e30 starter wiring help

[BFT_Boyle]

I'm looking at a diagram right now, and it looks like the left terminal controls your unloader relays K7 and K6.

http://wedophones.com/BMWManualsLead.htm under 88 325 electrical troubleshooting. Page 30 of that PDF.

[BFT_Boyle]

Hmm, it must be one of the terminal cables then. The top large terminal will/should always have positive power (it has its own dedicated cable going straight to the positive battery post. The two smaller side terminals only see positive power when you are turning the key, so it must be one of those.

Usually, the smaller terminal on the right is what gets power when you turn the key. The terminals on the left get power (normally, I could be mistaken) once you turn the key and the solenoid contact closes. On older cars at least, those terminals were a way to bypass the ballast resistor on the ignition coil resulting in a stronger spark which helped start the car.

Now I'm just speaking from starter experience, I'm new to the e30 so it could be something else unique to the car, but as far as starter solenoids go, that's usually what the extra terminal is for.

That all being said, you will do no harm doing a trial by error and leaving one wire off at a time. Just make sure the free wire is not touch anything else.

[theserj]

Should I do a trial and error by reconnecting each terminal one at a time until I figure out which terminal causes the short? Or is that a bad idea?

[theserj]

Ok. Spark upon removing power from the starter while running is normal. That being said, Sounds like the starter is not your issue. The last thing I would try is disconnecting all the cables to the starter and try turning the key over. If nothing happens and the car still shorts out as it did before , then I would seal the deal on the starter being the issue.


Note: make sure the disconnected cables do not touch anything else. That lower larger terminal you can leave connected.

Okay buddy we are making progress. So I disconnected everything on the starter. Then connected the battery, turned the key... Obviously the car didn't start, BUT it also didn't short out meaning the problem occurs whenever I connect the starter.

So now with all that information, what could be the problem?
The terminal cables maybe?

[BFT_Boyle]

Ok. Spark upon removing power from the starter while running is normal. That being said, Sounds like the starter is not your issue. The last thing I would try is disconnecting all the cables to the starter and try turning the key over. If nothing happens and the car still shorts out as it did before , then I would seal the deal on the starter being the issue.


Note: make sure the disconnected cables do not touch anything else. That lower larger terminal you can leave connected.

[theserj]

No worries!

You will want to apply positive power to that terminal, not negative. Normally when you turn the key, power gets applied to the solenoid. The solenoid is basically a big relay which connects that bottom terminal to positive power.

So I ran the test as you described and the starter turned on and continued a nice spin. There was a big spark as I was removing the positive terminal from the starter.

TO conclude from this test, I have a healthy starter?
I just bought it last week from AutoZone I assumed the starter should be good.

BUT now what is causing the shorting problem when I try to start the car?

[BFT_Boyle]

Oh and you will want your negative terminal still connected to the battery as you normally would. You don't need your regular positive terminal connected to your battery, so long as the jumper cable you are using is connected to the positive post of your battery.

[BFT_Boyle]

No worries!

You will want to apply positive power to that terminal, not negative. Normally when you turn the key, power gets applied to the solenoid. The solenoid is basically a big relay which connects that bottom terminal to positive power.

[theserj]

There are two large terminals on the solenoid. The top one will have a couple main positive cables connected to it. The lower large terminal should only have one cable connected to it which goes to the start motor itself. That is the one you want to apply positive power to. This will bypass the solenoid and all other connections. I would use a set of jumper cables to touch positive power to that terminal. The motor draws a decent amount of current so that is why I suggest jumper cables. It should spin up the starter but not engage the drive. If it has a big spark (like you are touching the positive cable to ground) and the starter doesn't spin, then the starter motor is grounded/shorted out.

Sorry for all of the questions but I just want to make sure I have everything down before I try this to I don't ruin anything

I will connect the black jumper cable to the terminal on the solenoid going straight to the starter. Then I will connect the other end of that black cable to a negative end of a battery?

And nothing else should be connected?

Other than that I believe I have everything down as far as locating the terminal and watching out for a certain spark or noise. Thank you

[BFT_Boyle]

There are two large terminals on the solenoid. The top one will have a couple main positive cables connected to it. The lower large terminal should only have one cable connected to it which goes to the start motor itself. That is the one you want to apply positive power to. This will bypass the solenoid and all other connections. I would use a set of jumper cables to touch positive power to that terminal. The motor draws a decent amount of current so that is why I suggest jumper cables. It should spin up the starter but not engage the drive. If it has a big spark (like you are touching the positive cable to ground) and the starter doesn't spin, then the starter motor is grounded/shorted out.

[theserj]

Ok, I would try to apply power to the starter motor terminal to make sure it spins at least. It looks like you have a permanent magnet type starter which does have somewhat fragile magnets inside that can break if knocked too hard. Ive even seen them separate from the inside of the case (they are just glued in) If it's not a PITA, you could also just pull it and have them test to eliminate that.

Just FYI: you won't be able to test for a short via a multimeter on the starter motor. It will pick up ground through the brushes.

Okay so I have disconnected and reconnected everything at least three times and everything is in proper place. All of the terminals only fit in one of the slots. So now I will do the test to give power to the starter motor directly. How do I go about this?

Should I connect a battery to the starter directly? If so, which slots?

Thank you

[BFT_Boyle]

Ok, I would try to apply power to the starter motor terminal to make sure it spins at least. It looks like you have a permanent magnet type starter which does have somewhat fragile magnets inside that can break if knocked too hard. Ive even seen them separate from the inside of the case (they are just glued in) If it's not a PITA, you could also just pull it and have them test to eliminate that.

Just FYI: you won't be able to test for a short via a multimeter on the starter motor. It will pick up ground through the brushes.

[theserj]

Did the original starter have the two additional terminals? Mine only has the one for triggering the solenoid.

Also, did you bench test the starter before installing? If it's grounded out internally, that would cause everything to short out. Pretty common from your local Napa/O'Reilly, what have you.... (coming from 5+ years in the starter/alternator rebuilding business) Try applying power to the start motor, bypassing the solenoid (the lower terminal) and see if it spins. The starter s
hould turn over freely since the drive will not be engaged. The engine itself won't turn over, but for safety sake, pull the ignition and make sure you are not in gear!

SO i did not bench test it, just bought it straight from auto zone assuming it should be good. I did not mess wit the terminal on the left that comes straight from the starter since that one was already connected.

[BFT_Boyle]

Also, no electrical difference on washer location, however generally they come right after the nut.

[BFT_Boyle]

Did the original starter have the two additional terminals? Mine only has the one for triggering the solenoid.

Also, did you bench test the starter before installing? If it's grounded out internally, that would cause everything to short out. Pretty common from your local Napa/O'Reilly, what have you.... (coming from 5+ years in the starter/alternator rebuilding business) Try applying power to the start motor, bypassing the solenoid (the lower terminal) and see if it spins. The starter s
hould turn over freely since the drive will not be engaged. The engine itself won't turn over, but for safety sake, pull the ignition and make sure you are not in gear!