Helping my neighbor out. He's got a 89 7.3 5spd with the Banks Sidewinder kit. Truck only has about 50k miles (owned by an old man who passed, bought from his wife). He's had it about 6-months. Truck has run pretty well for him, towing his 8k lb trailer frequently. Currently truck will barely start and run and blows white smoke.

He had some issues with the tank switchover valve and it's been run out of fuel numerous times until he figured out the issue.

Current issues:
-He was driving down the freeway and truck began to sputter. He pushed down on the accelerator and the truck continued to sputter and died. It was turning about 2500rpm at the time. Got towed home

-Truck currently will start but blows lots of white smoke. Research shows that this is unburned fuel or coolant. We don't see any signs of headgasket issues so we assume it is fuel.

-Truck will run for about 30-seconds and die. We've put clear lines on returns and we do have good fuel to the filter and from the return on the Inj pump.

-The return check on the injection pump was full of crud when we pulled it. I'm guessing this is NOT a good sign as you shouldn't have any crud inside the injection pump. Some of the crud is shiny and metallic. Once it fires up we typically weren't seeing fuel from the inj pump return as the check was getting plugged.


My hunch is that the injection pump is shot. It's also sent metal down to the injectors which now aren't closing all the way giving the white smoke. I think we need to get a new injection pump and all new injectors, but I want to get some other opinions before he drops the coin.


Things that have been fixed/check:
-Lift pump replaced
-Glow plugs replaced and will run for a good long time before clicking
-New fuel filter
-Rubber rubber return hoses from the filter & inj pump replaced. Next on the list is the injector O-rings, but I don't think those would be causing this issue.
-Filter check valve is bad, so we plugged the return and bled the air manually. Have not air coming out the schraeder now
-Batteries are good, motor will fire up quickly.

Thoughts?

Side note, I'm a 6.0 guy and I'm pretty impressed by the old iron. Fun to be able to actually SEE everything on the motor and how it can run with just power to the fuel solenoid. Plus costs are MUCH less on parts. With the Bank kit it's got some pretty good towing *****. It's got a lot more torque down low than the 6.0, especially with the 5spd manual.

 

Sounds like fuel strainers on pick ups are gone. Sucking air through tanks or air intrusion somewhere else. Make sure you have more than a half tank. You can take a diesel fuel can hose up from can to mechanical fuel pump to eliminate tank to pump fuel source this will help by process of elimination. Vacuum line test fuel system if vacuum drops within 5 minutes you have leak.

 

I'll bet you that the advance piston isn't advancing. IIRC, there's a little filter inside the injector pump for fuel going to that advance piston, because the early pumps had premature wear there.

One way to check this - loosen/remove all the injector lines on the IP, loosen the IP bolts, and rotate the IP all the way to the passenger side. Reinstall the lines(the vibration dampeners probably will not fit now, so you don't want to leave it like this very long), and fire it up.

If the white smoke is fixed(or much better), it's time for an IP replacement or rebuild. If not, you can look further around.

 

Update. My neighbor decided to remove the check valve from the IP as it kept plugging. The truck started up and ran without white smoke, so we figured the problem was the check and ordered a new one.

While waiting for the new check he decided to install a filter in the return from the IP. TONS of crap came out. Not metallic, looks fibrous, like piece of filter media. Truck actually ran fine without the check valve in the IP, just got hard to start in the morning. Just put back in the check and we'll see how it does.

He took a video of the crap he pulled out of the filter:

 

So... Actually, having the check valve removed is the "cold start" position. Once the truck warms up, the temp switch turns off and the check valve increases the housing pressure to 5 psi.

Without the check valve(lower housing pressure), you will be a few degrees more advanced than otherwise, which is probably why it's running better.

 

Does the temp switch increase the idle speed? It idles at the same rpm dead cold or hot. I believe around 700-800 rpm, I've never checked the number but it sounds like a normal idle speed.

 

Through a separate solenoid, it is supposed to.
The high idle solenoid is located on the passenger's side of the IP, right at the front. It pushes against the throttle lever to increase RPM.

This only works as long as:
1. The solenoid has power when cold
2. The solenoid is adjusted correctly, so it actually pushes the throttle lever enough to get the desired cold RPM.
3. the solenoid does not have enough power to push the throttle by itself; you have to "pump" the accelerator for it to engage. Once it activates, it will stay activated until it loses power when the temp switch turns off.

 

wow, that is a lot of crap in there!!!
i wonder where it is coming from? maybe a defective/deteriorating fuel filter?
i would try to flush the complete fuel system.