my 94 will not start

[bigbadrat]

ok i have a big problem with this and cant figure it out.car shut down on me and i havent been able to get it running again.what i have is a 94 supreme convertable witht he 3.4.i do not have any spark at all.i have replaced the ecm,coil pack,cranks sensors,cam sensors,checked all fuses and even replaced the ignition switch and sercurity box.my friends scanner said bad pass key.well that wasnt it.

so has anybody else had this problem or know something that i might have over looked.i really want my baby bad.

[RednBlack]

Car shut down while driving?

[bigbadrat]

yes it did.mother was driving it when it broke down.i did notice a burnt smell of wires or something electrical.the ecm smelled like it was burnt but i replaced that and didnt do a thing

[Doubt_Incarnate]

did they have the chip in keys for that car? if so maybe your chip fried or something, try the old ecm with the spare key.

[Mach10]

Pull out that trusty multimeter!

Turn the ignition to "On"

Check voltage to the coilpacks (pink wire, IIRC)
Check voltage to crank sensor
Check impedance to crank sensor (have friend crank over car, resistance should fluctuate), then check again at the coilpacks. Resistances shouldn't vary more than 3 ohms.
Check ground continuity from coilpacks

I'm pretty sure the reluctor ring can't fall off the crank in this motor (it's cast in, isn't it?)... It can happen on others, though..

If you smelled something burn, likely there's a dead-short somewhere in there.

Check *ALL* the fuses.
Check *ALL* the relays.

If any aren't working, look for your short on that circuit. a dead-short can cause all kinds of nightmare electrical problems.

[bigbadrat]

thanks for the input.i will have to check out those things.i did replace the ignition switch with a new one and the sercurity box to match.i am wondering if a wire or fuseable link at the starter might be the problem

[bigbadrat]

still havent figured it out.does anybody else has a thought on what it might be

[slick94prix]

Does it even crank?

I would suggest checking the resistivity of the chip in the key, as thats all that it is. Find out how much of a resistance your vehicle's ignition needs, and test your chip. If they are off, that may be your answer.

[bigbadrat]

yes it cranks but i have no fire.i replace the key and box with it and still does the same thing.i am lost and want it back.

[slick94prix]

No spark from any spark plug??

And you said the ECM and Coil packs are new as well.

I'm at a loss here. Maybe a bad computer?

[bigbadrat]

replaced that as well and still nothing.my friend scanned it before i replaced the igintion switch and it said pass key.well replaced and still nothing.i have no spark at all.

[Mach10]

If you are getting line voltage to the DIS assembly, and you are getting a control signal from the crank sensor, The only other possible thing it can be is the ignition module itself (not the coils).

The coils will fire if the module has voltage and gets a crank trigger signal. Even disconnected from the ECM, it should give a default timing curve (if I understand the wiring right).

I'd say it's the module, assuming you checked everything on my previous list.

[bigbadrat]

well i took that modgule from my old motor that knocked and ran and installed it on my car.i knew that was a good one.thats why i cant believe it still will not start.i guess i can try the other one i have on the dead motor under the shelf and see if that does it.

[Mach10]

Sorry dude. I'm not trying to sound like a broken record, but have you checked those two line conditions? What are the results?

'Cos they will narrow your search down considerably.

Trust me on this

[bigbadrat]

i havent tryied that but i wouldnt know really how to do it right.i just hate to see this sit into the summer.