I picked up the slick little '91 318is, lowered with 17's and a body kit from a kid who blew the motor. This is for my son's 1st car. We did an engine replacement, not swap (not putting more HP in to a beginning driver's hands <grin> ) using an engine from a member here. It's got a COP setup and chip but otherwise stock.
I have something wrong that has to be something major but i cannot figure out from the schematics where to start. Basically, there's no power to most of the relay-protected items (blower, windows, mirrors). They all seem to feed off the two unloader relays (K5 and K7) but I did some looking around today and didn't make much headway. I know all this stuff worked (with the exception of the power mirrors I think) before the swap and, I believe, after the swap but before the starter replacement (starter relay was hung and would run continuously, even when the key was off). The project has been a slow one so the starter was in the old engine and probably sat for 18 months. It was OEM so I thought I would use that vs the aftermarket that was on the donor engine. Too bad that didn't work out as I had to swap it after the engine was back in the car.
In any case, here's what I see -
Car runs, lights work, signals, dash lights, radio, etc all work. Power windows, blower fan and mirrors do not. Interior lights are a bit sketchy but the trunk light works.
The major common ground under the dash for these circuits is tight and intact.
Pin 30 on the unloaders has 12v and, when the key hits start, the other pin does as well. (can't recall the number but I think 85/86 energize to connect 30 to 87). The relays, if powered off the battery click so I don't think that they are hung up, but the fuses for all of these circuits have no voltage. It looks like the whole harness from under the fusebox goes to another box under the dash with a giant amphenol type connector like the one for the brain. FWIW, there is no voltage at the fuse panel for the headlights either unless they are turned on. There are multiple fuses for the same accessory so maybe one fuse carries the lightweight current for the relay and the other carries the operating current when the relay is energized? That's an area that I don't understand.
Anyway, the start was replaced and it's seems like you can't screw that up, the eyelets are sized for the post so they only go one way. Since that part is working, I was thinking that they problem must be elsewhere or maybe something caused by changing the starter in the car which really sucked.
I figured that one of these boards would be the place to start with some ideas on where to look. I've got the full electrical manual, but the way all the stuff is linked from page to page and trying to locate the ground points has been confusing. The only other place that I thought might be a problem is the ground post in the engine compartment. I think that all the wires in that area go on the post and that it doesn't matter whether they are on the clamp around the stub or the stud at the top as I get resistance back through the body on all connections.
Another seemingly odd observation was that turning on the headlights caused a drop in RPM and a bit of engine "hunt". That doesn't seem right.
Helpful advice appreciated, he gets his license in a couple weeks so we are finally at crunch time.
I have something wrong that has to be something major but i cannot figure out from the schematics where to start. Basically, there's no power to most of the relay-protected items (blower, windows, mirrors). They all seem to feed off the two unloader relays (K5 and K7) but I did some looking around today and didn't make much headway. I know all this stuff worked (with the exception of the power mirrors I think) before the swap and, I believe, after the swap but before the starter replacement (starter relay was hung and would run continuously, even when the key was off). The project has been a slow one so the starter was in the old engine and probably sat for 18 months. It was OEM so I thought I would use that vs the aftermarket that was on the donor engine. Too bad that didn't work out as I had to swap it after the engine was back in the car.
In any case, here's what I see -
Car runs, lights work, signals, dash lights, radio, etc all work. Power windows, blower fan and mirrors do not. Interior lights are a bit sketchy but the trunk light works.
The major common ground under the dash for these circuits is tight and intact.
Pin 30 on the unloaders has 12v and, when the key hits start, the other pin does as well. (can't recall the number but I think 85/86 energize to connect 30 to 87). The relays, if powered off the battery click so I don't think that they are hung up, but the fuses for all of these circuits have no voltage. It looks like the whole harness from under the fusebox goes to another box under the dash with a giant amphenol type connector like the one for the brain. FWIW, there is no voltage at the fuse panel for the headlights either unless they are turned on. There are multiple fuses for the same accessory so maybe one fuse carries the lightweight current for the relay and the other carries the operating current when the relay is energized? That's an area that I don't understand.
Anyway, the start was replaced and it's seems like you can't screw that up, the eyelets are sized for the post so they only go one way. Since that part is working, I was thinking that they problem must be elsewhere or maybe something caused by changing the starter in the car which really sucked.
I figured that one of these boards would be the place to start with some ideas on where to look. I've got the full electrical manual, but the way all the stuff is linked from page to page and trying to locate the ground points has been confusing. The only other place that I thought might be a problem is the ground post in the engine compartment. I think that all the wires in that area go on the post and that it doesn't matter whether they are on the clamp around the stub or the stud at the top as I get resistance back through the body on all connections.
Another seemingly odd observation was that turning on the headlights caused a drop in RPM and a bit of engine "hunt". That doesn't seem right.
Helpful advice appreciated, he gets his license in a couple weeks so we are finally at crunch time.
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