m50nv starter issues

[ecc3189]

So I I finally have everything together but when I went to start the car the starter spun without engaging. I saw that there was another thread with the same problem that I am having but when I shorted the starter solenoid it did pop out and engage but when I wire everything back up it now only engages and won't spin. So I don't think the starter is bad since I can get it to both spin and engage. Just not at the same time :(

The other strange part to the story is that when I turn the key to on, the coolant gauge flips to red, then when turn the key to start the gauge drops to zero and then goes back to red when I stop cranking. Any ideas why the coolant sensor would be seeing a voltage drop like this?

Here is my starter wiring and my adaptor wiring, seems like it is wired correctly for the starter circuit. This is a 92 m50nv going into an 87 325e.

[ecc3189]

Black/green thin starter wire

So while doing research on my adapter, I noticed that a 87 eta-m50nv build thread had a pinout with a c101 Black/Green wire in pin 15 that hooks up to the same color/pin on the x20. He has this labeled as a starter wire. Why does my c101 not have anything in pin 15?? could this be why my starter won't spin and engage the solenoid at the same time?

What is weird is that the symptoms keep changing, first it would spin but not engage the solenoid, and now it clicks the solenoid but won't spin...

[SkorcherX]

Test the starter on the bench hooked up a battery.

Also... maybe it is engaging and spinning, but if you don't have the right flywheel the starter might be over/under shooting the teeth on the flywheel.

Starter has to match the flywheel.

[ecc3189]

checked starter

I actually think that I accidentally put the m50 starter in by accident so I pulled it out and compared the m20 early, late, and m50 starters to make sure I put the right one in. I put in the m20 late model starter in but it still only spins without engaging. I noticed that the early starter appears to have slightly thinner teeth than the late model and m50 starters. Any clues on this? I would hate to have to use the early model starter since it is so big and the connecters are spades and not the posts that would pair with the m50 wires.

Edit: The flywheel is the m20 dual mass from the m20b27 that was in the car. Therefore the m20 early starter I have definitely fits, I just don't know about the late model that I have...

And does anyone know anything about how necessary the black/green wire is that is in pin 15?

A whole other problem became obvious while I was trying to crank the starter, the fuel pump relay gets power but the fuel pump is not running. Does this mean it is a bad relay?

>.< So many wiring problems...

[SkorcherX]

I am not real confident in providing any insight to your wiring woes. I spent weeks going over the schematics during my down time at work, and when it finally came down to do it I already have mapped out all the pins, and just followed my own instructions. Fired up first try... everything worked.

With that said... You have a dual mass fly wheel. Unless someone with more experience can chime in I believe you have to run the fat old starter. I junked the dual mass, and bought a single mass. Had it machined and resurfaced. Works great.

[ecc3189]

Well, to be safe I put the m20 early starter back on. So now the only problem with getting it to start has to be wiring...so off to the wiring diagrams for me. Any help would be appreciated from anyone!

Currently when I first try starting the car after reconnecting the battery, it clicks the solenoid but doesn't spin. After the first try it just doesn't do anything and the temp gauge still does its all the way right and then left dance..not sure what that is about

[ecc3189]

Problem solved, I added a ground to the passenger side and cleaned the ground strap I had on the driver side. IT LIVES!!!