I'm usinf my mates account to post this, as I tried for ages to create my own account, but the website kept saying I got the code wrong/asking me questions I had to google the answer to. (I'm not a beemer guy)
Anyway,
I've been helping my mate try and fix his 1988 NZ new factory manual E34 525i.
It has the single ohc M20B25 engine.
About 18 months ago, it dropped a cylinder. He tried swapping out the injector, and the spark plug and lead. Turned out it had two broken rocker arms/cam follwers. even swapping those didn't bring it onto all 6.
So Rather than trying to fix it, he started swapping in another engine from a donor car he bought. The previous owner of that car suposedly had $3k in recipts for having the motor overhauled. (My mate didn't get the recipts, so like "it's got a fresh engine bro" on trademe, we have to take that with a grain of salt) That said, it was VERY clean under the cam cover. The cam was in very good condition. (unlike the old motor, where the cam was f-d)
He got the replacement longblock bolted in. Then life dished up one of those curveballs, (sh*t happenes) and the car was parked up untill now.
Her indoors has decree'd that he has too many cars. (He does too) and after he bought another one recently, the beemer has to gtfo.
So we've started trying to get the bastard running.
Which brings us up to where we're at now.
We refitted the injection manifold, and reconncted all the plugs etc. Hooked the fuel and return lines up the fuel rail.
After much time was spent doing battle with it, the damn thing refused to fire.
I pulled the line off the rail, and no gas comes out when the the key is turned/when cranking. I don't know bout bmw's, but nissans prime the pump for a few seconds when the ignition is switched on. We aren't seeing jack sh*t. (it aint never gonna go till we do)
The annoying thing is that apart from the motor running on 6, it still ran prior to being torn down.
Before I resorted to asking here, I did some googling. I read somewhere that some BMW's rely on there being spark before the fuel pump will pump? (Which sounds crazy if you ask me) Now I don't know if that's the case with this car, but there is some kind of pulse sensor(?) on number six spark plug lead. We found a plug on the loom which seemed to fit the plug on the other end of this "sensor". Also, given that car makers love to change things with no good reason, we reused the manifold, tps, afm etc etc off the OG motor from this car.
The workshop manual we have ins't very good.
Any idea where I can find the fuel pump relay?
Also, the oil level sender fault is coming up. (I didn't see this, but my mate said it said this) He thought maybe that's why it wouldn't go? (I doubt this)
Where is the oil pressure switch on one of these? The one in the bottom of the sump looks more to me like an oil level switch. (And old 13B I had once had one of those) My mate is going to swap the og one back onto the new engine.
Sorry about the essay. Also sorry if I should have searched for the answers.
Any advice would be appreciated.