3.7L won't start

[BIG RED]

2002 3.7L - she sat for about 1.5-2 years. Last month I decided to get it on the road and did the rear crank seal that was leaking. Had the car on the road for two days when it decided to quit. I wasn't there when it happened, but my wife described it as chugging, smoking, and CEL flashing. It would drive, but very poorly, so she parked it.

The next day I check on it and can not get it to start. It will crank but not catch. So after getting it towed home I started troubleshooting. Codes were P0340, P0016, and I think there was one more that never showed again since. I clear them with the battery disconnect overnight each time I do something different.

Started with new fuel (new filter, tested cranking pressure showing roughly 50~60 psi) I thought maybe the filter was gunked up.

It has spark and while I was in there, also new plugs.

Checked all fuses and relays by the battery.

Next new crank and cam sensor. This time it actually started. It ran really well for about 10-20 minutes. Then it started having trouble running and almost didn't restart while I was test driving it. Did get it home and then it wouldn't start again. Now, at this point it is showing just the P0340. So I tried swapping each one out for another replacement in case one was defective. Still not starting.

I looked over the wire harness, but from a distance, haven't physically inspected the entirety of the harness though. It seems to be fine.

Oh and one other thing that the Auto Parts guy suggested was the CAM sensor wheel under the valve cover. It is snug tho.

I think that is it. I picked up a Haynes Manual, but not really finding too much useful info for troubleshooting this. Last point of hardware would be the ECU/PCU whatever you want to call it.

Oh and one other question that I could not get a clear answer from the Haynes Manual or search engines thus far. There is one ECU on either side of the bay. Pass side is a Transmission controller? Is that right?

Thanks in advance for any thoughts of what I am missing here. :help:

 

[tjkj2002]

Return the cam and crank sensors to the auto parts store and go strait to a dealership and buy OEM sensors.Common problem for aftermarket sensors to not work right or at all in the 3.7.

 

[Billwill]

2002 3.7L - she sat for about 1.5-2 years. Last month I decided to get it on the road and did the rear crank seal that was leaking. Had the car on the road for two days when it decided to quit. I wasn't there when it happened, but my wife described it as chugging, smoking, and CEL flashing. It would drive, but very poorly, so she parked it.

The next day I check on it and can not get it to start. It will crank but not catch. So after getting it towed home I started troubleshooting. Codes were P0340, P0016, and I think there was one more that never showed again since. I clear them with the battery disconnect overnight each time I do something different.

Started with new fuel (new filter, tested cranking pressure showing roughly 50~60 psi) I thought maybe the filter was gunked up.

It has spark and while I was in there, also new plugs.

Checked all fuses and relays by the battery.

Next new crank and cam sensor. This time it actually started. It ran really well for about 10-20 minutes. Then it started having trouble running and almost didn't restart while I was test driving it. Did get it home and then it wouldn't start again. Now, at this point it is showing just the P0340. So I tried swapping each one out for another replacement in case one was defective. Still not starting.

I looked over the wire harness, but from a distance, haven't physically inspected the entirety of the harness though. It seems to be fine.

Oh and one other thing that the Auto Parts guy suggested was the CAM sensor wheel under the valve cover. It is snug tho.

I think that is it. I picked up a Haynes Manual, but not really finding too much useful info for troubleshooting this. Last point of hardware would be the ECU/PCU whatever you want to call it.

Oh and one other question that I could not get a clear answer from the Haynes Manual or search engines thus far. There is one ECU on either side of the bay. Pass side is a Transmission controller? Is that right?

Thanks in advance for any thoughts of what I am missing here. :help:

I agree with tjkj2002 that you need to use only OEM parts for the cam and crank sensor.
The passenger side has the TCM and the driver side the PCM....both pretty robust and only change as last resort.

You can download the 2003 KJ Service Manual here...includes circuit diagrams in case you need to track down some bad Cam sensor wiring:

http://www.colorado4wheel.com/manuals/Jeep/KJ

 

[BIG RED]

thanks for the input. yeah, trying to avoid the PCM replacement. that's why i searched out a community for more suggestions. i actually did put a mopar cam sensor in. at the point where i was only seeing that code, i decided that i should try a factory part. i will do the same with the crank sensor today.

if that doesn't work, the circuit diagrams will be very helpful. the Haynes that I picked up has some diagrams, but nothing that outlines what I need... so thanks for that link!


:EDIT:

Dealer says the part is on backorder all over the country. Luckily we have the interwebs..

 

[tjkj2002]

thanks for the input. yeah, trying to avoid the PCM replacement. that's why i searched out a community for more suggestions. i actually did put a mopar cam sensor in. at the point where i was only seeing that code, i decided that i should try a factory part. i will do the same with the crank sensor today.

if that doesn't work, the circuit diagrams will be very helpful. the Haynes that I picked up has some diagrams, but nothing that outlines what I need... so thanks for that link!


:EDIT:

Dealer says the part is on backorder all over the country. Luckily we have the interwebs..

Got a MOPAR crank sensor(and cam sensor,AIT sensor,ECT sensor,MAP sensor,TPS sensor,oil pressure sensor,and IAC) in a few days ago,ordered through a dealer a few days before that.No mention of any back order.

 

[BIG RED]

ok, got ahold of mopar crank and cam. still won't catch.
from what i have read, the only other things it can be at this point is a bad wire(s) in the harness or the PCM.

Any other thoughts?

 

[BIG RED]

This is the most frustrating and perplexing problem I've come across in quite a while.

So.
I checked the harness and there were no problems there.

Then I was testing the harness and found that the PCM was only putting .6V to pin 3 on the Crank Sensor plug. New PCM came in today. Hooked it up and the 5V is there now, HOWEVER; it is still cranking and not catching just as it was before.

All harnesses are connected, all fuses are good. What the heck am I missing here???

 

[Snail Farmer]

Does it need to be programmed at the dealership maybe?

 

[BIG RED]

According to the company I bought it from, it is programed and ready to go. I didn't even think about it, since they made it sound like a turn key solution. They asked for the mileage and everything. Good thought though. I will contact the vendor and see what they suggest. Thanks.

 

[mad mechanic]

15 Turn the ignition off.
Disconnect the CMP Sensor harness connector.
Ignition on, engine not running.
Measure the voltage of the 5 Volt Supply circuit at the CMP Sensor harness
connector.
Is the voltage above 5.3 volts?
All
Yes ! Repair the 5 Volt Supply circuit for a short to battery voltage.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
No ! Go To 16
16 If there are no possible causes remaining,
Replace and program the Powertrain Control Module in accordance
with the Service Information.
Perform POWERTRAIN VERIFICATION TEST VER - 5.

do you guys have the immob sys built into your PCM, over here in uk we have to prog the secret key code to the skim sys...using the drb.

 

[BIG RED]

Yeah, verified with the vendor, it should be plug and play. He is sending another out just in case something happened with this one in shipping. I don't think that is the problem though.

 

[Billwill]

15 Turn the ignition off.
Disconnect the CMP Sensor harness connector.
Ignition on, engine not running.
Measure the voltage of the 5 Volt Supply circuit at the CMP Sensor harness
connector.
Is the voltage above 5.3 volts?
All
Yes ! Repair the 5 Volt Supply circuit for a short to battery voltage.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
No ! Go To 16
16 If there are no possible causes remaining,
Replace and program the Powertrain Control Module in accordance
with the Service Information.
Perform POWERTRAIN VERIFICATION TEST VER - 5.

do you guys have the immob sys built into your PCM, over here in uk we have to prog the secret key code to the skim sys...using the drb.

I agree that the Skim code was possibly not programmed into the PCM although if the SKIS code does not match the code in the PCM the SKIS light normally flashes and you are able to start the Jeep but it will cut out after a few seconds.

If however the SKIS light on the cluster stays ON....without blinking....while trying to start the jeep....and the Jeep will not fire at all... then it means that the PCM recognised the SKIS code from the SKIM module and chipped key but it..the PCM...did not get feedback from the ASD relay that the ASD realy had energised.

So @BIG RED...if the SKIS light is constantly ON inside the cluster..the engine turns over but does not fire....try swap the ASD relay or remove the ASD relay and jumper pins 30 and 87 together in the ASD relay socket...now try start it.

This is a problem I had due to a wiring problem from the ECM (on my CRD) to the ASD relay causing the ASD relay not to energise.

 

[BIG RED]

The SKIS light stays on without blinking. Jumped the relay with no success, also tried swapping the blower motor relay which is the same part with the same result.

Thanks for your help though.

 

[CactusJacked]

I also have an 02, but mine doesn't have the sentry key system. My key is a conventional black one. If your key is gray, then you do have SKIS. If the key is black, you don't and you may have gotten the wrong PCM. We should first clear up what yours does and doesn't have.

 

[BIG RED]

mine is gray.

 

[BIG RED]

one other clue that may or may not help. i am finding that when i try to start it and give it some gas, it struggles to catch and seems to get really close. it got me to thinking that maybe even though the fuel pressure tested to be around 60 psi, maybe the injectors are gummed up or something fuel related. so i am back to that train of thought again. shot some starting fluid in the intake, but that did nothing. although, if it was injector related, i am thinking it would still start and just have some misfire code. (just kinda thinking out loud here).

 

[Billwill]

The SKIS light stays on without blinking. Jumped the relay with no success, also tried swapping the blower motor relay which is the same part with the same result.

Thanks for your help though.

The SKIS light should under normal circumstances light up when the ignition is turned ON and should go out after a few seconds if the PCM is happy with the SKIM code it received from the SKIM unit.

I believe your problem is in this area....the suppliers of your new PCM have not programmed the SKIM code in properly....did you send them your old PCM so that they could pull out the VIN number and SKIM code?

 

[BIG RED]

They have the VIN, yr/make/model/mileage and we verified it on the phone. They are sending another out in case something is wrong, but I am suspect it is not the PCM.

The light does come on and turn off as you mentioned.

I think it is an electrical gremlin and he keeps moving every time I find him.

 

[BIG RED]

Add TPS to the list of parts that have been replaced. Harness put out proper voltage, sensor resistance didn't change. Replaced the sensor and it has the proper resistance now.

...still no start though...