E30 M52

[B C]

It started, its running.... poorly.

The positive: everything is connected properly, no leaks or strange noises that I can tell, lifters are much quieter than expected.

The negative: cylinders 2 and 4 seem to be dead.

Cylinders 2 and 4 have spark so I pulled out the compression tester 🤭 (horrible idea, I know) but to my relief they were both 190 psi. I removed and replaced the injector harness to ensure everything was clipped in correctly and ran it again with no improvement.

Possible issues:

-injectors are bad (they were cleaned and tested, but who knows)

-injector wiring harness is bad

-injector drivers (ECU) are bad

Overall, for all the screwing around involved with the engine swap, cam swap/timing, and obd1 conversion, im happy to at least see that it fires up and runs.

The next time I work on the car I will swap injectors around and see if the problem follows the injectors as well as checking continuity with the injector harness and ecu pins

I will win this

[Jeff]

Snap said:

It started, its running.... poorly.

[emoji29]

Too many valves????

[B C]

ROFL

[Daggerty]

If you need a noid light tester let me know I'm off the next three days.

[jc43089]

You could use a screwdriver or stethoscope to see if those injectors are clicking like the others while running.

Another thought is bad spark plug boots causing the spark to be shorted out when actually installed.  I assume you had the coil pack pulled out and laid on top to test?

[B C]

jc43089 said:

You could use a screwdriver or stethoscope to see if those injectors are clicking like the others while running.  

I tried a screwdriver and also a piece of hose and I wasn't able to really hear any real contrast. 

Daggerty said:

If you need a noid light tester let me know I'm off the next three days.

I'm a bit in the doghouse for wrenching so much this weekend (ha!), Is this a tool you'd be willing to let me borrow for a week while i find the right opportunity to get back into the garage?

I also wonder how much the mixture and old gas has to do with things. I dont have the O2 sensor connected because the exhaust isnt finished and the fuel in the tank is probably a year and a half old.

[jc43089]

Bad gas could be a significant problem.  Especially if it was not ethanol free.  I would disconnect a feed line and jumper the pump relay to pump it out into a jug.  Then hook the line back up and put fresh gas in and then run the pump with the jumper again for a minute to circulate it.  Then run it again.

o2 sensor isn't a problem for a cold start.

[GunMetalGrey]

I personally have never had issues with old gas, but I wouldn't rule it out. 

Is your ground coming out of the injector harness "box" good?
Easy enough to crack that case open and check the wiring at the injectors. 
Double check to make sure the plugs are all seated on the injectors, sometimes those can be a bit finicky. 

What spark plugs are you using? 

Glad it's running! I also like your throttle cable!

[B C]

GunMetalGrey said:

I personally have never had issues with old gas, but I wouldn't rule it out. 

Is your ground coming out of the injector harness "box" good?
Easy enough to crack that case open and check the wiring at the injectors. 
Double check to make sure the plugs are all seated on the injectors, sometimes those can be a bit finicky. 

What spark plugs are you using? 

Glad it's running! I also like your throttle cable!

Thanks,  and yes, I havent bothered to figure out how the throttle cable attaches quite yet. At the moment it would appear to be too long but its an E34 cable and its supposed to work.

I did re-clip the injectors in because those clips are abominable, no improvement unfortunately, but yes, thanks for the idea of popping the cover off, should make electrical testing a bit faster and easier

[B C]

jc43089 said:

Bad gas could be a significant problem.  Especially if it was not ethanol free.  I would disconnect a feed line and jumper the pump relay to pump it out into a jug.  Then hook the line back up and put fresh gas in and then run the pump with the jumper again for a minute to circulate it.  Then run it again.

o2 sensor isn't a problem for a cold start.

The only deal with the O2 is that I have a custom tune and it hasnt established any fuel trims, but otherwise yes you are right, it isnt a contributor otherwise

[jc43089]

I'm not sure what the learning procedure is for OBD2, for OBD1 I believe it runs on preset tables for cold start always, but I am not sure if it learns and adjusts after "seeing" the engine run at temperature.  You are probably right that with OBD2 it adjusts startup parameters based on warmed up characteristics.

[GunMetalGrey]

Snap said:

Thanks,  and yes, I havent bothered to figure out how the throttle cable attaches quite yet. At the moment it would appear to be too long but its an E34 cable and its supposed to work.

Ahh, you have an M52 Throttle body. 
I have no idea how to do that, or if it works with that cable. The e34 cable is a direct plug and play with the OBD1 throttle bodies. 
From looking at the throttle body it looks like some modifications will need to happen to the cable.

[Jdesign]

YAS!!! 

Coilpacks bad? I would try swapping those suckers around first. Did you ohm them out at all?

[B C]

Coil packs are brand new BMW/bremi units, switched them around, checked for spark, they are good

[Daggerty]

Yes you can borrow it, you know how too find me.

Mb your engine has too much compression.

[Daggerty]

As far as the car using set parameters for warmup that is not true for obd2 it still looks at the input of the sensors and will adjust. It just will do it if it goes out of the 1-6 range instead of the 3-4 range when it's warm. 

Numbers do not represent actual value of a sensor. 

I would at least shove the o2 sensor in whatever exhaust you have. But that isn't your problem.

[HipMF]

Did you remember to take the paper towels out before putting the intake manifold on? 

[B C]

HipMF said:

Did you remember to take the paper towels out before putting the intake manifold on? [emoji3]

You made me second guess myself for just a moment [emoji275]

[GunMetalGrey]

Snap said:

You made me second guess myself for just a moment

You'll realize it when you start shooting bits of paper out of the exhaust. 

Not that I would know....

[B C]

For Ben: Here’s the other throttle I have. It doesnt have a purge valve provision and it has a different cable connection. It does have the o-ring groove on the mating surface. I dont see a part# on it. The casting date stamp shows 96.

All of this 24v stuff is interchangable but different enough to matter