after manually priming, truck starts, then dies

[scootertrs]

After 818 sits for a couple of days, when I try to start, I have to manually pump the fuel. Holding the pedal about 1/2 of the way down, she starts right up but shortly thereafter, she dies and after repriming and cranking the engine for a while she then starts and runs like a top.I noticed that when I manually pump the fuel, the pressure gauge shows 60+ psi pressure but when running, the gauge shows zip. I saw where the op manual states that priming be performed at low temperatures, but says nothing at normal temps. I have never gotten a reading from the fuel pressure gauge though she runs at highway speeds without difficulty. Is my primary fuel pump shot?
Thanks

 

[pmramsey]

The fuel pressure gage on the priming system reads "0" in normal operation. The priming switch must be off after priming. I have never used the priming system in either of my 818s even when in the mid-20s F. They both fire off the first time. Sounds as if you are loosing fuel presure after the initial start-up.

 

[scootertrs]

Right, but after she starts up the second time, she runs great. and if I shut her off and restart a couple of hours later, she goes just fine. It is as if I develop an air bubble in the system, and when it starts, it is ok until the air bubble gets to the ip.

 

[pmramsey]

I agree with you on the air. Have you tired starting it while drawing fuel from the other fuel tank?

 

[73m819]

Air

 

[DaveP]

good chance its the selector valve.

 

[ca1517]

If not the selector valve, I would suggest checking the rubber hoses that come and go to the selector. They are bad about cracking.

 

[scootertrs]

no, I haven't. But I may do a "hose changeover" since they are the original ones and almost 40 years old now. Good idea on the tank tho

 

[Floridianson]

Almost needs to be a sticky about what to do to these trucks asap. Fuel and oil filters. If you have slector fuel valve change the rubber hose if not new. Check primer hose for cracks or leaks Check gear oils. Check antifreeze PH. If intanke fuel pump check presures there is more but I just woke up and got sleepy head.

Also the smaller hose goes on well and bottoms out well. The larger hose needs to be set in the sun and a little rubber lube put inside the hose with a Qtip is how I get it all the way on when the slector is still in place.
All the ones I have seen so far a barb fitting so just slice off and replace without hose clamps.

 

[kc5mzd]

The primer pump injects fuel into the intake manifold. It doesn't prime or pressurize the IP. The reason you start then die is because the engine burns off the fuel in the intake manifold.
It sounds like a air leak somewhere in the fuel system. The hoses going to and from the fuel selector will leak air if they get even the smallest crack. Your best bet is to replace them if you just got the truck even if they don't look bad. This will prevent problems on down the road.
I used a clear nylon tube in mine so I can see if it is getting air. I don't know how long it is going to last but it works good for now...

 

[jasonjc]

In order to "prime"with the primer pump you need to open the petcock up on the manifold(read the TM). The primer will prime the ip this way. Also check the in take pick up tube they can rust and leak also. Had it happen to me. And this has been cover alot.

The gague only shows how much presure is in the manifold nozzle when you pump the hand pump.
The "priming switch" is a glowplug in the intake. Buy the way it is 12volt and has its own wire going to the battery. That is what the small wire is on the batterys.

 

[Yohan]

I know this is a REALLY dumb question, but one can just buy regular fuel line at an auto parts store and cut to length for the new fuel lines on the selector valve, right? Unless I'm missing something, there should be no need to buy a "kit" from a surplus dealer, right?

I've read about this problem in another post and have a 5 waiting to be shipped. I figure I'll do this fix first thing. Thanks!

John

 

[EMD567]

On the 818, you either have a cracked rubber hose at the selector switch, or the rubber line from the fuel filter to the IP is cracked.
From the way you describe the engine is starting, I would place bets on the hose to the IP. Your 818 is doing the same thing as my 814- and I don't have the selector switch. My 814 would start up great- and die about 30 seconds later, as the fuel above the IP ran out. I would have to pump the primer to get the fuel from the filter to the bottom of the IP( where the primer gets it fuel) and then prime the intake so the Cummins would start. Once started the second time, she would run, but not well. I finally traced the air leaks(I had 3) and replaced the hose- the old one was made 2nd quarter 1972. I hooked it up to my air compressor, and it leaked so bad, I was amazed that the Cummins ran at all.

 

[scootertrs]

Thanks for the ideas. I will pressurize the system and look... but even if not, it is not that difficult to just replace the lot of hoses to and from tanks, valve and ip. Off the top of your head, remember which line size to get and approx how many feet? Truck is not near me and is in a remote location, I would like to bring with me all I need for the hose replacement.

I like the idea of getting new aftermarket hose instead of surplus since I would not know that nos hose has been laying about in a warehouse.

 

[EMD567]

I just removed the hose from the filter to the IP, and carried it down to NAPA. They made a hydro line for me- don't have to worry about that line wearing a hole, or cracking.

 

[area52]

I know this is a REALLY dumb question, but one can just buy regular fuel line at an auto parts store and cut to length for the new fuel lines on the selector valve, right? Unless I'm missing something, there should be no need to buy a "kit" from a surplus dealer, right?

I've read about this problem in another post and have a 5 waiting to be shipped. I figure I'll do this fix first thing. Thanks!

John

yep standard fuel line, forgot the sizes but my Napa had them.

 

[kc5mzd]

In order to "prime"with the primer pump you need to open the petcock up on the manifold(read the TM). The primer will prime the ip this way.

I never knew you could use the primer to prime the ip. I will have to try it as soon as I get home!

I have a 5 ton tractor, expandable van and just got a dump truck. The dump truck is hard to start after sitting. If I use ether to get it going it runs good. I haven't had time to go through the hoses yet. It would be much better if I could prime the ip to get it going instead of using ether. When I get time I will go through it and find out what is causing it to "loose prime".

 

[MyothersanM1]

good chance its the selector valve.

Ahhh! The Horror of it all. Seeing that six-legged monster brings back nightmares.

I would agree with an air drawing issue. Replace every single rubber fuel line you can find. Also, replace those two tiny o-rings in the primer pump...they will cause problems too.

mcmaster.com has the hose and fittings (if you need new ones) as well.

 

[sigo]

The "priming switch" is a glowplug in the intake. Buy the way it is 12volt and has its own wire going to the battery. That is what the small wire is on the batterys.

Hmmm, first time I've heard reference to the small wires running to the battery. Is this standard? I had a couple of wire remnants when I got my 813, but only once end was hooked to ground and the other was frayed and cut. no terminal was on the other so I couldnt see where it went. By chance my cold weather starting light doesnt turn on. I assumed it was a bad glow plug. I havent been able to troubleshoot at all, and after a cursory look I couldnt find those wires referenced in the TM. I assumed they were a local modification. I havent traced them to see where they go.

 

[jasonjc]

It is. In the TM 9-2320-260-26 page 2-167 (April 1995) is the start of the troubleshooting of the cold start system. It shows the wire. It's #569