Stalls at any speed W124 M102.963 - PeachParts Mercedes-Benz Forum

vegadonovan · #1 10-14-2007, 12:50 PM

Hi all,

It seems that the car now stalls at any speed making it safety hazard to drive it. It happens like this:

1) car will stall and dash likes all lighted , you won't notice until the power steering is gone.

2) If you pull to the side of the ride and crank it immediately, it will start normally and stall after 1-2 seconds. Seems like a fuel cut off as there was no stumble or shakes. Tachy just drops to 0 immediately.

A few attempts back to back would not bring up the car. If you wait for 30 seconds or such, it will start and nothing seems to be wrong.

3) It can happen anytime and anywhere but not always.

4) I did notice that there is a draggy feeling once in a while. A sharp braking feeling when you coast, very noticeable that passenger will ask why the brake was applied when coasting.

What could be wrong? From what I read, it could be one of the following:

1) Fuel pump relay
2) coil
3) fuel pump itself
4) distributor cap/rotor ( I checked under the cap, some carbon tracking but not serious
5) Trigger board ( Left fender which has the diagnostic port)

I didn't want to throw money at it or go to the dealer if I can try to swap some parts from the puller.

Thanks

vegadonovan · #2 10-14-2007, 12:54 PM

By the way, when it stalls, it's not even noticeable. Won't cough or sputter or hesitate, only when power steering is gone then its known. All music and blower will still be on. Thanks

vegadonovan · #3 10-16-2007, 07:41 AM

Hi all,

An update after a visit to the mech.

1) Distributor rotor and cap checked. mec sees no immediate tell tale signs that they could be failing.

2) Ignition coil tap by a spanner when engine is running. nothing is observed; rather unusual way of checking I would say, wait till I relate what they did to the fuel pump.....

3) Ignition control module tapped with a spanner again when engine is running.... no effects noticed.

4) Fuel pump relay pulled out when engine is running... engine died. What did they expect?

5) Checked ICV... Commented on a lazy ICV, I replied I rather get a high idle than a dead engine.

6) Now the fuel pump. They connected a fuel pressure gauge on the fuel line connected to the fuel distributor near the windscreen. Another took a big metal hammer and went to the back and started hammering at the bottom of the fuel pump. Car is not on jack. Saw no noticeable effect on the pressure and commented that the pump seems healthy.... I almost use the hammer on him.... just to prove he is healthy

7)Went for a 2 test drives, car is totally obedient like a student in front of the discipline master.

8) Changed out the V-belt which maskes a racket in another post.

9)And they commented that the CO2 is too lean and adjusted the mixture screw. After which the car experienced a high idle. And they had to tune it back. Now the car shakes at idle.... got to go back again.

10) They pry open the Fuel Pump relay and commented that it looks perfect; no need to change.

11) Klima relay checked as well. nothing unusual.

12) Mec commented that he can't do much on this stalling problem. They could only know the root cause until I had to tow it back if its totally out.

I went to a puller and got a used FPR from hungary aftermarket and replaced it.

So far car has not done any stalling yet.

I will update again.

Next possible change:

1) coil - cheap
2) Ignition control module - 166 USD used.

Anyone suspects the OVP? I checked the fuses. nothing wrong. The worst that this unit can do is hard start or bad idle right?

Thanks

ds190 · #4 10-16-2007, 11:31 AM

No, the OVP can cause symptoms such as you are experiencing. Just because the fuse(s) is(are) good doesn't rule out the OVP relay itself. I had similar behavior with my 91 300TE 103 engine some time ago. The very first thing we did was replace the OVP. Problem solved.

vegadonovan · #5 10-16-2007, 08:28 PM

Hi,

Any possible way of testing the OVP? Intermittent failures which I read from a lot of posts has a lot of other culprits possible.

Thanks so much for the help!

vegadonovan · #6 10-17-2007, 07:23 AM

Just an update. Its been 3 days since the last time it stalled while engine was on.

I wondered is it the fuel pump or the tinkering by the mech did some wonders.

Still I have this draggy feeling and slow to accelerate. I know my bowden cable is missing the nylon screw to adjust it but is shouldn't be a problem.

The problem is that it decelerate so fast when I let off the gas.... Seems like brakes were catching.

Still monitoring before venturing to coil and CPS and lastly ICM.

Thanks

vegadonovan · #7 10-24-2007, 07:29 AM

Hi all,

Just an update, since the last time I posted, I had no recurrences of stalling.

Car drives fine now. All I had changed out was the Fuel Pump Relay.

Coil wasn't changed since It doesn't seem to be the problem.

What I had also done was to top up the tranny fluid as it was not even appearing on the dipstick when hot. It has a leak but not massive. So monitoring it now.

If there are no more stalls again, I will close this thread as Fuel Pump relay being the cause of it.

Thanks