fuel problems. please help!!!

[ohfisherman]

86 m1008 with 18000 original miles. ran great. all of a sudden it seems to lose prime after sitting over night. pull the pink wire, crank, bleed, repeat. after it runs it will restart no problems. i put a new fuel pump on and same thing. going through the posts i saw something about a fuel pressure switch on the fuel filter base. can anybody post a pic or have any ideas? lines from the tank look good....no wet spots and no rust.

 

[dieselpony]

Afaik the problems with the fuel filter base don't occur that sudden when the filter system was left untouched for quite a time (e.g. no filter change lately). Check the fuel lines and clamps from filter to injection pump. Look into the valley between the cylinders for wetness.

Walter

 

[Hasdrubal]

Could be a faulty fuel cap, happened to me. After you park for the day , open the cap, hear any pressure difference?, put cap back on. If it fires right up next morning, there's your problem. Get a new one , or drill a tiny hole through the cap.

 

[ohfisherman]

checked the valley pan. no wetness. ran fine all day after putting a squirt of ether in it. once it starts its fine. will try to check cap tomorrow...

 

[Wolf.Dose]

If the fuel cap vent does not work propperly (what happens now and then), the vacum in the tank will pull back the fuel from the pump, if the fuel shut off valve does not hold tight. Two possibilities, which normally both have to be done: change the upper part of the injection pump with the selonoids in it to the most new one you can get and second: drill a 2 or 3 mm hole into the fuel cap. This helps by experience.
Wolf
372000 km on a M1009.

 

[ohfisherman]

any chance of posting a pic of the shutoff?

 

[3dubs]

First thing to always do is add diesel 911 to the fuel. Then pull the fuel return valve off the top of the IP and clean it. There is a glass ball inside so you should see straight through. I run the Diesel 911 about every six months just to keep any water out of the fuel. I also add Lucas fuel additive every now and then just to keep stuff clean. I drive my truck almost every day but it gets hot here in the summer. Start with the cheap easy fixes and then move up. The IP could be going out too. Do you add a lubricant to your fuel? The new Ultra Low Sulfur does not lubricate the IP or the injectors. If it comes down to the IP replace the injectors too. It is much easier to do them at the same time. I would go with the marine injectors for the 6.5. But like I said start easy because the IP is a pain to replace.

 

[ohfisherman]

always run diesel 911 every other fill up. i backed it into the yard last night and it fired right up! it sat for 24 hours. so now what? my driveway is on a slight incline so when its pulled in forward it sits up in the front. now the front of the truck is lower than the bed....

 

[wallew]

You might need a new fuel filter bracket. You can get them on Ebay for like $70 + s/h and they include a new filter and the bracket. Bolts right up and hooks right up and cured my similar starting ills.

If you do have an air leak at the fuel filter base, it could allow the fuel that is in the filter to drain back into the tank. Which means you got a LOT of cranking to do before it's empty of air and full of fuel. AND you should be 'bleeding' the air out instead of just cranking, cranking, cranking, if you know what I mean.

Just something to think about.

 

[3dubs]

Is there fuel leaking somewhere? If not it is not the fuel pressure switch Or the filter bracket. If it is running and diesel is poring out then look there if not you are wasting time. Did you check the fuel return valve? It sounds like something is up with the IP. I am not saying replace it yet. But pull the valve off (real easy) and look through it. Cost is free and takes less than five minutes. Then replace the fuel line from the fuel return valve with clear tubing. Start the truck and let it idle. There should be fuel returning to the tank. The tubing can be from Home Depot nothing fancy just make sure it the right size. Do those two things first before wasting money and time. If you see something in the valve or no fuel is returning get carb cleaner and clean it. An ultrasonic cleaner is great. Harbor Freight has them cheap and every one should have one. But I cleaned mine with carb cleaner and a wood toothpick. If the return is blocked the IO or injectors may have been damaged.

 

[maxim]

I fought this until I replaced the housing and filter. It can be drained regularly also as a bonus.

 

[3dubs]

How about just replacing the fuel lines? It is like someone saying they have leg problems so everyone is saying, Cut the foot off and get a new one. Who said it is the foot!

Just go get some florescent fuel dye. Mix it with a couple gallons of diesel. Poor it in your tank. Run your truck for a few minutes and turn it off. Get a black light. You can just go get a black light bulb and put it in a shop light. Then look around the fuel filter. If there is no glow leave it alone. If there is then see where it is coming from. Florescent dye is by far the easiest way to find a fuel leak. It sounds to me more like an the Injector Pump has some seals that need to be replaced. But I am not saying to take drastic action yet. Find out what the problem is first. There is also a small rubber line under the truck in a small space in the hard line. it is under the passenger side of the frame. Be sure to shine the light there.

Find the problem before you just start replacing stuff.

 

[Barrman]

The die is a great way fo finding fuel leaks. However, he seems to maybe have an air leak in his fuel lines. Not the same thing. Air molecules are smaller than fuel molecules. That means air will fit through a small hole that diesel won't. Since the line from the lift pump back to the tank is under a vacuum, this is an important distinction.

More than likely, a wet spot will be seen because once a hose starts to rot enough to make a hole, it will probably get bigger and bigger. Not trying to sound picky. Just wanted to point out that it is possible to do the die and still not find the air leak. In theory.

 

[ohfisherman]

alright....trucked parked nose up and it will not start. back truck in driveway, nose down, starts all day long...

 

[southdave]

check the rubber line in the rear of the truck and the pick up tube in the tank. I had similar thing happen to me on a f-250 a bub brought over syrgine thingy with a gauge on it and we found the problem....

 

[3dubs]

I am not trying to insult you. But you said you replaced the fuel pump. Did you use axle grease to hold the push rod up to the cam when you put the pump on? If not it will drop down and not make contact with the cam. Unless you use a heavy grease to hold it in place I would remove the fuel line coming off the pump and turn the engine over to see if fuel shoots out. If the pump is not working correct you will have to remove the pump and the plate that it bolts to. Take the rod out, it will be fine because it falls away from moving parts. Then put a heavy grease on it to hold it up on the cam when you put the pump back on. Hope this helps.

 

[dragonman]

I had a friend change the fuel pump on mine, it would not pump fuel either. I had him take it out and check for the same thing, it was in correctly still wouldn't pump fuel took it of again to make sure it worked, yep pumped fuel must be good put it back in still nothing put the old one back in started right up. Napa sold me the wrong one

 

[ohfisherman]

i put over 300 miles on it since replacing the pump. once it starts its fine. it just loses prime after sitting over night if you park it nose up in the driveway. i sprayed the **** out of the filter (which is new) and noticed diesel at the bottom of it after a hard day of driving. i am really thinking its the filter base that is bad. and believe it or not, while searching the threads somebody posted about parking it nose up or down as a check for something but i cant find the thread again!! thanks for all the suggestions. i will post follow up when i replace the base.

 

[chevkeith]

There is a small o-ring on the fuel filter base. It is attached to the "water in fuel" sensor. Check that for cracks. I saw a post a few months ago so I decided to take a look at mine and sure enough, cracked. Also, replace the fuel pump. I am still having the same issues though.

Has anyone installed an inline check valve? Seems like that would be a low cost alternative. I havent been home long enough to check the fuel lines, but I believe there is a line running to the bottom of the IP that is prone to cracking/dry rot...may be worth a shot. Dye might work good for that application.

Hope this helps, let me know what works!