no start

WWWWW · 25th March 2009, 02:28

Ok, selfishly admitting, I don't get on here until a problem arises -- go figure, my beast has been the rock-solid summer car without a problem .. until today.

She won't fire over! Starter cranks (as if there's no plugs installed). Engine is still hot and it's raining here so, I'll probably have to wait till tomorrow to investigate.
No problems starting - ever! (sounds electrical) My garage is FILLED with a head gasket project Snaab .... I'M SCREWED!!!
Any pointers? (i don't have a peak either) Is there a way to look up codes w/o one?
halp!!! (can't walk 30 miles to work tomorrow ... won't survive a day taking the wife's car)

TMcNasty · 25th March 2009, 05:56

Well a shot in the dark points to a fuel delivery issue. Most likely a fuel pump on these older M5's, but the fuel pressure regulator could also be messed up. Several recent threads. Check the fuses also! If you find a bad fuse there's a damn good chance that a failing pump caused it to blow.

If you read the two fuel filter replacement DIY threads you'll see pictures of the fuel filter attached to the fuel pressure regulator. The regulator has a valve just like on your tires. I'd drain the fuel from there to release any residual pressure. Then crank the car over for 5-10 seconds. Then see if a fair amount of fuel can be drained from that valve again.

At least it can be done w/o any expensive parts!

WWWWW · 26th March 2009, 02:22

Ok .. getting back to my g'raj basics ... no spark
(probably not endorsed on here but, I threw a shot of starting fluid down one of her throats ... not even a hic)
NOW, I get to learn about the ignition system. (at least I'm down to one system)
Not a fuse blown - that I can find. (although, my asscrack filled with rain probably didn't help the adventure)

Where to start with sudden loss of spark.???? I'll add, that yesterday was the first time I've had to drive her in the rain so ... something got wet - probably.

Any suggestions?

TMcNasty · 26th March 2009, 03:58

Sure I'll go for round two!

I'm going to assume your fuel pressure came back up doing the test I suggested? For the record I sorta made that up on the fly...that isn't any fuel pump 'test' for an M5 I read about here, but it seems to be logical. The fuel system IIRC runs at 5bar pressure...so after you re-crank/re-pressurize there *should* be pressure at that valve...*should* be. I assume there was?

A good, but not too easy, spark test would be to remove one coilpack from its normally installed position, but then reconnect it to its wiring harness. Then install any spark plug in that coilpack and ground the plug. You could do this by wrapping some stranded copper wire around the plug threads and then grounding the other end. As per a recent thread there is a grounding nut on the passenger side shock tower. Its the nut bigger than the other three. Its normally used for jump starting a dead car. You could use the M5's plug if you don't mind removing it and have a torque wrench to tighten it back up properly. Although air/fuel could come blowing out of that opening I suppose.

Have someone else crank the car over while you look for a spark! Be sure YOU do not become part of that circuit...it could be a real eye-opener.

firebird400 · 26th March 2009, 04:25

You should really find yourself a code reader. Either buy one, or borrow one from someone in your area. There's a few Chicago members here.

Couldn't it also be the immobilizer, though?

WWWWW · 26th March 2009, 04:50

Thanks guys - AGAIN!

I found the blown fuse ... after digging through some other posts. I have more pictures how to get here but, I'd really like to know what blew this fuse and what it's for. Anyone have that info?

And .. yea, need to get a reader AND a Bentley. Can't always just rely on you guys ... although, it's worked for me so far =) ... thanks again!!!

Wi_KeD_M5 · 26th March 2009, 05:06

Interesting. I'm glad you found out the problem.

I saw you chime in on everycredit's post about as well.

Do you know if the fuses in there only engine fuses or do they control anything else?

I am also kind of curious if there are any codes in your car due to the blown fuse. I figure something like this would blast a host of codes for things not turning on during the start process.

Of course it would stink if that is the fuse that controls the ability to write codes, but it couldn't be.

gsfent · 26th March 2009, 17:53

Quote:

Originally Posted by WWWWW

Thanks guys - AGAIN!

I found the blown fuse ... after digging through some other posts. I have more pictures how to get here but, I'd really like to know what blew this fuse and what it's for.

I don't recognize the fuse. Location??? Thx
Regards,
Jerry

WWWWW · 26th March 2009, 22:34

Ok - location;
Under the passenger side cabin air intake. Located in a sealed container.
Per pictures.
The closest fuse towards the firewall was blown.

Wi_KeD_M5 · 26th March 2009, 23:22

Quote:

Originally Posted by WWWWW

Ok - location;
Under the passenger side cabin air intake. Located in a sealed container.
Per pictures.
The closest fuse towards the firewall was blown.

Thanks for the pictures. I was actually checking in this area because to see how I could repair my E-Box fan. I had the hardest time getting the DME cover to come off and was actually not successful. It seemed like the cover was actually on a hinge.

Do you break any tabs getting the top cover off? Did you have to push it a certain way?

Thanks