ovp issues on 87 300dtd
 

ovp issues dont seem to get a lot of coverage in the diesel discussion.this leads me to beleive that gassers are more prone to serious symptoms caused by the malfunction of this unit.however ive found thru recent experience that the ovp can contribute to some nagging little problems on the diesel as well.lately ive been getting an antilock warning lamp and concurrent loss of antilock braking along with no tach and extremely low idle speed.these symptoms were intermittant and infrequent but PITA.after spending some time with my recently acquired 124 electrical manual i found the common source of power for the abs and eds cpus was the ovp relay.its a bit of a knuckle buster getting to it.but once removed i noticed a fair bit of the fluffy green stuff around the relay socket.probably has something to do with proximity to the battery.cleaned this up and reinstalled.after a short while the symptoms reappeared so i decided to remove again and have a closer look.this time i removed the aluminum case to examine the circuit inside.initial examination was inconclusive so i took a closer look with a magnifier.this revealed cold solder joints where the small relay attaches to the board.a quick resolder and reinstall and viola problem solved!! :cool:

I took the cowards way out and bought a new one for my 87 300D. Problem solved also but I was $70 poorer.

Joe

well we will see how long the patch lasts.$70 might prove to be more economical in the long run.although i suspect this is more like$100 cdn money :)

You mentioned a few electronic items acting up before finally solving them with a solder gun I presume!

Also, you described anti-lock disfunctions that mirror mine, but have thought this had to do with worn out anti-lock brake sensors.

I wonder if you noticed also if there had been any problems with some functions of the seat and steering wheel memory before you fixed? I would love for the fix to be as simple, because replacing 3 brake sensors are expensive, around $450!

similar symptoms
 

Folks,

There was another recent thread on the ABS lights. In there I noted my frequent ABS light occurances. Measured (electrically) all 3 ABS sensors, they were all the same. I pulled the ABS sensors out from the front wheels out and cleaned the ABS teeth on the rotor real well ( you can see the teeth from the sensor hole and I shot brake cleaner in there). No ABS lights for a week. But it was also warm that week and my ABS lights are triggered often in the cold.

This past week it has been very cold for NC, and I am back to getting light triggers - about 30% of the time I would previously. In the other thread they recommended the relay as a possible failure point. I think that may be next to try. I'll let you know how it comes out. Having a large sample of symptons, repairs, and results here is great.

Chuck

busybenz i would definately check out the ovp as a possible cause for the abs issues.im not sure if the other accessories are protected by the ovp.i think the primary function is to protect the abs and engine management computers.ill have a look at my schematics though and let you know. :sun_smile