Newer injections pump going bad? Weird symptoms. Just creeping along

[Rusgo]

Injection pump has 30k miles on it. Truck starts fast and drives well at first. A little lower powered than normal

After 5 minutes of driving power is way down. After 15 minutes I'm just crawling along and truck dies at stoplight! Power drop is linear. No surging. 5mph top speed.

Restarts fine with okay power. But power only lasts a minute

Have fuel out the schrader valve at all times. Electric lift pump seems solid. No fuel leaks.

Gotta be the injection pump??

 

[gandalf]

Where did you get the IP?

 

[Rusgo]

AutoZone. Remanufactured.

 

[aggiediesel01]

How's the fuel condition and how new is the fuel filter? Sediment and algae can fall down to the bottom of the filter housing after setting over night and then after driving stirs them up they can clog the filter.

 

[Old Goat]

I was thinking maybe the shut off solenoid acting up.

Un Plug it, and use a jumper wire from Batt pluss and touch the connector. you should hear a good solid click.
You might just connect the jumper wire to it and drive around to see if it acts up. Could be a loose conection in the wire harness.


Goat

 

[tradergem]

It might also be crud or shower head pieces from the fuel tanks temporarily clogging the fuel selector switch/valve.

 

[Clb]

No one gunna point out there are only ,what 3-4 competent builders out there?
Fwiw
Check fuel system integrity tank to ip first.
Timing second.
Then verify supply, then psi\gpm.
Then it should be apparent the issue I hope...
linkage good?

 

[Rusgo]

Yeah linkage is good. Fuel supply to IP is very good. No smoke at any point. Couldn't imagine timing being off and the engine running well otherwise.

Truck runs perfect for 5 mins then power slowly starts going down. Acts like it's starving for fuel. Even at 15 minutes it only dies when letting off gas slowing to a stop. No other time. I can even keep it going most of the time with feathering. Idle is still good. Maybe a bit low. Idles a stop even when power is low

Won't move much after it's hot. Creeping along at 5mph with the hazards on!! Shut the engine off at the stop lights and immediately restart it very fast and some of the power is back

Left my electric lift pump turned off on accident a long time ago and power was still decent. This is more like five guys trying to push the truck power

All symptoms are very consistent. Every time.

 

[Rusgo]

I had a filter assembly out of a newer IDI truck and upgraded filter laying around forever. Just installed it because why the hell not. Helps isolate the problem

Going to fill tanks and recheck tomorrow. Cycle the tank switch. Check the fuel supply when it's in 5mph mode

Leaning toward the injection pump. Like once heat soaked it starts having issues

 

[Rusgo]

I was thinking maybe the shut off solenoid acting up.

Un Plug it, and use a jumper wire from Batt pluss and touch the connector. you should hear a good solid click.
You might just connect the jumper wire to it and drive around to see if it acts up. Could be a loose conection in the wire harness.


Goat

Not super familiar with positions of it. Is the solenoid on/off only, or is there a middle range when malfunctioning where it'll reduce power?

 

[Clb]

I bet Yer ip is TOAST
Dump some water on it when it's in 5 mph mode and report back...

how many gph to the ip?
high idle solenoid working?
Disconnect it from cold then run test it and report back.
atf filter change it for grins.

 

[Selahdoor]

Put a couple gallons of water in the truck cab. Just normal room temp. Not ice cold.

When it is in 5mph mode... Pop the hood, with it still running, and slowly pour those jugs of water over the IP.

If it improves right there, it's the IP. Needs replaced.

 

[reinerh]

very very easy solution to these type of issues, install a fuel pressure gage = measure pressure going into the ip.

i consider this a mandatory mod to all diesels basically, even newer ones.

if good pressure, then the pump has an issue. but more likely another fuel supply issue.