'95 6.5td surging

[Toddketcham]

Hey folks, I have a a surging prob. This is a well serviced trk. Runs well most of the time but tends to surge and buck (sometimes) between 1600 & 2100 rpm. It's when I'm just feathering the pedal to maintain 40 to 50 mph. If I roll into the throttle it cleans up. Seems to be a bit temp related as wel. Anybody seen this?

 

[ak diesel driver]

check fuel pressure, put a clear line on the IP return to check for air, possible PMD

 

[Toddketcham]

If there is air in the clear hose, what does that mean? Scanned it this morn and got code 44 & 45. I can't seem to find any EGR stuff on the engine.

 

[JMJNet]

EGR is with 1500 trucks. It usually ties in with the vacuum system.

 

[WarWagon]

Welcome!
If you have air in the clear return line from the IP it means you have issues with the fuel system that are letting air in or a restriction that is boiling diesel in the fuel line. The IP will suck hard enough to 'vapor lock' the fuel line if you restrict the line. Tank sock, kinked hose, plugged fuel filter, bad lift pump... Fuel problems like just described will cause your issues.

Second thing is to use a highly complicated $0.01 paperclip that will read the correct codes out of the OBD I ECM via flashing the SES light. Once you verify the correct codes we can or don't need to go down the EGR codes on a vin F engine rabbit hole. Lots of scanners can't properly read a 1995 6.5 diesel esp. Snap-on.
Was this CA emissions?
Was the engine or ecm ever swapped?
is there 1 or 2 solenoids on the driver side back valve cover bracket? 1 is for the turbo the other is EGR if equipped.

 

[fentontruckdiesel]

surging is usually PMD. pull codes also, just because there is no light doesn't mean there isn't a code registered ....