I just bought a 2003 dodge 2500. nice truck but a major problem. It will not start. cold or hot. I have replaced injector pump. have new heater relays on order. have not put in new lift pump ( was told there is a new style that is in tank). if it is shut off and restarted with in 1 second it will start. other wise it will only start with starting fluid. don't not have gauges. shop told me it was my injection pump. so $1400. later same thing. once it is running its great, no smoke no lope. really responsive. any help would be great. I just do not want to keep throwing money out and still have this problem.

 

How many miles? Any performance upgrades? California engine? Auto or manual? Any major past engine work? If you fill out your signature block in the User CP section, it'll help us diagnose the problem.

-Adam

 

Sorry its a 2003 cummins with the 6 speed manual trans 4X4. unknown if it has mods. just bought it from a dealer this way. 150,000 miles. also if I let lift pump cycle without starting , I can hear injector tapping, Had valve cover off today and had voltage on 2 injector. cranking it over and different injectors had voltage after cranking. also lift pump runs for 15 to 20 seconds when key is first turned on. I have crack main line to rail with just lift pump on (not cranking ) and there is no pressure or fuel lose until it is turned over. I was told by a guy that lift pump pressure it should show, even with out cranking in fuel rail. I am new to the cummins world. Gas engine Mechanic and shade tree at that.

 

fuel pressure regulator or the injectors are bad. basically it is allowing the fuel to flow back and not build up the pressure to start. i wouldnt trust that shop they should have checked a lot of things before they said injector pump. crack the line right after the fuel filter before the fuel rail and see if you have fuel with the lift pump running before you change it out

 

Is there a way to test the injectors. with out a gauge. I was told to crack lines at common rail. but that would drop pressure on hole system wouldn't it? I know I have pressure at lift pump not sure if it is keeping prime. what is pressure is the lift pump . I do have a low pressure . 0-100 psi for gas fuel injection. same shop told me that I had 2300psi at lift pump and 13psi after injection pump. not sure if that is cranking.

 

their is a procedure for testing the injectors you can research here and get the process. if i remember right the pressure for the injectors was around 4k which is from the injector pump or more. the lp should produce any where from 15 to 5 psi out of it. put a gauge on it and check it running. normally these series trucks will not run if the lp is bad like the older models. no offfense but that shop doesnt seem to know too much about these motors

 

I totally agree, usually the Cp3 pumps dont go bad, Im not saying they dont but its fairly not common, especially like the older 98.5-02 Vp44 pump trucks. Id also say you have injector problems that are causing this. Rail pressure during idle is about 4k, Ill check out my rail pressure tomorrow morning just to make sure of this. I think your shop is kind of looking into the wrong area about this issue.

 

almost forgot check your releif valve.

 

ok I will check releif Vavle. and research how to check Injectors and see what I can come up with . keep you posted

 

Having gone thru this problem myself I can understand your frustration. Do as Rich said to check lift pump flow. You said that the pump does cycle for a time before it shuts off, so that in itself is an indication that it is probably building pressure.
Crack an injector line at the rail and crank it over. If there is zero flow of diesel, then you have other problems. Suggest that you remove the relief valve and plug the hole. With an injector line cracked, crank it over again and see if their is any fuel flow. An alternate way to check the relief valve is to tighen all loosened injector lines and remove the drain line on top of the relief valve. Crank the engine over again and see if any fuel comes out of the top of the relief valve. If so, then that is probably the problem. Now try plugging the relief valve and see if it will start.
Another thing you can try is to unplug the injector pump at the pump itself and repeat the above tests.
Let us know the results.

Be careful of using ether or any other substance to help starting your engine as it can cause expensive damage.

 

Don't use starting fluid. Codes?

 

the only codes I have is for clutch fan. found that the wires had been cut or caught in fan. don't think that would cause the engine not to start. cracked a injection line. had tons of flow. took bolt out of fuel relief valve and cranked it over I had fuel shooting out of that. I am going to try and plug the top of it off. will let you know . thanks for information

 

well . plugged top of fuel relief valve and cranked. no go. took bolt out of relief valve and had air bubbles come out. took line off at injection pump for LP feed and turn key on had a lot of flow. on plugging injector pump? witch line did I need to plug?

 

Try UnPLUGGING the electrical plug on the back of the CP3

 

So what does upplugging the cp3 suppost to do? Just thinking also if you paid 1400 bux for a new cp3 and its not the problem then id try and get the old one back. Would your rail pressure sensor throw a code if it went out and dident read that you had any pressure when its being cranked. Might be worth getting a rail pressure gauge and hooking it up to see.