No spark question
2002 SL1.
Crank no start. Security light goes out Checked coil towers for spark - negative Replaced CPS / checked resistance before install (732 ohms) Still no spark. Replaced ICM after checking for voltage at connector which there was 12v. I've been reading past posts so my understanding is that if the cps is defective or not delivering the correct signal to pcm the injectors will not fire either. The fuel pump comes on with key, fuel line stays pressurized. I have no way to check if the injectors are firing right now....doing this alone so no extra hand to crank while I listen. So before i buy a noid i checked all ground connections. Cleaned every major ground i can get to. Cleaned battery posts. Checked coil tower to tower resistance ( both @ 7 - 8k ohms). Derf in an old post you said to check resistance to ground at the ICM white wire on the harness connector. Should read 200 ohms. I am getting 52k ohms. Do you know where this is grounded at? Is it in the PCM? I cleaned the PCM ground real good. I'm starting to lose hair over this. I don't want to throw any more parts at it without diagnosing it correctly. I'd appreciate any input. Thanks. |
BTW:
Checked all fuses and cleaned them |
Bill,
This is a lame request but could you please post a link to my old post as I do not remember the context in any way shape or form but I'm of course willing to help. |
Derf,
https://www.saturnforum.com/forum/sa...o-spark-11040/ Post #10 is where you reference the resistance reading about halfway down. I believe you were helping to troubleshoot an SL2. Mine is an SL1 but I'm guessing it should be a similar process. Thanks, |
When you say you replaced the CPS, are you referring to the cam sensor or crank sensor. Most cars will still start with a faulty cam sensor. The crank position sensor is much more critical. Check it.
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Originally Posted by Rubehayseed
(Post 66031)
When you say you replaced the CPS, are you referring to the cam sensor or crank sensor. Most cars will still start with a faulty cam sensor. The crank position sensor is much more critical. Check it.
Speaking of this, I would like to check continuity from the cps to the pcm. I am assuming the wires from the cps go straight to the pcm? Is this correct? Would I pull the pcm wiring connector and find the right ones to test? Is that the right procedure? Thanks, |
Let me pull some wiring diagrams and see what the 200 Ohm measurement is about. Haven't tested an ICM in a decades.
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Bill, I'm NOT a mechanic but that sounds like a solid conjecture and procedure to me. I'm an old fart who misses the days of carburetors and fuel pumps on the block. Screwdrivers, vice grips, crescent wrenches and bailing wire were all you needed in those days. Nowadays you have to be a computer analyst in order to just find out what the hell COULD be the problem. Add that to having had 2 brain surgeries and I'm not very smart anyway, and that REALLY tells you how smart I'm NOT.
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Rube,
I'm right there with ya man. I miss the days of standing between the radiator and engine of my old Chevy to work on the distributor or something else basic. I can do basic diagnostics only because I know my way around commercial heating system electrical panels and such but I would rather take a nose dive off a tall bridge into a thin pile of cow manure than work on a car....period. But I have 4....count them....four....children driving so I must be a car mechanic until such time as my old back and failing eyes can't handle it or they become well off enough to actually pay a real mechanic. |
Sorry I've been dragging on the response. Doing some heavy investigative troubleshooting on my 95 SC2 at night while writing global acceptable computer usage policies by day. Mon pm was my deadline. Which I met.
I'll be back tonight or tomorrow with feedback. |
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