Stalled while driving, cranks but will not restart - likely spark problem... 1979 CDV
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RWD 19xx-1984 DeVille and Fleetwood,
1985-1996 Fleetwood and Brougham Forum Discussion, Stalled while driving, cranks but will not restart - likely spark problem... 1979 CDV in Past Cadillac Vehicle Discussion; Was driving the Phaeton around town today. Rolling down a slight incline towards a large intersection, I felt the car ...
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    Benzilla's Avatar
    Benzilla is offline Cadillac Owners Connoisseur
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    Question Stalled while driving, cranks but will not restart - likely spark problem... 1979 CDV

    Was driving the Phaeton around town today. Rolling down a slight incline towards a large intersection, I felt the car pull back... engine stopped. I made my way to the side of the road (kinda out of the way... very long double-turning lane) & had a look around. The car will crank just fine, but won't start. The engine was up to full operating temp, semi-aggressive driving.

    First I inspected my fuel lines, they look fine & I'd just replaced the rubber lines around the fuel pump. No visible fuel leaks anywhere. Took the air cleaner off & primed the carb by hand. I heard fuel squirt & saw a poof of smoke from the choke valve, so it seems to be getting fuel. A UPS guy pulled up behind me & tried to help. We tried squirting a bit of carb cleaner down the choke while cranking; nothing. Linkage looks fine. Checked all the plugs & wires for looseness etc. Plugs, wires, cap, rotor, & distributor base are all new...

    Only thing I can thing of is the Ignition Coil. I didn't replace it yet for whatever reason (cheap), wondering if it could have died while driving & now I'm not getting a spark? I had AAA tow it back to my driveway for investigation. Still won't start now that it's cooled down either.

    I looked through my service manual with inconclusive results. I don't have electrical diagnostic equipment on hand right now, any way to troubleshoot this more without it? Other ideas I haven't thought about?

    Thanks!!
    Ben

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    amunderdog is offline Cadillac Owners Connoisseur
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    Re: Stalled while driving, cranks but will not restart - likely spark problem... 1979

    Old school.
    Pull a spark plug
    hook it back to the plug wire
    hold the threads of the plug onto grounding metal on motor.
    Have someone crank the motor
    Got spark?
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  4. #3
    csbuckn is offline Cadillac Owners Master
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    Sounds like the coil to me. Grab an inline spark tester and confirm but I've been left stranded because of a coil so its always on the top of my list.
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    Benzilla's Avatar
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    Thanks guys! Haven't checked the spark yet, nobody around to help yet.

    However, I did visually inspect the coil for bad wiring, & popped the cap off the dizzy for a look around. The contacts that the rotor spins around & hit seem to have some gray carbon build up right where it contacts - all of them. The cap & rotor have less than 3,000 miles & less than a year on them. Could this cause the problem I'm experiencing? Car was running fine. Could a dying coil cause the contacts to carbon up? Scraped one lightly with a screwdriver & it felt like sandpaper.

    Was going to go ahead & throw a new coil on regardless & see if that fixes it. However now I'm wondering why the cap looked like that. Is a bit if buildup normal?

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    jamespowers is offline Cadillac Owners Connoisseur
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    Re: Stalled while driving, cranks but will not restart - likely spark problem... 1979

    Hmmmm.... I would check the wires to the coil just to be sure. I go hung out to dry once when the nuts backed off of the coil and the wires were not making good contact. There is so much vibration there that it can happen easily.

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    Fleetwood472 is offline Cadillac Owners Fanatic
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    Re: Stalled while driving, cranks but will not restart - likely spark problem... 1979

    pull the rotor off and look at the 2 wires coming off of the pickup coil in the body of the distributor. A lot of times they break. Very common especially if this is the original distributor. If the pickup coil is shot you have to pull the distributor, knock the roll pin out of the gear and pull the shaft to be able to change it.

  8. #7
    1980coupe's Avatar
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    Re: Stalled while driving, cranks but will not restart - likely spark problem... 1979

    Definitely the module under the cap. Looks like a small boomerang, that happen to me but car left me at my in laws, pulled out wire and checked for spark and no spark...got a new module and she fired right up..
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    Benzilla's Avatar
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    Re: Stalled while driving, cranks but will not restart - likely spark problem... 1979

    Distributor base including module is two months old. Cadrone rebiult unit. I upgraded from california 5 terminal to federal 4 terminal in order to bypass the ESS box. Would be very disappointed if a new part failed.

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    1980coupe's Avatar
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    Re: Stalled while driving, cranks but will not restart - likely spark problem... 1979

    I'd still check it. Maybe it was a defective one that why it only lasted 2 months...
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    cadillac_al is offline Cadillac Owners Connoisseur
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    Re: Stalled while driving, cranks but will not restart - likely spark problem... 1979

    Yup, bad ignition module. Sometimes I carry a spare in the glove box but I have so many cars it would most likely be in the wrong one.

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    lacville78 is offline Cadillac Owners Fanatic
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    Re: Stalled while driving, cranks but will not restart - likely spark problem... 1979

    Years ago, I had a 79 CDV. The car quit running, no spark. It turned out to be the control module, really easy to replace. Its under the distributor, after you pull the cap off get someone to crank it over and make sure the rotor is spinning. Then go ahead and grab a new module. I'm hoping it is just a module and no timing chain issues.

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    Benzilla's Avatar
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    Re: Stalled while driving, cranks but will not restart - likely spark problem... 1979

    Well, I went ahead & replaced my old ignition coil today, and switched the cap & rotor while I was at it. I figured for the cost, why not have all new AC Delco parts?

    It didn't fix the problem though, lol. Everything looks fine, no wires out of place. So from what I've gathered, it's likely a faulty electronic module. I read about a test I can do on the pickup coil with an ohm meter to rule that out. Also read somewhere that module failure can sometimes be caused by a failing ignition coil overloading the module? Sounds like that could be the case...

  14. #13
    cadillac_al is offline Cadillac Owners Connoisseur
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    Re: Stalled while driving, cranks but will not restart - likely spark problem... 1979

    Quote Originally Posted by Benzilla View Post
    Distributor base including module is two months old. Cadrone rebiult unit. I upgraded from california 5 terminal to federal 4 terminal in order to bypass the ESS box. Would be very disappointed if a new part failed.
    Like a lot of rebuilt parts, they are usually rebuilt half assed; probably even in China. They probably sourced the cheapest modules they could get and/or the kids forgot to put grease under it. That would be more likely than the pick up coil. Pick up coils seem to only die from old age and brittle wires. That carbon on the contacts inside your dist cap is pretty normal and happens pretty quick. It only looks bad it doesn't hurt much.

    It probably wouldn't hurt to make sure the dist hot wire has 12 volts before you replace anything.
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    Re: Stalled while driving, cranks but will not restart - likely spark problem... 1979

    Thanks for all the great replies!

    I've been thinking a lot about the possibility of low quality parts in the distributor. I'm going to run a test on the pickup coil tomorrow to absolutely rule that out. If it's the module, I have 2 choices that I can see. (1. rip out the distributor & have the whole thing replaced under warranty, with the same quality of parts. Or (2. Keep my otherwise fine distributor, replace the dead module with an AC DELCO part, and make sure the heat grease is applied in proper OCD fashion, giving me at least some peace of mind, if at a higher cost... Gotta say, if it turns out to be the module, I'm thinking option 2 right now.

    Checked the heat grease before I first installed the distributor. It appears to be present under the module, if not very precise...

  16. #15
    deVille33 is offline Cadillac Owners Connoisseur
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    Re: Stalled while driving, cranks but will not restart - likely spark problem... 1979

    The procedure for testing in this area is happenstance. I use a combination of tests along with the service manual procedures to check out things here. There is a tester for the module, but I have never found one. Bruce can most likely tell you how to make your own. I have an after market HEI tester, but there is no test for the module alone. So, the alternative is to check all the other parts and, provided they are all in proper operating condition, the module becomes the suspect. T&E process of elimination.

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