injection pump or pmd?

[chevybowtie]

i have a 94 gmc 6.5 turbo diesel and im have problems with it runing right. when im driving it when it hits about 2000 rpm it starts to break up and stutor and smoke blue out of the exhaust.:bang and also i just recently changed the head gaskets on this truck and priming the system was long and drawn out and ever sense then its ran like this what do you guys think

 

[LReiff]

Supply pump.

 

[Rob24vCTD]

Supply pump.

This, or the pressure switch that turns on the supply pump. After doing headgaskets its probably gummed up.

 

[chevybowtie]

now were would the pressure switch be located at?

 

[Rob24vCTD]

drivers side, upper, rear of engine

 

[chevybowtie]

What does the pressure switch look like im new to have ing this truck

 

[Rob24vCTD]

 

[chevybowtie]

Thanks man uv helped alot

 

[THEFERMANATOR]

Your switch will actually be black, not gold like the above posters pic. It is in the same basic location though if it is a 94 engine(if it is a 96 block it will be in front of the fuel filter under the intake). It is also known as the oil pressure switch as it runs the fuel pump and is teh sender for the oil pressure guage. The lift pump should run when you engage the starter and when the engine has oil pressure. A quick test and the easy way to prime the fuel filter is to remove teh starter relay and then rotate the key to the start position. If teh lift pump is working it will come on but since teh starter relay is out it won't turn over. The lift pump is mounted inside the frame rail directly under the drivers seat.

 

[chevybowtie]

I checked the sensor and the lift pump and they are both in working oreder what else could it be

 

[littleboy]

Did you check pressure ? Just because the pump runs doesn't mean it is making pressure .

 

[THEFERMANATOR]

With it idling, open the little t handled water drain on the front of the engine. Fuel should come out of it, if not and it stalls your oil pressure switch is bad.