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Thanks to any one who takes the time to troubleshoot this with me!
I swapped a blown engine in my sons G37 with same year same drive train donor car. It didn’t start at first but I had not clipped the long white plug in all the way under the glove box. After I fixed that it started and ran great for a day. Next day it would not start. I was pretty punchy at the end of this swap and I left a wire that was installed by the owner of the donor engine loose. It is a wire in between the white starter plug wire. I left it undone because I wasn’t sure if it needed to be open or closed to start car. It started closed but was left loose in brake fluid comp. I found it touching ac line when it wouldn’t start.
I get the orange key light and brake push when in car. Push start everything goes dark then back to display. I seem to remember that the dash lit up in acc mode, now it does not. Radio will come on. Fob locks and unlocks car.
Here is a list of what I have tried.
New battery fob battery battery disconnect fuse link ok new dash lock box thing cussing cleaned starter post jumped 12v to s on starter, it cranked no prob new starter relay next to battery checked fuses next to battery box cussing again
The steering wheel will lock and unlock and the button goes from acc to on to lock so I am at a loss here.
First, please refrain from multiple postings. It helps to keep everything in once place.
I think what is confusing me is this "mystery wire" that you mention. Engine swaps are plug-and-play for these cars. There should be no extra wiring.
Originally Posted by Jamesroach2525
...I left a wire that was installed by the owner of the donor engine loose. It is a wire in between the white starter plug wire. I left it undone because I wasn’t sure if it needed to be open or closed to start car. It started closed but was left loose in brake fluid comp. I found it touching ac line when it wouldn’t start.
Can you provide a image of this wire?
Also, does the key cycle from OFF->ACC->ON? If the key goes to ON (brake not pressed) can you try pulling any codes?
Being that the donor engine ran fine for a day then quit leads me to believe that it is something minor.
I hooked up a scanner and it showed no active codes. I don’t know how to pull codes with the pedal pushes.
I will verify what the button is doing
it looks to me that the wire is just breaking the white wire that plugs into the starter. The two ends were run into the cab of the donor car but I’m not sure how they were hooked up. The car was in a wreck so they were loose when I started pulling the engine out.
Last edited by Jamesroach2525; Jun 22, 2023 at 09:18 PM.
That wire goes directly to the starter control relay at the IPDM/er- this is the large fuse box/ module located to the left of the battery behind the fender. I would run a continuity test on that white wire from the starter itself to pin #80 at the IPDM/er:
Maybe I am missing something, but if you unplugged your blown engine and popped the new one in, why are you having wiring issues. Your son's original wiring should not have been touched.
If you have not already, go here and download a copt of the factory shop manual for your son's car. This will have every wire, fuse, and schematic for the car.
As for the "mystery wire" there is no telling. I could easily guess that someone may have wired in a anti-theft switch much as some folks do with the fuel pump. Again, only guessing and it is not worth trying to figure it out. As long as the starter wire is intact all the way to pin 80, that part of the problem is solved.
As for the shorting out, does the AC line show signs of arcing? This wire is only a signal wire for the solenoid that is only "hot" when engaging the starter. It is not a constant hot nor does it carry a lot of current.
As a precaution, I would, once again, check all of the fuses and fusible links just to make sure they are not fused. The electrics on these cars are very tough/ durable. Unless you "toasted some wires" I am sure damage will be minimal, if any.
Last edited by ILM-NC G37S; Jun 23, 2023 at 07:12 AM.
I have continuity between one of the starter relay pins to the wire in the pic. I’m not sure where pin 80 is in the fuse box you mentioned. I also checked to see if when the start button is pressed there is 12v to the starter relay but there isn’t. I also didn’t get any voltage at the other side of the relay to pass to the starter.
None of those codes should be preventing the engine from starting. The U0164 is HVAC and P0463 is fuel level. The only one "of concern" is the P0603- this is the KAM (keep alive memory). This is the power circuit that keeps the ECM long-term, learned data active. Being that you likely dis/ connected the battery repeatedly, this may have triggered that code.
Pin#80 is the large, white wire by itself:
Right now I would learn more toward the IPDM/er being the issue. However, any chance the ECU got wet?
The cursed coolant hose connector broke in half during my sons first drive, but it ran and started after that, ran the next day but then wouldn’t start after stop. I have a doner car I can grab parts out of if needed.
Thanks for the pic! I can feel that fuse box clicking when it is trying to start. I didn’t get 12v at the starter coil or at the other side of signal to starter. I do have continuity from the relay socket and the starter.
Still sounds like the IPDM/er has a issue. If you can, grab the part out of your donor and see what happens. There is no programming needed for the IPDM/er- plug-and-play.
Was the cover on the IPDM/er? Any chance it got coolant splashed onto it when the heater hose connector blew out?
Either way, I tagged BULL on your other post so maybe her can offer some input next time he is online.
