Air in Fuel System

Hi all,owned 86 M1009 for 2 years,has 85,000 miles,reliable until now.Started in morning ran for a few seconds,idle started fluctuating then died.Called my guru,sounds like lift pump,threw one on,bled injectors,2 days later same thing.Could be an clogged fuel filter,OK,threw on on,did the bleed routine,4 days later same sheisse.So,checked the filter air bleed,plenty of fuel comes out with a few cranks,When you remove fuel cap,pressure is released,doesn't seem to be air in this side of system.Thoroughly inspected all fuel lines,return lines,clamps,fittings,looks fine,OBVIOUSLY air is getting into system. Does it seem to be on IP side of filter if filter air bleed only shows fuel?Any ideas?..Looking for an easier way to bleed this beast,I know pink wire should be off to bleed filter,should I leave it off for a few cranks to fill IP before I try to bleed injectors?...Have to remove glowplugs cause starter drains batteries something fierce.Get fuel from drivers side and front passenger injectors after several good crank cycles interspersed with battery charging,3 rear passenger injectors take quite a few more cycles to purge air.Inadvertently becoming injector bleed expert,can't keep doing this twice a week, on the verge of desperation,Should I start replacing every rubber line in fuel system?Read about the fuel pressure switch in filter body,what does it look like?Is there a check valve in fuel return line?....any helpful ideas or similiar experiences greatly appreciated...cheers.

There is a fuel pressure switch in the filter housing that is known to be a common leak point. I would start with that. Some of the guys on www.mil-veh.net know it really well.

also, to help in starting with air in the lines, you can use "Pure silicone Spray" as a starting fluid. Its Glow Plug safe.

BTW.... Mine does to me from time to time, and I dont have that much trouble bleeding. I pull the pink wire, crack the bleed valve on the filter... crank with it open for about 30 seconds. run around and close it, and hook the wire back up, and crank till it starts (letting the starter cool of course) works pretty good for me.

OK,heres the mind-bender,if I open the gas cap releasing the pressure after I shut it down,It continues to run fine.If I leave it alone,in the morning I lose prime and it dies,WTF!!!...Checked everything multiple times,truck runs great,while opening gas cap is a small price to pay for forgoing 4hrs of injection bleeding,there must be a solution to this.Anyone have the foggiest whats up here??

could be a bad fuel cap...maybe, search the forum at dieselplace.com i remeber there being some threads on similar issues....pressure releasing out/air whooshing into the tank

Anyone know what the purpose of having pressure in the tank is for?..On my M1009 I've been cracking the cap when I park as a temporary fix to my"air in injection system"gremlin,worked for a month,coming home juiced on tequila,forgot,dies in morning.Some guy on forum suggested drill a small hole,so I'll try that.Meanwhile when it stops after 5-10 sec of running,there's fuel in the filter,and IP.When I go to bleed injectors,drivers side has fuel right away,rear 3 passenger side have air,would this indicate air entering thru return line?..how can it enter injection pipe?..Perplexed!

You need to replace the fuel pressure switch in the fuel filter housing. You can buy the NOS from

http://www.owens-export.com/index.html

Or you can remove it and plug the hole behind it where fuel enters the switch and no more problem.

Or pull out the pressure switch and tap the hole in the filter base with a 1/4 tap (thread the 1/4 inch hole) put a 1/4 inch screw or bolt in it to plug it closed. No more air leak. cheap fix. I also shop vacumed out the metal shavings and used loc tight.
has worked 4 years.

OK folks, this is a known issues with the CUCV's

The fuel filter BASE can develop air leaks

yes, where kentuckycucv said, but they can leak air at several places, mainly any place that has a screwed in plug ) top and side

Check the last post in the following thread - I explained the issue pretty completely...

http://www.steelsoldiers.com/cucv/53784-these-normal-glow-plug-issues.html

You guys have resurrected my 6 year old thread? I've long since replaced the fuel filter base. Still have the small hole drilled in the fuel cap, haven't replaced it yet. Doesn't seem to matter.