Help Starter

[hjbutler]

1988M5 My son is driving it last night and car will not crank. I tell him to push start it to get home. This morning I wake up turn the key car starts perfectly. My son starts it washes it start it again to put back in the garage no problem. I have started it 2 more times with no problem. My question is do I need to replace the starter or is there another problem.

[Mark_88_M5]

before I worried about the starter itself. What is the condition of the battery and battery connections? Start with the easy and lesser expensive things first.

[vze33jng]

don't rule out loose or dirty battery connections! Not cranking always makes me check the battery first!

Ra!
'87 <b>528e</b> "is" 214.5k
'88 <b>M5</b> 193k (Head removed, ready for reassembly)
Dinan gen.1
OEM Front & Rear Fuzz-buster

[hjbutler]

The battery is 2 months old. I will check again. Thank you

[hjbutler]

In the electronic troubleshooting manual 1240-0 it does not appear to me that the two relays are required to have the starer engage. Am I incorrect in my interpretation? I can get some new relays but the car has started perfectly all day. Thank you

[wjosh]

My 91 M5 had a problem where it would not crank. When you turned the key it would kick the starter for half a second the go dead. I checked the battery, its connections, fuses and all that. The end result was a bad engine ground. This would happen in frequently to start with. However as time went on it got worse. You could always bump start the car.

It is easy to check this, the engine ground is located on the bottom of the car passenger side engine mount. Undo the each side, clean it skuff it up slightly and give it a try.

My experience.

wjosh
The start of my profiles:

[Mark_88_M5]

Looks like either a battery voltage or start contact in the ignition switch problem. Check the battery and it's connections. Next time it happens you could try jumping pins 14(12V) to pin 11 (starter hold in coil), in the diagnostic connector, and see if the starter will engage. If it does that would point you to a bad contact in the ignition switch.

[bruce in Montreal]

but that hardly pinpoints the problem.. really if the problem is intermittant you can not tell much by it working from the plug... maybe you can wire up a pushbotton starter from the diagnostic plug and run it inside the car.. THEN if you find a time when the key is turned all the way to crank position and held there and it does not crank.. and at the same time as you continue to hold the key forward, them you push the button, you may see if they key switch is a problem.. alternatively you can wire a small light from the small wire on the started to the driver's view and you will see if the solenoid is energised when you crank.


I know I know... always a stickler for details, but people are so easily misslead by lack of clear information.

[vze33jng]

The only thing keeping that starter from turning over would be:
A) Bad ground
B) No power from batt (Dirty and/or corroded terminal)
C) Intermittent break in lead from ignition to starter
D) Faulty ignition switch (Uncommon, but not impossible)

A few of these things can be checked for at any time, like B & C. To check B, you should pick up a cheap battery terminal cleaner that does both the battery post AND the terminal. Make sure they're extra clean and have a solid contact when reconnected. (You don't need to deform the terminal when you tighten it)
To check C, you can disconnect the switched lead at the starter and use an ohm-meter or a buzzer to test for continuity. However, this scenario is quite unlikely, unless some work has recently been done to stress the harness.
Unfortunately, A & D will be best tested with the problem present, and given the intermittant nature, are more of a shotgun procedure. If you're handy, then you can remove the starter and clean the ground, or inspect all of your motor-to-chassis grounds first to eliminate any faults there. Without the ETM handy, I can't recall if the unloader relay is energized when the starter is engaged, by the starter lead or by the absence of power from a different terminal in the switch, but it might help in your diagnosis to use it as an indication of the switch's functionality.

Again, I'll mention how my car had this problem twice, and the headlights and ALL accessories functioned, but if I tried to crank over, I got nothing. No clicks from the relays or the starter, and the accessories would lose power until I rolled the switch back to off and then on again. Going to the trunk and wiggling the gorund terminal was the fix for me, and then cleaning and tightening it when i got home. Another big tip that led me to believe it truly was the starter circuit from the battery: I could always bump-start the car.

Hope this helps Jack
'87 <b>528e</b> "is" 214.5k
'88 <b>M5</b> 193k (Head removed, ready for reassembly)
Dinan gen.1
OEM Front & Rear Fuzz-buster