Intermittent No-Start Condition - '94 C280

[jgl1]

'94 C280 with 53K miles has an intermittent no start condition - when the ignition key is turned, all instrument cluster warning lights illuminate and then nothing else happens: no clicking sound, no starter activation, just silence. Repeated start attempts are typically unsuccessful, as is jiggling the key in the ignition switch. Then, perhaps 10 minutes later the vehicle starts and runs flawlessly. The no-start condition is quite random, happens infrequently (6-8 times a year) and does not appear temperature/weather related.

The vehicle has had this problem since new; despite repeated attempts, the dealer has been unsuccessful in locating the trouble - no fault codes are ever displayed. The ignition switch has been replaced but the problem continues.

Any suggestions? TIA.

We are having a similar problem with our C220. We bought it a few months ago, it's a 96 with 93000 miles. We started having random no starts, so in reading off the message board everyone recommended changing the OVP relay. So we did and it started every time for a week then it started having the same problem again, it also stall on us once. We have no idea what could be wrong. We have been told to check the fuel sensor unit or try having the wire harness replaced. I talked to our MB dealer and was told the wire harness alone without tax and not including installation was a $1000. So we are hoping someone out there may have some other suggestions to try first. This is our first Mercedes and we love driving it, so we can't wait to get it fixed.

[Mike Michalek]

The starter could have a dead spot in it. I had the same problem on my Celica. I brought a rebuilt starter and they over tighten the contacts. Which made the new starter bad also. Talk about pulling your hair out trying to figure out the problem. Now when I buy any rebuilt parts if they can be tested I insist that they test them first.

[mbdoc]

The 1994 & later US model C-Class have a starter interlock relay!!
On cars without an alarm system the central locking system MUST send signal to this relay before the starter will engage.
If the car has a factory alarm then the signal cones from the alarm ECU.
Next time that this happens TRY locking & unlocking the car several times & then see if the starter will work.
ALSO the central locking system MUST work.

[David C Klasse]

MBDOc,
I read about this in my owner's manual (starter will not engage unless doors are unlocked using the key)...

But I tested it...

I left the windows down, locked the car with the key, then reached in and put the key in the ignition (w/o unlocking doors), and it still started!?

[mbdoc]

David, someone has by-passed your starter interlock!
I have by-passed many myself!
You still need a key to start the car.

[David C Klasse]

OH

Perhaps the alarm people did it! Oh well, when my alarm is armed, the started is disabled anyway.

And what do you mean I still need the key to start it? Is it not possible someone could shove a screwdriver (theoretically) and get it to start (if no electrical intervention.. no chip in key).

Ok, I went out to try your suggestion about locking and unlocking. The first time I tried to start the car it almost started, so I locked and unlocked the car a few times and then tried to start it again. Nothing, so I tried the process over again still nothing. Any other suggestions??? Thank you so much for the help!!

Hi, this is regarding our '96 C220 that my wife has posted about. I'm not sure if my wife explained the problem right, and it sounds like some of you might be confused too.

FYI:

The owners manual might be incorrect. I have noticed that with the alarm activated, the starter will engage, but the ignition won't. I believe that the relay you guys are talking about kills the ignition, not the starter. Any comments?

Our problem:

The starter seems to engage just fine. If I try to start it, the motor will start for a fraction of a second, then stall immediately. If I touch the gas pedal at all, the engine floods. On the rare occasion that it does start, the motor runs and idles just fine. To start any motor requires fuel and spark. Since it almost starts, and runs fine when it does, I assume it's getting both fuel and spark. Since the engine seems to flood if I touch the pedal while starting, I'm assuming it's getting enough fuel. My theory is that it's not getting enough spark, or not cranking the engine fast enough to start.

Any ideas? Could faulty plug wires or fouled plugs cause this? Could the starter not be cranking fast enough cause this also?
The motor has almost 100k on it and probably needs new plug wires anyway.

Thanks,

--Mark

[David C Klasse]

Well your accelerator is electronic. If the car is not on, the gas pedal will not be doing anything. (Actually 1/4 of the travel is mechanical................come to think of it).

Just wondering if the electronic accelerator is active while the car is only turning over.

That would seem to be the case, although hopefully someone here can answer that definitively.

Since the car idles and runs perfectly once it *does* start, I'm thinking the problem isn't related to the fuel system. I'm still coping with owning such a complex vehicle.

Could the crank sensor (or whatever it's called) cause the ignition to cut off? Does it have a threshold speed where it won't turn the ignition on until the starter cranks a certain RPM?

I'll probably have to take it to the dealership since the manual (on CDROM) is on back-order, but I'm certainly interested in understanding the problem that's keeping us from driving our cool car!


--Mark

[David C Klasse]

What about the wiring harness? Have you replaced that? Has it been replaced? Is it detiorated?

The W202 Service CD is in?! They told me it wouldn't be until a few months after the W140 was to be released in October! I'll call them now!

No we haven't replaced the wiring harness. We will probably hound the dealer and / or the factory. From what I've read here, sounds like I have a decent chance of getting them to do it for free.

Thanks,

--Mark

Update:

I charged the battery on a charger and now it starts every time, although it still hesitates for a split-second when it first starts, then it idles fine.

I've seen american cars that would start with the battery almost dead, turning the starter at like 1 rpm. Man, these MB's sure aren't very forgiving!

--Mark