Intermitent/No Ignition on Explorer
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Intermitent/No Ignition on Explorer
I have a '97 Explorer which will intermitently not start. I know that it is an ignition problem (no spark). I have checked the ignition circuit including the CKP, ignition coil, ignition switch (all positions), fuses, relays, etc. In desperation I decided to replace the PCM (engine computer). Still no help. One significant clue is that when I initially turn on the ignition key the PCM Power Relay closes for a few tenths of a second and then opens back up. This is caused by the ground return to the relay opening up. This return seems to be controlled by 5 common pins on the PCM. I strongly suspect that the PCM is sensing something that is not right and is refusing to supply ignition and deactivating the PCM Power relay. HELP!!!
Postmaster
Joined: Oct 2003
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From: SoCal
The PCM does'nt provide the ground for the PCM relay.
5 wires from the PCM AND the coil side of the PCM relay share a common ground (G-101)
Have you checked G-101 for a clean tight connection?
The PCM relay is wired thru a splice (S-137)and then to G-101
The problem could be a bad connection in that splice.
What are you using for a wiring diagram? If it's worth the paper it's written on it will tell you the locations for G-101 & S-137.
5 wires from the PCM AND the coil side of the PCM relay share a common ground (G-101)
Have you checked G-101 for a clean tight connection?
The PCM relay is wired thru a splice (S-137)and then to G-101
The problem could be a bad connection in that splice.
What are you using for a wiring diagram? If it's worth the paper it's written on it will tell you the locations for G-101 & S-137.
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G101 ground post and S137 splice
Thanks for the tip. I thought the G101 "circuit" was some kind of strange ground return for the PCM relay. Sounds like the connection is definitely a problem. Do you have any idea where the G101 ground post/connection is and/or the the S137 splice?? Thanks again.
Postmaster
Joined: Oct 2003
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From: SoCal
If I had a scanner, i'd post a picture showing the location of G-101 & S-137.
G-101 is on the radiator support/drivers side black wire/white stripe (BK/W).
S-137 is under the hood/drivers side fender near the ABS control module. It's a 7 wire (all BK/W wires) splice.
BTW, the ignition switch is wired to interior fuse 19, which is wired to the PCM relay.
When it wont start do you have voltage to fuse 19 with the key at start or run?
What you really should have for troubleshooting ANY kind of electrical problems on your Explorer is the 97 Explorer electrical & vacuum troubleshooting manual.
About 30 or 40 bucks at helminc.com & worth every penny.
G-101 is on the radiator support/drivers side black wire/white stripe (BK/W).
S-137 is under the hood/drivers side fender near the ABS control module. It's a 7 wire (all BK/W wires) splice.
BTW, the ignition switch is wired to interior fuse 19, which is wired to the PCM relay.
When it wont start do you have voltage to fuse 19 with the key at start or run?
What you really should have for troubleshooting ANY kind of electrical problems on your Explorer is the 97 Explorer electrical & vacuum troubleshooting manual.
About 30 or 40 bucks at helminc.com & worth every penny.
Elder User
Joined: May 2004
Posts: 508
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From: Webster, NY
Not that this is the issue but worth a try... my 97 would not start last week... in a panic I checked out all kinds of things... turns out it was that the shift lever has slipped a little (it would seem) and when in "Park" it really was not, so the PCM was, correctly, not allowing the truck to start. I moved the level all the way over to low and then back again (hard) and then it started OK. I now need to figure out how to re-align that.... once I find my shop manual I'll get that done.
It was only when looking at the EVTM that it dawned on me that this might be the problem... when not working it would still make the relays under the dash click and it sure sounded like something else was wrong.
Just a thought.
-JB
It was only when looking at the EVTM that it dawned on me that this might be the problem... when not working it would still make the relays under the dash click and it sure sounded like something else was wrong.
Just a thought.
-JB
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To 87XLT: Thanks for the info, I will check this out tomorrow and try to locate the splice and ground post and will let you know how it goes. You may be right I may have to break down and invest in a electrical manual.
To K2JJB: Thanks for the thought but I am pretty sure it is a bad ground connection.
To K2JJB: Thanks for the thought but I am pretty sure it is a bad ground connection.
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