Hey guys, great forum here with lots of useful info. I tried to search for an answer before posting but I came up short on any definitive answers.

I bought a 91 350SD (engine replaced my MB @100,000K) and it ran flawlessly from the point that I picked it up in Oregon, drove it to Alaska and ran great for most of the winter.

The problem I have found is the IP is started leaking, which I will fix as soon as I get home from a trip im currently on. However the car will not start if it has sat with the nose up (like a driveway) for more than a minute or so.

So my issue is fuel starvation....is this caused by the leaking IP??? Im assuming it is allowing air into the system....or is there a lift pump that has gone bad?

The car starts just fine on level ground.

Also what are the symptoms of bad Transmission Mod valve? I was stranded a few months back on the highway when the trans decided to shift into neutral out of the blue, then acts normal, then shifts late....early etc..... im being told its the modulator valve.

The trans has the classic static leak when sitting.

Sorry if these are newbie questions, im well versed on toyotas and other vehicles, but the MB and any automatic trans is sort of a mystery to me.

Thanks in advance


Luke

Anyone?

There might be some correlation between the IP leaking and the inability to start. The question that needs to be answered is where the leak is on the IP?

If the IP is leaking out of one or several of the top fittings, it's possible that the delivery valve seals have failed on one or more cylinders. However, I'm not sure that one or two of these would prevent a start.

The Vacuum control valve on the OM603 can be finicky. If it's not adjusted properly, the engine can "flare" between shifts..........it basically runs away like it's in neutral.

I had a similar problem on the '86 when I adjusted the vacuum control valve all the way to the stop to try to firm up the shifts. It wasn't pleased about this.

The setting is to loosen the two screws and have somebody press the accelerator all the way to the floor. Rotate the valve clockwise until you feel a bit of resistance and then tighten the screws. This eliminated the flare on the '86.

You'll need a vacuum gauge to properly test the VCV to watch it's output under various driving conditions.

Curious that it always starts on level ground but not on a 2% incline (typical driveway). Makes me wonder if this might not be the rare instance where a lift pump has failed???

Fix the DV's and confirm it doesnt have any other leaks first.

In the mean time, when parking, back in to driveways, etc.

__________________
Terry Allison
N. Calif. & Boca Chica, Panama

09' E320 Bluetec 77k (USA)
09' Hyundai Santa Fe Diesel 48k (S.A.)