5 ton multi fuel injector pump bleeding.

[avalenti]

Hello all, This is my first post, so please forgive me if I am not doing this correctly. I have a 1968 5 ton multifuel that I have owned for about 15 years. I loaned it to a friend to make a few dump runs one day, but the starter button got stuck in the on position and he didn't notice. Anyway, the starter turned into a generator and completely melted down and actually caught the batteries on fire! Lucky I had an extinguisher on board and he put it out before things got too exciting. We were able to pull start the truck and drive it home. a week or so later I dropped the starter and found it was completely shot. The brush holders melted and the armature came out in ashes! I ordered and installed a new starter and the truck kicked over and fired, but ran for only about 5 seconds. I could not get it to restart. After some basic troubleshooting, I discovered the lift pump was not running. I pulled the junction box and the fuse holder was shot. I replaced that and got the pump running. In my diagnostics, I had loosened the fuel line fitting on the tank to see if I had fuel pressure, so I know I could have introduced some air into the system at the point. So.... once I had the lift pump running, I purged the low pressure lines by opening the fuel petcock on the filter housing, I also purged the line to the IP, but I still can not get the I.P. to give any fuel. I did follow the advice in the manual and loosen the injector lines starting with one, but I get not a single drop of fuel at the injectors when I crank. I am at a loss as to why the IP would fail spontaneously after this starter issue. This truck has run flawlessly since I bought it. It seems awfully coincidental. Is there anything else I should look at before pulling the injector pump? Thank you in advance. Alan

 

[dmetalmiki]

If the in tank pump ran out of juice, (doubtful), Something else is awry.
You have a good fuel flow through the filters and lines,? ,
Is it a good flow?, Not just a dribble.
(Including the 'Scraper mesh' filter on the drivers side chassis).
Check the throttle control rod is not stuck shut. (freely moves in both directions).
(On the Hydraulic Head inside the cover with the two screws).

Check the quill is moving up and down when the engine is cranked.
Under the bolt in the center of the Hydraulic Head.

Before all that (Except re-check the fuel flow),

Try to start the engine on a Teflon Penetrating oil spray. NOT Ether. (softer on the engine and no banging etc). The engine may well 'pick up' after running on the spray.
Pressurize the fuel tank. (NOT overly.).

Report back, I am certain others members will chip in.

 

[avalenti]

If the in tank pump ran out of juice, (doubtful), Something else is awry.
You have a good fuel flow through the filters and lines,? ,
Is it a good flow?, Not just a dribble.
(Including the 'Scraper mesh' filter on the drivers side chassis).
Check the throttle control rod is not stuck shut. (freely moves in both directions).
(On the Hydraulic Head inside the cover with the two screws).

Check the quill is moving up and down when the engine is cranked.
Under the bolt in the center of the Hydraulic Head.

Before all that (Except re-check the fuel flow),

Try to start the engine on a Teflon Penetrating oil spray. NOT Ether. (softer on the engine and no banging etc). The engine may well 'pick up' after running on the spray.
Pressurize the fuel tank. (NOT overly.).

Report back, I am certain others members will chip in.

Thank you for the reply. The in tank pump died because the fuse holder was corroded. After I replaced it, that pump started pumping again. It does flow nicely, If I open the drain on the first filter on the frame I get good flow. If I open the petcock on the top of of the dual secondary filters, I get a solid stream that shoots up 18 inches or so. I didn't put a gauge on it, but it sure seems like at least the 2 PSI they spec in the book. I was able to get the truck to run on wd-40 spraying into the intake. I didn't however run it very long that way (maybe 5 seconds. The hand throttle moves fine, though, I must admit I am not familiar with the term quill. Is that some sort of cam mechanism? Thank you Alan

 

[G744]

Silly to mention it, but make sure the engine stop is not pulled out...

DG

 

[avalenti]

Lol, yeah, it's in. I made sure it was still connected too. Thx

 

[Floridianson]

Well for here I would pull the timing cover / some call it a shut down cover on the IP and check the fuel control unit assembly is moving free. Only two screws and 5 min. to check. I would do this before removing the center plug and checking the plunger for movement at this time. The nice thing about the multi fuel is the system is self bleeding of air when the in tank pump is running so no need to bleed the injectors. As long as the head is getting fuel but a no start then the problem most of the time is in the head. Fuel control unit assembly, fuel delivery valve or the timing button has come off the plunger. The fuel delivery valve is another quick check.