Oxygen

I noticed this is starting to happen more often, at first I thought it was just something off.

This does not happen every time, but sometimes, especially if car has sat for a while when I go to start it, it will crank a few times then basically it stops and the RPM gauge goes all the way to max and then back down. Turn the key to the off position and attempt start again, it fires right up.

Sometimes it does this when it's hot, sometimes it does it when it's cold... I thought maybe the battery was going bad so I bought a new one, same behavior.

Any ideas on what this could be? I saw nothing out of the ordinary when diagnosing with SDS. Starter? Fuel Pump? Coil? Spark Plugs? Some sort of a sensor?

FormulaZR

Do any other lights/gauges act stupid when this happens?

If not, could it be a crank or cam position sensor acting up?

Oxygen

Nope, only the RPM gauge goes to the top and then back down.

The sequence is like this: CRANK>CRANK>RPM MAX>STOP happens in a matter of about 3 seconds.

radride

I had the same problem in my CL65. I use the keyless and go and I hit the button on the gear shifter and it did the exact same thing. Did it 3 times in a row and then the car finally started. This has happened to me maybe 4 times in the past 3 months. It hasn't done it for the past 9 weeks though so maybe it was just a minor hickup. Keep us posted on your progress.

R.K.

Oxygen

Okay glad I am not the only one! I stopped using KeylessGo when it first started doing it, seems to do it more often with the KeylessGo than it does by using the key (maybe that's just my imagination?)

Anyways, looking at this thread: https://mbworld.org/forums/3688172-post11.html seems like it might be a bad coil pack also.

mkhurley

My SL600 has done it a few times using the KeyLess-Go, turning the car off and then hitting it again causes the same, but holding the button down to start, it starts right up, or using the key.

That said, I've had misfires also, finally found a decent tech and he reproduced the misfires and is replacing the drivers side coil pack. Will know more when I get it back, hopefully next week. From other posts here it may resolve this starting issue also.....we'll see.

andymlow

Just had a no start this week on my 07 CL600. Cranked great but no start. Got towed to the dealer and the next day it fired right up for the tech. Unable to find any issue to explain it. Looking thru the NetStar, the car had 2 no starts prior to my ownership. On the first the starter was replaced and the second the battery. I'll bet it was the same issue and they were guessing at what caused it. Anybody else with weird starting issues on the biturbo 12?

Oxygen

Update... I changed my oil and it starts perfect every time now... Key or KeylessGo... what the hell?

Oxygen

Maybe it's the colder temperatures?

rennvader

My 2009 S65 also does this occasionally. Taking it into the dealer to see what gives.

Shifter

I know your problem. You need to have the flywheel greased with special grease...dealer will know this.

biker349

i've heard some keylessgo get stuck, or stiff and need to be replaced.

rennvader

Service advisor requested that I bring both keys in so I think you may be onto something with Keyless Go.

biker349

so what was the outcome?

rennvader

Dealership says they cannot reproduce and there are no error codes; so no idea...

andymlow

It died at the dealer as they were returning it to me
They ended replacing the engine computer and the keyless go computer and it is still having trouble
Sometimes no crank and sometimes crank no start

Oxygen

So what you're saying is no one actually knows what's going on?

andymlow

That is absolutely correct. Now they they think it could be the main wiring harness which takes 50 hrs of labor to replace. I'm thinking of trading for a new A7 or used M6

Thericker

I had exact same symptoms on my past S-class w220 turned out to be Crank Position Sensor.. (Someone already mentioned this may be cause 5-7 posts ago)

andymlow

That was the first thing they replaced long ago. I think they have it doped out now. It was a unit called the SAM or signal acquisition module that sits under the fuse panel in the engine compartment. They had the car running and jostled the SAM and the car went totally haywire. I'll know more in a few days but it seems promising.

2MANYCARS

Same issue with my 08 S65. I don't know if it's keyless-go related or mechanical faults with ignition & sensors. I tried holding down the start button until the car starts before releasing, that didn't quite solve the no-start problem 100%, so what I had tried is this, press the start button to turn on the car, wait 2-3 seconds then crank the car over, so far it'd been working good, car started every time. I know this technique seems ancient, but you have to remember our engines came from the 90's, and with ancient tech, sometimes old school does the trick.

andymlow

So what it really turned out to be was a corroded circuit board in the fuse box that all the computers and modules plug into. After they replaced that all was good. I think there was a crack in the fuse box that allowed water in.