Hi everyone,
I am new on this website, and would appreciate some help.
I have a 1996 dodge 3500. For 2 years I have had this problem. At will without any pattern sometimes this truck is very hard to start. Sometimes tomorrow it don't want to start then other times it will start easy after 2 weeks. Cold, hot wet dry no patterns. I have changed the lift pump. Haven't done much else, because I don't want to just throw parts at it.
Anyone with suggestions please respond.
Thanks.

 

You need to figure out if the hard starting changes with fuel tank level.
If so you could have a fuel line leak on top of the bell housing or inside the tank module.

 

Would it be more likely to occur with more or less fuel?

 

More problems with less fuel.

 

Actually I can't tell that fuel level changes it.
What about the fuel shutoff? I was once told the contacts on the shut off may need cleaning. As to the fuel line issue, is that a problem that would be intermittent?

 

The fuel shut off could be going bad. You can wire it up and try it, but of course it won't shut off like that.
And I would check the return line at the back of the head. It will leak air in but not fuel out. It may be a cracked line at a seam.

 

Sounds like there is a fuel leak in the system. There is a lot of info on the boards about it but basically you can have a leak and not even know it. The primary symptom is hard starting.

The solution is to replace part of the fuel lines (if not all of them) and also to remove or replace the fuel heater.

I just did mine and am very happy with it. Mine used to start OK but would quickly choke out and die (air in the fuel). I replaced all of the fuel line from the tank to the engine and just removed the fuel heater completely. Now the truck can sit for a long time and it fires right up like it is supposed to.

There is a way to tell if you have a fuel leak by pressurizing the tank. I did not do it with mine but it might be a good idea to check. I believe most people use a shop-vac with a rag around hose in the fuel fill and let it pressure up that way. You only want a few pounds on the tank and then you should be able to see the fuel leak. Hopefully that makes some sense; If not let me know.

 

well the fuel shut off could have something to do with it.. my truck was actually taking longer to start, and ran worse because the solenoid i had was becoming very weak.. one of the mechanics at a cummins dealer showed me how he could just shut the truck off with one hand while it was running

 

The solenoid is probably the most needlessly replaced item on a 12 valve, expensive too. The solenoid is a very simple, sturdy device that will easily last the life of the truck. It either works or it doesn't, there is no such thing as one getting weak.
My bet is at least 99.9% of solenoids are replaced needlessly. Dealers love to throw the part at the problem.

The problem is almost always a corroded blue wire from the driver's side battery or a bad relay on the firewall. The rubber boot that protects the solenoid can fall apart allowing gunk and rust to bind the solenoid, clean it up and replace the boot.
Relay and boot are availible for a good price here http://www.fostertruck.com/dodge/default.htm

1970, your problem could be the shutdown circuit. Next time you have a hard start leave the key on pop the hood and see if the solenoid is lifted all the way up. If not start with the simple stuff first, check the blue wire then progress to the relay.

 

Thanks Bill,
Sounds logical, I will check thaat next time it doesn't want to start.
Should I just insure power on the blue wire to shutoff?

 

When the blue wire, actually a fusible link, is corroded it can cause intermittent problems. What happens is a partial connection gets hot and welds itself back together to allow enough juice to flow until it corrodes again. The corrosion is often under the insulation where you can't see it. Sometimes the wire can still carry juice, just not enough of it. This why folks sometimes will get 12 volts at the relay or conductivity through the wire but it still doesn't work. The corroded wire just can't carry the high amount of current the lift up solenoid coil requires.

Set up an ohmmeter with clips to free your hands, one to the battery post, the other to the relay on the firewall then start wiggling the wire around. If the meter needle starts jumping around you've found the problem.

 

Excellent, I will try that today or tomorrow.