I have an e46 Bmw with an ls2 from a GTO, the car is awesome when I can use it. It was running fine then died on me after I gave it the beans about 20 mins later after turning over but not firing I got it refired. Same thing happened the next time I drove it but it has never stayed running again. I've replaced the fuel pump, with walbro 450, the crankshaft position sensor even had another e40 computer tuned with the same tune I had in it Vats removed pcms for less did the tune. The best it will do is wake up periodically sing the song of its people (20 seconds or less) then not fire again hours/days. I've tried ether it wont fire just misses and pops a bunch, I did have no injector pulse codes which is what prompted me to try the other e40. Does anyone know what rabbit I should chase next I am lost for some reason I just cant get my head around it. Car has an ls2 from a 2006 GTO w t56 factory harness and computer with a few deletes only a cam/ spring upgrade any pointers are greatly appreciated!.

 

A lot of people with swap vehicles don’t install good grounds.

Check your battery ground, your harness grounds (BMW and LS harness grounds), and you need good ground straps to the engine.

I had an e40 ecu just brick itself the first time I tried firing my car but it was not intermittent it just died. I had to get a new ecu - never figured out why and never had a problem again.

 

I added a ground strap from the alternator bracket over to the chassis ill go through looking at the rest, I'd think if both were bricked it wouldn't ever start. Iam about to just order a termx and start rewiring.

 

I had a problem similar to this and it turned out to be one of the ground eyelets on the back of the driver's side head had broken. When I would check grounds with an ohm meter they all check out good. It wasn't until I physically reached back behind the head did I find the broken ground eyelet.

 

This!
Either that or the bolt didn’t get tightened.
Tripped up more than a few folks.

 

+1 and It was on my terminator, the ground bolt to asenger side head wasnt grounding through the protective coating the rebuilders spray on teh aluminum..