Thanks to everyone who gave me advice for the postings I made about in the past on this vehicle. I never did solve the problem, but I got it working adequately to move it for street sweeping. Now, finally, its gotten worse and it won't start.

I'm not consistently getting fuel coming out of the fuel lines going into the fuel injectors. I can open the line at the injector, and crank the starter for an extremely long time, and eventually I will get a drip from that line.

Once fuel starts coming out of that line I can re-connect it to the injector and the vehicle usually starts. If it does start, it is necessary to keep the accelerator pedal pushed all the way down for a while, otherwise the vehicle will immediately stall. Racing the engine after a start guarantees that the vehicle will stay running for a few minutes, but it will eventually stall again.

I'm assuming that I'm pumping air out of the lines while doing this, but am concerned that it may indicate that some other fuel line issue is acting up intermittently.

I've had occasional stalling issues over the last year, and they always get worse after doing a lot of driving on hills. At first I was assuming either water or sediment in the tank was the problem, but I don't seem to have a ton of water coming out of the separator, and I replaced the fuel filter. You guys on here told me that I may have air getting into the lines, but I never found where.

If the vehicle has started recently, its generally easier to get it to start again right away, without 'pumping the air' for as long. Otherwise I have to run the starter for a long time.

Also, the fuel in the tank is almost a year old. I took a sample from the filter and its not cloudy or dark, but it doesn't feel/smell exactly the same as diesel from the pump. I don't see how 'degraded fuel' would explain the lack of fuel to the injectors.

Also, an infrared thermometer indicates that the exposed tips of the glow plugs won't get above 60 degrees F. Three of those are brand new glow plugs and they test fine - low internal resistance. They are getting 12v during the 'warm up the glow plugs' phase of starting. I realize this may be due to damaged batteries, but the starter sounds strong (plenty of current there?),
and I don't see how damaged batteries would explain the lack of fuel to the injectors.

The injector pump is an obvious suspect, but once I start getting the drip of fuel from the lines, and as I reconnect the line (while starting the van)
there is a brief period of pressurized fuel spray before I finish tightening the fuel line - so I think the injector pump is fine.

are the tops of the injectors wet around the leak-off tees and return hoses alot of times if these old idi's sit around for a while the o-rings under the return tees go bad and allow air to enter the system just replace the ones on my 83 6.9 for that very reason, starts and runs like a dream now

Hope this helps

Bryce

are the tops of the injectors wet around the leak-off tees and return hoses alot of times if these old idi's sit around for a while the o-rings under the return tees go bad and allow air to enter the system just replace the ones on my 83 6.9 for that very reason, starts and runs like a dream now

Hope this helps

Bryce

Bryce, thanks for the suggestion. I'll take a look at it. Before reading your post and checking google I had no idea that the leak-off fuel was sent back through such a simple tee, I just thought is was more complicated than that. Wow, it would be so great if all I had to do was replace some o-rings!

http://www.thedieselstop.com/contents/images/69injector14.jpg

yeah the o-rings and the hoses i've rarely seen a leakoff tee go bad but there are places that sell the injector install kits which come with all the tees hoses and o-rings, as well as the washers for the injector tips good luck and let me know if this works if not i'll try to help you figure it out

Bryce

Bryce, thanks again. It turns out that I wasn't even getting a decent amount of fuel up to the engine because there was a little filter attached to one of the pumps that was completely clogged. I temporarily took that off and placed a clear inline filter and a screen in its place.

After that, vehicle started much better (after pumping air from the lines), but I still had the recurring air-in-lines issue and (now that the fuel can reach the engine well) a *very* obvious leak around one of the injectors, just like you said.

So I ordered high temp o-rings of size "a-111" (is that the correct size for a 91 ford e350 7.3). They arrived yesterday and I replaced them. I made sure everything was clean, and rolled them down into their grooves. (Someone said I should use oil but I didn't have any.)

The two replacement rings are the same size, but one of them fits super snug and the other is loose enough to slide-rotate in its groove. Should they both be the same size? Is it okay that one rotates slightly?

The orings seem to fit tight against the leak-off tee, as I have trouble putting the leak off tee back on. Maybe thats my problem? I push it down past both orings, but there is still 2mm or so before its flush with the injector. I figure the seal is at the oring and that gap should matter (is that right?) and I can't seem to get it all the way down.

It looks (?) like the leak is coming from under the leak-off tee - suggesting, like you said, the orings are at fault...but they are brand new and they are seated in their grooves.

Is it possible that the orings are right, and make a perfect fit, but if there is a problem elsewhere (with pressure) the leak would come from the leak-off tee?

I just noticed in the picture I posted (not from my van) that the bottom oring exactly matches the place where the leak-off tee should be positioned - there is no room for error there.

Maybe I'm mistaken about my van, cause i wasn't looking at both from the side when i took it off. I thought the leak-off tee was a good bit larger than the space between the orings. If my van is like that picture (and maybe even if it isn't?), then i'll have to get it pushed all the way down.

Is it okay if I'm really forceful about that? Also, when i finish tightening down the nut that holds the metal fuel line in place, it does *not* force the leak-off tee all the way down. Thats another thing that concerns me, it seems there is too much space between the top of the injector and the bottom of that nut...that, or there is something im not doing right.