'88 300E stalling out... - PeachParts Mercedes-Benz Forum

#1 10-29-2002, 10:40 AM

Hi.
1. I have an 88 300E that has been stalling out while slowing down. This has typically happened after driving at 65-70mph, then slowing to 15mph to pass thru toll booths. The tach drops to ~500rpm then the car stalls. Sometimes, the tach will stay at ~700rpm and it's fine. This is intermittent. Occasionally in city traffic, I'll notice the idle dropping to ~500, I'll tap the throttle in neutral, and it'll settle back at ~700.

2. My right turn signal flashes the exterior lamp failure light as well, ONLY when the headlights are on. I've replaced all the bulbs, all seem to work. I've swapped left and right bulbs, front and rear and the problem remains only when signalling right turns.

Any help would be appreciated!
Thanks
Glen

G-Benz · #2 10-29-2002, 12:43 PM

The stalling appears to be a fuel related problem, but I can't tell you where to begin...I'm not an expert on fuel issues..

The OVP could be on it's way out, and one of the symptoms is stalling when slowing down, cornering, etc. As it worsens, it's difficult to start a warm engine.

Your indicator light problem is a loose metal rail in the right taillamp housing. The metal rail houses the bulb sockets and has loosened enough to lose ground contact, causing the bulb failure light to come on.

Remove the housing and press firmly against the metal rail near where the turn signal bulb resides (with headlights on), and turn the signal on to see if the indicator light disappears from the dash.

Also, make sure your replacement bulbs are of the correct wattage (10 and 21W bulbs only). The correct one for each socket is embossed on the taillight housing plastic. Make sure you stay with Philips, Sylvania or OSRAM bulbs with the nickel-plated holders. The cadmium-plated GM-type bulbs will give false readings to the bulb failure system because it presents differing resistance values...

Abaloneman · #3 10-29-2002, 03:34 PM

Glen,

I also have an '88 300E which stalled on deceleration near idle. I tried the usual suspects ... OVP, fuel pump relay, etc. However, mine turned out to be the hall-effect sensor located on the back of the speedometer head. My 300E hasn't stalled since I changed that little two pronged devil, which senses the vehicle speed and also provides input to the cruise control system.

If your cruise control is erratic, or doesn't work at all, I'm willing to bet this is your problem. You can pull the instrument cluster and remove this sensor from the back of the speedo head. If the solder at the base of either one of the two prongs is broken and/or the prong is loose, then this needs to be replaced. These were common problems on the '88/earlier 300Es and there is an updated hall-effect sensor now to replace the older defects.

Let me know if you want more information on removal/checking this bugger.

Chris

Snibble · #4 10-29-2002, 08:32 PM

My 300sel has the same engine as you.. and it too stalled. But all this stalling crap stopped when I switched to using Shell premium gas. Prior to that I used Speedway since it was closer to my house. Might be worth seeing if that does anything. good luck

#5 11-06-2002, 04:09 PM

Update.
For the record: this car has 82k original miles.

I have now noticed that my stalling problem occurs ONLY when starting from completely cold, i.e. first thing in the a.m., after a few minutes, if I stop and restart the engine the idle will be 'fairly normal'. It will still fluctuate though, between 700 and 1100 rpm, but it won't stall on decelleration. Accelleration is okay, the car never stumbles, and hot starts are fine.

I haven't noticed any air leaks and the air filter seems okay.

Also, what is the OVP part# and where can I get one, if that's the problem.

I still haven't tracked down the light problem yet, (see first message) but that's no emergency, the bulbs outside all work properly.

But this stall thing has me baffled and I don't feel like shelling out $75+/hr and part costs to have M-B techs chase this devil around!

Thanks all who've replied so far!

#6 11-06-2002, 04:12 PM

Oh yeah, the cruise control works normally. I use it often and never have a problem with it.

Abaloneman · #7 11-06-2002, 07:58 PM

Glen,

My 300E did exactly the same thing ... stalling on the first deceleration after getting warmed up, after that it was generally okay. It always restarted without any problem. It is almost as if the computer lets the idle drop too low for a split second on deceleration, allowing it to stall.

There is a whole laundry list of things that have been known to cause stalling problems on this car ... fuel pump relay, OVP, flywheel sensor, etc. ... if I can find the thread I'll copy it for you. But again, your stalling problem sounds exactly like what I had going on ... although logically it should affect your cruise control.

Chris

Abaloneman · #8 11-06-2002, 08:05 PM

dtanesq
Senior Member

Registered: Oct 2000
Location: Northern California
Posts: 272 My pleasure

Quoted from the shop print-out my tech gave me (gramattical errors were not corrected - I proofed this very carefully for accuracy of reproduction):

"The owner states that the engine dies intermittently when coming to a stop. (Maintenance note: This problem has been around for a long time. Mercedes-Benz has published several bulletins about the problem. See Diagnostic Directory 07.3-88043/30T93031/07.3-91043/54-89101/AF07.32-U-6701A & TIN 07.3/6. There are about a dozen things that can cause the engine to die. We normally see on about 3 or 4 cause all the problems. Sometimes there can be more than one of these things acting up at the same time. That's when it gets hard to find the problem. The components that cause the most trouble are the fuel pump relay, the flywheel position sensor, and the over load protection relay. We have also seen the Hall Effect sensor, the tachometer, the distributor cap and rotor, the ignition coil, the oxygen sensor, the ignition module (see D/D 15-89041), the idle air valve, temp sensor, wiring harness, EHA valve & the electronic accelerator (see D/D 30T93031). We try and replace the most common things first and if that doesn't take care of it then we get into the more unusual components.)"

Again, upon replacement of my fuel pump relay, mine hasn't stalled. Before I purchased mine, I drove my neighbor's 87 300E as a sort of test-drive-by-analogy to see if I'd like the model. I drove it exactly as he suggested (hard-with apologies to Hottee18 for all the advice we old guys gave to him on that subject awhile back) and I went red in the face when it stalled after coming down quickly from a very hard acceleration run. The owner had never had it going that fast and it had never stalled before. I cleared my throat, it restarted and we drove home. It hasn't stalled on him since. Probably undiagnosible.

Good luck.

__________________
David

1993 BMW E34 - 525i ("Beauty")
1988 Mercedes W124 - 300TE ("Bette")
1974 BMW E10 - 2002 ("Bam-Bam II") under restoration

This is the part of the thread I was referring to. Hope it helps. And thanks again to David.

Chris