03 no start

[Mallgeyer]

i have an 03 SO, that will not start without either, it will start when i cap off any of the injectors at the rail. its was hard to start last week had to use either once then it cleared up and started fine, now its back to not starting. fca and fuel filter have been changed, 10 lbs of lift pump pressure, it does not matter what injector i cap it will start in about 30 seconds. truck runs fine when running, have good rail pressure and lift pump pressure. also had ez on 2 but it is off now. crank and cam sensors ohm out ok. unplugged fca and it will not start. i am leaning towards the high pressure pump but that alot of money for just winging it. no codes or check engine light. and once u hit it with either it fires right up!



thanks

michael

 

[Prairie Dog]

I'd try capping the relief valve before winging the HP pump. Or, maybe you could trade your relief valve with somebody just to test it?

BTW, is it safe to use an ohm meter on the crank & cam sensors?

 

[Mallgeyer]

i have the relief valve capped, now it has gone back to taking 30 seconds to start. yes it is ok to test crank and cam sensors with an ohm meter (dvom) the out of range high ohms is 1000ohms

 

[MickeyMiller]

Isn't using either in a truck with a grid heater a little dangerous?

 

[FourBarR]

brave guy using ether ,if the grid heaters are not disconnected.

 

[JHardwick]

Isn't using either in a truck with a grid heater a little dangerous?

it'll just be a quick blast :-laf

 

[Mallgeyer]

grid heater is unhooked, u gotta do what u gotta do to get to work

 

[Prairie Dog]

i have the relief valve capped, now it has gone back to taking 30 seconds to start. yes it is ok to test crank and cam sensors with an ohm meter (dvom) the out of range high ohms is 1000ohms

Ok, I only ask because some OHM meters put out 1. 0 to 1. 5vdc to make a resistance measurement and some automotive sensors operate at the milivolt level.

 

[sag2]

If it will not start unless you have an injector capped off you have a bad pump or a leak in the injector circuit. That can be a relief valve, a connector tube or an injector. If the injector is stuck open you really risk a piston(s) melt down. Do you have white smoke on start up? If you don't have the tools to run the fuel tests, follow the steps in the injector change with photos post to retorque the connector tubes.

You need to run the injector return flow tests to isolate the problem. You need the Miller 9012 to do the test. It is more likely you have high return flow than a bad pump. The reason it starts with an injector capped is the pump is able to build enough pressure to fire it off. Usually above 2500 psi or so. When you give it a shot of ether, it builds enough speed for the pump to provide adequate pressure/flow.