Injector #4 will not bleed out - Constant Air.

[Old Nordby]

Truck got to running rough again, lost some power, accompanied by some blue smoke. Finally got around to going through the low pressure and high pressure bleeding to see if it was an air problem.

All injectors showed air, all changed the idle when I cracked them while running and ran clear fuel within 5 seconds at the most. Except for #4. Constant foaming and air. Did not change the idle when cracked. Ran for 30 seconds like this, pushing foam. Really cracked it for 5 seconds, still did not clear up, ran for 30 seconds more, still just pushing foam.

This is a brand new PW injector. I'm hoping for the simple fix - swapping in one of the factory injectors I still have laying around, but is this really a sign of a bad injector? Or am I back to a possible cracked head or head gasket problem with compression air coming back through the injector.

Thanks for any help guys! Happy holidays to all!

Jon.

 

[ScottB]

Im really not to sure but I'd say from my experiences it would be a bad injector. Sorry I'm no help but if or when you figure it out post the solution.

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93 W350 White 4" stack Headache rack with Lights. Gauges 27pnds boost Banks quick turbo. Hand Throttle CB

 

[cullmanboy]

Nordby, if the foam is coming out where u are cracking the injector, I would think it is coming from somewhere else, maybe pump trble, are u still having trble or have u replaced the injector yet...

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1993 Dodge/Cummins D250 LE ext cab 185000 miles

1970 Dodge W300 Powerwagon with 8 ft dump bed

 

[AlK]

nordby, to determine whether you have a bad #4 injector switch it say with number #3. I hope it is nothing serious, keep us posted.
---
Al

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92-LE,4x4,5spd,3. 54,Borgeson steering shaft, Tach,Isspro Pyro & Boost, 16cm2, PW injectors

 

[Old Nordby]

Arggh. . Intermittent, and it moved.

I swapped a stock injector back into the #4 hole, drove fine for about 20 miles. Back to the smoke, miss, power loss, etc. Dug up some time over the new years weekend, and dang, #5 won't bleed out now. What gives??? And I mean masses of foam, with no idle change when I crack the high pressure, left it there for 30 seconds too, it would not bleed out. All others had minor air, then they bled out fine. All air was focused on one injector, for well over 30 seconds, and never did quit foaming.

Started this morning, tons of gray/blue smoke. Drove for about 1 mile, started running fine, idling fine, no smoke. Drove it at lunch, runs fine, idles fine, no blue/gray smoke, just the black stuff.

I believe I am in for the injector pump for this weirdness (153K miles, power screw in a turn, smoke limiter in . 5 turn). This truck will not turn off sometimes. I turn the key off, and have to apply 1/4 throttle to get the selenoid to click over to get it shut down.

Any ideas why this might be so intermittent, and move around? I'm going to trace fuel lines again tonight or tomorrow night for signs of air leaks back to the tank, but I don't think an air leak would cause all air to go to one injector.

thanks for the support guys!,
jon.

 

[CBratten]

nordby I would closly look at the fuel line(in the tank, connections at the tank and going to the transfer pump). Sounds like air is being suck in as the fuel is being tranfered the injection pump and mixing with the fuel. Charles

Originally posted by nordby:
Arggh. . Intermittent, and it moved.

I swapped a stock injector back into the #4 hole, drove fine for about 20 miles. Back to the smoke, miss, power loss, etc. Dug up some time over the new years weekend, and dang, #5 won't bleed out now. What gives??? And I mean masses of foam, with no idle change when I crack the high pressure, left it there for 30 seconds too, it would not bleed out. All others had minor air, then they bled out fine. All air was focused on one injector, for well over 30 seconds, and never did quit foaming.

Started this morning, tons of gray/blue smoke. Drove for about 1 mile, started running fine, idling fine, no smoke. Drove it at lunch, runs fine, idles fine, no blue/gray smoke, just the black stuff.

I believe I am in for the injector pump for this weirdness (153K miles, power screw in a turn, smoke limiter in . 5 turn). This truck will not turn off sometimes. I turn the key off, and have to apply 1/4 throttle to get the selenoid to click over to get it shut down.

Any ideas why this might be so intermittent, and move around? I'm going to trace fuel lines again tonight or tomorrow night for signs of air leaks back to the tank, but I don't think an air leak would cause all air to go to one injector.

thanks for the support guys!,
jon.

 

[Don D]

Put a section of clear hose between the transfer pump and inj. pump. If you see bubbles while the engine is running you will at least rule out the injection pump. This procedure pionted me to a bad transfer pump once when the engine started running like you described. I'm not sure if air in the system would cause your fuel shut-off solonoid to act up or not.

 

[Old Nordby]

Thanks Don D and Field-Boss-Cb - these are excellent suggestions. The lift pump is fairly new, < 8K miles, but I'm sure new pumps fail too.

I'll get some clear hose in place and go from there. Sounds like seeing air in here, while the truck is acting up, would rule out the injection pump and move me back towards the lift pump, and supply lines from the tank to the lift pump. It'll be a few days before I can sneak away and rip into this, I'll post results.

Thanks for the ideas, jon

 

[Caltruck]

Based on what you've explained, since the air problem is only isolated to one injector and you've replaced the injector and the problem transferred to another injector, you can rule out everything up to the injector pump.

Since you've described a problem with shutting off the truck means that you already have one problem with the pump. My guess is that you have some sort of internal leak in the injector pump sucking in air.

Just my two cents.

 

[Old Nordby]

Quick update:

No obvious leaks on the gas line between the lift pump and the tank. By looking for wear spots, by feel as much as possible, and by starting fluid while the truck was idling (hoping it would pull the fluid with any air and the idle would change).

Gonna have to pull the tank to check feeder lines, may have to wait until next weekend. Arggh, no time.

Still trying to source clear tube for the line between the lift pump and injection pump, so I don't have a visible on the air.

Swapped injectors on 4 again, and it would not bleed. Put the stock injector back in, and it bled out fine, so I think it is safe to say I at least had an injector problem. One confusing thing to me was that both the could injector and bad one were wet with diesel fuel when I pulled them, is that correct? Seems fishy to me.

Truck is running OK now, a little more blue smoke than normal on startup, but it is real cold out and it clears up fast, after the heater grid quits cycling. So whatever this is, it is not a consistent problem.

Sometimes doncha wish the truck would just die so you could fix it?

More as I know it, thanks, jon.

 

[Old Nordby]

Sorry for the slow update, but I basically just had to park this truck for a while and hitch rides and/or drive the other truck built by a manufacturer best not named in this conference that burns something other than diesel fuel.

Finally ripped into this thing. Pulled the tank, completely emptied and cleaned it. Inspected every drop of gas that came out - poured it 1 gallon at a time into a glass bottle to take a look. Not much there, maybe 1 oz of water over the 7 gallons of fuel that came out of it.

Pulled and cleaned as best I could the big 'ol feeder mechanism, inspected the feeder and return lines. Traced the feeder and returns from the front of the truck as well. Pulled all the lines between the lift pump and filter, and filter to the injection pump.

The only real problem I found through all of this was a really loose connection between the filter and the injection pump. This is a two-piece line for some odd reason, and the fitting where the pieces fit together was hand tight - a big source for air I'd guess.

I also pulled the PW injectors and put the stock ones back in. Bolted it all back together, refueled. Started up, ran rough for a while until I bled at the injectors, and now runs fine with no smoke (small amount of expected black smoke). Power is good. Shutoff solenoid is next - truck still runs after I turn the key off.

So, now I have 20 problem free miles, and counting. We'll see if it turns out to be that loose fitting - or injectors.

I'm in the process of finding a fuel pressure gauge, and finding correct sized fittings to make a clear line between the filter and injection pump to look for air.

Thanks again for the suggestions here,
jon.