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Need help diagnosing issues

G600854

New Member
Joined
Jul 12, 2022
Messages
5
Location
Houston, Texas
1997 Jeep TJ 4.0 I6 with 225k miles

2 days ago, I go from a red light, cross the intersection and get up to 30mph, suddenly jeep completely shuts off. Engine off, Power off, Power steering gone. I coast to the nearest parking lot and pull in. Get it towed home and begin diagnosing.

When I turn the key, the starter is firing just fine, power is on, electrical seems good. I can hear the fuel pump in the back priming but engine will not start. Friend suggested I replace all the spark plugs. They have never been replaced by me so we decided to go ahead and replace all 6, replaced the distributor and rotor and cables. Also replaced cam shaft sensor while I was at it.

Engine still wont start. moved on to the next part this morning, replaced the ignition coil and ASD relay.

Engine still wont start. now I am at a loss, not sure where to go from here.

Any advice is appreciated.
 

CharlesHS

TJ Expert
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Jacksonville, FL, Quezon Philippines
When you state you replaced the Camshaft sensor; is that the sensor inside the distributor or the sensor that is bolted to the transmission bell housing beneath the head ?
The CKPS will interrupt the ignition if the Hall Effect sensor goes bad.
When the engine is turned over with the starter; do you see the tachometer needle moving ?

 

CharlesHS

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Mar 10, 2020
Messages
4,637
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Replaced the sensor on the transmission bell housing. and no, I'm not getting any movement on the RPM gague.

Check the (3) ECU harness 32 pin connectors for oxidation and firmly reinsert into the receptacles.
Inspect the ECU harness split wire loom area that wraps around the threaded head stud in the right rear corner of the head. The threaded stud is known to rub thru the split wire loom and wiring insulation. When the signal voltage shorts to ground; the communication will be interrupted and shut off the engine immediately.
 
OP
G600854

G600854

New Member
Joined
Jul 12, 2022
Messages
5
Location
Houston, Texas
Checked all 3 connectors, no oxidation or corrosion what so ever, inspected the wiring harness end to end and all insulation is intact, no exposed wire, no fraying wire.
 
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G600854

G600854

New Member
Joined
Jul 12, 2022
Messages
5
Location
Houston, Texas
Alright, just wanted to update on this one and not have a dead end thread. There was absolutely no way I was going to figure this one out. After days and a bit of cash trying part after part I caved and took it to a shop I trust.

Mechanic did a full electrical diag, OBD port non functional, power missing all over the place, took him 4 hours to find the issue, traced all the way back to the fuse box, dismantled the fuse box and found that the under rail that connects all the fuses into the power system was warped and on side had clear burn marks. He said it looked like it got a surge of power some how and thankfully failed rather than caught fire. Found a junkyard fuse box that he managed to salvage some parts from to fix mine.

Jeep is working 100% now, 110% even! that full tune-up I did trying to diag clearly made my boy happy because it is running better than ever now.

Sometimes, it helps to get an expert on the job, I usually try and fix things on my own but sometimes you just gotta get some help.
 
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