Timing and Crank Position Senors

[modifiede30]

I think I may have figured out what's wrong with the car I'm working on but need some clarity on the timing components of an early eta. The question is:

Where does the flywheel need to be in relation to top dead center in order for the position sensors working off the flywheel to detect proper timing, firing and injector pulse, etc. My theory is that the flywheel wasn't aligned properly and the ecu is picking up incorrect timing from the flywheel sensors. Can anyone confirm that this could create potential problems?

[rs4pro3]

On the end of the crank where the flywheel mounts there is a little metal dowel to line them up the flywheel also had a larger hole on only one bolt to fit over this dowel. So yes it must be aligned.

[modifiede30]

So can it be aligned wrong based on the fact that there is a dowel? Also, how many reference marks are there on the flywheel? I only found one and it looked like a hook almost.

[rs4pro3]

If the dowel is still in place it can't be misaligned unless whoe ever did it was a true idiot and enlarged the bolt hol on the flywheel to make it fit. And yes there is only one pick up point, On the auto flywheels it a little arm that sticks straight out, and on the manual it's a small rectangulor piece of metal attached to the side.

[modifiede30]

Let me ask a different question about this. What would happen is a super eta flywheel is used with a standard eta engine? Is the timing mark in a different place since the timing is different between the two engines?

[rs4pro3]

I realy am not sure about that, I thought the super eta didn't use the timing marks on the flywheel and used the pulse and crank sensor up on the front of the engine.

[modifiede30]

Do you have any standard eta flywheels lying around . I need one for an automatic -the earlier the better.

[rs4pro3]

nope I've got 2 5 speed ones laying around but no auto.

[modifiede30]

Well, I confirmed my suspicions. The 82 and 83 eta has a completely different flywheel than the later model eta's 84 on. I suspect BMW decided to make them all the same when the 3 series came out with the same engine.

The reference marks are in different locations and style, and the ecu picks them up at different points than in the other models. Unfortunately, they're very hard to find. I think I may have identified one but I'll have to take it out of the car myself since its at a junk yard.

[rs4pro3]

Interesting good luck with it, I've still yet to get our 5er to start I ran ac ompression check the other day just to rull that out and all 6 cylidners were within 10psi of 150psi. I've ran out of ideas on what to check and have almost pushed it out into the driveway a couple time to let it sit outside instaid of in the garage.