Car is dying occassionally - PeachParts Mercedes-Benz Forum

190edude · #1 11-08-2004, 02:50 PM

Did a search and came up with a billion possible causes for this but let me see if I can give some specifics that might ID the problem:

Car will occassionally die when coming to a stop. Happens maybe 3 or 4 times a day in city driving.

Suspected possibly ICV or OVP. Cleaned ICV real good and checked OVP. Fuse is still good did not check the module. Anyone know what reading I should get if I put a meter on it?

After I cleaned out the ICV I noticed something new. With the car in park, I would rev up to about 3.5k or 4k rpm and let up completely on the throttle, the car would die just about everytime I did that. It had not done that before.

Does this give anyone any idea what might be happening and help narrow it down any?

rudy · #2 11-08-2004, 04:23 PM

Sounds like your "fuel pump relay " is going south. Have it check and/or replace ...Hope this helps ..

ejsharp · #3 11-08-2004, 05:18 PM

My guess is the ovp relay. Fuse seldom blows but the relays frequently go south.

Do a search to see if you can find a test for the relay. I don't know of one eventhough I have had to replace mine twice so far.

psfred · #4 11-08-2004, 07:40 PM

Replace the hoses on the ICV if at all hard -- mine were so hard they were actually loose on the barbs and leaking air something fierce. Also check for other vac leaks. Stall on decel is usually a bad idle control valve sticking shut, but a significant vacuum leak will also do you in from the resultant overlean condition at idle, engine doesn't pull enough air through the fuel meter to give enough fuel to stay running.

You must fill the valve with solvent (brake or carb cleaner), cover the holes, shake for a bit, then dump the solvent until it's completely clear. This will take a while, there is usually a ton of stuff in there.

If that doesn't fix it, replace the OVP.

If it also hiccups or stalls while driving sometimes, you probably also have a bad fuel pump relay.

Peter

jppowell · #5 11-08-2004, 08:59 PM

My 89 260E had the same problem. Spent months trying to figure it out. I replaced OVP and fuel pump relay and it fixed it. (Swallowing hard first. I just couldn't have this continue and I could not figure out how to test, other than visual inspections for damage. I actually think it was the fuel pump relay in the way the car just quietly died, usually decelerating for a turn. But that is my gut feel.
I think I still have a vacuum leak somewhere, but the car has not died since the two parts were replaced.

ejsharp · #6 11-08-2004, 10:30 PM

I reread you post and I'm almost certain it is your fuel relay. The stall happens because there are little electomagnets mounted to the circuit board of the relay. These are relatively heavy components of the board and because of ther weight, cracks form where the pins of the magnets are soldered to the boards circuit. The change of motion of the car and weight of the magnet coils causes the cracks to open and to lose contact with the boards circuit, thus shutting down the fuel supply.

You can easily repair the relay with a few drops of solder. Pull the relay... open it up (case separates at the bottom edge... then using a magnifying glass look for circular cracks (around the pin being examined) in the solder beads of the circuit board (back side of board). One to three of the beads may have cracks around the pins that stick through to the back of the board. To repair simply remelt old solder around the pin and drop a dash of new solder on the pin.

Use thin wire flux core solder. You can buy it at home Depot or Lowes in the plumbing department for a few dollars. Electric soldering iron can be purchased in tool section of store for about $6.00.

Presto! You saved yourself a small fortune.

190edude · #7 11-09-2004, 08:16 AM

Sounds like a plan. Only question I have is where is the fuel pump relay on the 190e. I have the service manuals, but I cannot find any reference to location on it.

mctwin2kman · #8 11-09-2004, 08:27 AM

Behind the battery there is a black cover. The fuel pump relay, OVP, and Klima Relay's are all back there.

190edude · #9 11-09-2004, 09:43 AM

Never mind, found it.

190edude · #10 11-09-2004, 01:52 PM

Well, pulled the fuel pump relay opened it up and there were no signs of cold solder joints or cracks around the pin mounts. Put it back together, stuck it back in and now the car does not stall anymore. My guess is the relay just needed resetting. Only thing I need to adjust now is a fast idle. Mysteriously enough several gremlins cleared themselves up as well. Speedo and tac now work correctly and cruise control works again.

190edude · #11 11-15-2004, 11:36 AM

Pulled the Fuel Pump relay, checked all the solder and found no cracks or problems. Reinstalled it and the car ran perfect for 3 days. Now the stalling has started again.

Any ideas now?????

190edude · #12 11-15-2004, 02:35 PM

Checked the idle control valve again and it was not completely opening and closing so I freed that up and then checked the voltage coming to the ICV and it was 0v. Checked the ohms and it was an open. Next question is, where does this get fed from some I can go there and check the connection there?

psfred · #13 11-15-2004, 09:48 PM

Engine computer.

Probably time to replace the OVP.

Peter