Archived HELP '97 12v loses power at 2000 RPM

[rbolten]

Have '97 3500 4x4 with intermittent problem mostly under a load. At around 2000RPM sometimes will lose power and fall on its face, then I can let off the throttle and stomp it and it gets going again, kind of like experiencing a vapor lock problem with a gas motor. Fuel filter is new, Please HELP!!!!!

 

[BCFAST]

Sounds like your overflow valve is on the fritz to me... to check it, remove the valve, lay it on a level bench and put a drop of oil on the top. If the check ball is seated correctly, the oil will not seep past it. This test will not check the spring tension, however. Call Piers on this, as he sells them for around $40-45... I bought mine from Bosch and paid $70!!

 

[Deezul1]

Get a fuel pressure gauge on it so you can tell what its doing. Also you can pull the spring out of the overflow valve and measure it. It is supposed to be . 500 long new and it can be stretched to . 550 and reinstalled as a test to tell if that solves the problem and whether you need a new one.

 

[rbolten]

where is the over-flow valve located at?

 

[Joe G.]

It's located on the engine side of the injection pump even with the first delivery valve. It looks like a banjo fitting. When you remove it you should cram a rag in the gap below it to catch the washers.