Long story short i have a 90 rs with no spark. All ignition components have been replaced.(coil, icm,rotor button, pickup coil,ignition switch). and yes the dizzy spinning. have 12 volts going to the coil and out of the coil going to the control module. and the control module has retested 3 times at 3 different auto parts stores. so its good. have done continuity check on the 4 prong plug going to ecm. all wires show good from distributor to the ecm.



heres the kicker briefly had it running yesterday pulled coil of buddy's s-10(same coil) put it on and it started let it run for a minute then shut it down and went to get new coil. replaced and NOTHING. tried buddy's coil and would not start again!!!!! and both coils run his truck fine.

oh yea forgot to mention it's a 3.1

any help plz i'm outa ideas. is it possible ecm but why would it start once? or is there anything in my tach/ instrument circuit that could cut it out???just a shade tree guy but i will welcome and try any ideas

 

Yes, the TACH can shunt the ignition primary so that there is no spark. If you can, try disconnecting the white TACH wire and retest.

 

OK thanks for the reply. Tried that still nothing! how bout the ecm?? may be grasping at straws i guess im not really sure what the ecm controls. I know these cars have wiring harness problems in general but i thought maybe the continuity check from my icm to the ecm ruled out that. and my VATS is disabled and car cranks so i thhink that rules that out. Its driving me crazy becuz it started once and now i cant figure out what we did different! OK ive got a headache again!!! help is much appreciated

 

Have you pulled out each spark plug wire and tested each one individually by taking a screwdriver and placing against a ground and seeing if it archs? test it and see if each one is working properly, you could be getting and arch from each one but it not be arching enough and just flooding the engine. Your distributor itself could be bad, did you check and make sure all the timing was correct on it as well? and that the firing order was exact?

 

yes have not pulled every plug but at least 2 on each side. i have power(12v) into the ignition coil ( its outside of distributor cap) and 12 v from ignition coil to the control module but i have nothing from the primary spark plug wire over to the distributor. as far as the timing on it. i should still have spark even if it was out time time. if i am correct. if not correct me please. the dizzy is spinning and the firing order is correct for sure. the car just backfired and quit on me about a month ago. so i checked to make sure i had not broke a timeing chain right off.
i just don't understand how i can have power into my coil and nothing coming out when i know the coil is good. if im not geting voltage out of my coil to the top of distributor the how can my distributor be bad?
i replaced the pick up coil in the dizzy. any other parts than can go bad inside the dizzy? i know the magnets can get weak but i've never seen that happen. thanks again for your help guys

 

Hmmm, you are right, even if the timing is off it will still do something. I'm kind of stumped on this one as well, I no that when my distributor went out i couldnt ever get it to crank over or anything. the only thing i can suggest is go get a new and give it a shot, if it doesnt work then you can just take it back and get your money back. other than that im out of ideas.

 

Yeah me too. just trying to figure out if investing in a ecm is worth it. cuz once you buy one its yours. no returns on electrical parts. especially a ecm. may try to grab a used dizzy out of a local junkyard just to see if it helps but i just don't think thats my problem unless someone can walk me through why it would be. Can anyone tell me if the ecm would even cause a no spark condition. im showing the 12 code in diagnostic mode ( which is normal i think with engine not running) and service engine light comes on when key is on so i was thinking that means my ecm is not fried.
spent quite a but of cash on something that probably a bad wire or something anyway just trying to figure out which direction to go next. thanks again for the ideas and help

 

The ecm could cause that problem if there is something wrong with it. Its normal to see the light at turn key and the 12 code is normal also. luckly for you, your ecm would only cost 70 dollars if you no where to go for it. You could get a wiring diagram online and check all your wires for cracks, splits and cuts in it and see if there is anything that is not grounded properly. make sure all your fuses and relays are good as well. and that its not something as simple as a disconnected sensor or missing one.

 

yeah done that ran continuity checks from the 4 wire plug on the ignition control module back to the corresponding pins on the harness that plugs in to the ecm so i know the wires are good to go there. whether the ecm is sending the right signal or not i dont know. does the ecm control electronic spark control or does the ig control module do that?

 

the ecm sends a signal to the ig control to spark if it is working properly

 

SO if my coil is working properly and dizzy is good. the ignition module is good. the wiring all checks out then. the only thing else it could be is the ecm!!! RIght? anyone know if there are any other parts that are replaceable and could go bad in the dizzy besides the pickup coil? especially if it just backfired and quit im thinking the ecm may have just fried crispy!!!

 

you have replaced the pickup coil, cap and rotor so the only thing left is either the distributor itself or the ecm.

 

MY thinking too! Anyone got any other ideas before i spring for the ECM ? welcome any and all suggestions!!! thx