I couldn't get my '95 12v to hold idle and when starting it was difficult to get it going and would run really rough and would blow tons of white smoke. I figured there was an air leak so I replaced the two rubber fuel lines with LarryB's kit. I also removed the fuel heater and put on a new fuel filter. I filled the new filter with fuel before putting it on the truck. After a couple of tries the engine started coughing and coming to life, about 5 seconds after starting it died. I couldn't get it started again, it just cranked and cranked. I tried bleeding the lines but air just kept coming out after 45 min or so. I removed the fuel filter and saw that about an inch of fuel had been used. I filled it back up and same thing, it cranked and finally coughed to life for about 5 seconds and then nothing. I repeated process one final time with same results. I just can't keep it going. Thanks for the help!

 

On your 95 you have a flexible dip tube in the tank that fails. There are also two flexible lines from the tank to the frame that require periodic replacement.

Also, do not use airplane type fuel hose clamps, but use the compression bands that are the OEM style. The screwdrive clamps tend to leak over time as the hose takes a set.

Another thing I would check is the overflow check valve that is located on the inside wall of the injection pump next to the engine, and is where return line is connected. If the check valve or spring fails the symptoms are the same as an air leak in the fueling system.

 

I have tried removing the overflow valve but can't get it out. When loosened all the way it gets pinned right up against the engine and it won't move. Any tips on getting that out? Thanks!

 

Put it back in nice and snug, then take a die grinder or small grinding tool and relieve some of the cast from the head where it interferes. It does not take much, just enough to clear the valve when you pull it.

Use brake cleaner and clean all the debris away from the area before you pull the overflow valve, so you do not get filings in the injection pump.

The new two piece valve will be a snap, it comes apart and does not take as much room to install.

 

I don't see anywhere that you pumped the system back up with the manual primer on the LP???????

Try that before you get too far into this thing.

 

I've found that many times in the struggle to replace the short hoses behind the engine that you end up cracking the steel line on top of the bell housing. It has a weak point where the bolt down tab is welded to it.
That's why I now abandon the entire stock fuel system and run diesel rated hose all the way from the engine to tank. A little bit more expensive but easier and more reliable.

 

Thanks for the help! After two weeks and about 16 hours of tinkering with it after work I got her running again. It ended up being the rubber o-ring at the fitting that feeds the prefilter assembly. Actually, it was the steel pipe. It had worn down where the o-ring is and too small a diameter for the o-ring to seal. I had a guy cut the pipe about 1/4 inch shorter and put a new o-ring on the normal size pipe that remained. I screwed it back into the top of the prefilter and off she went. Runs like a charm. Thanks again, I really appreciate the advice!