6.9 Stalls after start occasionally

[dday]

I have an 86 6.9 (with about 130,000 miles) that had a severe starting problem when I bought it last summer and the problem got much worse as the weather got colder.

Here's what I did:

Replaced all return lines using a nice kit...the lines were dry but cracked so now they are good...did that last fall.

I also replaced the glow plugs.

Problem continued and didn't seem to change...it seemed much worse when facing uphill.

So I went ahead and removed the mechanical lift pump replaced with an electronic one...followed the instructions on this site which saved me...thank you.

Seemed to fix the problem...for about a week.

After the car sits (when facing uphill) the car starts perfect and then stalls after about 10 seconds sometimes.

I don't have to wear out the starter now though which is good...I just bleed the shrader valve on the fuel filter with the ignition key turned so that the fuel pump is running.
I see air in the beginning when I do this if I am trouble starting. After bleeding I can start in less than 10 seconds. It also runs a little rough while warming up sometimes but runs perfect when hot almost all the time...very little starting problems if truck faces downhill or on level ground I believe now.

Here was my plan but I am not sure if its an efficient one:
I was going to buy a Chilton book first and then trace the fuel lines to the tank, maybe replace the line if its not too hard...its probably original...I haven't messed with the injectors or IP but they seem dry and truck runs perfect after it warms up...I was maybe thinking that the fuel selector valve (I have to figure out where that is) or ditch the water separator (install a separator/fuel filter combo and ditch the original water separator).

Any help that can save me time and money will be much appreciated since I have neither in my life right now...What is the most likely thing that could be letting air intrude?

Thank you always for the time and help

 

[no mufflers]

how much fuel is in the tank?

 

[dday]

Guages don't work so well but I've driven 135 miles after filling both tanks.

I would say my front tank has 5 gallons in it and the rear is likely at least half full

 

[Knuckledragger]

Your starting problems might be in the fuel tank, if the showerhead has crumbled (they all do eventually). Both pickup tubes will starve out if the truck is pointed uphill. Take out the sending unit to verify. Real easy on the front tank. Just blow air (or vacuum) on the lock ring before starting to get dirt off.

The FSV is mounted on the driver's side frame rail behind the cab.

There are other places you could be sucking air, but keep looking on top of the engine. A long starting routine usually means: air intrusion, worn out IP, bad injectors, low compression, and a few other things others will chime in about.

 

[riotwarrior]

Search here for OLIVES...there are a few that need replacement.

What elec fuel pump did you get and where iz it installed?

Did you remove the factory lift pump and nlock it off?

I am guessing you have a steel line running down lh side of engine to return fuel to tanks?

Tons and tons and tons of no start threads...

Please fill in you signature too and welcome to OB.

 

[dday]

Thank you kindly for the tips.

The compression is good since it started and ran well in cold weather without working glow plugs

 

[Knuckledragger]

Olives are the square cut O rings in some hard lines on top of the engine. Sometimes you can just tighten the nut to get a good seal, others you need to replace the olive. They last a long time but are a place to suck air and don't make a fuss or even leak fuel, usually.

 

[dday]

I'll check that out...thank you sir.

 

[dday]

Search here for OLIVES...there are a few that need replacement. I will thank you

What elec fuel pump did you get and where iz it installed? facet duralift installed according to instructions posted here above the passenger wheel well

Did you remove the factory lift pump and nlock it off? Yes

I am guessing you have a steel line running down lh side of engine to return fuel to tanks? yes

Tons and tons and tons of no start threads... yes, I will keep researching

Please fill in you signature too and welcome to OB. Ok thank you sir

 

[JLtoolman]

Replace all the soft fuel line with new. I had a worm drive clamp leak air in, but was not leaking fuel out. You can buy full circle clamps at the AP store. I think they are called injection line clamps. Use a piece of clear hose in a few places, and you will be able to pinpoint the leak, by seeing where the bubbles collect in the line. Look before you start it, and again as it is running. I am using the yellow Tygon fuel line from Mcmaster Carr, for low pressure line. Just my .02.