rivervalleyinn

Forgive me as I am not to puter litterate. Anyhow I have a 94 3/4 ton 2x4 with slushbucket. She seems to be a cold blooded thang. Start real good when temp is cool, when it warms up and you shut it down it willnot start till it cools Once it cools to ambient temp It starts and runs fine till it get up to temp agin shut it off and it won't start. yesterday and today just for kicks and gigle I opened the lid and installed the cold water hose, pionted it at the fuel pumpfor about a minute and low and behold it fired up and run like a good cummins should . could my lift pump do this. Since last aug when I baught the truck, occasionaly when on the highway at speed it would start to miss and shake badly if you let off the pedal it would die, I would pull off the road and restart then it would usely run fine for aweek or two then actup again any help would be apreciated.

RCW

On your 94 take a look to see if you still have the single unit overflow valve on the inside of the injection pump. That is the usual source of hot no-start. They develop a hot fuel leakby and let the head pressure on the injection pump drop too low to allow it to properly pump the fuel. If you have the old style overflow valve, get the new replacement upgraded valve from Cummins. If you valve has been replaced with the newer two piece valve, clean everything carefully and pull the small nut and inspect the spring, the follower, and the check valve ball. Sometimes you can stretch the old spring and get them to live a while longer, but will need a new kit if it is broken or there is damage to the ball or follower.

The next place to look is the fuel heater, and what you want to do is unplug it and fill the jack with dielectric grease and then plug it back in and see if the problem goes away. If it does, the insulation on the heating element is failing and allowing air to infiltrate.

Another common problem is a plugged screen in the fuel heater. A lot of people just flat forget to change that screen, and it develops gum and crud and will create enough resistance to keep the lift pump from working if the fuel is hot.

Missing and shaking at highway speeds would lead me to look for a failed overflow valve or a plugged fuel filter or the screen in the fuel heater. It can also be a symptom of too low a timing setting, and these engines will back down over time until they are reset and the timing gear nut on the injection pump properly torqued.

Never, but never use cold water on your warm injection pump! That is a sure fire method to trash the delivery valves and the pressure pistons by causing them to bind from uneven temperatures. If that has happened in the past, then you could have excessive pump clearances and will be shopping for a rebuilt injection pump.

rivervalleyinn

Thank you I'am not to mechaniclly inclined don't like grease under fingernails. but I am not stupid either or atleast I don't think so, my engine was only warm to the touch when I applied the hose. It seems that the temp doesn;t have to be much more than barley warm to have this happen. If I get a few sinaireos then I can go to a dealer and maybe not take it in the shorts to bad. agin thanks