I just bought a gorgeous 94 E320. Super low miles and obviously very well taken care of. I do have a wierd problem however that is stumping the mechanics.

This has happened three times - never the first start of the day, but usually after I run the car 30 or 40 miles... leave it for 90 minutes or more, and get back in the car.

The car starts and idles perfectly. As soon as I give it some throttle, the car surges like crazy, like you're cutting power to the ignition or something. It has also happened while I'm going along at 65 mph. It feels like the motor just quits. I look at the tack and can see that the motor is actually still running, but no power whatsoever. I limped it into a parking lot, and it sits and idles perfectly. Try to move the car... and it jumps around, surging continously.

Two independent shops tell me the Wiring harnesses go bad in these cars, and when they do, it causes all kinds of wierd codes and happenings. "Replace the wiring harness and most of these elusive "short" type problems disappear"... so they tell me.

Well, I picked the car up today after the wiring harness replacement, and it ran great for 40 miles. Got it home and parked it. Got into the car 2 hours later... same deal.

The first time this happen (pre-harness replacement) the code read: "182 Safety Fuel cut-off switch signal for LH/HFM N/34"

This last time, there were no codes even though I was disabled with the car for over 40 minutes.

Any ideas?

I have more or less the same car and the same problem. Itīs been like this for six years now, but only on hot days or if I am in slow traffic for too long.

The limp mode is what causes the stumbling but nobody knows what causes the limp mode. I just ventilate the engine bay for 5-15 minutes depending on outside temp and the car runs fine again. It has nothing to do with engine overheating, but some part, like the crank sensor or another sensor or connection seems to be sensitive to ambient heat. But impossible to diagnose so far....

Do a search on "OVP relay"....

I have left off the bottom, under engine shroud to get more air flow through the engine compartment.

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I've spent 2 hours reading about OVP relays, and haven't seen a problem that sounds just like mine. My car starts and idles perfectly. Something seems to be kicking it into Limp Mode occasionally. Turning the car on and off several times usually solves the problem... until the next time.

I also gather that the OVP can trigger a lot of different symptoms, so I'll look into it further. The shop that did the wiring harness a few days ago has the car again.

I saw one posting where a guy had a similar problem and it usually reared it's ugly head after he drove for a while and then parked it. He thinks the heat buildup in the engine compartment contributes to the problem... that's why when he gets in the car an hour later, the problem shows up.

Is that the thought behind removing the bottom engine cover?

In my case, I have got a new OVP and the same problem remained, I have also removed the bottom cover with little or no difference. It is mainly the heat that builds up under the hood when parked or in slow traffic that causes the bad signal. i have also looked into the throttle linkage and reprogrammed the CPU without success. It leaves no fault codes at all....

Btw, if I can build up the limp home speed enough to engage the cruise control, it will override the limp setting and usually the car cools down enough to work normal again pretty soon...

Hi Vulpro,

Any success that you can share??

Could it be that the multirib belt slipping becuse the AC got the protection fuel saftey shut off otherwise look into the klima relay and try to heat it up with hot air to se if the problems occur when the car is not warmed up if there is some soldering is in bad shape, in the relay is the fuel shut off function.

On my car this can happen with or without the AC working. Where is this relay located and can it shut off the fuel without the AC engaged?

If so, maybe it would be easier to put some ice on it when the LHM appears next time? Or just check and resolder anyway...

It`s in back of the battery behind the plastic cover it's a black relay 6zyl/klima stands on the top of the relay when the relay is the problem the car stop completly but check it out anyway sometimes things can happen that should not happen,

do you got the cruise control?(tempomat) what are the rpm on the tachometer when this thing happens if the rpm are 1500 it could be the cruise control Idle speed control acutator

Yes I have cruise control. The limp mode can start at any speed, often after just idling at a traffic light, or as I described, when overtaking at high revs.

Today I was lucky, driving 650 km nonstop in 28°C with no problems, but if I go out and start the car now after an hours rest it will most likely be in limp mode again...

To find out if the cruise control is a part of this, can I remove a fuse or what?

Edit: I did just that, restarted the car, it was in limp mode now, removed the fuse, no success...