'95 JGC died on road, weak spark, no start.
07-24-2009, 09:22 PM
#17
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Crankshaft Position Sensor Connector
:
PROCEDURE
- Near the rear of intake manifold, disconnect sensor pigtail harness connector from main wiring harness.
- Place an ohmmeter across terminals B and C. Ohmmeter should be set to 1K-to-10K scale for this test. The meter reading should be open (infinite resistance). Replace sensor if you read any resistance. That would be the test you where trying to find online Brian. However I believe your sensor is good, never rule out a bad wire though.
What does infinite resistance look like on a digital meter?
08-04-2009, 08:52 PM
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The signal from the Crankshaft Position (CKP) Sensor is used to determine crankshaft angle, engine speed, and basic timing. Powertrain Control Module (PCM) also uses the signal from the CKP sensor combined with the input signal from the camshaft position sensor to properly synchronize injection.
If you have a strong spark at the coil you have confirmed that the crank sensor is working. It is difficult to determine spark plug spark strength simply by the color of the spark. See if you can borrow a spark plug wire/plug kilovolt test meter. Made by snapon or otc. Or you could simply put a timing light on each spark plug wire as you turn it over you will see a timing light blink which will indicate that you have enough spark . Did you check fuel pressure and injector pulse. Can you get your hands on a noid light to check that the injectors are working? Most overlooked is the fact the the fuel injectors have their own fuse, but in this case a shut down relay. Check that each injector has battery voltage with key on at dark green with black wire on each injector. If no power suspect broken wire between injector harness and auto shut down relay. Also be sure to check pcm grounds at the engine block on the right side about 8 inches behind the distributor.
If you have a strong spark at the coil you have confirmed that the crank sensor is working. It is difficult to determine spark plug spark strength simply by the color of the spark. See if you can borrow a spark plug wire/plug kilovolt test meter. Made by snapon or otc. Or you could simply put a timing light on each spark plug wire as you turn it over you will see a timing light blink which will indicate that you have enough spark . Did you check fuel pressure and injector pulse. Can you get your hands on a noid light to check that the injectors are working? Most overlooked is the fact the the fuel injectors have their own fuse, but in this case a shut down relay. Check that each injector has battery voltage with key on at dark green with black wire on each injector. If no power suspect broken wire between injector harness and auto shut down relay. Also be sure to check pcm grounds at the engine block on the right side about 8 inches behind the distributor.
The injectors showed only 7 volts with Key-On and the battery reading 12.35 volts.
When I tested the connectors, with leads @ each wire, it showed nothing.
When I tested with one lead on the Grn/Blk wire and the other to ground (the manifold) it showed 7 volts.
I located the ground for the PCM near the Dist. just beneath the Coil.
I noted the wire color (Brn w/Pink?). When I looked at the harness @ the PCM I found two wires side by side that had the same colors.
With my meter I had a lead on the bolt securing the ground wire, and the other lead into the terminal @ the harness. My meter shows "OL"
Since there were two identical wires @ the harness, I tested both. Results were the same.
The meter bounced around for a few seconds before settling on "OL"
Where do I stand?
08-04-2009, 09:40 PM
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08-05-2009, 07:36 PM
#23
Caracticus Potts The Mod
take a test light and place the lead clamp on the positive battery post and the touch the brown w/pink wires at the pcm. if the ground is good the test light should light.
"OL" on the meter means that it is "out of Limits", I had a brain fart when I told you other wise. Sorry. "out of limits" in the ohlm scale is another way of saying that the circuit in question is "open" or the wire is "broken" Infinitiy is zero to the lazy eight.......000.000000
resistance on the meter will always display in a number form, but an open or broken circuit will be "OL"
"OL" on the meter means that it is "out of Limits", I had a brain fart when I told you other wise. Sorry. "out of limits" in the ohlm scale is another way of saying that the circuit in question is "open" or the wire is "broken" Infinitiy is zero to the lazy eight.......000.000000
resistance on the meter will always display in a number form, but an open or broken circuit will be "OL"
08-05-2009, 07:44 PM
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take a test light and place the lead clamp on the positive battery post and the touch the brown w/pink wires at the pcm. if the ground is good the test light should light.
"OL" on the meter means that it is "out of Limits", I had a brain fart when I told you other wise. Sorry. "out of limits" in the ohlm scale is another way of saying that the circuit in question is "open" or the wire is "broken" Infinitiy is zero to the lazy eight.......000.000000resistance on the meter will always display in a number form, but an open or broken circuit will be "OL"
"OL" on the meter means that it is "out of Limits", I had a brain fart when I told you other wise. Sorry. "out of limits" in the ohlm scale is another way of saying that the circuit in question is "open" or the wire is "broken" Infinitiy is zero to the lazy eight.......000.000000
resistance on the meter will always display in a number form, but an open or broken circuit will be "OL"So, potentially I have a bad CPS and a bad ground wire?
Since Im broke and dont have a test light, could I perform a test with the meter on the wires?
08-05-2009, 08:49 PM
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Update...
I went and got a test light.
I tested it and the light lit up but not as bright as when I tested the light itself. (touch lead to probe) In fact, it was hardly noticeable at all, but it did light.
So it that meaning a solid ground? Is it only a pass/fail test... it either lights or it doesnt?
The connection feels very tight, but could there simply be corrosion between the the ground wire and the block? Like how you get corrosion between the terminal and post on the battery?
Could a weak ground lead to my only getting 7volts to the injectors?
thanks!
Last edited by shibbershabber; 08-05-2009 at 08:57 PM.
08-25-2009, 09:14 PM
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as of now, I am looking to replace the wire harness from the injectors back. One from a dealer is $1300!!!!!! ********!
So a used one is all I can hope for, we'll see if that takes care of it.
So a used one is all I can hope for, we'll see if that takes care of it.
10-11-2009, 07:07 PM
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It was the coil...
Even though it passed all tests and tested with the same results as a brand new one... I replaced it and it fired right up, like nothing had ever happened.
Even though it passed all tests and tested with the same results as a brand new one... I replaced it and it fired right up, like nothing had ever happened.
09-15-2010, 01:54 PM
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Same here
I have a 95 jgc n i have changed cam sensor, crank sensor, cap & rotor, pluss the computer.. And still no spark.. At the coil. Plus i noid tested my fuel injectos & when i turn key n try n start it fashes then dosent after that.. If u or any one can help that would be great..