XM818 a semi failed recovery

[goldneagle]

http://www.steelsoldiers.com/showthr...ghlight=M820A2

post #24

http://smile.amazon.com/gp/product/B...?ie=UTF8&psc=1 base for unit.

http://smile.amazon.com/gp/product/B...?ie=UTF8&psc=1 filter

 

[mattgunguy]

Well after a day of fiddling off & on I have this to report. I have double checked the little filter on the pump & it is good n clean. The truck will idle just fine till until the engine is revved up. Then once it slows back down (neither revving nor slowing back to a idle is very responsive, there is a definite time lag there) to an idle it'll either choke & sputter for a minute and die, or just flat die. He'll start back up almost right away though. I also now have fuel leaking from somewhere on top of the pump. Looks to be from around the base solenoid / dodad with the manual fuel shut off. Maybe also from the bell looking thing on the rear of the pump. I have not pulled the main filter again yet to see if it's collected more crap. What's the best way to pressurize the tank, so I can maybe spot any pin holes?

 

[doghead]

You haven't touched the emergency shutoff on the dash, have you?

If you have, you need to manually reset it (by hand under the hood)

 

[mattgunguy]

Nope. Been leaving it alone. Once I figured out it didn't rest itself that is.

 

[fasttruck]

Pressurize fuel tank: 0n a tractor you have to remove the deck plate above the fuel tank the selector valve is set to, which will facilitate inspecting the fittings there, remove one screw from the fuel gauge sending unit, remove chuck from tire inflator hose and place tube over screw hole and apply air. This is easier on a cargo or dump truck where there is no deck above the fuel tank. Air will force fuel up to IP. Plan B is to get an extra fuel cap and braze a schrader valve on it to introduce air into fuel tank. Don't need too much air pressure to prime engine this way.

 

[Baradium]

Pressurize fuel tank: 0n a tractor you have to remove the deck plate above the fuel tank the selector valve is set to, which will facilitate inspecting the fittings there, remove one screw from the fuel gauge sending unit, remove chuck from tire inflator hose and place tube over screw hole and apply air. This is easier on a cargo or dump truck where there is no deck above the fuel tank. Air will force fuel up to IP. Plan B is to get an extra fuel cap and braze a schrader valve on it to introduce air into fuel tank. Don't need too much air pressure to prime engine this way.

For low pressure, I've just taken an air hose with a blower nozzle on it and stuck it in the the fuel filler hole and stuffed rags around it. You need two people usually to do this (unless you're really good with the rags), but you also don't have to remove or modify anything. You don't really need all that much pressure, and you can regulate the air down to a comfortable level.

 

[mattgunguy]

Pressurize fuel tank: 0n a tractor you have to remove the deck plate above the fuel tank the selector valve is set to, which will facilitate inspecting the fittings there, remove one screw from the fuel gauge sending unit, remove chuck from tire inflator hose and place tube over screw hole and apply air. This is easier on a cargo or dump truck where there is no deck above the fuel tank. Air will force fuel up to IP. Plan B is to get an extra fuel cap and braze a schrader valve on it to introduce air into fuel tank. Don't need too much air pressure to prime engine this way.

Thank you. I've got an extra gas cap & a bunch of valve stems. Time to play with a torch

 

[Baradium]

Thank you. I've got an extra gas cap & a bunch of valve stems. Time to play with a torch

How about a drill and a tap? I guess that would probably require buying a different schrader valve though...

 

[goldneagle]

How about a drill and a tap? I guess that would probably require buying a different schrader valve though...

They make one with 1/8" pipe thread on one end. I bought one from AMAZON to repair a missing one on a 14.00-20 rim. http://smile.amazon.com/gp/product/B0081TJO72/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

I am gong to make one setup using this valve stem attached to a spare fuel tank cap.

 

[MidnightDuramax]

Just use a standard Rubber snap in valve. Rubber snap-in valves are available to fit either .453" or .625" diameter holes in the rim and have effective lengths ranging from 7/8" to 2-1/2". Or you can use the bolt in ones.

 

[tennmogger]

Good way to blow up a fuet tank. Please be careful.

 

[rmgill]

My M813A1 had a bit of plastic from a sprite bottle floating around in the tank that would cause fuel starvation. I found it when I did a clean on the fuel tank and pulled the pump. Bloody thing had been partly sucked up the fuel pickup.

 

[goldneagle]

My M813A1 had a bit of plastic from a sprite bottle floating around in the tank that would cause fuel starvation. I found it when I did a clean on the fuel tank and pulled the pump. Bloody thing had been partly sucked up the fuel pickup.

That sucks!

 

[mattgunguy]

I can almost relate. Just not sure yet. Tightened all the lines after work today, then let him sit and idle for about 30 minutes while I worked on dinner. All the while just idling away like nothing has ever been wrong at all. So ok, it almost dark & things are going good. Let's go for a drive around the block. End of the street maybe 600 yards ( could be less, I've got a bad eye for distance ), around a warehouse. Another couple hundred. Up a drive to turn back on my street, and things went sour again. Bear in mind that all this road is very bumpy. A few shots of starting fluid and a few choice words later, back in the driveway.

Fun thing is, now that I think about it, the truck did just fine till I hit rough road on a uphill stretch in Mississippi. Then my problems started. Probably just be pure coincidence.

 

[jasonjc]

Hey I had a bad fuel shut off vale on mine hit a pot hole and the truck would die. Try turning the over ride screw on the shut off and see if that helps.

 

[goldneagle]

I can almost relate. Just not sure yet. Tightened all the lines after work today, then let him sit and idle for about 30 minutes while I worked on dinner. All the while just idling away like nothing has ever been wrong at all. So ok, it almost dark & things are going good. Let's go for a drive around the block. End of the street maybe 600 yards ( could be less, I've got a bad eye for distance ), around a warehouse. Another couple hundred. Up a drive to turn back on my street, and things went sour again. Bear in mind that all this road is very bumpy. A few shots of starting fluid and a few choice words later, back in the driveway.

Fun thing is, now that I think about it, the truck did just fine till I hit rough road on a uphill stretch in Mississippi. Then my problems started. Probably just be pure coincidence.

Check the fuel tank for junk on the bottom. maybe hitting the rough road stirred the contamination into the fuel. See if the filters are dirty again.

I have an idea. How about using a clean fuel container (5 gallon or so) and just shove the fuel line into it. See how it does with clean fuel. Had that type of issue with my Deuce a while back.

 

[goldneagle]

Hey I had a bad fuel shut off vale on mine hit a pot hole and the truck would die. Try turning the over ride screw on the shut off and see if that helps.

That is a good idea. Easy to do. No cost involved. You can shut off the truck with the emergency cut off handle. Then just reset it manually.

 

[mattgunguy]

Check the fuel tank for junk on the bottom. maybe hitting the rough road stirred the contamination into the fuel. See if the filters are dirty again.

I have an idea. How about using a clean fuel container (5 gallon or so) and just shove the fuel line into it. See how it does with clean fuel. Had that type of issue with my Deuce a while back.

This is my next plan. Might be a while though. My wife has informed me that I must get her Bronco fixed before I can fiddle with the truck. Oh the joys of not having a garage to work in, & it's about to get cold again. Anyone wanna help pull a 351m out of a 79 Bronco. Just gotta do rods & mains. I hope :l

Maybe I can sneak in the fuel can bit in there somewhere.

 

[Doug Roberts]

I'm guessing #6 from Trailboss's assessment

 

[M920]

Well after a day of fiddling off & on I have this to report. I have double checked the little filter on the pump & it is good n clean. The truck will idle just fine till until the engine is revved up. Then once it slows back down (neither revving nor slowing back to a idle is very responsive, there is a definite time lag there) to an idle it'll either choke & sputter for a minute and die, or just flat die. He'll start back up almost right away though. I also now have fuel leaking from somewhere on top of the pump. Looks to be from around the base solenoid / dodad with the manual fuel shut off. Maybe also from the bell looking thing on the rear of the pump. I have not pulled the main filter again yet to see if it's collected more crap. What's the best way to pressurize the tank, so I can maybe spot any pin holes?

What you described about the rpm coming down really slow after revving it up, is a very typical tell-tale for air in the fuel!
I would definitely look for an air leak. Pressurizing the tank as suggested is a good way to try to find it. As was pointed out, make sure the tank vent line is free of obstructions and vented to air when you put the air to the shrader valve on the cap.
This will let some air escape, but still build up enough pressure to find any leak without blowing up your fuel tank.

Soni