# D21 crank no start....coils???



## Pynikal (Dec 11, 2008)

Well i just bought a 86.5 HB and it cranks good but will not start. i have tested for spark after the coils and have nothing. but i have soild 11.6v at the plug to the coil but nothing out of the coils.

i am stuck thinking that it is the ICM (ignition control module) because how wierd would it be that both coils go out at the same time. and that is the next thing that is in line with the coils.

and also does anyone know were the ICM is located?? i have read that it is right behind the driver headlight, but that is were the coils and air pump are all at?!?!? is it hidden some were in there??










thanks for any help that you guys can give me on this.


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## brookwood61 (Aug 18, 2005)

It's in the distributor, and it's not servicable. You have to replace the whole unit. Before you start replacing parts, check and clean all your grounds, and connections. & make sure the computer under the seat is grounded good. If you just bought it, and it's been sitting, corrosion could have started building up.
Good luck


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## Pynikal (Dec 11, 2008)

the guuy i bought it from just replaced the dizzy about 4-5 months before the truck quit running. he also replaced the ECU under the seat so i will be sure to check the grounds there as well as other engine grounds. are there any manuls that can direct me to other grounds that might be hidden??


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## zanegrey (Dec 5, 2005)

check the main relay on the inside pass fender...


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## Pynikal (Dec 11, 2008)

zanegrey said:


> check the main relay on the inside pass fender...



is this the only relay there?? how do i test it once i find it?? any pics??


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## Pynikal (Dec 11, 2008)

i found it, kind of obvious once you get there! lol but i pullled it out and tested the resistance of the coil side of the relay and got 74.5 ohms. so it looks like it is good. next???


also looking at the wiring diagram on the trim levels what is the mpg model and how do i know if i have that maodel or not??

thanks again for the help!


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## Pynikal (Dec 11, 2008)

anybody on this???


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## Pynikal (Dec 11, 2008)

taking the dizzy and coils to work tomorrow to test them. well see, hope this solves the problem!


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## scout (Aug 24, 2007)

*try this*

I've got an 89 d21 and it seems I remember reading about a light emitting diode in the distributor that shines thru a series of slots to provide the timing and spark. They get dirty and cause problems. Might try looking for that as a problem. Good luck


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## Pynikal (Dec 11, 2008)

yeah you are right. i got it to work and took it apart and it is a hall effect sensor that fires the coils, not a pick-up coil like other dizzys. im going to hook it up to a scope on friday and figure out if it is good or not.


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## mserino (Dec 16, 2008)

i had the same problem with one of my previous cars (a dodge shadow) the car would just die out of nowhere driving on the highway or city or it jsut woulnt start and the problem was the hall effect sensor under the distributer. The car would crank over perfect however it wouldnt let power to the spark plugs so there was no spark


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## Pynikal (Dec 11, 2008)

did you have power to the coils but not out of the coils?? that is the problem that i am having now.


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## mserino (Dec 16, 2008)

yeah the coil had power. maybe try a reset on the computer. its been so long since ive had that problem. if i remember correctly i pretty much changed everything on the ignition system to chase the problem down.


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## Pynikal (Dec 11, 2008)

a reset on the computer??? how do i do that?? i hasnt had a battery for almost a year. is that a good enuf reset or is there another way?


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## zanegrey (Dec 5, 2005)

if i may.. u r getting power b4 the coils but not after.


i think the icm u are referring to is mounted on the coils themselves..

so test the coils and there counter parts ..u r calling the icm


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## Pynikal (Dec 11, 2008)

i saw those down line of the coils and thought that they might be the ICMs for the coils, but was not sure. how would i go about testing them? put them on a scope and see if they pulse??


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## zanegrey (Dec 5, 2005)

just check for power in and out.


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## Pynikal (Dec 11, 2008)

i will do that tomorrow.

if i have power in and out probably a dizzy issue???


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## zanegrey (Dec 5, 2005)

either the dizzy or ecm ..


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## Pynikal (Dec 11, 2008)

zanegrey said:


> either the dizzy or ecm ..



ecm has been replaced already. anyone know were to get a dizzy for one of these things?? parts store wants like $260 for one!


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## Pynikal (Dec 11, 2008)

so i just tested both of them and got 12.26v at each one.

but one is a 4 pin connector and the other is a 3 pin connector. whats the difference there? exhaust and intake side coils?? if so what is what. thanks


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## zanegrey (Dec 5, 2005)

one is exhuast and one is intake.

the coil closets to ther front of the truck gets plugged into the front one on the dizzy
so look at them and it should indicate which is which...

i have dizzies for sale..

pm me if interested..


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## Pynikal (Dec 11, 2008)

you have PM sir.


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