96 850 turbo no spark, most of the time Topic is solved

greg850r · Post by **greg850r** » 06 Feb 2018, 06:41

Take out the red stars in circuit 3 to make it look just like one. When cranking it behaves the same as just key on. That's what I've got. Gonna probe a running one just for kicks so I can see it because the green one on #3 did vary in it's intensity when cranking, but never flashed red, just dimmed the green for a second.

Post by **RickHaleParker** » 06 Feb 2018, 10:07

Gonna probe a running one just for kicks.

Not just for kicks, your learning a new tool. The way to learn is to connect an unknown to a known.

because the green one on #3 did vary in it's intensity when cranking,

That could be the pulse train we are looking for.
If it is rhythmic dimming for the duration of the cranking, it is the pluses for sure.
If it just dims when cranking, we can be 99% sure you looking at pulses.
If #3 dims but #1 does not it is the pluses doing the dimming.

A ignition coil if fired by interruptions of the ground. That is one disconnects a coil to fire it.
If you know what Pulse Wave Modulation is you got an idea of what your looking for.

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gswede · Post by **gswede** » 06 Feb 2018, 19:38

I`d check the coil to distributor cord. Had a similar problem and I found the brass part that attaches to the coil plug had corroded off the wire itself, inside the wire boot. Look for green corrosion inside both ends of coil wire boots.

greg850r · Post by **greg850r** » 07 Feb 2018, 14:47

I already used an ohm meter to check the coil wire so am satisfied it's good. As far as the probing of the coil signal wires, my running car shows the green going on and off while cranking and the one with no spark does not. What it does show is a very minor variation in brightness that is nothing like the interruption of ground shown by the running car. I think I have no (or and extremely weak) signal.

Post by **RickHaleParker** » 07 Feb 2018, 15:14

What is the other car, does it have the same Ignition Coil and IDM?

greg850r · Post by **greg850r** » 07 Feb 2018, 15:34

Yes. It is a 96 850 n/a. the dead one is a 96 850 turbo.

Post by **RickHaleParker** » 07 Feb 2018, 15:38

Swap the Ignition Coils and IDMs, then see if the 96 850 turbo fires up.
If it does not, check the pluses at the Ignition Coil with the one from the NA installed in the turbo.

greg850r · Post by **greg850r** » 07 Feb 2018, 16:09

It did and ran fine. I suspected as much. It was a known good coil off another car I had put on the other day but I went through the motions anyway. Interestingly, the probe test with the coil unplugged caused the running car to throw a code, 0305 misfire.I performed the same test on the dead car repeatedly, cranking it while probing the plug and it has never thrown a code. Question: Cranking and probing with the IDM unplugged why would a different unit bolted to the fender not give the same result since it was not connected anyway? Answering my own question here, you want me to leave it plugged in and probe COIL terminals while cranking to see if it was the coil or the IDM.

Post by **RickHaleParker** » 07 Feb 2018, 16:29

P0305 is misfire on cylinder 5. Don't read to much into the fact it happen on one but not the other. With the coil unplugged all the cylinders misfire, P0301 - P0305 but only P0305 set the other four did not.

Correct if there has been a miscommunication.
1. You have a known good coil and IDM on the 96 850 turbo.
2. Your not getting a good pulse signal at the coil.
3. Your not getting a good pulse signal at the plug to the IDM.

Post by **abscate** » 07 Feb 2018, 19:04

Unless the engine is running, and relatively smoothly, misfire codes are meaningless. Proven here over and over and over again

Well, they aren’t meaningless , but they mean little.

96 850 turbo no spark, most of the time Topic is solved

Re: 96 850 turbo no spark, most of the time