How do I double check if Injector pump is working?

[7bicks]

1994 7.3 IDI Turbo
I would love to know if I am missing something.

My truck died while idling, just like the key was shut off. I got it restarted a few hours later and it seemed to be fine, shut it off and restarted several times. Next morning, only a sputter and no start. Since then nothing.

I checked fuel flow after the filter and it is good. I opened an injector line and only had a couple of small droplets coming out. I checked voltage at FSS and has 11.4v. I checked voltage while cranking and had 11v. I removed the top of the IP and verified that the FSS was working. All linkage inside seems to move freely.
Is there any thing else to check?
Can an IP just quit like that?

 

[Diesel JD]

Sure it can...but instead you probably have an airlock of some kind. You have to bleed the air out of these things to get them to restart usually. Now why did it just shut off like that? Usually the engine starts to suck air and it coughs sputters, dies, if it shut off like you turned off the key it could still be that but it makes me wonder..... since you had the governor cover off I really hope you have a way to choke the air or fuel supply off in case it tries to run away on you which is a very very scary thing.... Now you did say that the linkages moved as they should and you verified an audible "click" from the solenoid when voltage is applied and removed (Key on) correct? 11.4 volts is kind of low but it's enough to get the job done (min. is 10.5 v) Usually the cutting off problem is from fuel starvation and the usual cause for that is that the tank was run below about 1/4 of a tank, in many cases the plastic foot/strainer have rotted off over the years.

 

[7bicks]

I never opened anything up to get air into the system before it died.
I used a jumper wire form the battery to the FSS just to verify that was not the problem. Solenoid works fine with the IP cover off. I can hear it click each time it is keyed or I use a jumper wire. Linkage looked good as well.Top of IP is full of fuel all three times I opened it up.

Tanks is 3/4 full and I have very good flow out of the fuel filter and have a lift pump that is only a couple months old.

I have never heard of an IP just dying like that. i want to make sure I exhaust every option before sinking $500 into an IP.

I took the timing cover off today and verified that the IP is turning as well, just to ease my mind.

 

[ameristar1]

If you have more than 100-150k miles on the truck, it's just due. Do the lift pump, injectors and pump at the same time if you can manage it.

 

[Michael Fowler]

Can you temporarily install an electric fuel pump to feed the fuel system and see if that allows the engine to start?
You don't have to open up anything for there to be an airlock in the system. Leaking-even very slightly injector caps and/ or return lines will allow enough air to enter the system that it can become a problem. You can also install a clear section of tubing in the fuel lines to see if bubbles are present.

 

[Mat J]

when you crank it can you get white smoke to come out the tail pipe to see if your getting fuel or not.

 

[7bicks]

Mileage is up, 340K, but I do not know the history of IP replacement. I just have not had any trouble with it, not even acting funny.

No smoke at all out of tailpipe. It only has small droplets of fuel on an open injector line.

I may try an electric pump and clear tubing just for fun.

Thanks for some ideas.

 

[Diesel JD]

If it's making any fuel at all the IP is working, but you have to get fuel at least at several injectors before you can get a start. Also even after the IP starts making fuel at the injectors there can still be a lot of air in the system. I usually cycle the glow plugs 2 times, foot to the floor and it usually takes at least 15-20 seconds of cranking to get it to light off. I'm sure you know not to crank more than about 15 seconds without a respectable cool down period for the starter. Being in MT you probably are having some cold weather which is not making this any easier. At 340K miles though that IP may just be too weak to pop the injectors. Who knows.... but with the fuel system I think you're on the right track. Good luck

 

[Michael Fowler]

If it's making any fuel at all the IP is working, but you have to get fuel at least at several injectors before you can get a start. Also even after the IP starts making fuel at the injectors there can still be a lot of air in the system. I usually cycle the glow plugs 2 times, foot to the floor and it usually takes at least 15-20 seconds of cranking to get it to light off. I'm sure you know not to crank more than about 15 seconds without a respectable cool down period for the starter. Being in MT you probably are having some cold weather which is not making this any easier. At 340K miles though that IP may just be too weak to pop the injectors. Who knows.... but with the fuel system I think you're on the right track. Good luck

The good news is that, since its a diesel, we KNOW the problem is the fuel system. If this were a late model gasser, it could be the fuel system, or the ignition system, or any of dozens of computer sensors and their connections.
Diesels are easy--ITS THE FUEL SYSTEM!.

 

[Agnem]

It's not clear from your post if it died while it was hot and had been running a while, or if it was just started, ran for only a second or two and then died. If you could clear this up, this info is vital to the correct diagnosis.

 

[7bicks]

I had just replaced the clutch on Friday and was warming it up while bleeding the slave cylinder. I had just came off of the high idle for about 30 seconds or so when it died, it was never to full operating temperature.
It restarted a few hours later and I let it run to operating temp, shut it down and restarted it several times, it seemed like nothing had ever been wrong.
The next morning it would not start again, although it did fire briefly and then nothing.
I have tried starting it at several different times for the last couple of days.

Weather has been cool not but no too bad recently. I already checked GP for function a couple of weeks ago just to be ready for winter. It started no problem when we dropped down to 0 about two weeks ago.

 

[Agnem]

That does NOT sound like an air problem then. I'm suspicious that your fuel shut off solenoid may be failing. I'd suggest swapping the top cover with another IP. Or, if you don't have one to swap, you can just try and start it without a top cover, but that's going to make one heck of a mess. You would use your finger to shut it down then once it starts.

 

[7bicks]

I did verify with the cover off that the FSS works. Does the linkage move a valve lower inside the IP? I can see where the FSS touches the linkage and when engaged lets the spring loaded linkage move towards the front of the truck. That should cause a valve in the IP to open if I understand it correctly.

I don't have a spare IP to compare operations.

I may have some help this afternoon and let somebody crank it while I have the cover off and move the linkage by hand to see if it fires.

Thanks for the input