bleeding the fuel lines.

[Big Ray]

Been working on my diesel 'burb this a.m. I removed all my glow plugs, cracked the fuel lines at the injectors, and run air through the return line to prime the (factory square) filter.

Spun the motor many times. Less than a minute, with several minutes between to let the starter cool.

I got fuel at the filter bleed port. I ran air through the rubber hose that connects where it connects at the fuel shut off solenoid on the i.p. Still dry as a bone at the injectors.

What did I do wrong here?

 

[campfire]

Been working on my diesel 'burb this a.m. I removed all my glow plugs, cracked the fuel lines at the injectors, and run air through the return line to prime the (factory square) filter.

Spun the motor many times. Less than a minute, with several minutes between to let the starter cool.

I got fuel at the filter bleed port. I ran air through the rubber hose that connects where it connects at the fuel shut off solenoid on the i.p. Still dry as a bone at the injectors.

What did I do wrong here?

Is the filter bleed port open?

Is the fuel solenoid is getting 12V and opening properly (you can hear a faint click when it opens)?

I have no way of testing this, but if you floor it it should be trying to push more fuel through the lines. I reason that should help, but that's just a guess.

What prompted you to crack the lines in the first place? If they were completely dry (new lines) it will take a bunch of cranking to get fuel to them. If they swallowed a small air bubble, you should be able to crank it out of the system without cracking the lines.

 

[Big Ray]

I swapped in a new fuel pump about 2 years back, and it hasn't run right since. It lost prime and has been sitting for a year and a half now. I have a rebuilt pump and injectors, I'm thinking about swapping them in. When I parked it, I drove it home from work. Would not start for love or money after that. A LS swap keeps looking better & better...

Don't know about the solenoid, I'll' check it the next time I work on it. We have plans tonight...

Mama wants it running or gone.

 

[Cucv_M1008]

bleed it from the rubber return line of the pump.

 

[campfire]

I swapped in a new fuel pump about 2 years back, and it hasn't run right since. It lost prime and has been sitting for a year and a half now. I have a rebuilt pump and injectors, I'm thinking about swapping them in. When I parked it, I drove it home from work. Would not start for love or money after that. A LS swap keeps looking better & better...

Don't know about the solenoid, I'll' check it the next time I work on it. We have plans tonight...

Mama wants it running or gone.

You have a new lift pump? Or a new injection pump? Not sure which you're talking about. It sounds like your lift pump is fine. Is this still a mechanical lift pump, or has it been electrified? If electric you have a much easier time when priming the lines before the IP. Either way, you're stuck cranking to get the IP primed. One of mine loses its prime every time I shut it off. I bleed it out (electric pump) before I start it and it never causes a problem. If I do manage to swallow the air bubble, it usually takes a minute of total cranking time (including pauses) to get it running again. Keep the pedal down. The engine will start running when fuel gets to the first few cylinders, but it will try hard to stall. And the engine speed will surge back and forth as the governor slowly gains control of the engine speed. I don't take my foot off the throttle until it is well above idle speed (though I try not to get it moving too fast, it's not that easy to control during the first few seconds).

I'm sad to say I've gotten pretty familiar with bleeding out the air bubbles every time I start cranking too soon (before all the air gets purged out).


If mama wants it running or gone, it sounds like you're on an unknowably tight schedule.

 

[Big Ray]

bleed it from the rubber return line of the pump.

The lift pump or the i.p.?

You have a new lift pump? Or a new injection pump? Not sure which you're talking about. It sounds like your lift pump is fine. Is this still a mechanical lift pump, or has it been electrified? If electric you have a much easier time when priming the lines before the IP. Either way, you're stuck cranking to get the IP primed. One of mine loses its prime every time I shut it off. I bleed it out (electric pump) before I start it and it never causes a problem. If I do manage to swallow the air bubble, it usually takes a minute of total cranking time (including pauses) to get it running again. Keep the pedal down. The engine will start running when fuel gets to the first few cylinders, but it will try hard to stall. And the engine speed will surge back and forth as the governor slowly gains control of the engine speed. I don't take my foot off the throttle until it is well above idle speed (though I try not to get it moving too fast, it's not that easy to control during the first few seconds).

I'm sad to say I've gotten pretty familiar with bleeding out the air bubbles every time I start cranking too soon (before all the air gets purged out).


If mama wants it running or gone, it sounds like you're on an unknowably tight schedule.

Sorry. I installed a new mechanical lift pump 2 years ago, and I have a rebuilt i.p. and injectors in the garage on standby.

 

[Cucv_M1008]

The lift pump or the i.p.?



Sorry. I installed a new mechanical lift pump 2 years ago, and I have a rebuilt i.p. and injectors in the garage on standby.

The I.P.

 

[KirsL]

Well if the no start issue happened after you changed the lift pump I'd start there. You might have an air pocket between the tank and the pump. Pumps suck (pun intended) at pulling fuel long distances. Simplest thing is start at the tank and check for fuel at each conections. It's a pain but its the most through way to do it.

Oh and holding the pedal down while cranking a diesel doesn't help. Once it's sorta running you can hit the pedal to keep it running.

 

[Cucv_M1008]

Pressurize the tank and lines with air.

 

[KirsL]

Pressurize the tank and lines with air.

You can do that too. Just be careful how much pressure you put in the tank. 5psi should be more them enough.

 

[Big Ray]

Pressurize the tank and lines with air.

I did exactly that.

Well if the no start issue happened after you changed the lift pump I'd start there. You might have an air pocket between the tank and the pump. Pumps suck (pun intended) at pulling fuel long distances. Simplest thing is start at the tank and check for fuel at each conections. It's a pain but its the most through way to do it.

Oh and holding the pedal down while cranking a diesel doesn't help. Once it's sorta running you can hit the pedal to keep it running.

It ran for a couple of months, but was gradually getting worse until I parked it

 

[campfire]

I did exactly that.



It ran for a couple of months, but was gradually getting worse until I parked it

What was happening? Getting air in the line and losing prime while sitting (like my rig)? Or was it having trouble delivering fuel while driving?

 

[Big Ray]

the latter...

 

[campfire]

Ah. You would have to be sucking a lot of air to lose power like that. Could also be a failing IP.

 

[diesel4me]

You can also apply vacuum to the return line T fitting near the IP to bleed the system out before cranking it--remove the hose from the T and put a vacuum to the T fitting.....
I have used another gas powered vehicle's engine to supply the vacuum via a long length of vacuum hose before...I've used this method to bleed stubborn brakes and clutch cylinders too...I even used a wet/dry shop vac as a "vacuum pump" and it worked...I duct taped the vacuum hose to the shop vac's hose..

When I first got my pickup back in 2003,it had sat a long time with a freshly installed used engine that the former owner couldn't get to start...

I tried everything suggested here and still only managed to kill the batteries several times,and probably took years off the starter's life as well...after getting pissed off enough to say screw it,and start looking for a gas engine to put in it--I tried one more thing..

I ended up using the method everyone says NEVER to use...starting fluid!...had a friend spray it while I cranked,after I unplugged the glow plug controller so they would not activate,it fired right up,and he kept spraying short burts for about 10 seconds to keep it running--after it bled itself it started right up with one turn of the crankshaft..

After awhile of road use the truck started dying out after a hard acceleration,(like merging into heavy highway traffic !),and I'd have to pull over and feather the throttle to keep it from stalling in neutral...
I had installed an electric fuel pump close to the tank,and it would usually keep the fuel filter full and the system air free,but I discovered several flaky rotted areas on the main fuel line from the tank to the firewall that were weepy--once I chopped that line out and replaced it with copper,no more troubles..I think it was sucking air through the rotted areas,it didn't "leak" enough to drip,just appear moist..

 

[campfire]

I had installed an electric fuel pump close to the tank,and it would usually keep the fuel filter full and the system air free,but I discovered several flaky rotted areas on the main fuel line from the tank to the firewall that were weepy--once I chopped that line out and replaced it with copper,no more troubles..I think it was sucking air through the rotted areas,it didn't "leak" enough to drip,just appear moist..

Same here. It was just last fall, after 2 full years of leaking, that I finally spotted an area weeping fuel. And it's at the mechanical lift pump. Can't decide whether to replace it (have the part already) or just pitch it and run electric only.

 

[Big Ray]

I think I'll swap out the i.p. and injectors. Next weekends project...

There was a place that sells military take out 6.5's near by for about a grand. They no longer list them on their site. Sent them an email just in case.

Worse comes to worse, I'll drop an LS in it. That'll be a shame because I actually enjoyed the diesel.

 

[diesel4me]

If the truck sat a long time its possible a rubber fuel hose has a liner that is collapsing or blocking the flow of fuel...I assume you tried blowing thru the fuel lines back to the tank ?...any fuel getting to the filter ?..new filter ?--or an old one clogged with mold and dirt?..
I'm not sure but the injector pump may have a screen in it --also read about some "glass check ball" device that can gum up and block fuel flow..

I bet if you keep plugging away at it,you'll eventually get it to fire up..
I had to run my truck off a gas can because the PO had completely fubared the dual tank setup--no dash switch,wires twisted together--no factory fuel selector under the truck,just snipped wires !--and they put a manual valve in the fuel lines instead,which was weepy..

I just snipped the "main" fuel feed hose going to the filter and put that and the return line in the gas can..after I finally got the thing to run,I just took off all the crap the PO had jerry rigged and found the wire that ran the gas gauge,and only plumbed up and used one fuel tank,since one had a leak,and I never go anywhere far enough to need 2 tanks of fuel--back then filling 2 tanks would have cost as much as I gave for the truck!..

I understand your frustration,I was ready to rip the diesel out of my truck too..till I got it to run...

 

[KirsL]

If it gets worse as its driven, I'd agree with its probably a line going bad between the tank and lift pump. Fuel lines are relatively cheap to buy and do. I'd try that before changing the ip and injectors.

 

[longbedder]

• Disconnect the fuel hose which feeds the IP - the one that runs from the filter. If it's a hard line, adapt a length of rubber fuel hose to it.
• Get a clean jug of some sort which you can connect to the rubber fuel hose. One with a nipple like a gear oil bottle works quite well.
• Put diesel in the jug.
• Attach the nipple to the hose and invert the jug.
• Have someone or some apparatus hold the jug in place above the engine - this will feed the IP directly with gravity and eliminate any possibilities between the tank and IP.
• Try to start the truck.

I did this after a long downtime which included a new IP install. The engine fired right up after just a few cranks.