I will guess 2005 or 2006 with NGC PCM
not the 2000-2004 TJ with JTEC+ PCM and more simple OPDA and camshaft position sensor

helps if you share basic info like year of TJ and engine

 

Doh! Totally missed that, thank you, added to the original post but yes, 2006 4.0L NSG370 manual

 

That is a pretty long crank but appeared to idle smoothly after starting. If the long crank is caused by intermittent or total loss of either cam or crank signal you should be getting a CEL, codes & be in limp mode limiting the RPMs to about 2200. Also if the cam/crank sync is not within PCM parameters you should be getting a CEL & code. You apparently are not getting any of that.

There is not normally rough idle or running associated with any of this either.

Since none of that appears to be happening I do not think you have an issue related to the OPDA.

I know your scanner is showing things that do not appear normal but I’m not sure what is should actually show. I have read that when using the dealers DRBII to check & set sync after engine warm up it raises the engine idle slightly & reads it & can be adjusted at that point.

 

first blush fuel delivery issue - leaky injector high up on my list

 

Yup no CEL at this point even when its running at its worst. Some times it will idle smoothly at first but it doesn't last long. I would love to rule out the OPDA out but the out of sync message its puzzling me. I am considering that I may have a worn down camshaft but not sure exactly what symptoms that would cause. I was thinking fuel delivery or injectors but after testing the fuel pump thoroughly and replacing the injectors with new, not rebuilt, Bosch injectors there was zero change. One day it started running really rough and I got an O2 sensor CEL. I thought I was on the right track so I changed that O2 sensor with an NTK and the light went away and its back to how its been running for weeks before that. If I cannot figure it out I plan on swapping in a lower milage engine I have back in my garage or possibly swapping out to an '04 4.0L / ECU / 5 speed drivetrain that I was saving for my LJ. I have alway loved my TJ's but this Benzified version is kicking my butt.

 

that would require a different flywheel/flex plate a different tranny bell and a completely different harness plus would not pass emissions if tested

does the CEL come on like it should with key on engine off?

 

CEL works correctly, everything is matched. The '04 setup I have is complete. I parted out the Jeep it ran well, engine, trans, t-case, ECU, all harnesses, etc. I will likely keep the '06 setup though as I planned on swapping in the low mile engine anyway. The LJ is my next summer project and was looking forward to a 5 speed LJ.

 

yep swap is only way to get a 5 sped LJ as in 04 they were only auto and in 05-06 manual was the crappy German 6 speed

 

Just spitballing some ideas that come to mind:

• Possible PCM voltage supply or ground issue. Try cleaning all battery cable connections, incl at the PDC, and all grounds at G105. Verify you're getting full battery power from the ASD relay output.
• Possible dirty or otherwise faulty IAC. Try cleaning the IAC and its air passage in the throttle body, check wiring.
• Possible TPS dirty/worn. Try cycling the gas pedal full travel 10-15 times before attempting to start to see if that makes a difference. Can also check signal voltage is in spec and tracks smoothly with pedal movement.
• Possible compression/valve sealing problem. Perform a compression check and leak down test as req'd.
• Possible lifter bleed down problem. Pull valve cover and verify proper rocker operation at initial crank attempt.

 

Thank you that gave me a few things to try I checked the voltage and PDC it all seems good. I removed and thoroughly cleaned the IAC and checked voltage and it seems ok. I dont think its compression because at times it has full power and runs perfect but I will be able to do a lot more thorough diagnosis of that type when I get back up north to the garage.

That brings me to the TPS. I noticed that the old TPS housing was cracked so I replaced it with an NTK (made is US) part. Screenshots below are the readings of: key on running at idle, key on not running with pedal fully depressed and engine running at idle. Somehow I don't think these numbers are right, should it be more like 4-5V at pedal fully depressed? Should it have some percentage throttle while it is running at idle?

TIA!

 

The FSM states:
-- The PCM receives an input signal voltage from the TPS. This will vary in an approximate range of from .26 volts at minimum throttle opening (idle), to 4.49 volts at wide open throttle.

Just went out and checked my '05 which has no running or drivability issues, it shows TPS voltage as 0.51v foot off the pedal and 3.33v with the pedal to the floor, so I'd say your readings are within normal parameters.

 

Hmmm yes I agree that voltage is pretty close, appreciate you checking that.

 

....... I don't think these numbers are right, should it be more like 4-5V at pedal fully depressed? Should it have some percentage throttle while it is running at idle?

Your TPS is defective. It should be within about 10% or less of the high and low range of .26 volts at minimum throttle opening (idle), to 4.49 volts at wide open throttle.

Have the Cam sensor and Crank sensor synchronization tested. Read this: Wayback Machine

You are NOT using Bosch or generic auto parts store O2 sensors, correct? NTK is the best and only replacement.

 

Your TPS is defective. It should be within about 10% or less of the high and low range of .26 volts at minimum throttle opening (idle), to 4.49 volts at wide open throttle.

You got me questioning the readings I got on my code reader that I posted earlier, so I went back out and took voltage readings with a meter directly at the TPS connector. Throttle closed I'm seeing 0.59v and throttle held full open I see 3.70v, so I'm sticking with those readings are normal, at least for an '05/'06 with the 4.0L engine.

 

4.0L
The throttle shaft end of the throttle body slides
into a socket in the TPS (Fig. 34). The TPS must be
installed so that it can be rotated a few degrees. (If
the sensor will not rotate, install the sensor with the
throttle shaft on the other side of the socket tangs).
The TPS will be under slight tension when rotated.
(1) Install TPS and retaining screws.
(2) Tighten screws to 7 N·m (60 in. lbs.) torque.
(3) Connect TPS electrical connector to TPS.
(4) Manually operate throttle (by hand) to check
for any TPS binding before starting engine.
(5) Install air cleaner tube to throttle body.


1 - TANGS
2 - THROTTLE SHAFT
3 - THROTTLE BODY
4 - TPS

Fig. 34 TPS INSTALLATION - 4.0L

 

DESCRIPTION - COMPONENT MONITORS
There are several components that will affect vehi-
cle emissions if they malfunction. If one of these com-
ponents malfunctions the Malfunction Indicator
Lamp (MIL) will illuminate.
Some of the component monitors are checking for
proper operation of the part. Electrically operated
components now have input (rationality) and output
(functionality) checks. Previously, a component like
the Throttle Position sensor (TPS) was checked by
the PCM for an open or shorted circuit. If one of
these conditions occurred, a DTC was set. Now there
is a check to ensure that the component is working.
This is done by watching for a TPS indication of a
greater or lesser throttle opening than MAP and
engine rpm indicate. In the case of the TPS, if engine
vacuum is high and engine rpm is 1600 or greater
and the TPS indicates a large throttle opening, a
DTC will be set. The same applies to low vacuum if
the TPS indicates a small throttle opening.
All open/short circuit checks or any component that
has an associated limp in will set a fault after 1 trip
with the malfunction present. Components without
an associated limp in will take two trips to illumi-
nate the MIL.
Refer to the Diagnostic Trouble Codes Description
Charts in this section and the appropriate Power-
train Diagnostic Procedure Manual for diagnostic
procedures.

 

Messed around with it this morning with little luck. I cannot figure out how to test the O2 sensors or graph anything with the Thinkdiag2. So I decided to try my old reliable BlueDriver to look at the 02 sensors. I don't know much about how they work except comparing each bank to see if there are any differences. Something seems off but wondering what your opinions would be on these two graphs or if there is something else I can check. Bank 2 sensor 1 was throwing a code and not working correctly a few weeks ago, I swapped it with an NTK at that time and the code immediately went away. The non-working one I swapped out was a Mopar btw. The other 3 are unknown. Suspecting a possible bad sensor at bank 1 sensor 2? This was closed loop after running for quite some time. Any opinions on these graphs? TIA.

 

Easy way to see if the o2 sensors are causing the problem at hand is to disconnect them and take the Jeep for a drive. This forces the PCM to stay in open loop, thus eliminating the sensor signals from the equation. Normally you'd only need to unplug the upstream sensor(s), but there's some evidence that on the NSG equipped Jeeps ('05 and newer) that the downstream sensors also play at least a partial role in fuel scheduling, so you'll need to unplug all four. You will have a CEL with the sensors disconnected, but ignore it and pay attention to whether or not it runs any better when stuck in open loop. Be sure to secure the unplugged sensor harnesses, you don't want to melt any on the exhaust.