I need troubleshooting help. tried everything

[hfmt93]

I have exhausted my troubleshooting abilities. I am an aircraft mechanic not a diesel. Please help.

I had what I thought was a injector pump going out. It had low power and hard to start. So, i got a rebuilt ip off ebay.

I installed it and these are the problems:
-It will start after sitting for a long time (hours or a day)
-When it starts i hold it at high throttle. It starts and runs as normal for about 30sec to a min. Then dies like i turned it off (no stumble).

Things to know:
-I have everything partially installed. The manifold it on with only the back bolt with the three grounds.
-A month or so ago I installed a spin-on filter. It ran after the install.
-I run jet fuel in it when not driving on the road. It was running with the same batch that is in it now.

Things I have tried:
-Removed the inlet side of the pickup pump and feed the inlet with a fuel tank on the ground to elemenate a clog in the tank.
-Put a clear hose on the ip outlet(return). No bubbles noted
-Took a seperate battery and used it to hold open the ip shut off solinoid.

All troubleshooting attempts produced the same results of starting if it sits and then dies abruptly after a minute.

Please give me some input from your experiences.

 

[tiger422]

Sound like you are losing fuel or sucking air. Look over all the fuel lines and filters. I am not familiar with your truck but if there is a primary fuel pump check that it is working correctly.

 

[Ken_86gt]

It does sound like it is starving for fuel. You could try putting a flexible hose on the IP and into a small container of fuel, have someone start the truck. If it runs well then you know it is not IP related.

 

[Ken_86gt]

When it stops, can you restart it immediately?

 

[raiburn]

Yeah, sounds like air in the system.

 

[hfmt93]

It does sound like it is starving for fuel. You could try putting a flexible hose on the IP and into a small container of fuel, have someone start the truck. If it runs well then you know it is not IP related.

You mean bypass the pickup pump and have a can directly suply the ip using gravity?

When it stops, can you restart it immediately?

No, I have to let it sit for a while. Usually overnight.

Thanks for your input.

 

[hfmt93]

I thought by putting a clear hose on the return of the ip and not seeing any bubbles means there is not a problem with air.

I am going to try to hook a fuel can directly to the inlet of the ip and see if it does anything. I will let all of you know tomorrow.

 

[MakersTeleMark]

Fuel pump? Maybe start with the fuel filter. Do you get a gushing amount of fuel out of the line?

 

[Ken_86gt]

Yes, I mean for you to bypass the pickup pump, the ip will have no problem pulling fuel. You could try to prime the hose.

If you loosen the gas cap can you hear air rushing into the tank? If so, it could be a tank venting problem. You could also try running with the cap loose.

 

[MASIC]

Install a swing check just past the filter on the engine side of the filter. Your losing prime for your injection pump. My 5 ton does not have a lift pump and this is the cats ass as far as starting the truck within the first 4 revs of the engine off the starter. Make sure the swing check is installed open towards the engine and closed towards the filter/fuel tank

 

[hfmt93]

Fuel pump? Maybe start with the fuel filter. Do you get a gushing amount of fuel out of the line?

The pickup pump is less that a year old. I did the test in the manual where you turn the motor for 15 sec and see if you have a quart or something. I had way more that what it called for so I didnt bother putting a gauge on it.

Yes, I mean for you to bypass the pickup pump, the ip will have no problem pulling fuel. You could try to prime the hose.

If you loosen the gas cap can you hear air rushing into the tank? If so, it could be a tank venting problem. You could also try running with the cap loose.

I elemenated the tank by using a different fuel source but also tried with no cap on the factory tank.
Going outside to try feeding the ip directly.

 

[hfmt93]

Install a swing check just past the filter on the engine side of the filter. Your losing prime for your injection pump. My 5 ton does not have a lift pump and this is the cats ass as far as starting the truck within the first 4 revs of the engine off the starter. Make sure the swing check is installed open towards the engine and closed towards the filter/fuel tank

When it starts, it start imediatly. You think this check valve would help my dieing after 30 sec?

 

[91W350]

I would guess that the fuel solenoid is failing to hold the shut off open.

 

[rnd-motorsports]

 

[grayw0lf]

I would guess that the fuel solenoid is failing to hold the shut off open.

I've always wondered... Is the fuel shutoff solenoid normally open when running, or normally closed?

 

[hfmt93]

I've always wondered... Is the fuel shutoff solenoid normally open when running, or normally closed?

12v holds it open.



I figured it out. I feel stupid.

If you read the TM on bleeding the fuel filter it labels the shut off solinoid as the aft connection. The whole time I had the pink wire and the green mixed up. If you look at the TM on changing out the engine wire harness it shows the correct configuration.
Thats why it would die and not start for a while. the green wire would provide enough voltage to the shut off solinoid untill the engine started to warm up.

I also had some bubbles in the ip return. Ended up being the end of one of the filter hoses where it had cracked some.

I feel stupid to have done this much troubleshooting. Hopefully somone will read this and not make the same mistake. Thanks for all the help.

 

[doghead]

Great news that you have it figured out, and thanks for sharing it here.

We all learn from our mistakes(and better yet, can learn from others by posting it here on SS).

 

[Warthog]

Great news. Glad you figured it out...