csnow,
In other words, you are saying that it could be a fuel pump problem rather than the relay? Maybe I should change the relay first since it is much cheaper (I assume) & if the problem persists, then it is the fuel pump?
I couldn't find the fuel pump relay in my W124 as shown in Azhari's pic; I guess it must be under the car.

Could be either. Or some other electrical problem.
Tough to diagnose if you cannot reproduce the problem while stopped.

If it cuts out pretty reliably while underway, you could rule in or rule out the Fuel Relay by jumping the pins, and driving around.

__________________
1986 300E 5-Speed 240k mi.

azhari, csnow, ejsharp
I replaced the fuel pump relay today. So today is day 1 and will monitor for a couple of weeks. Hope the "sudden death syndrome" will not recur. Incidentally, I was told that the other relay next to the fuel pump relay is for the air-con. So I didn't bother with it. Keeping my fingers cross now!

autori

That is correct, the relay next to the fuel pump relay is for climate control (a/c) and has the word "KLIMA" printed on it.

Just for your info, if the fuel pump relay doesn't work out, the OVP relay costs about half the price of the fuel pump relay.

No worries, dude. Let us know how it goes.

Good luck!

By the way, my experience with a failing fuel pump is that it would buzz louder than normal and sometimes, the buzzing itself would be inconsistent.

A normal working fuel pump should buzz consistently while the engine is running and the sound can only be heard from the exterior of the car when you are standing close to the rear.

My 2 cents...

Cheers.

azhari,
Forgive my ignorance, but just where is the OVP relay? Is it the air-con relay next to the fuel pump relay as in your picture? I only see 2 relays behind the battery.

In my car, the fuel pump relay is in front of the a/c relay.

The OVP relay is located next to the ECU.The updated version (like mine) is a silver relay with a red top. The older version is silver with a black top.

Do you see it?

Your car has a M102 engine with KE-Jetronic, just like mine.

azhari,
Afraid I don't see it. In your pic, it is very visible, but in my W124, it's not in that position. I tried asking the dealer where I bought the fuel pump relay, but he just look blankly at me and ask me for the part number. Couldn't give him. Anyway, I read somewhere in this website, that the OVP is buried down next to the 2 visible relays that I saw. Looks like I will have another look later. Today is day 2 since I changed the FPR and day 5 since the last occurence.

Is the plastic cover removed from behind the battery so you can see the ECU and OVP?

I can't remember if it's in the same location in a M102 W124.

Or you could also look inside and around the fusebox (driver's side).

azhari,
Yep, I have to remove the black plastic cover behind the battery. There will be the FPR and the relay for climate control. That's all. Like you said, the OVP could be on the other side, just behind the fuse box. I'll have to check. Thanks for accomodating my queries.

Today is day 05 since I changed the FPR and day08 since the last occurrence of "sudden death". The car still behaving itself but I still won't be confident yet for at least another week. Will keep this forum informed. Thanks!

Azhari/Csnow/Ejsharp & others'
Just to update you all on my "sudden death" problem. Well, its been 5 weeks since I replace the FPR and thank God the problem has not recur. Certainly looked like the relay is the one giving me the problem. Thanks a lot to you guys out there. I'll certainly be a good samaritan myself if the opportunity arises! Cheers!

I think this was definitely the problem - I had exactly what you had, though mine never stopped whilst driving, it would just decide not to start on occasions.

When it finally quit, I spent quite a while (though not nearly as long as you might) figuring it out, then resoldered - never had a problem since.


I believe you'll be fine now.


Rusty

__________________
190E's:
2.5-16v 1990 90,000m Astral Silver
2.0E 8v 1986 107,000m Black 2nd owner
http://www.maylane.demon.co.uk/190esmall.jpghttp://www.maylane.demon.co.uk/190esmall2.jpg

Pentoman,
I certainly hope the problem is behind me. It's certainly scary when the engine just dies while you are driving, not to mention downright dangerous and you just lose confidence in the car knowing that it can happen again anytime. Well, you are certainly more knowledgeable about engines in the first place; me, I don't even know where the FPR is!! Now I have only 1 problem left and that is, the engine shakes while I am on D but not in N or P. My mechanic says it's time for a top overhaul. Guess he's right. Cheers!

Autori

I think you are too trusting and guessing that your mechanic is right could be an expensive waste of money.

There are a myriad of reasons why your engine could shake whilst in D but not in N or P. I am no expert but my guess is as you move it to D the idle speed drops (this is normal) and the engine becomes lumpier at low revs (normal) but you may have bad engine mounts (not normal) and this is transmitting the vibration to the chassis.

I offer this, not as a definitive diagnosis, just as an alternative scenario.

Do you trust me?

Get a second opinion or at least get this mechanic to explain his logic!

Good luck.

__________________
NormanB
230 TE (W124) 1989 with 153,000 miles on the clock - hoping for at least another 100K