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Old 04-03-2009, 06:51 PM   #1
dieter
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1987 Olds 98 won't start and has no spark

It has a 3.8 engine and has a control module with three box-like coils. I am assuming they are coils. I removed and took the control module to Autozone and it checked okay. I did not check the coils other than an ohm check where all appeared to be the same. I have not been able to get any spark. The starter will tune over the engine and I have a new battery. I am of the old school and I am not savvy on the wiring of these newer ignition systems. I am able to get 12 volts at the first and third (starting from the firewall) wire points of the control module harness. I have only a Haynes manual, which is only better than having nothing.

I would appreciate help without initials and slang because I won't understand.
Copy me at dieter@one.net in the chance I can't find my way back to this site.

Thanks,
Dieter Schmied
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Old 04-03-2009, 08:00 PM   #2
ctwright
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Re: 1987 Olds 98 won't start and has no spark

You may have a bad crankshaft position sensor, you would have to remove the harmonic balancer(crankshaft pulley) in order to get to it. The ecm gets a signal from the crankshaft position sensor and sends the signal to the ignition module which then turns into the ground pulses needed for the coil packs(those three square coil things you was talking about), I may have worded some of that wrong but that's basically it.
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Old 04-03-2009, 08:16 PM   #3
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Re: 1987 Olds 98 won't start and has no spark

I was wrong, the crank sensor first sends the signal to the ignition module, then from there it goes to the ecm, and then back to the ignition module, I just looked at my Haynes manual for this vehicle. It's different for some vehicles that's the reason I said it the way I did the first time.

Just wanted to correct myself either way I think it's your crank sensor.
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Old 04-03-2009, 08:54 PM   #4
brcidd
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Re: 1987 Olds 98 won't start and has no spark

Try my trick- put a "197" bulb (from autozone- it is a side marker bulb)- bend the wire tabs out- insert it in one of the fuel injector harnesses- then crank the starter- if the light pulses- then your crank sensor is okay- if not- then replace crank sensor. Cranks sensor feed ignition module and ecm to send injector pulses.....no injector pulses means bad crank sensor....
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Old 04-03-2009, 09:29 PM   #5
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Re: 1987 Olds 98 won't start and has no spark

Thanks for the information. I'll get on it tomorrow. I'll let you know what happened.
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Old 04-04-2009, 07:25 PM   #6
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Re: 1987 Olds 98 won't start and has no spark

Success!

It turned out that I was getting spark when I reinstalled the control module/coil assembly but it was still not starting. I made the test of the crank sensor as recommended and it was good. So I eliminated the module with Autozone and the crank sensor. I thought the gas might be weak as my brother bought the car, unstarted and consequently at a low $500. price, and parked the unstarted car in my garage SIX F------- YEARS AGO! Anyway, I sprayed in some starter fluid in and got a pulse but no start.

Then I saw something fishy; the cylinder numbers on the coils did not match up. I put the coil back on the module just as it came off or I should say the Autozone guy did in front of his boss and myself and I watched closely. I have been away from working on cars for a number of years but I was especially alert to possible wiring mismatches. The even numbers were nearer the front of the car and one connection in the internal wiring appeared forced when we opened the coil/ecu up. Haynes has a picture of the coil and nothing was forced so I changed a terminal and reversed the coil so that the odd cylinder terminals were up front and the engine started.

Tomorrow, I have someone follow me and I'll put the car in my brother's driveway with the keys under the carpet. I'll be that sucker won't even recognize the car and the old grouch will call the police for someone parking in his drive. Hell, I got to get some pleasure out of this.

Thanks again!
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