Random no-start/stalling issue

[Kornbread]

This started several weeks ago and I would like to get it fixed before I really need it for something. The truck randomly won't start. Sometimes it won't start from the get go, other times it will stall and won't start again for awhile. It's not the PMD because I swapped out for another one while it was throwing a fit and it didn't help. So far I have replaced the fuel shutoff solenoid, changed out glow plugs to the Instaheat kind, changed out the in-tank fuel pickup. It seems to get worse when the ambient temperature is warmer. After it dies it will crank over normally, just won't fire. Then after a little while it will catch a little and die and eventually start. I don't think its air in the line because I have bled this thing out multiple times. I know it isn't timing because when it runs it runs perfectly. It all started after I drilled and tapped the intake for a boost gauge. I don't know whether it was just a coincidence or not. It is throwing a couple of codes, I don't have them here in front of me but one was, Injection pump metering control high, reference signal A, or something. The other was code 0350 or something....Please Help!!!

P.S. The dash lights all work, the WTS light blinks on a off about 6-7 times, takes about 15 seconds to go out.

[oldyeller6.5]

i would say timing might be advanced a bit much, rotary head possibly warped. or bad OPS or lift pump. my friends 93 (mechanical) was a hard starter sometimes, come to find out his timing was set 2x what it should have been. and it ran like a top, but it blew a lot more smoke than mine. he fixed that and now its running even better and starts alll the time. i thought my 93 had a warped rotary head because of mid temp starting issues. come to find out my batteries are about to be dead and crank full when cold. starts fine with no glows when hot. but between hot and cold my batts will die under load of about 30 seconds. if it does not start after cranking ten secs, i jump it and it starts and runs fine.

start with ops and lift pump, then batteries. then check the timing on your pump. then check your injection pump out to make sure its not just worn out. these pumps have very tight clearances and after a while the clearances get bigger and the pump needs to be re-built or replaced with a new and upgraded one

[trukdoc]

...you drill the intake? did you take off the upper plenum? did you check to see if you pinched wires between plenum and intake? if this started with that operation then you should check these things...you could have harness problems under or around intake\pump area...jd

[Kornbread]

So I have searched all over, what is the OPS? I didn't take the intake off. I drilled the hole on the backside of the "bent" part.

[BeelzaBubba]

OPS is about the size of a roll of quarters and is black plastic w/ metal base; connector located at the top. look at the drivers rear of the engine by the valve cover.

[jimclemjr]

When my OIL PRESSURE SWITCH went out, it partialy fail apart when I touched it taking off the connector. It could be when you were running your gauge tube, you hit it or pulled the cable and it partially started to come apart, etc. Worth replacing if you never have. They are cheap (less than $25) at parts store and worth carrying a spare. Search this forum for better brand names recommended by the seniors and long timers.

[Racer5551]

Fuel fill cap have a plugged vent?
Do you get a lot of suction when you remove the cap?

[grancito]

Bad ignition switch?

[Kornbread]

So I went digging for the OPS today. After about 15 minutes of looking at the left rear of the engine where all of them are located I gave up. On my way out I glanced down into the valley and there it was. So mine is located between the intake manifold and the fuel filter, down in there. I thought this would make it a little easier to get to but come to find out there just isn't enough room to get a socket down over the top of it to get it out without pulling the intake. Should I do that or should I relocate it to the back of the engine like all the others?

[Racer5551]

Just use a plumbers basin wrench to remove/install the sending unit.