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  #1  
Old November 3rd, 2019, 18:04
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cemeyer cemeyer is offline
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Angry 98 wonít start

After a suggestion of starting my own thread, Iíll repost here.
I hope maybe one of you guys can point me in the right direction. My 98, 4.0, AW4, had a dead battery, I jump started it the other day to move it up into the garage to replace the badly cracked APN header. Before I Started the header swap, I stuck the charger on it, turned the charger to high amp for engine start, it did not start. It cranks, but will not fire. The fuel gauge doesnít register, the volt gauge reads nothing, the ASD relay and the fuel pump relay do not pull in. All fuses check good. I pulled a cover off a relay, stuck it in fuel pump slot, tripped it, fuel pump does run. I unplugged the CPS, the one on the fly wheel, it did not change anything. The CPS ohmís open. I have unhooked all sensors. I have power to PCM. I have no 5V output. I cannot get the code scanner to connect to PCM. Where should I look next? Could I have fried the ECM, when I turned the charger to boost or when I ran it on a dead battery after I jump started it?
Thanks in advance for your help!
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  #2  
Old November 3rd, 2019, 20:20
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Re: 98 wonít start

No 5v ouput on the ckp or from the PCM?
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Old November 3rd, 2019, 20:25
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Re: 98 wonít start

& Have you checked all grounds?
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Old November 3rd, 2019, 20:26
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Re: 98 wonít start

No 5V at pin 17, orange wire at pcm.
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Old November 3rd, 2019, 20:28
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Re: 98 wonít start

Grounds at pcm all check out good. From pcm to battery, pcm to body and pcm to engine block.
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Old November 3rd, 2019, 21:48
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Re: 98 wonít start

Have you tried another battery, or do you know for certain this one is good?
If A4 has ground and A17 hasn't any voltage at all, I'm a bit inclined to lean towards the pcm. your voltage gauge not reading anything is a bit suspicious as the pcm should still read this if it were a sensor, No?
Do you have access to a working pcm?
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Old November 4th, 2019, 05:59
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Re: 98 wonít start

The battery actually took a charge and passed a load test with my tester. I’ve maintained 12+ volts throughout my testing so far. A4 has ground, A17 has no 5V. I don’t have another pcm to try. My understanding that if a sensor is shorted, it could cause the 5V signal to drop out. I think I’ve pretty much rules out a sensor short, could be in the harness I guess. I’ll do some more testing with my meter to see if I can determine that.
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Old November 4th, 2019, 07:34
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Re: 98 wonít start

Yes as you said you've disconnected all sensors. You've verified ground to the pcm on plug A and there is no 5v out on plug A.
On plug B there's another 5v out you could check (B31).
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Old November 4th, 2019, 16:11
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Re: 98 wonít start

No voltage at B31 either. So I gambled and tore open the pcm. It is smoked.
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Old November 4th, 2019, 18:55
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Re: 98 wonít start

Yeah, kinda figured unfortunately. But hey, you found it.
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