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Cranking but no spark.


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I went driving around with my Comanche earlier today and had no problems whatsoever. However, a few hours later I went to start up my Comanche and it just cranked and wouldn't start. I got out and tested the ignition wire coming from the ignition coil and there's no spark whatsoever. Could it be a bad ECM or ignition coil? It has a brand new cap and rotor, all new ignition wires, spark plugs, etc. I didn't go with anything except factory parts. I did not replace the ignition coil when I did all of this.

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Checked the CPS that's fine. Ended up being the ignition module. Replaced it, lasted about twenty minutes of driving and crapped out, replaced that one, nothing. HOW MANY BAD MODULES CAN ONE PARTS STORE HAVE?!!!

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CPS sensors are known to be temperamental and unpredictable once they start to die. I'm not saying it's your CPS for sure, but you wouldn't be the first that had a CPS that checked out ok but was eventually found to be the problem. 8)

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Checked the CPS that's fine. Ended up being the ignition module. Replaced it, lasted about twenty minutes of driving and crapped out, replaced that one, nothing. HOW MANY BAD MODULES CAN ONE PARTS STORE HAVE?!!!

How did you check the CPS? It is EXTREMELY unlikely that the ignition module is bad, and even more unlikely that you got a brand new one that would also go bad within 20 minutes.

 

However, sporadic malfunctions, progressively getting worse, is characteristic of a bad CPS.

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I have a feeling I TOO am headed for this...

 

NO reason to say that...its running SUPER GREAT right now. Even getting great mileage!! I got 20 MPG for a recent trip. Remember, That's on 33's and 4:46 gears!! I drove at 65 on speedo all highway.

 

I keep it in the glove box... Along with a couple long extensions and a wobble, just in case!!!

 

CW

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I used my ohmmeter and tested for continuity through the CPS. It should be somewhere close to 0. I got 0.25 which is close enough. But just for grins and giggles I'll give it a shot.

That's not how you test a Renix CPS. You should test for A/C volts when cranking.

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6 or 7mm I think.

 

I used a swivel socket, a 12" extention, a universal, another 12" extenion and I think a 6" extention on that, and that put the ratchet behind the transfer case.

 

I supported the contraption on the socket and in the middle, while my father turned the ratchet, and it was in and out easily.

 

I also lowered the transmission down as much as it wanted to (4 or 5 inches), and that made it a ton easier.

 

Lastly, DO NOT drop the CPS bolts into the bellhousing.

 

Good luck

Matt

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6 or 7mm I think.

 

I used a swivel socket, a 12" extention, a universal, another 12" extenion and I think a 6" extention on that, and that put the ratchet behind the transfer case.

 

I supported the contraption on the socket and in the middle, while my father turned the ratchet, and it was in and out easily.

 

I also lowered the transmission down as much as it wanted to (4 or 5 inches), and that made it a ton easier.

 

Lastly, DO NOT drop the CPS bolts into the bellhousing.

 

Good luck

Matt

 

I think its 11mm actually. 7mm is really small!

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I'm going to have to do it tomorrow since it's already dark outside. I'm going to swap in the new CPS and try it with the old ignition control module. If the old one works I'm going to go get my $112 back from AutoZone for the thing. Thanks for the info on how to do it the easier way because that's a real tight spot for me to do it the way I was trying (reaching as best as I could trying each socket blindly.)

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Got the old CPS off, that thing looks like hell. The wiring where the unit connects with the flywheel teeth is all cut up. I'm taking a little break before I put the new one on. I'm going to try the new CPS with the old ICM and see what happens. Like I said before, if the old ICM works I'm going to get my money back.

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??????

 

Connects with the flywheel teeth?

 

The CPS doesn't connect with the flywheel. It sits right next to it, such that the high spots on the perimeter generate a magnetic pulse when they spin past. The pule is converted to a very low electrical impuls (I think it's 0.5 volts a/c, IIRC).

 

Be careful to route the wire on the new one well clear of the exhaust manifold or the insulation will cook and the wires will short out.

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Got the new CPS in and swapped in the old ICM, started right up. But now that I lowered my transmission (about 4 inches) to put the new one in and put everything back in it's place the transmission doesn't want to come out of first gear.

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Nevermind, just added some more transmission fluid and all good to go.

 

Oh good thing; I had no idea why it would have gotten stuck, and I would have felt terrible if my advice broke something on your truck.

 

Good to hear you got her fired up.

I would also be lost without this site.

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Well when money isn't an issue I'm going to go ahead and due a complete tune up on her. Ignition coil, ignition control module, spark plugs, ignition wires, well you know the list. She runs pretty damn good but I can't wait until I can afford to do the exhaust system. I'm going to do an oil change tomorrow.

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