cahnge the sensor? I swapped the computer out with a working one and got no result. The car is back to not starting at all again. Ill check that sensor

Simple, you turn the wheels to the right, remove the plastic cover like you're changing the oil, and there are two 10mm(?) bolts holding it in place. Make sure that the replacement is lined up exactly with the old one. The bracket can only bolt on the motor one way, but the sensor can be adjusted.

Forgot to say, it's on the passenger side of the car, right behind the harmonic balancer.

ill have to try to check that this weekend sometime, after I replace teh starter which has crapped out from all the cranking. Thanks for the help, ill keep you updated

ill have to try to check that this weekend sometime, after I replace teh starter which has crapped out from all the cranking. Thanks for the help, ill keep you updated re: no spark on your buick. I would also check the cam sensor as well as the crank sensor. Also check fuel pressure on the fuel rail and make sure the fuel pump is running. This all the ideas I have. Good luck.

Hi, my 87 lesabre is having the same problem: no spark. Been in the shop 10 days, drove to shop to have cv joints put on, mechanic started to drive into shop, it died and has not started since. He has replaced the computer, cam and crank sensors. Said timing is fine and so is the coil....getting fuel but just no spark. He thinks it may be bad injector(s).....any input on this. I need my car back soon.
It has 172k on her....she was a good car for the month that I drove it.
Thanks much.

Pull one of the wires off the coils, and try starting it. If you can't see the exposed post sparking, then the ICM is bad (assuming the mechanic actually changed the things he said). Fuel injectors being bad won't cause no spark.

I know its been a while, but I finally got a chance to work on the car, replaced the crank sensor, still nothing. What else can it be?

I know its been a while, but I finally got a chance to work on the car, replaced the crank sensor, still nothing. What else can it be?

Hi,
Somewhere on the board I read the bracket that held the sensor had a minor crack, so when the engine will heat up the sensor position will be screwed. You may wanna take a look at that bracket thing. Again I am not a mechanic ,it is just what I read.. just something to check out.