Help Troubleshooting Potential Sticking Metering Valve

[huskerfan]

Hi Guys - looking for some input on a potential sticking metering valve on my IP

I swapped a used IP into my M1028 a few months ago. The fuel screw on it was turned up all the way due to it coming off of an old 6.2 that had a turbo on it. Timing on it is about 2 line width's advanced. It still idles a bit rough, so i know i need to mess with the timing a bit, but I was on a time crunch for an offroad trip so i left it as is. I accidentally almost had a runaway incident when i adjusted the timing the first time and accidentally bumped the starter without the governor in the IP. That was scary, but choked off the intake and pulled the fuel supply line within a few mins, and got it all back together and it ran fine. Only issue now though is that after the truck sits for a day or so, upon first fire up, it'll idle just fine, but once i give it throttle to back it out of the garage, it'll stay stuck at that throttle position even after i let off the gas, and then then i shift it to park, it starts to runaway. I shut it off, and fire it back up, and then everything is normal and i wont have any issues the rest of the day. Only thing i can think of is that the metering valve is sticking or something maybe?

One other thing to note is that the check valve on the return line off of the IP i bashed out the glass ball inside during the offroading trip because it was all gummed up and the truck would not stay running. Not sure if that would cause this issue with it running away upon first start up and throttle input?

 

[Barrman]

If you had to bash out the internals of the return line check valve. Your injection pump is coming apart inside and needs to be rebuilt. Getting that done will probably fix your problem.

Another thought I has was your fast idle solenoid. Do you push the throttle about half way down after turning on the ignition switch but before starting a cold engine? If so, your fast idle has been activated and probably adjusted correctly. However, if you don’t let the solenoid move to the fast idle position before starting. You could have one that is way out of adjustment and when you give it a little throttle to move the truck, it engages and is holding the throttle open.

I still think you need to get your IP rebuilt, but check the fast idle solenoid adjustment if you haven’t been using it on purpose.

 

[huskerfan]

If you had to bash out the internals of the return line check valve. Your injection pump is coming apart inside and needs to be rebuilt. Getting that done will probably fix your problem.

Another thought I has was your fast idle solenoid. Do you push the throttle about half way down after turning on the ignition switch but before starting a cold engine? If so, your fast idle has been activated and probably adjusted correctly. However, if you don’t let the solenoid move to the fast idle position before starting. You could have one that is way out of adjustment and when you give it a little throttle to move the truck, it engages and is holding the throttle open.

I still think you need to get your IP rebuilt, but check the fast idle solenoid adjustment if you haven’t been using it on purpose.

That's what i thought when i bashed it out was that that debris in there was from the IP failing or so i thought i read that on these forums.

That's the weird thing too is that my old IP, the check valve was clear, but it would die after you let off the throttle. Thought it was bad internals and not returning the governor spring to normal position. New IP i swapped in didn't have that problem, but now has this new problem.

But no, when i go to start it, i do key on, wait for the glow plugs to cycle and turn off, then it fires right up. No throttle input required....