1996 Stalling 300E
 

Hello All:

I have a 1996 300E in perfect shape... except for the stalling. I have had it checked by 2 Dealerships and 2 mechanics.

We have changed vacuums, fuel lines...

The car did not stall all winter but when it get's hot, the car will stall.

Any ideas?

Let me know.

Thanks.

Matt Laird

I'm assuming that it's a '96 E300. It could be the K40. Mine engine quit while driving, and I think the K40 was at fault. From reading the archived threads here, they seem to cut out more often with time. Bad connections can definitely be temperature-sensitive.

I opened it up and resoldered the connections, and it's been fine since (knock on sheet metal).

This is a guess...but I had a similar problem with my 6.5ltr. TD Blazer when the EGR valve would get full of carbon and slugged up. I use to clean the EGR
valve and port periodically with a little carb cleaner and a popcicle stick to scoop out the thick stuff. The EGR on your MB is obviously different but just pull it and check to make sure its clean and functioning properly.

Did these "professionals" check fuel delivery pressure from the injection pump?
Or did they just replace lines?

Pull the fuel filter (if you have not already done it) and fill it or a new one with Diesel Kleen and put it back on while the engine is cold and run it. See if that helps at all when it warms up. I know its frustrating but try the cheapist things first....

K40
 

K40?

I'm a dope and have no idea what that is.

To complicate problems now my security system is coming on and not letting me restart the car for about an hour.

Does that make sense?

Thanks for the help.

Matt Laird

Matt, I am assuming your in the USA. All vehicles sold in the US from 1996 on have an On-Board Diagnostic System required by Fed. Law with a unversal plug under the drivers side dashboard. You need to to have someone with a diagnostic code reader run a scan on your systems at this point. You can also rent them or buy one and do the diagnostics yourself. It sounds like mutiple things are going on and the only way to sort them out is to read the trouble codes stored in the diagnostic system....it will at least get you pointed in the right direction.
Good luck!
Cheers

The K40 failure may not result in a code. Also, it seems to be a common failure in our cars as they get older.

It's inside the box under the hood, rearmost at the passenger side (LHD car - no idea about RHD). Remove the four screws, and the K40 is the piece in the front with (probably) three fuses. A new module is about $125 from the dealer here, special order. I took mine apart and noticed hairline cracks in many solder joints, so I resoldered it and hopefully it won't be a problem for some time.

When mine quit, the engine wouldn't restart immediately, but it did restart after a few attempts. There was no action by the drive-authorization system (DAS).

Note that while the '96 E300 does have OBD-2 as required by federal law, it really can't tell you much. There are only two tests that it supports, comprehensive and EGR. Mine coded for the glow-plug circuit after the failure, which is probably unrelated, and the code did not return after fixing the K40.

Search for K40 here. You'll find lots of posts.

K40 fixed problem
 

Thanks for the tip about the K40 relay. I'm going on two weeks with no stalling. But now my AC is giving me fits....:eek: .