can anybody tell me how to check out a fuel pump regulator for an 88 300e without having to go to a dealership? the engine cuts out while driving. sometimes twice in a day, sometimes it goes a week without cutting out.
had a complete tuneup and fuel filter changed.

At one point, I owned a '73 450SL. The car would drive fine, but every once in a while driving down the highway, the car would start to stall/hesitate... as if the engine were going to die. Wasn't the filter... but the fuel pump. Found the problem in a sort of unorthodox manner - hooked up a pressure gauge to the fuel line feeding the injector ‘loop’ and drove down the highway with the gauge duct taped to the front cowl. Only then, could I see that the fuel line pressure would fluctuate and correspond to the almost-stalling/hesitation. Once the fuel pump was changed, the fluctuation went away.

This can be a very tricky test with gasoline in the pressure line sticking out of the front hood. I do *NOT* recommend this sort of testing methodology unless the driver/mechanic is fully versed in how to hook it up safely. But an indi-MB Shop should be able to competently create such a test jig and confirm or deny an intermittent fuel pump issue.

If not the filter (you had it changed) and if the fuel pump shows OK through pressure testing, then process of elimination should point more toward the regulator.

Thank you for the info MBDUDE, this is my first time posting. It is nice to know that there are good people wanting to help.

Remember what goes AROUND COMES AROUND, HOPEFULY SOMEONE WILL GIVE YOU GOOD ADVISE SOME DAY.


DALDOG FROM SONOMA COUNTY Ca