Cranks but no start

[Ebaron]

First Thanks for this forum! I’ve just joined and see a lot of knowledge here.
I’m a fairly experienced home mechanic with decent tools and a lift. But, I’m more old school, and have never dug into the computer control stuff. Believe it or not, worked at Delphi in late 80s testing their fuel injectors that didn't have the greatest reliability back then.

I‘ve other posts and have downloaded the FSM and done diagnostics..
I have a 2006 TJ , 4.0 6 spd. It mainly gets towed for camping and we barely put 1k miles a year on it, so it sits too much.

so as of today, it’s cranking over, I smell fuel, have tried starting fluid and tested successfully for spark at coil rail. It’s not starting at all.

History of problem.
- Won’t start, battery a bit weak, starter disengaging, during cranking. Charged battery, tried with jump, still no start.
- Changed spark plugs, with Autolite Iridium’s , gapped at .035.
- Had more issues with starter disengaging during start, managed to chip starter gear and flywheel.
-Checked CPS, looked damaged from a possible fragment from gear.
-Had starter rebuilt by a good shop.
-Dropped transmission, put in new flywheel.
- Replaced CPS, but used a Standard Mfg sensor. Didn’t see Mopar recommendation yet.
-Was able to get it started, after many tries, ran for just about a few minutes, but idled very poorly. Died, have not been able to restart since then about 3 days ago.
-Got 3 codes on 3 O2 sensors, Heater Control Circuit Low ( P0037, P0051, P0057) and V0155 Lost Communication with Instrument panel. These codes, nor any others have come back.
- Checked 02 wiring near transmission, looked good. Last year, changed B1S2 and B2S2 sensors with recommended NTKs. Other two were not changed as old ones would not budge. Have had no O2 codes in past year.
-Put in another stronger battery ( not new, but fully charged), cranking much better.
-Learned about the fuel issue with regulator or check valve, I likely have this issue as it always took several tries to start after sitting for longer times ( weeks). So I turned ignition on multiple times as recommended, multiple times. Can hear fuel pump run.
-Cranking better still no start, can smell fuel. Wondering about old fuel.
-Checked ASD relay. ASD relay is getting coil signal for about 2 seconds with ignition on, then shuts off if no engine rotation. So, correct as per manual. Checked out ASD and Fuel pump relay functions with multimeter, all good. Also tried swap with another relay previously.
-Checked for 12v at coil rail, and it stays on through cranking for approx. 15 seconds. I assume this indicates a good CPS and camshaft sensor and signal, ASD relay and PCM control of it all.
-Checked coil rail spark with inline tester. All coils and locations firing during cranking.
-Doublechecked one spark plug gap. .035.
-still no luck, battery still holding above 12v.
-Tried starting fluid at Throttle body. I got absolutely nothing that sounded like it wanted to start after several tries!
-Last I pulled and checked Camshaft sensor / OPD. No obvious issues with camshaft drive gears . This was replaced about 5 years ago ( only about 2k miles ago) with Dorman unit, as I didn’t know better. It has Dorman sensor, but I did save the OE unit somewhere. But doesn’t the firing at coil rail rule out a bad sensor?

Since I got spark at coil rail, I am assuming that ignition / PCM working correctly, but with no difference with starting fluid, I must be missing something. I’ve not checked fuel rail pressure since starting fluid didn’t help and I can smell fuel.

My Next steps
-Get a new battery, as sitting and towing ( with an onboard electric braking system ) are likely not friendly to battery.
-Should I just get a Mopar CPS?
-Should I dig out original camshaft position sensor and put it in?
Seems like just part changing to me, if I m getting spark at coil, but I’m clearly missing something. I’m tempted to change plugs again, but believe the Autolites were recommended for this motor.

One last thing, the starter still seems disengage momentarily during a long crank, but much less often with a better battery. Is this normal, just low voltage or anything related to PCM?

Thanks for any help!

 

[macleanflood]

I'd still check fuel pressure...

-Mac

 

[JKP]

You need to talk to Mark @Wranglerfix. 05 and 06 PCMs are dropping like flies here lately. The O2 codes are a common indicator of the PCM going out.

 

[Ebaron]

Ok thanks. I’ll contact Mark.
Regarding fuel pressure , just checked and my fuel rail has no pressure test port. Is there another location/ method to test?

 

[JKP]

You have to get the test kit and insert an adapter between the rail and fuel line. Pain in the butt.

 

[macleanflood]

https://wranglertjforum.com/threads...ne-with-a-tj-check-their-fuel-pressure.72475/

 

[GregBelleville]

Plus one on the recommendation to talk with Mark @Wranglerfix . It's puzzling that you say you've got spark at the coil but it's not starting on starter fluid?

 

[hear]

Plus one on the recommendation to talk with Mark @Wranglerfix . It's puzzling that you say you've got spark at the coil but it's not starting on starter fluid?

The fact that it did catch once but ran rough has me wondering if the timing has gotten out of whack.

 

[Ebaron]

Well I put in a new high CCA battery to get that out of mix. No luck.

I’ve been wondering about timing as well. I only messed with OPDA earlier today and was careful to take it out and back in with pin aligned.

From what I’m reading, it seems that timing could only be affected by CPS ( or bad PCM I assume). So wondering if I should get a Mopar CPS to get that variable out. Is there any way to check timing on this motor?

After new battery, I noticed a bit of slight smoke from air intake pipe after several start attempts. No backfire though. Starter still kicks out though as if something’s telling it to stop cranking.

Have email out to Mike at Wranglerfix.
And will need to get fuel rail adaptor.

Thanks for all the input!

 

[JKP]

Your 06 should start if one or the other of the cam and crank sensors is bad. If both are bad, you are done. It will be a long crank if one is bad.

With the pin in the OPDA, the crank pulley timing mark should align with the timing pointer on the timing cover. This would check that the timing chain hasn't jumped.

 

[hear]

From what I’m reading, it seems that timing could only be affected by CPS ( or bad PCM I assume). So wondering if I should get a Mopar CPS to get that variable out. Is there any way to check timing on this motor?

I thought there was just enough rotational play in the OPDA that you could influence the timing slightly. I also read a while back about the manufacturing tolerances in the sensors or the tone wheels that you could have been on the edge of the timing limits, but then something moved or was replaced and now you're outside the tolerance. But I'm just speculating.

 

[JKP]

Spark timing is set by the PCM based on the crank sensor under normal circumstances.

If the crank sensor is bad, 05 and 06 models should be able to determine spark timing using the cam sensor.

Normally, the cam sensor is only used for injector timing.

 

[Ebaron]

Problem solved! I’ll provide the details in hopes of helping a future member.
1st special thanks to Mike at Wranglerfix! We had a good discussion this am and decided I should check timing and grounds before sending in PCM.

Timing checked out fine.

So since it sat overnight and I a new battery gave it another try. After about 10 ties got it started but ran poorly. Many crank attempts ended in starter kicking out on its own again, even with fresh battery. This time I timed it and there was no consistency, anywhere from 7 -18 seconds before starter kicked out. While it was running, surging a bit, the instrument panel was connecting and disconnecting. Voltage was about 9 v on gauge, but as I gave it some gas, I saw my added voltmeter read 18v , so I shut it down. Got 5 codes. Communication to Instrument panel fault, and Low O2 sensor heater circuit on all 4 sensors.

Checked ground point on right side of block ( Battery and about seven other wires.) Connection was tight and looked sound, but nut looked rusted enough risking a stud break, which is why I avoided it earlier. After looking very close, I spotted wht you can see in pictures. ! Look close at picture. Wire insulation retained, copper retained, but broken or corroded out in between!

luckily stud came out, so I replaced stud, all new terminals on sensor wires and it fired right up! Ran great! I also replaced battery cable from block to battery as copper didn’t look great and I’m thinking that may have been cause of starter kicking out during cranking

That darn connection cost me a starter, chipped flywheel and damaged CPS, and heck of lot of troubleshooting. Live and learn.

Thanks to everyone on this forum and to Mike at Wranglerfix! All the threads, plus the availability of the FSM here is what taught this old dog to figure out this computer controlled stuff! It’s time to become a supporting member.

 

[Danarch]

Problem solved! I’ll provide the details in hopes of helping a future member.
1st special thanks to Mike at Wranglerfix! We had a good discussion this am and decided I should check timing and grounds before sending in PCM.

Timing checked out fine.

So since it sat overnight and I a new battery gave it another try. After about 10 ties got it started but ran poorly. Many crank attempts ended in starter kicking out on its own again, even with fresh battery. This time I timed it and there was no consistency, anywhere from 7 -18 seconds before starter kicked out. While it was running, surging a bit, the instrument panel was connecting and disconnecting. Voltage was about 9 v on gauge, but as I gave it some gas, I saw my added voltmeter read 18v , so I shut it down. Got 5 codes. Communication to Instrument panel fault, and Low O2 sensor heater circuit on all 4 sensors.

Checked ground point on right side of block ( Battery and about seven other wires.) Connection was tight and looked sound, but nut looked rusted enough risking a stud break, which is why I avoided it earlier. After looking very close, I spotted wht you can see in pictures. ! Look close at picture. Wire insulation retained, copper retained, but broken or corroded out in between!

luckily stud came out, so I replaced stud, all new terminals on sensor wires and it fired right up! Ran great! I also replaced battery cable from block to battery as copper didn’t look great and I’m thinking that may have been cause of starter kicking out during cranking

That darn connection cost me a starter, chipped flywheel and damaged CPS, and heck of lot of troubleshooting. Live and learn.

Thanks to everyone on this forum and to Mike at Wranglerfix! All the threads, plus the availability of the FSM here is what taught this old dog to figure out this computer controlled stuff! It’s time to become a supporting member.

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Thank you for updating us on the solution.