New Engine Install - Rough start then Stalls

[roaniecowpony]

I took yesterday off. Too long a day on Saturday. I hate electrical gremlins.

Before installing the new engine, I installed the original engine harness, knowing it would be much easier out of the vehicle.

Can you pull codes from all modules? Sounds like theft prevent but might not be.

The Uconnect asking for a code generally only happens with stupid battery problems. You kill the aux battery?

1. When we pulled codes, it was a super long list. Looked like everything.
2. I was of the same thought as well about the battery. I have a Genesis dual system, which eliminates the Aux. The batteries got charged before first start attempt. Cranked but stumbled and died, repeated until no cranking. Charged batteries. But lost the ability to crank. Put in my large new truck battery. Still no crank. Batteries seem to drain quickly. There's a load obvious when connecting the battery(spark).

If the uconnect display is asking for a security code then your PCM is either offline or you installed the PCM from the donor JT for some reason.

Make sure you're using your stock PCM and it's properly plugged in. I strongly suspect you either damaged the pins or didn't plug the engine harness in properly.

• PCM is original. Never removed from original mount. Didn't get the JT PCM with the engine. Connectors looked good at the PCM.
• I also suspect I either didn't plug the harness in properly or damaged a pin. Thinking about the big connector near the back of the engine. I need to get to that and check it.

I appreciate all the input. I'm not well versed in CANBUS systems.

I'll go through the suggestions and report back.

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[jeepingib]

I took yesterday off. Too long a day on Saturday. I hate electrical gremlins.

Before installing the new engine, I installed the original engine harness, knowing it would be much easier out of the vehicle.

1. When we pulled codes, it was a super long list. Looked like everything.
2. I was of the same thought as well about the battery. I have a Genesis dual system, which eliminates the Aux. The batteries got charged before first start attempt. Cranked but stumbled and died, repeated until no cranking. Charged batteries. But lost the ability to crank. Put in my large new truck battery. Still no crank. Batteries seem to drain quickly. There's a load obvious when connecting the battery(spark).

• PCM is original. Never removed from original mount. Didn't get the JT PCM with the engine. Connectors looked good at the PCM.
• I also suspect I either didn't plug the harness in properly or damaged a pin. Thinking about the big connector near the back of the engine. I need to get to that and check it.

I appreciate all the input. I'm not well versed in CANBUS systems.

I'll go through the suggestions and report back.

With a spark, and high rate of discharge you have something shorted I would guess. Start disconnecting and double checking all plugs. I'm currently helping a kid in the bay next to me doing similar on a large wheel loader that was struck by lightning.

 

[alphawolff]

I took yesterday off. Too long a day on Saturday. I hate electrical gremlins.

Before installing the new engine, I installed the original engine harness, knowing it would be much easier out of the vehicle.

1. When we pulled codes, it was a super long list. Looked like everything.
2. I was of the same thought as well about the battery. I have a Genesis dual system, which eliminates the Aux. The batteries got charged before first start attempt. Cranked but stumbled and died, repeated until no cranking. Charged batteries. But lost the ability to crank. Put in my large new truck battery. Still no crank. Batteries seem to drain quickly. There's a load obvious when connecting the battery(spark).

• PCM is original. Never removed from original mount. Didn't get the JT PCM with the engine. Connectors looked good at the PCM.
• I also suspect I either didn't plug the harness in properly or damaged a pin. Thinking about the big connector near the back of the engine. I need to get to that and check it.

I appreciate all the input. I'm not well versed in CANBUS systems.

I'll go through the suggestions and report back.

You really need a scan tool here to make sure the PCM is active on the network before rulling it out. A radio asking for a security pin is a sure fire way to know that the radio and PCM aren't communication to each other at the very least. The radio looks for the PCM vin number to make sure it isn't stolen on every boot cycle. A start and stall condition can also indicate a security issue, though I don't think the JL uses this type of anti-theft but I may be wrong

 

[Stetson]

The security is an issue, but also that heavy drain on your battery is pretty suspect. if it’s a high enough drain it might not let your fuel pump or injectors or plugs operate properly.

Something is drawing a high drain if it can pull down a dual genesis battery set up.

 

[roaniecowpony]

Could a bad intelligent battery sensor cause this kaos ?

Also, my PDC has something rattling inside when removed from the vehicle and shaken or rolled over.

 

[alphawolff]

Could a bad intelligent battery sensor cause this kaos ?

Also, my PDC has something rattling inside when removed from the vehicle and shaken or rolled over.

No, the IBS has nothing to do with this concern. Really need to do proper diagnosis here rather than throwing darts at the wall.

Clear all the codes and start it a few times. See what codes come back and go from there

 

[roaniecowpony]

No, the IBS has nothing to do with this concern. Really need to do proper diagnosis here rather than throwing darts at the wall.

Clear all the codes and start it a few times. See what codes come back and go from there

I'm at a no-crank situation.

 

[SadRobot]

I'm at a no-crank situation.

Any progress? I hope you are able to get this figured out after all the work you put into it.

 

[mwilk012]

I'm at a no-crank situation.

KOEO codes will perform a circuit test at a minimum.

What sort of no-crank is it? click click, no click, no lights at all? Ignition switching normally from off/acc/run?

 

[roaniecowpony]

KOEO codes will perform a circuit test at a minimum.

What sort of no-crank is it? click click, no click, no lights at all? Ignition switching normally from off/acc/run?

All the interior and headlights work. I get a click. Even with a full charge battery. My big ass truck battery wouldn't do any better. I put a socket and breaker bar on the crank and it rotates freely. Installed another starter known to work, it didn't change.

Today, I checked the PCM connectors very closely, pins and sockets. I didn't see anything that caused concern.

A friend of a friend is a mechanic for the fire department. Called and we talked. He did a head replacement on a 3.6 recently and recalled that there were 2 grounds on the back of the engine on the injection harness. I did everything I could to check, but just couldn't get a good look. So, I laid out the 2024 Gladiator harness that came with the engine, and found them. Since it's been a few weeks since I installed the harness on the engine, when it was out of the vehicle. It had both grounds connected when I pulled the intakes off and checked today.

 

[mwilk012]

Easiest way to quickly determine if the engine is properly grounded is with a good set of jumper cables. Connect the battery directly to the block.

This sounds like PDC damage.

 

[roaniecowpony]

I'll put it all back together today. I borrowed a friend's Autel MP808S, mainly to use the camera accessory he has for it. But, it's a scan tool as well. I'll scan it with this tool and see what it shows.

 

[roaniecowpony]

Quick question. Do i have use a security gateway bypass cable with the autel mp808s?

 

[mwilk012]

Quick question. Do i have use a security gateway bypass cable with the autel mp808s?

You have to either bypass the SGW or have permission to access for any real work. Service relearns won't work without proper authorization. We don't use our Autel for these because it's a pain in the ass.

 

[roaniecowpony]

In addition to the previous fuse and relay checks, pcm connector check, and PDC connector check, I ran the Ignition Off Draw (IOD) parasitic test. After waiting for the modules to shut down, the system only had 12 ma of residual draw, which is well within the 50 ma limit. Passed.

The Power Control Relay is not stuck in the open position. Normal for the PCR is closed (connected). Passed.

I put in my SGW bypass harness and hooked up the Autel MP808S with the ignition in the "ON" position, engine not running. Tried to get it to read the VIN and that failed. I manually entered the VIN and it confirmed the make/model/year correctly. When I had it check for codes it said there was no communication with the PCM. Fail.

I installed the wireless BT bridge in the SGW bypass harness and opened JSCAN. Ignition "ON" engine not running, cleared codes, JSCAN gave me a U0100 code "lost communication with engine control module/power control module. Fail.

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