Archived 1998 12v won't turn over -- air in fuel?

[BlameCandida]

Well this is embarrassing. My very first post on this forum 3 years ago was for this same problem. Today I changed the fuel filter and cleaned the prefilter. I reinstalled everything after filling them with diesel, lubricating the o-rings, and then made sure everything was tight. I performed the manual bleed procedure by cracking the small bolt and priming the lift pump. The first time I tried this some bubbles came out and then stopped, so I tried to turn over the engine. I think I got close a few times, but no luck.



So I tried to bleed it some more and spent a long time priming with bubbles coming out. Eventually they stopped, but I never got fuel to come out of the bleed bolt. Now when I attempt to turn it over, all I hear is the starter, as if the engine is dry. What do I need to do next? Thanks.

 

[GAmes]

To be clear. The starter won't spin the engine or the engine spins, but won't fire? Are you familiar with Joe G's fuel system writeup?



http://www.cumminsforum.com/forum/94-98-engine/58777-joe-gs-fuel-system-writeup.html



If you aren't getting fuel from the bleeder hole you are sucking air from somewhere.

 

[BlameCandida]

The engine spins but won't fire. I think the first few times I tried to start it I used up all the fuel in the IP. Now when I try to start it, the engine just won't fire, since there is not even any residual fuel. I've been looking through TDR the past few hours and seen references to the writeup, but I had never seen it myself. Thanks.

 

[Missouri Mule]

After you get no bubbles there will be a small amount of fuel coming out of the banjo bolt on top of filter (did you crack the supply bolt to filter or the line/bolt to p7100?).

When you get to the point of no bubbles (sometimes fuel) you need to tighten the bolt (supply to filter) back up and push the primer button at least thirty times or until you hear the overflow valve sqeaking. Also you need push the go pedal almost to the floor when you crank it the first time. (At least when I change my fuel filter this how I do it. Mule will blow white smoke for a short time . )

 

[Bob V]

I woulde start looking at the pre filter area for a sealing problem

 

[BlameCandida]

I only cracked the small 10mm bolt that is on top of the banjo bolt. I did not realize that I could crack multiple bolts for bleeding. I will check the prefilter again. I suppose I could pull off the fuel heater while I'm at it, but I'm not sure I want to risk messing anything else up. Also, I don't have a fuel shutoff solenoid. I've had a PTO cable in its place for a few years. Should this be in the open or closed position during the bleed?

 

[BlameCandida]

I started fresh this morning and still haven't had any luck. I checked to make sure everything was tight, and did the fuel heater delete and made sure the prefilter sat flush. I also had some deteriorating vacuum fittings so I replaced those. The 10mm bleed bolt going to the IP won't open anymore. I try to crack it, and it spins, but won't come up. If I stripped it, do I need to replace the entire banjo bolt? Although I can't really see having stripped it. I was just opening and closing it without too much torque.

All of this started when I tried to fix the issues in this thread: https://www.turbodieselregister.com...?239811-Can-t-break-60-65-MPH-all-of-a-sudden

 

[Bob4x4]

I don't recomend using that little bolt on the filter for bleeding purposes. I have seen too many people strip them and it is a unique bolt. It does have a part number in the dodge book but I have not checked to if it is available still. you can accomplish the same thing by going all the way to the injection pump and loosen the banjo bolt. After you get fuel to this point you will have to crack about 3 injection lines to bleed the pump.

 

[HHhuntitall]

Stripped..... #@$%! That SUCKS!!! Only thing you can do is replace it or drill it out and retap it larger with different bolt and copper washer..... It is still available (as of 4 months ago) from Cummins. I have a part number somewhere, but will have to look deep..... It might be just as easy to use a solid banjo bolt.

 

[HHhuntitall]

Found. Screw, Captive Washer Cap (small 10mm head, M6x1. 00x10) Cummins part number 3905403



Screw, Banjo Connnector (M12x1. 50x24) Cummins Part number 3911446



Screw, Banjo Connector (M12x1. 5x24 without bleed bolt in top, used on top of fuel filter next to bleed bolt) Cummins part number 3916361.

 

[BlameCandida]

Just to clarify, I need to crack a banjo bolt on the IP and about 3 of the injectors, and then bleed them? Since the 10mm bolt is stripped, can I seal it with some Lok-Tite or something until I replace it with a new banjo bolt?

I don't recomend using that little bolt on the filter for bleeding purposes. I have seen too many people strip them and it is a unique bolt. It does have a part number in the dodge book but I have not checked to if it is available still. you can accomplish the same thing by going all the way to the injection pump and loosen the banjo bolt. After you get fuel to this point you will have to crack about 3 injection lines to bleed the pump.

 

[HHhuntitall]

Just to clarify, I need to crack a banjo bolt on the IP and about 3 of the injectors, and then bleed them? Since the 10mm bolt is stripped, can I seal it with some Lok-Tite or something until I replace it with a new banjo bolt?

Yes, loosen the fuel supply line on the pump to evacuate the air, or even the return line banjo bolt. Then bleed until fuel comes out the line, then tighten and bleed a few more. Then loosen three of the injector lines and crank until a little fuel starts to come out. Pressing on the pedal will help with this(not pumping, good solid half throttle or so), but be sure the fuel shutoff solenoid is in the RUN position, or no fuel will go to the injector lines... . Then tighten lines, and crank. It may run rough once it starts but should clean up pretty quick. Pressing the pedel will make the pump pump more fuel, pressing the air out faster... .



Unfortunately, I'm not sure the bleed screw will hold fuel pressure if the lift pump is working properly... . I'd suggest finding a replacement bolt, if possible. The bolt next to it will work, if you could find one in a wrecking yard or nieghbor's bonepile to replace the one with the bleed screw. You really need to verify the fuel line is intact and the lift pump working, or you won't know where you stand on the rest.....

 

[BlameCandida]

I tried the procedure this morning, and had luck up to a point. I cracked the banjo bolt on the IP, and pumped the primer. Fuel sprayed out of the bolt nicely. I primed it some more, and opened three of the injectors. I cranked the starter for 30 seconds and then let it rest for 2 minutes. I went through this cycle about 4 times, and saw that a little bit of fuel was coming out by the injectors. I tightened them back up, but I had no luck cranking the engine again. I guess there is still air in the lines in the IP. I made sure that the PTO cable was pushed in (as if the solenoid were in the run position).

 

[HHhuntitall]

Once the pump is primed, you should hear a "squeaking" noise, as fuel or air is bypassing the overflow valve in the return line. If that isn't happening, it's not primed, yet.....

 

[BlameCandida]

Since the truck is broke down in Austin, and I'm not local, I put it in a shop today. I hate having to do that for something as simple as a fuel filter, but I just didn't have the time to deal with it. *

While messing with the truck today, the mechanic pulled off the hose between the lift pump and the fuel filter. When pushing the prime button, no fuel would come out. So does this mean the lift pump has failed, or is something else going on?

 

[GAmes]

No, it more than likely means there is an air leak between the pump and the fuel tank. As a side note, the lift pump is actually two pumps. One is actuated by the hand primer button and the other is powered by a lobe on the cam. When you cleaned the prefilter are you sure you seated the square cut o-ring properly? Did you delete the fuel heater? They are really bad about causing problems and really serve no useful purpose.

 

[BlameCandida]

I did delete the fuel heater, and made sure the o-ring on the prefilter was lubricated and sitting correctly. I read Joe G's fuel system writeup, so to test between the lift pump and the tank, I can just disconnect the supply line from the tank, put it in a bucket of diesel and attempt to prime that way, right? If there is a leak, the lift pump won't be able to pull fuel from the bucket.

 

[HHhuntitall]

Or the pump is bad..... There is a connection at the bellhousing, as well, you need to check... . Putting a hose in a jug of diesel off the fuel pump will tell if it's good, then you go to the fuel line at the tank... .

 

[Cosmo]

When I switched from the mechanical pump to my Airdog, I no longer have to manually bleed the system.

Which is handy, since I cut my draw straw too short (measured length while the tank was sitting on a table instead of hanging) my truck dies at 1/8 tank or pretty much any time below 1/4 tank if I hit the brakes too hard. A bit of cranking, 5-10 seconds or so and it fires right up.

 

[BlameCandida]

Turns out it was the lift pump. Truck is now running again. Thanks for your help, everyone.