Truck doesn't want to start, why??

[HomerDog]

Guys,

I was running some errands this morning. When I went to start the truck for the 2nd time today it would crank but not start. Thinking it was a fuel problem, I got out and pushed my fuel primer about 20 times and then it started. Thinking it was a one time event I shut it down at the 2nd stop. Same thing, had to pump the primer to start. Drove it home and shut it down and it would not start again. I just had a tune up at Cummins 2 weeks ago where they adjusted the valves, set the pump timing, wastegate adjustment and some other things. I also changed the fuel filter just before I took it there. When it's running it runs fine with no problems and it has never done this. Where do I go from here. Any thoughts would be appreciated... .



Dave

 

[jmeehan]

Have you checked your fuel return line for leaks? I understand this will cause a hard start problem. I'm guessing the system looses it's prime and needs some time to fill up.

 

[EMDDIESEL]

This may not be the problem but you amy want to know this. I have the DC installed keyless entry/alarm. I had pulled my power window fuse when i had my windows tinted so nobody would open them by accident.

I went to start the truck and it would not start, it cranked, but there was no fuel. It turns out the alarm is wired to the power window circuit. If you pull the window fuse, the fuel pump relay wont energize. Pretty bizzare but good to know if you are ever going nuts trying to start your truck, check the window fuse. Also a good thing to try to keep your truck from getting stolen.

 

[RT66DOC]

Check the fuel lines. Mine [and lot of others] acted the same way.

 

[HVAC]

Fuel Shut-Off Solenoid

Since you have the 12v motor Homerdog, things are a bit different compared to our 24v fuel systems. Both of your pumps are mechanical, but there is a fuel shut-off solenoid on your engine. Might want to check that out. Might not be opening as it should.

 

[illflem]

The return line leaking on your 12 valve is probably the problem. They can let in air without seeing a visable diesel leak. It will cost you only $2 for the new hose, but a lot of cussing installing it. Check the achives, there is much info on the replacement.

 

[HomerDog]

Thanks for the replies. I've been looking at my service manual all day. I agree with RT66, 85CJ, and ILL. I first thought it was the lift pump but the the truck would run fine after it was started and I think it would run like crap if it was the lift pump. EM--thanks for the info and I've already checked that--that's good stuff to know. HVAC--I'm aware of the fuel shutoff solenoid but I thought that was related to shutting down the engine only. I'm thinking it's a return fuel line problem since the truck runs fine once started. I couldn't see any visable leaks/problems--the engine is clean-- What needs to be done is a check the fuel pressures and I don't have the equipment to do it. I'll take it to Cummins who did the tune up. Thanks to everyone who posted, I can at least give the guy a starting point. I'll post after the job is done so other's may learn... .



Dave

 

[Missouri Mule]

HomerDog,

Leaking fuel line is top one for no starts but fuel return valve ranks right up there with it.

Leaking fuel lines, return valve, tranfer pump and a bad injector pump would benefit from priming to start engine.



I don't think it is fuel shut off solenoid because priming gets it started.

But the fuel shut off solenoid will keep the truck from starting. When you turn the key to run position the rod on solenoid moves up a bout 1/4 inch.

When you turn key all the way to start position it moves rod all the way up to bottom of solenoid. The run position will hold it there.

But if in start positon the rod does not move to top no fuel will be allowed to reach injector pump thus no start fuel situation.

Good news every thing dealing with fuel shut off solenoid is easy to check out. Usually the fuel shut off relay could be acting up or bad connection/wires.

 

[Howard Durand]

HomerDog,



I'll side with the return hose solution. Mine did the same thing except it took a couple of days for it to leak back enough to be a problem. It would always start after cranking a few seconds. (These things start so easy that 5 seconds of cranking seems like forever).

If you have to prime it after only being shut off for a short while. it must be leaking back fast.



After priming, look under the truck to see if fuel is dripping anyplace. Make sure the tank is full so there will be some back pressure against the return line.

I replaced my supply line first because I couldn't see anything wrong with the return line.

When I pumped the primer to start the truck, I saw a stream of fuel leaking out of the return hose.

It was cracked so bad that fuel was running out the end where the clamp was. The whole thing had checks and long splits in the outer layer of rubber. The supply hose was not checked but was worn almost through where it had rubbed on something.



Change them both out!



If you do replace the hoses, They are much easier to get to from underneath the truck. Just remove the starter and disconnect the front driveline at the front end and you can reach up far enough to easily remove the clamps and hoses.

The return line is the longest and worst one to get to.

Starter removal is much simpler than you might think.

Even if you don't think it is the hose, this is probably a good time to change it out.



The original clamps are worth saving if you can. They are much better for rubber hose than most of the clamps you will find in hardware stores or auto shops. If you have an auto racing supply available, they usually have high quality clamps.

They are pricey (about $2 each) but worth it.

They work good on transmission line hoses too.

 

[HomerDog]

And the winner is... ... HVAC!



I took it back to Cummins today and they found a bad fuel shutoff solenoid relay (i thought this didn't affect "starting" but I was wrong). They replaced the relay and found that the shutoff solenoid itself was also not opening all the way so they replaced it. Also fixed my idle since I just had it tuned up there. If your interested in the cost: The relay was only $7 but the solenoid was $262. With some other parts and labor--$488.



Thanks for all the information,



Dave