1991 M5 won't start - help please

[Springfield1952]

I have a 1991 e34 M5. It has been sitting for a few months in the garage. I put in a new battery today. When I turn the key I get nothing - nothing. No clicking, no noise, zippo. I checked the fusable (sp?) link near the battery and it seems fine. All fuses seem okay and I'm stumped where to turn. Any help would be appreciated.

[Dr. evil]

are the battery terminals clean?

[bubba966]

I'd be asking this question over here http://www.m5board.com/vbulletin/e34-m5-discussion/

When you turn the key does it disengage the steering lock? As you're getting nothing my first guess (assuming battery is charged and connection is good) is that your steering lock is broke. Easiest way to tell if the steering lock is broke is if the steering wheel won't unlock when you turn the key over. If you had an automatic (which you don't) the transmission wouldn't be able to shift out of park either as a busted steering lock also leaves the tranny locked.

Can give you part #'s and info if that's the case. If so, build date & airbag or no airbag info would be needed.

[Springfield1952]

The battery is brand new, shiny clean, fully charged. The key unlocks the steering wheel. all the lights come on, seatbelt chimes are chiming. But when the key is turned to the start position, nothing. And it has an airbag.

Before it sat it always started with no problem.

[sal_park]

The battery is brand new, shiny clean, fully charged. The key unlocks the steering wheel. all the lights come on, seatbelt chimes are chiming. But when the key is turned to the start position, nothing. And it has an airbag.

Before it sat it always started with no problem.

Perhaps the starter motor is stuck ? Turn the ignition on (to unlock the steering) and:

a) pop it into first, engage the clutch, take the handbrake (parking brake) off and rock the car backwards and forwards (the more people the better)

or

b) if you have a hill/incline you can go down it and try to 'unstick' the starter motor by bump starting it.

or

c) smack the solenoid on the starter motor with a rubber mallet while someone has the key turned to the start position


With any of the above please be careful !

Also, even though the battery is brand new, do you know if it works ? You many want to prove it by trying to start another car with it.

Or have you tried to jump start the M5, eliminating your new battery from the equation ?
( Given you can't open the rear doors without power you must have done something like this already* )

hth

Sal

* assuming the battery is under the rear seat.

[whiskychaser]

You didnt mention if the dash lights dim when you turn the key. If not, power just isnt getting from the battery to the starter or there is a break in that circuit. Couple of things to look at:
1. Is the earth lead from the engine to chassis OK? Confirm by connecting a jump lead from the engine block to the body and try the key
2. Are you getting a low tension voltage at the solenoid? Confirm by connecting a bulb and light or DMM to the small solenoid terminal and turn the key. If not, check starter relay
3. Starter stuck? Dash lights should dim
4. Starter solenoid stuck? Give it a tap while someone else turns key. There is another test but I dont want to encourage you to risk setting fire to it or injuring yourself

[bmwrp8]

not sure if it has but immobilizer?

[Dave M]

Lots of good advice provided already. You stated the battery is "fully charged". Have you tested it at the terminals or are you assuming its charged since its new? If you haven't tested it, grab a DMM and do it.

I think someone may have mentioned testing for voltage (12+V) at the starter solenoid. If so, I just said it again ;)

Dave

[Springfield1952]

Okay! A laundry list of work for me tonight - thanks for all the input. To answer a couple of the suggestions:

No, the dash lights do not dim when the key is turned to start. Everything appears and sounds normal, all the chimes chime, the lights on the dash come up, there's just nothing when the key is turned. I will roll the car tonight to make sure the starter is not engaged. The battery is brand new and the voltage checks out with a DMM. Terminals all clean and brushed before connecting. I'll double check tonight.

If it's the solenoid I'll have to wait until the weekend when I can get some extra help.

Anyone know how to check the "immobilizer" function?

And bubba966, I did post on the M5 site - thanks for the tip.

Thanks for all the support.

[Derek A.]

You can use a jumper wire at the diagnostic port to put 12v directly to the starter solenoid. That will confirm that you do not have some alarm/obc/ignition switch problem. Just make sure you have he ignition off and the car in neutral before jumping the wire.

[Tiger]

Don't forget the starter safety switch... by the clutch... push the clutch in and make sure that switch goes in and out.

[Blitzkrieg Bob]

not Sure If It Has But Immobilizer?

It's A 91

[Blitzkrieg Bob]

a) pop it into first, engage the clutch, take the handbrake (parking brake) off and rock the car backwards and forwards (the more people the better)
or

b) if you have a hill/incline you can go down it and try to 'unstick' the starter motor by bump starting it..

OMFG....DO NOT EVEN TRY THIS.....

never roll an S38 powered car backwards in gear...all it takes is to get some slack in the timing chain and you are hammer f*cked if you slip a few teeth off a sprocket.

[Blitzkrieg Bob]

don't Forget The Starter Safety Switch... By The Clutch... Push The Clutch In And Make Sure That Switch Goes In And Out.

It's A 91

[Blitzkrieg Bob]

Sounds like the solenoid is stuck or dead.

Try to jump pins 11 and 14 in the big data plug. If that does not do anything put the front up on stands or ramps and try to jump the solenoid terminals to spin the starter motor...if it spins but does not engage the flywheel. Your solenoid or the wire to it are suspect.

[Tiger]

Are you saying you can start a manual tranny BMW without stepping on the clutch? Of course you can't... there is a safety switch.

[Blitzkrieg Bob]

Are you saying you can start a manual tranny BMW without stepping on the clutch? Of course you can't... there is a safety switch.

I dunno, I started mine this morning...maybe I am doing it by habit..but I don't remember having to step on the clutch...Hmmm I'll have to take note when I start it tonight.

[Dave M]

Are you saying you can start a manual tranny BMW without stepping on the clutch? Of course you can't... there is a safety switch.


I'm saying you can start a manual tranny BMW without stepping on th clutch ;)

Did it 4 times today,

Dave

[Tiger]

Wierd... I though all manual transmission cars must have starter cutoff safety switch to prevent accidental surge while cranking engine.

[Paul in NZ]

Wierd... I though all manual transmission cars must have starter cutoff safety switch to prevent accidental surge while cranking engine.

i have never driven a car that requires this,only a couple of late model motorbikes...

[Jr ///M5]

The clutch switch simply shuts down the cruise control if it is engaged. No need to apply clutch for starting.

Bob's right, you stand a chance of bending a valve if you roll that sucker backward in gear, that's why they say, "In a spin, clutch in"...

M5's of the era, just like all E34's do have the "immobolizer" or "anti-theft" feature built in to the OBC. It disables the starter power so the vehicle can't even be hot wired. Maybe there's an outside chance that before storage, a code was entered and forgotten about and the car is just doing what it has been told to do. That's the purpose of the code button on the OBC. I can't remember if there is a work around to get the code off the OBC without going to the dealer or not. That's why for the past 10 years and 3 E34's I've never messed with that feature, it's because I can't remember crap anymore....now, what was the question again?

JR

[Blitzkrieg Bob]

M5's of the era, just like all E34's do have the "immobolizer" or "anti-theft" feature built in to the OBC. It disables the starter power so the vehicle can't even be hot wired. Maybe there's an outside chance that before storage, a code was entered and forgotten about and the car is just doing what it has been told to do. That's the purpose of the code button on the OBC. I can't remember if there is a work around to get the code off the OBC without going to the dealer or not. That's why for the past 10 years and 3 E34's I've never messed with that feature, it's because I can't remember crap anymore....now, what was the question again?

JR


I think the OBC immobolizer system resets when the battery is disconnected, so it would be disarmed after a dead battery.

[BMWDriver]

It happened to me once that I misentered the code I usually put in. So, the procedure is to unplug the bat, re-plug it in and the OBC initiates a countdown of 15 minutes while the key is in position one. Until the OBC reaches "00:00" you cannot start the engine.

[Springfield1952]

It happened to me once that I misentered the code I usually put in. So, the procedure is to unplug the bat, re-plug it in and the OBC initiates a countdown of 15 minutes while the key is in position one. Until the OBC reaches "00:00" you cannot start the engine.

Just trying to understand all this. So I should disconnect the battery, then reconnect and turn the key to position 1 and the OBC will start a countdown timer that runs for 15 minutes. After 15 minutes the car should be reset and if that is the problem, the starter should be getting power. Is that right?

[ILoveMPower]

Is there a red light on next to the OBC? If so I believe this is the OBC immobiliser function at work

[Ross]

Check for power windows and such. Me say the fusible link.