• Welcome, Guest! We hope you enjoy the excellent technical knowledge, event information and discussions that the BMW MOA forum provides. Some forum content will be hidden from you if you remain logged out. If you want to view all content, please click the 'Log in' button above and enter your BMW MOA username and password.

    If you are not an MOA member, why not take the time to join the club, so you can enjoy posting on the forum, the BMW Owners News magazine, and all of the discounts and benefits the BMW MOA offers?

Starter not turning....

Hi Folks,

Pressed the starter button today (after turning the key) and not so much as a solenoid click. Charged the battery (2 years old). Valeo starter installed 5+ years ago. Did a rudimentary check for pinched, cut, and grounded wires and found nothing. The horn and lights work.
Measured the voltage on the battery as the start button is pushed and no drop in voltage. I have been remarkably fortunate in that this bike (1988 R100 RS) has never left me high and dry in the 10 years that I have added 60,000 miles to its total 85,000 miles.
I add this photo as I do not even know which module is the starter relay. Will someone point it out as well as tell me what a replacement part number is for a substitute?
Any other diagnostic tests you would suggest?

DSC_0208.jpg
 
I don't have same model as yours, so don't know which of the relays is the starter. Kurt is probably right, it is one of the three gray boxes. But, from the picture, hard to tell if those things above the coil are relays as well, or just connectors. Somebody will point out which is the starter.

In the mean time, can't hurt to disconnect each one of the relays and clean up the connectors a little, just to rule out corrosion.

Could the starter switch be the problem?

Barron
 
I just did this on my old R90S. We slide the connector slightly back from the relay and connected a DVM probe to the relay lead, the other end of the DVM to ground. Push the start button and look for power. We had power, but the relay only operated about 1/2 of the time, totally silent the other 1/2. The relay (not sure it is the same on this bike) was easy to open and repair. One of the small wires leading to the coil was broken at the solder joint. A bit of solder and all was well.
 
85 is the input from the starter switch. You can disconnect the relay and hook up a voltmeter to the wire that connected to 85 and the other voltmeter probe to ground. Turn ignition on and press the starter button. The voltmeter should show your battery volts.

If that works - with ignition off, relay removed, gear in neutral - connect 87 to ground with a 16 gauge wire. Juts tip on ground...and it should engage the starter. Means, the starter works and the relay has a fault.

But I like hint to do an easy visual inspection first: Remove the relay cover and take a close look.

/Guenther
 
I bought a new relay at NAPA - $17, cheap - and stuck it in. Oddly, when I pressed the starter button with the key in the OFF position, the relay would open and close, audibly. When the key was turned to the on position and the starter button depressed, no solenoid sound and no relay opening. Also, no starter turning.

I have an old working Bosch starter in the garage that I am considering swapping for the current one. Any other bright ideas?:banghead

Rick
 
I bought a new relay at NAPA - $17, cheap - and stuck it in. Oddly, when I pressed the starter button with the key in the OFF position, the relay would open and close, audibly. When the key was turned to the on position and the starter button depressed, no solenoid sound and no relay opening. Also, no starter turning.

I have an old working Bosch starter in the garage that I am considering swapping for the current one. Any other bright ideas?:banghead

Rick

IMO, take the original relay, and carefully dissemble, clean and re-assemble. Be careful because there is always a "hot" wire to the relay.
when you hit the starter button the relay relays the hot voltage to the starter. Be sure to make sure that the starter button is relaying the hot signal to the relay, and then that the relay is connecting the hot voltage to the starter. I would do this before I would replace starters,
 
I bought a new relay at NAPA - $17, cheap - and stuck it in.

I doubt you're going to get OEM functionality with a relay from NAPA. The OEM relay has internal features/diodes that the over-the-counter relay isn't going to have. Get the right relay or dig inside the current one and see if you can clean it up as others have suggested.
 
Oddly, when I pressed the starter button with the key in the OFF position, the relay would open and close, audibly.

Sounds the wrong way round. How did the Napa guy know which relay is right for you?

Before suspecting the starter test it by shortening the starter's battery connection to the starter's solenoid spade with and "OLD" screw driver.

/Guenther
 
I cleaned the female contacts for the first time in 10+ years and wiped the dust off the spades. Stuck the old relay back in and the starter turned right over.

This gave me pause as experience tells me that systems do not repair themselves. It can be argued that the contacts were fouled and needed cleaning, which they got.

I am planning to look further into why the NAPA relays did not work. Their use in this application came from a source here in Colo Springs who is both a friend as well as a known authority of the highest order on Airheads.

In the mean time, I had an opportunity to dissemble the starter button which tested OK. I also undertook one of those jobs that I have put off for years: the allen head that clamps the R control assembly had a stripped head. I got to drill out the head and remove the screw with a tiny spiral bolt remover and replace it with a fresh one.

This bike has been an absolute pleasure to own and ride and some of its systems are beginning to tell me they want some maintenance, so I am doing some of the more overlooked items now.

Thanks everyone for your insights and encouragement.
 
I am planning to look further into why the NAPA relays did not work.

What part did NAPA sell you? Joe 'Cuda Glowacki of the Airheads Beemer list doesn't offer any generic replacements for the '88 relay...he does for others model's relays. Joe is probably the best at understanding wiring, relays, etc., for Airheads.
 
OK, update. What appeared to be the starter relay was not indeed the starter relay. The bike would not start a few days ago, after several days of running just fine. Keep in mind that nothing was replaced. All that I did was to clean the terminals on the relay and give the battery a charge.

I had the bike towed over to Matthew Parkhouse's place. He removed the battery which showed 12+V. He then put a load on the battery and low and behold, it would not light a 20W bulb. He put in a new battery. End of story.
 
Another validation of the rule that 9 out of 10 electrical problems are actually a bad battery?

Good deal getting it fixed and great that you have Mr. Parkhouse within towing distance.

Barron
 
Matthew observed the relative scarcity of the problem - battery showing adequate voltage yet unable to sustain a load - in that in his experience, he has seen this less than a handful of times in the last decade.

Let this be a lesson to all of us.
 
Yes.

I tried a generic starter on my 1978 R80/7 with no luck. BMW starter was $28.15 from dealer. Since this will probably still be functioning some 30 years past my trip to the graveyard, its money well spent. Good luck with yours.
I doubt you're going to get OEM functionality with a relay from NAPA. The OEM relay has internal features/diodes that the over-the-counter relay isn't going to have. Get the right relay or dig inside the current one and see if you can clean it up as others have suggested.
 
starter not turning

I have frequently encountered this in batteries. Under load if the voltage drops rapidly yet returns rapidly on release its a defective cell, if it returns slowly it is either under charged or sulphated. Cell connectors inside can become open/high resistance. If open no danger just no start but a high resistance can heat rapidly enough to ignite the hydrogen gas inside & blow the top off of the battery = acid in face. Use caution around a battery.
 
How does one diagnose whether or not the starter button is working?

Find out which wire is the wire that connects from the starter button to the starter relay, and check both to see if there is hot input to the starter button first, and then check to see if there is hot output from the button (if there is hot to the button).

Your problem sounds to me like it is this or the relay. Don't just buy a new relay. Then can be disassembled, cleaned, and re-assembled and sealed with good success.

If there is hot going to the relay (from the starter button) then check to see if relay is working (clicking) and then see why there is not hot going to starter.
 
Back
Top