97 E300D Sudden Shutdown - PeachParts Mercedes-Benz Forum

jim314 · #1 10-26-2006, 08:37 PM

I hope someone on this forum, in their infinite wisdom, recognizes these symptoms. Actually two symtoms:

1) Periodically the motor will just shut down like the key was turned off. I have to let it sit for 3-4 minutes before the GP light comes back on. If I try to start it before the light comes on and goes off, it just cranks, no fire even with a warm motor. After the GP light comes back on and goes off, no problem with starting right up.

2) I think this is related somehow. Periodcially again, after turning the motor off and going into a store or refueling, when coming back out and trying to start again, no GP light. I sit 3-4 minutes, try again and the GP lights, goes out, and can start the motor with no problem.

Both of these problems seem to happen in cycles. I can go two weeks with no problems and then suddenly it happens. The car runs great otherwise, actually purrs on on the interstate with plenty of power (at least as much power as a 97 E300D can produce) so I don't think it's fuel filter related. On cold mornings, the glow plug light cycles and the car starts with no problems, so I don't think it's the GP's either. What I'm afraid of is this is some type of intermittent electrical problem that is going to be hard to track down. Has anyone else experienced this same thing? And if you have, what was the problem. Thanks in advance for the advice.

Jim

TimFreeh · #2 10-26-2006, 08:45 PM

Do a search on "K40 relay" - common problem that is easily fixed.

jim314 · #3 10-26-2006, 09:14 PM

Thank you, I'll do that.

mitcheeew · #4 10-26-2006, 10:43 PM

Up until 2 weeks ago, I had a 96 E 300 that was doing that. Started as yours back in August. I replaced practically every component in the fuel supply,as well as replacing O rings & washers on IP.The problem got progressively worse & in the end after replacing :all filters,lower fuel pump (near tank) "K 40 relay,fuel shut off selenoid,discovering IP leak, & then fuel line leak,it ran fine. Hopefully yours won't take as many trials to fix. I would seriously first look / inspect & test all fuel supply lines to see if they're sucking in air. I wonder if my complications happened because the system ran dry too many times. When I searched the forum I swore it was the infamous K 40, but after installing it,problem persisted. I just sold the car, & gave the K 40 with it. too bad..Good luck.

jim314 · #5 10-26-2006, 11:13 PM

Well that's encouraging

I think the first replacement will be the K40. I can't find any fuel leaks. Now I just got to figure out what a K40 looks like. I know about where it's located after reading all the posts from the search. I hate not having anything to do on the weekends.

TMAllison · #6 10-26-2006, 11:19 PM

In this instance i vote for the K40 relay also. It is probably responsible for cutting power to the shutoff solenoid when driving and the GP relay when trying to start.

The CEL is not on, right?

The K40 is number 98. http://www.detali.ru/cat/oem_mb2.asp?TP=1&F=210020&M=606%2E912&GA=722%2E438722%2E600&GM=717%2E446&CT=F&cat=45P&SID=54&SGR=040&SGN=03

jim314 · #7 10-27-2006, 07:43 AM

Thanks for the link Terry. The CEL doesn't come on until the motor dies. Goes right off after it starts back up.

TMAllison · #8 10-27-2006, 09:47 AM

You should get that code. May well be it is a fault recordered at teh shutoff valve if/when power from the K40 relay was interupted causing it to close while driving....but could be something else.

jim314 · #9 11-02-2006, 02:01 PM

I'm going to declare victory. But first, I want to thank everyone that helped diagnose this and give me the courage to go ahead and tear into the K40 relay. I didn't do it without much trepidation.
After reading the responses to my original question, and many of the older posts about the K40 relay, I located it last Sunday morning. I removed it from the car and broke the tabs holding it together. I pulled the relay out of it's case and it looked brand new, no problems that I could see anyway. The solder joints are very small, so I got a jewelers loop and looked at them magnified many times. There were several with tiny cracks, some looking like they ran all the way around the solder joint. I ended up resoldering every joint, whether it looked cracked or not. Put it back in the car and the glow plug light came on and the motor started right up. There hasn't been a single instance of the glow plug light not coming on or the car suddenly shutting down since I did this.
So thanks again to everyone, I would never have been able to do this on my own!