Need a car ready for BFest, so please help out :)

[mazur]

I'm helping a friend out with a swap and we are stuck. This is basically the last day we have to get it running to make it to Bimmerfest. Here's the story:

Stock rebuilt M50 swap. We got it started one night, but I ended up stalling it due to not having a properly bled clutch. Ever since, we have not been able to restart it.

Things we have checked/confirmed/replaced:

-New crank sensor

-We have fuel and spark with all grounds hooked up

-EWS wire is cut (using TRM tune, if that matters)

-Adapter wiring is correct

-Original wiring harness is from an E36 Auto. All that was done was the removal of the Auto trans ECU connector.

-Put a half cap of oil in each cylinder after reading about some fresh engines not starting due to lack of compression, so the oil is supposed to help seal the cylinders.

Things I was thinking about checking/doing tonight:

-Check compression values with my tester

-Swap cam sensor with known good one from my car

-Check timing with timing light.

-Check to see if fuel pressure looks adequate


Does anyone have any other ideas on what might be our problem. This is getting quite frustrating for us to figure out.

[Tchao]

Make sure all connections are good, ie Coolent temp, O2, knock, cam sens, crank sens.

Make sure alternator is wired up correctly and car is getting consistent juice.

Make sure Fuel/main/etc relays are good and not sticking.

Make sure fuel pump is on and getting signal it all times (loose wire? bad relay? Jump it continually, to see if it keeps running)

Dunno if the M50's are the same, but make sure Cam syn is in the proper harness plug, and make sure crack sync is also in the right plug. (doubt it)

[mazur]

Make sure alternator is wired up correctly and car is getting consistent juice.

It's wired correctly, but either way the car should start and run as it has a brand new battery. Once it starts I'll check voltage.

Make sure Fuel/main/etc relays are good and not sticking.

They're good.

Dunno if the M50's are the same, but make sure Cam syn is in the proper harness plug, and make sure crack sync is also in the right plug. (doubt it)

Can't switch them since one is male and the other female.

[FredK]

Yeah, I'd check the fuel pressure. I got my car inspected and the guy stalled the car three times in quick succession, and the fuel pump fuse blew out. Maybe the fuel pump isn't functioning properly, so a pressure test would be useful. Too bad the OBD-I rail doesn't have a Schrader fitting for a fuel pressure gauge.

[Farbin Kaiber]

Dunno if the M50's are the same, but make sure Cam syn is in the proper harness plug, and make sure crack sync is also in the right plug. (doubt it)

Can't switch them since one is male and the other female.

But, one can be mixed up with the connector on the IAC. ( I know )

[e30s52]

Is it a vanos or non-vanos? did you maybe swap the too crank wheels? does the ECU have power?

If you are still having trouble on thursday I can come by and try to help out if you want.

[BigD]

-Put a half cap of oil in each cylinder after reading about some fresh engines not starting due to lack of compression, so the oil is supposed to help seal the cylinders.

Holy hell... what?! Where did you read this? You sure you don't have some broken pistons/bent rods now?

When I was getting an engine rebuilt by a top notch builder, he explained to me how to break it in properly but in the same breath he said it's really overkill now - that with the modern seal technology, this is almost a non-issue.

Back on topic though, I agree with everyone who said fuel supply. Try jumping the relay with a fuse - there will be no question, you should hear the pump(s?) going and fuel rushing through the rail. Triple check your fuel lines that they're not reversed. I wouldn't worry about the sensors - your engine would still sputter if they were faulty - you've got a fundamental air/fuel/fire problem. You say you have fuel, did you actually check the fuel pressure at the rail?

[mazur]

Is it a vanos or non-vanos? did you maybe swap the too crank wheels?

It's VANOS with original pulley.

does the ECU have power?

I have not checked it directly, but I am assuming so since we get a CEL. If that's not an indicator, then that'd be a good thing to check.

If you are still having trouble on thursday I can come by and try to help out if you want

Cool. I'll let you know.


Holy hell... what?! Where did you read this?

On here, but it's no big deal either way. Not like it hurts anything.

You sure you don't have some broken pistons/bent rods now?

Where did you get this notion from? If you're talking about the oil, you should re-read my post.

When I was getting an engine rebuilt by a top notch builder, he explained to me how to break it in properly but in the same breath he said it's really overkill now - that with the modern seal technology, this is almost a non-issue.

I highly do not believe in that. If you do not place high load the engine within the first hour, you will have problems. Ask my friend who took it easy on his fresh rebuild for 1000 miles and now has blowby.




Wasn't able to work on the car tonight, but will tommorrow. Stay tuned guys.

[loonibab325i]

yeah, i'm pretty positive your ecu is fine, that's what i was going to say to check since my last problem was due to an ecu being bad, then i tested out another ecu to make sure my car was fine and still no freaking luck, third one was the charm though. hah.

[318isbmw]

I highly do not believe in that. If you do not place high load the engine within the first hour, you will have problems. Ask my friend who took it easy on his fresh rebuild for 1000 miles and now has blowby.

I've got 3 motors that argue with that. No you shouldn't go flog on your freshly built motor. The first 20 minutes if its completely rebuilt will be to break in the cams, that's before you even move the car under its own power. Ya you need to drive it around at some point, but no you shouldn't go beat the shit out of it, you'll create new problems. Sounds like your friend has other issues.

Did you try switching the ecu with another good car? Just incase something went haywire inside the ecu for some reason.

[mazur]

I've got 3 motors that argue with that. No you shouldn't go flog on your freshly built motor.

No ones "beating it to shit". You do your loading when everything is fully warmed up. If you truly think this is the wrong way to break in an engine, you better call up BMW over in Munich and tell them to stop ruining every engine that comes out of there.


Did you try switching the ecu with another good car? Just incase something went haywire inside the ecu for some reason

Tried the ECU on my car and it started up fine.

[surebimmer]

How's your ground from body to motor mount arm?

[mazur]

UPDATE:

So here it goes. Basically just a list of bad news...

1. Did a compression test. After the first two cylinders only registering 40psi, we decided to go pick up a leak down tester to see wtf was up.

2. Did a leak down on all cylinders. All readings were between 45%-70% with air only rushing into the crankcase.


So I believe the consensus is that somehow the piston rings are fubared. Even though the engine is cold and the rings have not seated yet, I believe it's still too high of a leak to be normal. I'm going through it in my mind and I cannot see how this problem has arisen.

Installation of the rings went smoothly, with the gaps having good readings and all positioned opposite eachother as they're supposed to. Then the engine ran fine for a full 10+ min. without issue until it stalled the second time on our drive and wouldn't restart.

My friend and I are at a loss right now and cannot believe that we're probably going to have to tear back into her. This sucks!

[416stroker]

That sucks.. what was the ring gap? I Just hope if you broke a ring the cylinders and the pistions are ok ...That sucks.

[416stroker]

Is there fuel in the oil? It should still run if it had two dead holes just like dog shit.