NPR no fuel to the injectors

[JmooreNPR]

Hi I am hoping you diesel/npr experts can help. We are getting fuel to the fuel filter and to the injection pump but not to the injectors. The fuel solenoid is getting power. Below is the whole story for context because we did get it to run.

2003 NPR sat for about a year, mechanic unstuck manual primer and got it primed and air out of system, using starter fluid we got truck running for about 3 minutes and it shut off going to the process a few more times we got it running for a good 20 minutes then truck would not shut off with the key but it finally did after a few tries. We were noticing that the fuel filter was not filling up completely maybe about 80%, (towed to diesel mechanic - not NPR guy) after changing the broken manual hand primer pump we are now getting lots of pressure to the fuel filter and injection pump but truck does not start and no fuel to injectors. I don't see him going through the same routine as the other guy bleeding air etc, he thinks it's not necessary maybe just to see it get fuel to the injectors.

Although the fuel solenoid has power could that still be the problem?

 

[Toddgarage]

I hear you, been working on these trucks for many years. From the late 90’s trucks to the DEF trucks today.

My guess is that you have the 4.8 4HE1 turbo.

My suggestions.
1) check the feed and return lines from tank. Correct suction line routing from tank, to water separator, mechanical lift pump/primer and spin on filter.
2) some had banging bolt filter screens. I’ve seen debris, dead bugs, and general junk clog these little filters and create a fuel starvation issue.
2.5) new filters and fuel. Bleed the filters.
3) If you have leaking fuel anywhere, air will be introduced into the system and you will continue to have issues. Leaks at the water separator happen when the plastic bowl gets old.
4) gentle on the starting fluid.
5) turn the ignition key, do you see the fuel shut down cable move? If I remember, it’s a black box near the front cross member, cable goes to the high pressure pump. Should cycle on/off with the key. Other cable is the throttle.
6) most the of vacuum operated devices by the drivers tire aren’t necessary for it to run, but it does improve the drivability
7) do not remove the cold start solenoid. You will loose the timing on the pump and removing the pump is usually the only option.
8) check the little black hose from the intake manifold to the injection pump. It compensates for boost once running. I find the brass nipple on the intake is often clogged with carbon. This shouldn’t affect starting or idle.
9) mechanical injectors absolutely need to be bleed of their air before running.
10) check return line. Pull line off, put into bucket. Is the fuel foamy? Clean? Do you see fuel?

 

[Toddgarage]

 

[Toddgarage]

In the video you’ll see the cable move just before starting.

 

[JmooreNPR]

I hear you, been working on these trucks for many years. From the late 90’s trucks to the DEF trucks today.

My guess is that you have the 4.8 4HE1 turbo.

My suggestions.
1) check the feed and return lines from tank. Correct suction line routing from tank, to water separator, mechanical lift pump/primer and spin on filter.
2) some had banging bolt filter screens. I’ve seen debris, dead bugs, and general junk clog these little filters and create a fuel starvation issue.
2.5) new filters and fuel. Bleed the filters.
3) If you have leaking fuel anywhere, air will be introduced into the system and you will continue to have issues. Leaks at the water separator happen when the plastic bowl gets old.
4) gentle on the starting fluid.
5) turn the ignition key, do you see the fuel shut down cable move? If I remember, it’s a black box near the front cross member, cable goes to the high pressure pump. Should cycle on/off with the key. Other cable is the throttle.
6) most the of vacuum operated devices by the drivers tire aren’t necessary for it to run, but it does improve the drivability
7) do not remove the cold start solenoid. You will loose the timing on the pump and removing the pump is usually the only option.
8) check the little black hose from the intake manifold to the injection pump. It compensates for boost once running. I find the brass nipple on the intake is often clogged with carbon. This shouldn’t affect starting or idle.
9) mechanical injectors absolutely need to be bleed of their air before running.
10) check return line. Pull line off, put into bucket. Is the fuel foamy? Clean? Do you see fuel?

@Toddgarage thank you so much for the reply. You exactly right on the engine type and I am sure all of the things you mentioned are exactly what is needed to get this thing running. I am having the truck moved to a mechanic shop that does understand these engines. He suspects that it is the engine shutoff as you are mentioning as well. Before moving it the other mechanic instead of disconnecting the cable from the engine shutoff he just disconnected the box at the wire harness and tried starting it but again doing nothing else to purge air etc. I will report back on how this was solved and I'm sure that everything you place in this thread will be helpful to several others

 

[Toddgarage]

My daily work truck is a 1999/2000 NPR and it’s been around the block. But it doesn’t complain when the throttle is buried on the floor (what’s left of the floor).
The Aisin Auto trans is built proof. Keep it happy with clean fluid.

#1 look at the ground wire off the battery to the frame. These cables fail, frame gets corrosion, and there is minimal frame to engine grounding.
#2 there are relays behind the glove box. One of them controls the CSS.
#3 the main cab wiring terminal block is behind the front grill. It’s common for it to corrode.
#4 inspect brake lines. They corrode fast.
#4.5 also the metal vacuum lines
#4.75 transmission cooler lines too…
#5 thermostats fail, engine won’t reach operating temp and it stays in cold mode.

I have no option, but I’ve heard this from another diesel mechanic about older trucks. “The ultra low sulfur fuels don’t have enough lubricity and you should run an additive like Lucas upper cylinder.”
Your call.