Wont start

[FestYboy]

^^Then why would an aftermarket tach get its signal off that yellow wire? i've ran a tach like that before in my old green festiva... the yellow wire has NOTHING to do with how the coil operates.... if you don't believe me, take your volt meter, check for continuity from the yellow coil wire to the back of the cluster where the tach would get its signal

I've messed around with and modified enough wiring in a festiva to know what i'm talking about

JoDan explains... the coil HAS to have a ground in order to create a field to collapse onto the secondary winding. yellow wire is ground.

[Bert]

I'm an old fart from the bygone days of 'first check for gas and then look for spark'. Exactly as you describe my car also suddenly died a few weeks ago. There was gas (not as easy to check as in the old days) and there was no spark. Just like you I found live wires to the 'coil' but none coming out and consequently emptied my parts bins in replacing/swapping things. Ultimately I woke up and pulled off the timing belt cover. No continuous timing belt; no spark signal to the coil. Thank the Lord for 'non-interference' engines. Good luck with your baby.

[FestYboy]

^ i would have thought you would have heard that the engine had no compression at that point. though i know most people don't know what that sounds like, so i can't blame you.

[milehighbear]

OK, the book says to test the ICM harness, connect a light between ground and idm terminal on harness, if it lights up you have power, which I do. Next it says to test the switching signal of the icm by unhooking the coil harness connector. Connect an led light between the idm terminal of icm connector and other end to positive side of battery, crank the car and the light should flash. If it does not, replace icm. Does this sound right to you. I did this and it did not flash. What bogles my mind is when I connect the coil harness back up, i put led light back on idm terminal and ground and i have power.

[crazyrog17]

Well coils make spark by sending current through an outer coil of wire. To get current to flow, you need a constant +12 volts through one wire and a pulsed ground from the ECU from the other.

When current is sent through the outer winding, it builds a magnetic field. When the current stops, the magnetic field collapses and sends a massive amount of voltage through the second winding. That makes the thousands of volts required to make sparks jump on the spark plugs.

It's good you have +12 to the coil. You need the signal from the ECM though. The signal is 'amplified' by that 1" by 1" square 'diode' (really a transistor) that was described earlier. There are three electrical connections to it. The first is the constant ground it gets from being bolted to the coil bracket. Second, +12 volts. Third, the 'weak' ground from the ECM.

The ECM times the ignition with a micro controller that pulls milliamps - not enough to run the current needed for the coil alone. The transistor has to be there to allow more current through and drop it in an instant, repeating this for each spark. Without the transistor working, no spark.

[JoDan]

I'm an old fart from the bygone days of 'first check for gas and then look for spark'. Exactly as you describe my car also suddenly died a few weeks ago. There was gas (not as easy to check as in the old days) and there was no spark. Just like you I found live wires to the 'coil' but none coming out and consequently emptied my parts bins in replacing/swapping things. Ultimately I woke up and pulled off the timing belt cover. No continuous timing belt; no spark signal to the coil. Thank the Lord for 'non-interference' engines. Good luck with your baby.

Lol the old days when your car wouldn't start and you would open the hood and smell gas after pumping the pedal in attempt for it to start and knew right away that you had a spark problem. I love working on old cars because engine operations were so simple, just more physical labor involved.

[JoDan]

OK, the book says to test the ICM harness, connect a light between ground and idm terminal on harness, if it lights up you have power, which I do. Next it says to test the switching signal of the icm by unhooking the coil harness connector. Connect an led light between the idm terminal of icm connector and other end to positive side of battery, crank the car and the light should flash. If it does not, replace icm. Does this sound right to you. I did this and it did not flash. What bogles my mind is when I connect the coil harness back up, i put led light back on idm terminal and ground and i have power.

Ok, now that we know you have no pulsating ground then you either have a ICM that isn't grounding or a bad dizzy not telling the ICM to ground.

[drddan]

Okay, all the above is a lot of good info, but what you have is a bad Ignition Module. Get another module or another disty, and it will run. Power to coil and no spark= bad module.

I carry a spare disty in my car, just for that reason.

[FestYboy]

OK, the book says to test the ICM harness, connect a light between ground and idm terminal on harness, if it lights up you have power, which I do. Next it says to test the switching signal of the icm by unhooking the coil harness connector. Connect an led light between the idm terminal of icm connector and other end to positive side of battery, crank the car and the light should flash. If it does not, replace icm. Does this sound right to you. I did this and it did not flash. What bogles my mind is when I connect the coil harness back up, i put led light back on idm terminal and ground and i have power.

sounds good to me. they say use an LED, i say use a test light, same thing. i test quick and dirty (kinda have to to keep the customer happy).

[FestYboy]

Lol. I love working on old cars because engine operations were so simple, just more physical labor involved.

are you kidding!? have you SEEN all the plastic crap stuffed into engine bays these days? it's crazy!
i'd much rather work on the older stuff where i can climb INTO the engine bay to work on it.

[JoDan]

are you kidding!? have you SEEN all the plastic crap stuffed into engine bays these days? it's crazy!
i'd much rather work on the older stuff where i can climb INTO the engine bay to work on it.

Lol I have seen all the plastic stuff I work on them every day but it don't take too much to pull them off and throw em on the side and I'm also pretty tall so I never sit in the older cars. I can even change a dizzy on a Chevy truck without even kneeling on the bumper

[FestYboy]

oh that's just CRAZY talk LOL. you must be 7'10" to do that!

[milehighbear]

Yea, Im from the good old days too. If car would not start, you pumped the throttle of carb and looked into the bowl to see if you were getting gas. Got gas, then you check for spark to plug, and work your way back to coil. These new cars have me baffled, lol. I just put a new timing belt on the car about 6 months ago. I guess I could pull cover just to make sure it is turning. By way, I do use a test light too. I really do appreciate you guys helping me with this. A lot of it is sorta over my head, but I do understand most of it. I'll get a new ICM and see what happens. Now, I don't know if the admin guys will tell me to start a new thread, but if anyone has a good ignition module and a good distributor for 93 let me know what you will take for them. And again, I really appreciate you guys helping me with your knowledge. Im going to re-read each thread to see if I can better understand what your saying and read the book again. TY

[JoDan]

oh that's just CRAZY talk LOL. you must be 7'10" to do that!

6'7" and some pretty long arms lol

[milehighbear]

By the way, when they say tower, is that the part of coil where coil to distributor wire connects to coil.