Hard to start

[JeffAS]

My 1971 M35A2 is hard to start, last week I replaced all of the fuel filters and the fuel pump but it still very hard to get started, once it is running it runs good but it is just hard to get it running

 

[steelandcanvas]

In tank pump working? Did you purge all the air out of the system?

 

[sandcobra164]

you've got a fuel line leaking somewhere. It may not be a bad enough leak to spill fuel but it's bad enough to allow air to seep in when the truck is not running. I've been there before, I suspect the hard plastic lines!!!

 

[Clay James]

Crushed fuel line under the radiator? A fairly common occourance in GL trucks. My A2 is hard to start too and I figured that's the problem, but I've been too busy fixing other stuff to replace it.

 

[JeffAS]

My truck has always been hard to start so I replaced the fuel filters after doing that I found that the fuel pump was not working so I replaced it, got the truck started and went on a 30 mile drive yesterday, tried to start it today and no luck

 

[hoop]

Sucking air at the Primary filter.

 

[rrrr]

How are you trying to start it ? Do you use the hand throttle, give it fuel at the pedal, etc.

I start mine by turning on the power and waiting about 5 seconds for fuel pressure to rise from the electric in tank pump. I then give the pedal a pump or two. Then I hit the starter using the pedal giving a little fuel for starting. Mine fires right up using this method. Other methods required much more time and starter engagement. After its running, I set the hand throttle to keep it running until it warms up.

Trying to start with the hand throttle doesn't work for my truck.

If it runs fine once running there could be a slight air leak causing the fuel lines to loose prime as mentioned by other posts above.

Are you sure your in tank fuel pump is working ?

 

[dutchguy]

Just a thought, before you try to start, turn on the master switch, get out and crack the bleeder on the secondary fuel filter housing, see if you get bubbles or a nice fountain of fuel. Then close it off, and try to start it. Also, I have to use about a quarter-pedal of throttle to start easily.
One other thing, I think with the multi-fuel's system, you can leave the in-tank pump running for five minutes and it will bleed most of the air through the return system, if there is any. I just changed all of the filters, and replaced a couple of the lines. The only bleeding I did was at the secondaries, along with running the pump to prove out my manifold preheater. I could hear bubbles moving through the system for several minutes. When I did crank her, she started right away.

 

[rrrr]

I don't recommend running your in tank pump for very long without trying to start the truck. You can force fuel into the engine and cause a hydraulic lock. I've changed my fuel filters multiple times and it only took about 20 seconds to get the air out of the fuel system. If your engine runs great once started it will purge air out. If its hard to start after the truck sits then you are loosing prime and have an air leak.

This problem can be even more of an issue if your in tank pump is not working. You need to veryify this. There is a fuse underneath the cover on the pump on top of the fuel tank. Make sure its good if your pump is not working. You should be able to hear your pump operate once you have air pressure and your not hearing your air buzzer going off while trying to start.

 

[Katahdin]

Mine isn't a quick starter either but the "MultiFuel Engine Truck Operator" Guide says never to pump the accelerator pedal. Should this warning be ignored or is there some real validity to it?

 

[rrrr]

Mine starts better with a pump on pedal. What they are referring to is that there is concern about putting fuel into the engine and causing a hydraulic lock. Mine just starts better that way. I don't hold down the pedal just a quick pump. Then I start cranking and add a little pedal. My truck normally fires up right away. Even in 15F temps it starts right away with no other assistance.

 

[greg2560]

Mine isn't a quick starter either but the "MultiFuel Engine Truck Operator" Guide says never to pump the accelerator pedal. Should this warning be ignored or is there some real validity to it?

Wtf this is not a gas engine with a accelerator pump. . There is no need to pump. HH does all the work with compression. Mash the throttle = more fuel when motor is turning over. So compression is low or the injection pump is not right.. . It is all about heat with a diesel...Humm why where glow plugs put in or a flame heater...

 

[rrrr]

Figure out what your truck likes and go with it. My 932 also likes some pedal while starting.