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Old 02-23-2003, 04:52 PM
Posts: n/a
Question '86 300E with Voltage Problems and poor acceleration from a stop

Hello, I have recently purchased a '86 300E from a good customer of mine for $4000 (canadian). I have already put over $8000 into it and have almost entirely lost faith in my mechanic. I should have come to this site long ago!

Please excuse the length of this post, I'm trying to give as many details as possible to assist in anyones possible diagnosis. =)

Ok, as for the problems. It has numerous problems, all of which I firmly believe are closely associated with each other, possibly all from the same root problem, I shall list them all:

It accelerates acceptably if accererating lightly But unter heavy accelleration, the car will just about die, and accelerate slower than if I just eased onto the pedal, but then suddenly have a surge of power once the RPMs climb to roughly 2,000

The major issue is a very strange electrical problem that also seems to influence the mentioned acceleration issue. My heater fan is the most obvious place it influences. I'm not sure how to best describe this, but I shall try. the 'auto' setting for fan is very erratic, sometimes on, full blast of entirely off, never in between, so I use the low setting. When sitting at a light though, for example, the fan set at the low setting, will after a few minutes begin to surge higher. The longer you sit, the more frequent teh surges till it runs full blast consistantly. Any load such as headlights, seat heaters, or rear defrost will make it many times worse. In extreme cases my radar detector will begin flashing 'low voltage' though no dash light comes on.

Closely associated with that is that though much more strange, is that when I select 'high' speed on my fan, it will not go to high speed for a delayed amount of time, namely untill there is a load on the system. If I'm sitting at an idle it will come on immediately, but otherwise it will come on if I hit the brakes, turn teh seat heaters on, turn on the rear defrost, etc. As a side note, the rear defrost and seat heaters barely heat up enough to be considered on, but the lights on the car will dim noticably when either one is turned on. The accelleration problem I mentioned already seems to be closely related in severity with how bad the electrical problem is at teh moment.

I had trouble also with my ABS. The 'antilock' light would randomly come on, but the brakes would pulse seemingly randomy when at low speeds even if only stopping very lightly. I unplugged my abs module, covered up the 'antilock' light on my dash, and just live with regular brakes.

I also seem to get pretty pathitic mileage and rough idling.

Now, as for what my mechanic has done. The entire exaust system has been replaced, along with the O2 sensor. The transmission was rebuilt because it was toast. I regret spending that much money on this car, but now that I have I need to stick withit because I can't get my money back out of it. =^/ The spark plugs have been replaced. The fuel pump and fuel filter have been replaced. The heater fan has been disassembled and checked. (said there were dirty contacts that they cleaned up) And just a few days ago I replaced the 'overload relay'. The alternator has been rebuilt (they said it had been running on 2 of 3 windings. But the rebuild didn't help.

That's all that comes to mind at the moment, thank you very much for your help in advance! =)
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