1985 380SE W126 Stalling - Fuel Pump Relay ? - PeachParts Mercedes-Benz Forum

gmercoleza · #1 06-10-2006, 11:48 PM

85 380SE approx. 130K, suddenly stalled on me today. Had done it only twice in the last 2 months and approx. 5,000 miles of driving since I got it, all I did was cycle the ignition key off and back on and it started right back up (did this while rolling both times, no need to pull over). Today, cycling the ignition didn't help and I ended up pulled over on the side of the highway. Thought I ran out of gas (fuel gauge not the most accurate) so had a friend pick me up, got gas can, added 2 gals., and it started right up.

On way to gas station, it stalled again. Same deal - wouldn't start back up. A fellow motorist helped me push into a parking lot. Called my wife to bring VOM and service manual, checked out diagnostic for fuel pump relay, and jumpered - car started right up. Removed jumper and put fuel pump relay back, car wouldn't start anymore. Replaced jumper, car started right up. Ran to store, got box of paper clips for 38 cents, stuck a paper clip in there and did the same test, swapping relay back in, and each time the relay was in it wouldn't start. Put paperclip back in and drove it all the way home without incident. Had to pull the paper clip when I got home because the fuel pump kept running (I guess that's why MBZ put a relay in there and not a paper clip).

I just ordered a fuel pump relay from fastlane because I'm 99 percent sure this is the problem. But can anyone else out there confirm my diagnosis? Is there anything else I should be looking at? FWIW, previous owner experienced something similar a few years back and resoldered the fuel pump relay - he said it never happened again after the soldering job and I know he drove it quite a while after doing so. When I pulled the relay out I noticed there is still clear silicone from when he re-sealed it. So I'm guessing something other than the solder joints failed inside the relay, like maybe the contacts or something?

Maybe the relay, after 21 years, is just finally ready for the bone yard... Any comments?

86560SEL · #2 06-11-2006, 02:51 PM

Sounds like we have a similar problem. Ironically, I also have a SILVER, 1985 380SE. I have 266K on mine now. Mine stalls too, but not as often and it seems to be only on the 2nd trip or more out. If I am off and run several errands, it stalls during the 2nd or 3rd trip out. 1st trip it is fine. It stalls like when I am at a traffic lamp. It always starts right back up, but sometimes stalls back out when I place it in gear. Sometimes too stalls out when I start it and place it in gear, like when I leave a store or something. Its starting to agitate me, but not too big of a deal now, because when I have mulitiple errands, I usually take one of my other cars. I would like to repair it however, because I was thinking of taking it on my vacation next week, but we will probably end up taking the stationwagon. I have been told that my problem could be the idle control valve, but I have not had a chance (or the desire) to remove it. I am afraid of making something worse, or damaging something.

Here is a photo of my car, from your description, yours sounds identical. I am not sure of other shades of silver were offered in 85' or not.... is yours this color well? (Overlook the condition of mine, because my paint on the hood, top and trunk is very faded).

ctaylor738 · #3 06-11-2006, 06:42 PM

I would say that you have solved your problem.

gmercoleza · #4 06-11-2006, 11:10 PM

86560SEL, here are some pics of mine, I bought it for $800 from forum member Q. It's almost in perfect condition both mechanically and cosmetically, with recent timing chain & guides, water pump, and a bunch of other stuff. I just have to buff the paint (I know it's already "glossy" but I want it to really glow). The only weak area was the interior which was dried out from the sun, but I already took care of that with a full re-dye which ran me well under $100. I'm also in the process of re-gluing the wood. You can see pics of the interior - leather is in great shape now.

raymr · #5 06-12-2006, 10:38 AM

How did you redye the seats? Mine has the blue leather that's intact but faded and dried in some areas.

gmercoleza · #6 06-13-2006, 11:13 AM

I used SEM interior color. Do a search - it has been discussed before.

Monomer · #7 06-13-2006, 07:51 PM

Man, I wish my first-gen w126 looked that nice...

gmercoleza · #8 06-16-2006, 10:22 PM

Got my FPR from Fastlane today. Kinda weird - usually when I order stuff from Fastlane it gets here literally the next day or the day after. This time, it took a whole week. Oh well...

Anyway, slapped it in there and drove it around tonight several miles. Runs great! I'll keep the custom paperclip jumper in the glove box just in case (along with the old relay in the trunk).

MrT · #9 06-18-2006, 12:14 AM

Great looking MB. Like the pics.

gmercoleza · #10 06-27-2006, 12:58 PM

Just wanted to report back - so far I have driven several hundred miles without any issues at all. FPR appears to have done the trick. I'm keeping the old one though - want to crack it open and see what "makes it tick."

gmercoleza · #11 08-29-2006, 09:04 AM

Just an update - stalling is GONE.

86560SEL · #12 08-29-2006, 08:41 PM

That is excellent news. I am still having my stalling issue, but mine seems to only stall when coming to a stop or when I shift into reverse when the engine is hot. I am thinking I may have a vacuum leak or something. ICV is checking out OK.

I remember reading your post now, but never came back for a followup. I am just now seeing the photos you posted of your car. I cannot believe you only paid $800. for this car. What a super deal. I wish my paint gleamed like that. My paint is deal and all of the clearcoat on top is bad. My interior is in about the same condition, still like new, but it is the MB-Tex, dark blue... seems like that stuff will never wear out.

Mine also lacks the airbag option.

Good to hear you got it repaired.

86560SEL · #13 01-27-2007, 11:03 PM

gmercoleza - I am wondering... when your car was stalling, did it also have a "miss" as well at times? As mentioned, since the weather has cooled, my engine has not stalled, but now I have developed and engine miss problem. It misses worse when it is in park, or neutral, or when it initially shifts from 2nd to 3rd and 3rd to 4th when it goes to the lower rpm, then it will smooth back out.

I have been told on other threads that it may be the FPR. Before I pay out all of that $$$ I would like to know this is it. I wonder if I would be safe to get a used one off of a low mileage "wreck"? I wonder if only a 84-85 38oSE would work properly?

Also, do you have a photo of the relay, so I will know which one is the possible culprit? I found a "KAZ" (made in Germany) FPR - are these OK, or should I only go with a MB relay?

Thanks again!

gmercoleza · #14 01-28-2007, 08:21 AM

My problem did not involve a miss, only a stall. The car would be running fine and then just stop for no apparent reason. It always started right back up, though. That is, up until the last stall which it never recovered from (the FPR evidently locked up). Since the car stalled near a Wal Mart, a good samaritan motorist helped me push it into the parking lot. I ran inside and bought a box of paperclips, then jumpered the FPR and the car started right back up. I drove for several days with the jumper in place of the FPR and it became apparent that the stall was completely gone. I suggest you do the same - jumper the FPR and drive the car. This will tell you for certain whether or not your FPR is faulty. For a pic of the FPR, just use Fastlane above.

86560SEL · #15 01-28-2007, 07:08 PM

Thanks for that info... now, how do I "jumper" it? With a paper clamp or something? Is there a chance it could overheat the circuits or something could be damaged?

Quote:

Originally Posted by gmercoleza

My problem did not involve a miss, only a stall. The car would be running fine and then just stop for no apparent reason. It always started right back up, though. That is, up until the last stall which it never recovered from (the FPR evidently locked up). Since the car stalled near a Wal Mart, a good samaritan motorist helped me push it into the parking lot. I ran inside and bought a box of paperclips, then jumpered the FPR and the car started right back up. I drove for several days with the jumper in place of the FPR and it became apparent that the stall was completely gone. I suggest you do the same - jumper the FPR and drive the car. This will tell you for certain whether or not your FPR is faulty. For a pic of the FPR, just use Fastlane above.