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Showing results for tags 'wiring'.
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Hey gang So I'm in need of a little help here. I pulled the m50b25 from my 1991 325 sedan, and with an m52 I bought as well, I now have the iron block m50 2.8 stroker. M52 single vanos head with s52 cams too ? I've got everything back together, I'm using the original dme and wiring harness from the car; the starter motor turns the engine over but I can't get it to start. I've read through a gazillion threads in various forums, testing this and that, but I've just reached a point where I need some help. If there is someone in the Christchurch area who would be interested in coming and having a look in exchange for their favourite tipple, it would be very much appreciated. Shoot with any other advice and what not too. Cheers Shaun
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I am having a starting issue with the M30B35 in my E28. I'll start from the beginning so that all the details are here. When the motor was in the E34, the fuel pump was jumped between the ignition 12v pin and the pump power wire to get it to work. I tried a relay (which was unknown condition) to see if it would work but it did not. The car also developed a very bad miss just before I pulled the motor out until the day I drove it to the place I was working at to pull the motor out. What would happen is the car would start ok but missed and backfired under throttle, the more you pressed the worse it was. It was driveable cold but got worse as it warmed up and became pretty much undriveable when warmed up. The day I was driving to pull the motor, it stalled on me a block from the place. I tried to start it but it wouldn't fire and the battery went completely flat. So we towed it. Once there, I jump started it to see if it would start and it started a bit rough, then came to life and ran perfectly. Drove it up and down the road a bit and it ran without a single issue. So I took it inside and pulled the motor. Once the engine was in my E28, when we first started it, it ran rough like it did in the E34 when it was missing. I fiddle around a bit, left it for a day with the battery disconnected and then the next day it started up fine. Ever since then the car was running fine, except for a slight miss at low revs, until I pulled my gearbox off to change the clutch. When I put it back on, it did the same thing. It ran rough and missed, so I let is sit for a couple hours with the battery disconnected. What do you know, started up and ran perfectly fine. Last weekend I decided to swap the loom and DME to see if it would solve the fuel relay issue and other issues like the ICV not working at all. It gets 12v to all 3 pins with ignition on. The fuel pump relay gets 12v to all pins when key is in except ground which is grounded, yet the relay (tried 2, one was definitely good) does not work. Anyway, so I swapped the loom and DME, turned ignition on. ICV buzzed as it should. Then I tried to start the car. Nothing. It cranks but will not fire. I triple checked everything and even tried my old ECU, still nothing. ICV no longer buzzes but gets 12v at all pins. Grounds test at 12v, however the coil only gets 9v. I ran a relay for it to test but that only gave it 10v, even though the power wire was a completely new one. Also tried different coil, still nothing. Took my crank sensor out and tested it on my friend's M30 and it worked perfectly fine on his car. All issues the same as with old loom. So I swapped my old loom back on and still have the same issues and won't start. It am 99% sure the DMEs are fine, will test on another car to be 100%. Is there anything else that could cause the car to not fire? One other issue I've had since the car had an auto on the 2.7 is that it won't turn over on the key occasionally, especially when the engine is hot. But this could be bypassed by starting it through the diagnostic port, which worked every time on both the old motor and this motor. I tested today and the starter trigger wire only gets 6v when the motor won't turn, but gets 11.9v when it does. I know this issue is unrelated however I don't know if maybe because of this something is not getting a signal and therefore not starting. But it seems odd that all of a sudden there is a problem. Sorry for the long description but I felt that the details could be necessary. TL;DR: Engine always had some odd wiring issues but ran, swapped harnesses and DME and car wouldn't start. Swapped back to old harness and still won't start. I semi-admit defeat and would appreciate help.
