Hello I am new here and I could use some help. I have a 2005 Tj with a 4.0. Was running fine with no issues, went to work and after my shift was gonna go home and had a crank no start. There was codes for crank position sensor. So I replaced it and nothing changed. Sometimes it will start and run for about 30 seconds and other time it will crank but won’t start. I checked the wiring harness and found no issues. The pcm is sending 5v to tps and crank sensor. So the pcm is sending power. The fuel pump kicks on for the 3-5 seconds to prime. Battery has a full charge, and fault codes change from iac to crank to o2 to no codes at all. The fuel and voltage gauge peg all the way to the left and the key cycle. I really don’t know what to check or look for next. Anything can help
Crank but no start
- Thread starter Nickflorida
- Start date
I’ve always looked at the battery terminals first when chasing an electrical problem. Clean shiny posts and corrosion free terminals.
Next check all your grounds.
Next check all your grounds.
Check the three or four ECU 32 pin harness connectors for oxidation and firmly reinsert the connector into the ECU receptacle.
Inspect the ECU split wire loom that is routed between the valve cover and fire wall; paying special attention to the section that curves around the threaded head stud (right rear corner of head). The threaded head stud is known to rub thru the split wire loom and wiring harness insulation causing intermittent shorting to ground of the ECU sensor signals. This will interrupt the ECU communications causing problems with the instrument cluster gauges and engine operation.
Inspect the ECU split wire loom that is routed between the valve cover and fire wall; paying special attention to the section that curves around the threaded head stud (right rear corner of head). The threaded head stud is known to rub thru the split wire loom and wiring harness insulation causing intermittent shorting to ground of the ECU sensor signals. This will interrupt the ECU communications causing problems with the instrument cluster gauges and engine operation.
Battery connections are clean took them off and used a scotch bright pad cleaned them up. I have an optima and there we no corrosion. I pulled all 3 pcm plugs and there is no corrosion. I also pulled the harness and found no breaks rubs or broken wires I also ran new wire loom on the harness. I checked all the wiring from pcm to crank, iac, o2 sensors, injectors, cam sensor, on the back of the block to the fuel pump to throttle body. Found no issues on the harness and on the 05 they fixed the harness on the stud problem. The put a high rise plastic case that goes around the valve cover. There are no blown fuses. I also swapped the asd relay and still nothing
Shodge97TJ
New Member
I am having the same problem with my 97 TJ. It has not run in over nine months and has been sitting in my garage and I work on it when I can. I have done everything possible. I have fuel and fire, but it still won't start. I took the front of the engine apart last night to check the Timing Chain and gears. I will post on here again when I put it all back together, but my mind is blown, and I have a mechanic background. I'm Not a Mechanic Anymore but, usually when you have spark and fire and a not start issue it is usually a timing issue. I have checked all the usual things that everyone lists in this forum. I just posted a post earlier. 
My mind is blown.
My mind is blown.
Gainesville. I just recently took off my harness and inspected and relooked the harness
The fuel pump is the first thing I would check. As you say the it comes on for 3/5 seconds but that is simply a function preset primer timing from the PCM but is not indication you actually have fuel pressure. I would get loaner fuel pressure tester from your local auto parts store and verify you have fuel pressure.
Gday from Australia . My 2006 TJ just stopped idling and I get a crank no start. I have 4 02 sensor codes, have also tested everything, can’t find the issue either. I will have to strip all wiring . No blown fuses at all. ASD works fine, just sent my ECU for testing and they maintain it’s fine. So I share your pain as I can not start this vehicle. It never missed a beat until this happened. I’ll redo all my tests and post .Any help is appreciated. BTW I replaced my 02 sensors about 4 years ago and since have done about 50000 kms or 30000 miles. Every time I cycle the key the 4 codes come up. P0031, P0051, P0037, P0057 all sensors test fine off vehicle. Even with these codes, I believe the car should start. Mine has no valve to test fuel pressure. Bummer. I have tested all sensors and they all test in spec. Any thoughts welcome. Cheers Chad
Good morning from Miami Chad
Who did you send the computer into for testing? Bench testing will not tell if this computer is bad for part of Australia are you in?
Thanks,
Mark
Who did you send the computer into for testing? Bench testing will not tell if this computer is bad for part of Australia are you in?
Thanks,
Mark
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