350SDL Replace Fuel Injector Tips? - PeachParts Mercedes-Benz Forum

ezrider · #1 11-22-2002, 09:01 AM

I have a 1991 350SDL (original owner) with 146K miles. It has a rough idle problem. Local shop wants to replace injector tips and calibrate the injectors, they say they have the correct Bosch test equipment to do this and that the worn injector tips are likely the source of the rough idle. They say that the injector tips should be replaced every 90K miles. Can anyone comment on this based on experience?

Thank you.

oldsouth · #2 11-22-2002, 10:07 AM

I have over 200,000 miles on mine and car runs great except when first cranked on a cold morning. It runs rough like a miss for about 5 seconds or so. And it is not the glow plugs. Same problem but exagerated at high elevations (over 5000'). I have thought about replacing the injectors but the problem is very minor.

ezrider · #3 11-22-2002, 10:22 AM

Oldsouth,

The shop tells me that the initial rough idle from a cold start is likely the result of leak down in the pump? One shop told me there is 1500-1700 psi coming out of the pump to the injectors.

oldsouth · #4 11-22-2002, 10:37 AM

Why would it be worse when it is cold? When I went to Colorado last spring and had a bad problem with miss and excessive smoke, the dealer there said that it could be the injector tips kinda dribbling fuel instead of a good spray. But I guess the pump could cause the same problem if it starts without enough pressure.