I am cursed - New ECM New 2.0l LDK

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cdover2005

Member
So at this point I have run in to 2 major problems.

Problem 1 - I have been chasing an electrical gremlin for over a week with no luck. I am pretty sure the ECU is shot. I am working on removing the harness, un-tapping it and going through every connection to make sure it is right before I buy a new ECU

Problem 2 - I am looking at getting a new LDK long block from ZZP. My Donor Engine is cursed with a porous block. (after complete rebuild, I still have coolant in the oil pan, engine hasn't started since rebuild).

Is it possible to program the new ECU with the new engine if the old ECU is shot and I already scrapped the donor so I don't "own the car" anymore or the vin.
 
Ross

Ross

Goblin Guru
You are wondering about programming the VIN number into the ECU? Why? Do you already own an HP Tuner licence for that VIN? Do you think the state motor vehicle people will check? I have heard of LKQ selling ECUs with a custom VIN, but it is stored in multiple places in the code, so I'm not sure if HP Tuners will notice.
 
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Gtstorey

Goblin Guru
There are a lot of post on HP Tuners forum about this but I don't remember the exact procedure and there is some disagreement about what can be done. Look for post by Cobaltoverbooster, MikeM173, gmtech16450yz or codename Bil Doe as the ones that know the LNF platform the best. It may be universal across all of HP Tuners but I don't know.
 
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Gtstorey

Goblin Guru
You won't be putting in the VIN of the new engine, if you need to change it you will need to match the BCM number. I'm pretty sure mine didn't match anything and I know it didn't match the "vehicle/frame" number.
 
Ross

Ross

Goblin Guru
No need to match the BCM... I have replaced that 3 times without changing the ECU. The only thing that cares is HP Tuners, as it costs $100 for each VIN number registered in their database.
 
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Gtstorey

Goblin Guru
I think you can find ECM that will have your VIN programmed in but don’t know what the cost difference would be vs random ECM plus HPTUNER credit.
 
Lonny

Lonny

Administrator
Staff member
If it was running before you tore it down I would assume the ECM is good and focus on a wiring harness or ground problem.
 
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Gtstorey

Goblin Guru
He thinks he has voltage to ground from the case of the ECM. I asked him about any bare wires touching but I don’t think he answered.
 
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Gtstorey

Goblin Guru
I’m not able to check mine for anout the next week but I wonder if the case itself is normally grounded though one of the connectors. If so you may still have a wiring problem where you have voltage feeding a ground wire. Normally that would blow a fuse but you didn’t say whether that happened when the case arced to ground.
 
Mahkoi

Mahkoi

Well-Known Member
Hey, I think you and I were chatting on FB messenger the other night. Does the voltage on the case go away when you unplug the smaller X2 connector off of the PCM? I'm not sure what you have checked prior to this but if case voltage goes away with X2 unplugged and and you have ground on pin 1,2 and 4 on the X2 connector it would make me think you have something screwy in the PCM it's just strange that it came out of a running car and now it has issues. I'm wondering if you take a meter to the PCM and check continuity from any 12v or 5v pin on the PCM to each of those three grounds and to the PCM case would be able to prove an internal short on the PCM. Wiring isn't my strongest area so anyone feel free to correct me if I'm wrong I'm just guessing about proving the internal short on the PCM

29923
 
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cdover2005

Member
Situation is improving! @Mahkoi , @Gtstorey , @Lonny , @Ross, and @Desert Sasqwatch, pin 41 on ECU X2 connector should run to B4 on the X3 connector on the BCM (I think), it does not on my harness, I had it running to a junction of brown wires for the lights. also the throttle position sensor wires were FUBR. I am fixing the issues I have found so far. Do we have a complete harness diagram for the Goblin yet? If not I would love to make one.

Also, I was able to connect with a GM engineer here in Detroit who rebuilds engines on the side. He has an LHU long block from a Regal GS that I am going to pick up later today. From what I can tell, I should be able to adapt it to the Goblin without issue. I'll keep you guys updated and thanks for your help
 
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cdover2005

Member
Update - The new LHU Long Block is in. I have it all back together now. I replaced the fuse box which help with a lot of my issues. Now i have response from the Gas Pedal, Fuel Pump primes, ECU communicates with my code reader. The only code I have is for the crank position sensor. Still no cranking when the key is turned. I can jump the crank relay, but haven't got it to fire yet. Any ideas gents?
 
Ross

Ross

Goblin Guru
The crank position sensor is probably important to do spark timing. Does it need a CPS relearn, a new CPS, or is there a CPS wiring issue? Break out an electrical meter and check.
 
TheNuker

TheNuker

Goblin Guru
Make sure your CPS is connected, my LDK came with a weird plug and it was hidden down by the starter. I ended up having to get an adapter to plug it into the harness on my LDK. Not sure if LHU is the same way.

Nuker-
 
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