Crank, no spark, no gauges, fuel pump runs constantly - Jeep Wrangler Forum
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Old 12-13-2019, 05:22 PM
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Crank, no spark, no gauges, fuel pump runs constantly

97 tj 2.5 manual, was driving it at work about a week ago shut it off 5 mins later went to start it and nothing. Checked for spark at plugs and had nothing. Had it towed home once off the roll off it fired up and ran fine, shut it off then it wouldn't start again. The next day i went out and checked all fuses and relays and it started for me again but hasnt since. Replaced the crankshaft position sensor no change.

Noticed that it had a refurbished ECU that had been opened since warranty sticker was broken. So i replaced the ecu with one from flagship1 enterprises and it still will not start. Battery voltage is good and all grounds seem to be ok. When i crank it i can smell fuel and the constant running has caused a very light weeping of fuel from my #1 injector but its so light i doubt it has anything to do with it not starti .still no spark and no gauges. Sometimes if i cycle the ignition several times the gauges will twich momentarily but will not start.

What should my next step be?

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Old 12-13-2019, 05:38 PM
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I have spent a lot of time on this forum reading other post with the same issue and that is what lead me to replacing the CPS, and eventually the PCM.

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Old 12-13-2019, 06:31 PM   #3
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Most of the time no start, no gauges is caused by loss of the 5v output from the PCM. Many times, especially on ‘97s with 2.5s for some reason, the PCM turns out to be bad. Since you have replaced the PCM & also because it has been somewhat intermittent it may be something else.



The first think to do is check for 5v outputs at PCM connector 2 (black) pin 17, orange wire & connector 3 (white) pin 31, violet/orange wire.

Report results & can advise further.
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Old 12-13-2019, 06:52 PM   #4
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Since you have a no spark, I'd move one step up the food chain and go to the ignition coil and test there.

It should have power coming from asd relay. You can unplug the connector or backprobe the dark green/black wire. Use a test light hooked to ground. That wire should be battery positive or light a test light when the key is moved to run or start. That wire comes from the ASD relay. It wont stay lit without the engine running but it should come on for a few seconds.

The other wire from the ignition coil is the computer controlled ground. Should be grey on a '97. Use the following video to help test that.

testing ground on ignition coil:
The way to test is explained in this video at around 9m.

Report back what you find.
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Old 12-13-2019, 08:40 PM   #5
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Old 12-14-2019, 11:48 AM
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Im guessing i need to unplug the connector and check it at the female pin on the connector itself with key in the run position correct? And if that is right at the orange pin in position 17 on the black connector i found only .84v and at the violet/orange connector at pin 31 on the white connector i found no voltage at all. Battery had 12.25v when i started the test.
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Old 12-14-2019, 04:29 PM   #7
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If you disconnect the PCM connectors, you will not get 5v. The 5v is an output of the PCM. Better off testing for 5v at the cam sensor or crank or map sensor. Unplug it, hook up a vom then turn the key and look for 5v.
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Old 12-14-2019, 04:35 PM
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Ok that makes a little more sence. I know the PCM is good its new i just need to find what is keeping it from allowing the ignition system to open. I am curious what sensors were those supplying power too? I know that the sensors are 5v but which ones.
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Old 12-14-2019, 05:35 PM   #9
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So now are you getting 5v at both pins?

The primary 5v are the 3 wire ones. TPS, MAP, speed, crank & cam sensors.

The speed sensor is on pin 31, the rest on 17 but both pins are internally connected in the PCM.

Getting a full 5v is important.

If any of the 5 sensors has an internal short or the wiring to any is shorted it can cause low voltage & no start, no gauges.

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