Air in fuel AGAIN

[msoumas]

My M1009 HAD been on a good run lately, starting every morning just fine, running well, all that good stuff. One day a few weeks ago, I went out to start it and out of the blue, no start. Wore the battery dead cranking, and not even a hint of wanting to start. Since then I've only gotten it to start at all twice. The first one, I got it started and it sounded like it was going to quit so I lightly touched the accelerator to get the RPM's up. Engine surged and quit. I cracked the bleed valve on the fuel filter, and sure enough, plenty of horrible little bubbles. The next time I got it started was after a marathon session of cranking, bleeding, cranking, bleeding, and more cranking. I managed to keep it running this time through a delicate dance with the accelerator, but it wanted to quit for the first five minutes before it smoothed out. Even when it smoothed out it wasn't quite "right". Sure enough, it gave me the same hassle the next morning.



I've had air in fuel issues before with this truck, but they seemed to disappear when I replaced the IP. Now they're back, and I have no idea where to look.

Anyone got a list of the most common points for air to get in?

 

[2deuce]

Fuel filter base. Specifically the ste-ice connection is notorious for pulling air.

 

[hounddog]

I changed my fuel filter the other day and although mine starts up, it takes a bit longer than before. I noticed the TM calls for changing the seals on the vent and drain plugs. Couldn't find anyone who has those seals.

 

[cleb]

The fuel heater and related seals on the filter base can leak. I also wouldn't rule out a bad mechanical pump, although it sounds like your getting some flow to flush the bubbles out? When I replaced my IP I dropped the tank and replaced every single soft line between the tank and the IP. It was a lot of work, but the truck started quickly every time I needed it to after that.

 

[1986Blazerk5]

Fuel filter base. Specifically the ste-ice connection is notorious for pulling air.

Agreed, i have a spin on fuel filter and i love it alot more than the factory design

 

[bronconut]

1986blazerk5, ive heard others talk about spin ons before, may i ask where you got it

 

[msoumas]

Fuel filter base. Specifically the ste-ice connection is notorious for pulling air.

Where is that connection, and what can I do about it?

 

[kassim503]

hey! I have that same spin on, its a really good primary, the only downside is it dosent have a hand pump or a air bleed valve. Got it from NAPA, asked for a universal spin on primary.

 

[2deuce]

Its easier to see when your filter is off. It is behind the filter and has 2 wires coming in from the side to a round plug. Air can leak past that. If you remove it you probably will have to seal the hole behind it or get another base. Do a search on the different ways others have solved it. The civvy bases don't have the ste-ice connection. I changed my filter recently and just from that, I'm getting alittle air especially if I park my truck nose up. Air can get past the filter itself.

 

[shannondeese]

Mine is a NAPA spin on for a 1983 GMC dually with a 6.2. I have the primary like the one pictured above and a secondary right behind the airfilter mount, where it meets the intake. Switching to this set up relieved all of my air in fuel problems.

 

[wallew]

Fuel Filter Military Pickup Trucks CUCV NEW Chevy GMC: eBay Motors (item 400148618184 end time Sep-04-10 18:39:17 PDT)

Buy it now is $60. Shipping to Denver was like another $12 (ish). Took less than an hour to swap the whole thing out.

Disconnect the batteries. Unbolt the current fuel filter backing plate from the firewall (four bolts) and unplug the sensors. CAREFULLY move the whole assembly out of the way. Put your new fuel filter assembly in place, bolt it up. Hook up the sensor connection to the new fuel filter backing plate. THEN, move each of the fuel hoses from the old assembly to the new one.

Bleed the air out of the system.

That SHOULD resolve ALL the air in your fuel issues.

It did for mine. It literally fires right up and runs WAY better than it used to.

 

[msoumas]

Sealed up the sensor hole and got her started again... ran rough again for a minute when I started out, but I assume it could have still been chucking out some air I missed. Seemed to run great after warming up, no surging or stalling. The real test is gonna be in the morning after it's had time to cool down again.

 

[msoumas]

No dice! I cranked this morning until the battery was dead, and it only even sounded like it wanted to start up once. I cracked the bleeder a couple of times to see what was going on, and there was much much much less air in there this time, just a couple bubbles here and there. I might have a second problem going on.

 

[stump]

You more than likely have a bad fuel filter base. Change to a round filter and fix the problem. I got one from Walmark it was in with the fishing gear and was 26.00 dolars or so. The filter reads not to use for diesel but mine has den on my truck for 3 months and ben fine. Also a fram fuel filter will work on that base. I run wvo and diesel and you can fill this filter befor you install it making it easier to start if you do have porblems. I havent yet but want to remove the mechanical pump and put in a electric pump and a bleed screw on the fuel filter housing.

 

[Seabee15]

how can you please a spin on filter? Just fill it with diesel before you put it on??

 

[Seabee15]

Also, what do you do about your fuel heater and electrical connections?

 

[Brad M]

Ok I have a new possibility. I just ran into this with mine. The fuel guage is off and I am out of fuel at 1/4 tank so running it that low gets air in the fuel. Make sure you fill your tank up at least above 1/2 and flush the air. Then notice when it starts to stumble and keep it above that point. It has helped me and it might help you.

 

[wholden]

I just ran into the same issue with my second M1009. Sucking air somewhere in the filter base. After it sits a while I crank, it starts up them dies. Have to bleed the top bleeder a couple of times, getting a bunch of air. Once it pulses steady fuel, it will start. My other M1009 already has the spin on filter so I have had no issues with that one.

Called up Oreillys for the WIX Part number 24309 (filter base) and they found one in a south Anchorage store for me. So to make the mod (remove the old Stanadine filter base) you will need the following:

Filter Base: WIX Part Number 24309
Fuel Water Separator Cartridge: WIX Part number 33123 OR 33418
MISC fittings to attach fuel supply and send lines

The 33123 is the shorter of the two filter cartridges, that’s the one I would go with.

As far as the wires, on my other M1009, they are just taped up and neatly tucked away.

Here is the WIX link for you to check out, then do a search on their site and they will list all your local stores with numbers so you can call for availability.

http://www.wixfilters.com/filterlookup/fuelseparators.asp

Hope this helps.

 

[Hasdrubal]

I had this same symptom, ran great after bleeding, wouldn't start in the morning. It was a faulty fuel cap! All the experts I spoke to wanted to rebuild half the truck. Had to bleed the injectors several days in a row, got pretty good at it. Figured it out by cracking the cap after stopping for the night, heard a release of pressure or vacuum sucking in. Next morning fired up, couldn't find a replacement cap quick, so drilled the smallest sized hole right through the cap, been running good for years now.

 

[dependable]

As mentioned many times, the fuel filter base had an upgrade that was not installed in many CUCVs.I believe OEM surplus still has the mill spec NOS improved filter bases. I think they are about $60 with filter plus shipping. One spin on option is to get a filter base from a civy 6.2 truck from 1982-1983, water in fuel sensor may not work. filter available, has water drain, these work well. On some older diesels with questionable fuel tanks, I have used a Racor aftermarket filter. These options will all work. If you are using questionable fuel source, a Racor type or similar allows you to see if water and sludge are building up. With the CUCVs I have gotten from GL, The new NOS filter bases have worked for me.