'87 5th ave. No Spark to plugs, Yes Spark from coil.

mgbeda

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Hi folks. My '87 Fifth Avenue was running just great when I parked it a few days ago. Then the next day it would not start (turns over well, smells like gas). I started testing and found that there was no spark. BUT when I test for spark directly from the coil wire it does spark.

I've got the 1987 Chrysler Service Manual, and went through its list of tests. Most of them seem to be checks for broken or shorted wires. They all pass. Which according to the manual leaves...replace the spark control computer. My worst nightmare.

I should point out that here in California this car, being only 36 years old, still has to pass smog, visual as well as actual emissions, so I'm not allowed to lose the lean-burn (or whatever they called it by '87).

Does anyone have any advice? Or (almost ridiculous to ask) a working spark computer? I read somewhere else on this forum someone recommending to "bypass" the computer and see if it runs, but I have no idea how to do that. Lastly does anyone else have experience keep this era M-body on the road in California (or Colorado which also has the same smog law)?

Thanks,

-mB
 

Camtron

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Check distributor and its cap and rotor.
 

Aspen500

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The spark computer can't cause your symptom. Sounds like either the center contact in the cap came out, the tab came off the rotor, rotor burned through under the contact, etc.
 

mgbeda

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Well that's good news. (Not being the computer.) I did look at the cap and rotor and they didn't seem damaged, just a bit worn. But I have spares and will swap them out and cross my fingers. Thanks!
 

mgbeda

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Well I'll be a monkey's uncle, that worked. I've see rotors break before, but both the cap and rotor looked OK, nothing obviously broken. (See the pictures). And it was so weird that it literally went from just fine to zero spark overnight. Also the cap and rotor had only ~10,000 miles on them. But whatever, it works now. Thank you ever so much for the good advice!

-mB

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Aspen500

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I've found many times over the years, a visual on a cap and rotor means nothing. At work, can't tell you how many older Vortech 4.2L or 5.7L GM trucks came in as a no start. Those are the ones with the flat cap and plug wires out the sides. The cap would look like new but replace it and the engine would fire right up. Same with ones that still ran, but ran rough, backfired and misfired. In every case, cap LOOKED good as new.
 
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