Recently bought a 03 duramax , truck will turn over but will not start, spray starter fluid in intake and it will start but you have to keep spraying to make it run. I changed fuel filter , cracked bleeder pump primer pump , shut bleeder and pump more but my primer pump doesn't get harder to pump , not sure where to look next or what to do, plugged in a code reader and there's no codes I NEED HELP ASAP
03 crank but will not start
- Thread starter Harris.levi7
- Start date
You have a fuel problem. Check all fuses and relays. Something is not initiating your fuel or injector's. Start with electrical and work towards mechanical if not found. Lot's of info on google. Just search
03 duramax crank but no start, no run
Do the opposite of this. Make sure you have fuel making it to the cp3 and if not look for gremlins.
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Absolutely right brain fart earlier. Wasn't thinking that it might not be getting ANY fuel. First just assumed that it was.
For reference generally speaking all this motor need's is fuel and compression. People have been able to start them with either when they will not fire on their own.
Awenta can probably elaborate further however I believe that it need's 1200-1600psi of rail pressure to fire. It needs fuel to get there.
Not getting fuel
Went to check fuel pressure I unthreaded the fitting by my alternator push down on the priming pump and fuel shot out , left the fitting off went to start the truck and no fuel shot out , got my multimeter hooked it to the top of the fuel pump by priming pump and had no power, went to my fuse box and started checking different fuses for pump and none of them read anything, the truck is wrecked in the front end , do these truck has a inertia switch or a shutoff for fuel pump.
Went to check fuel pressure I unthreaded the fitting by my alternator push down on the priming pump and fuel shot out , left the fitting off went to start the truck and no fuel shot out , got my multimeter hooked it to the top of the fuel pump by priming pump and had no power, went to my fuse box and started checking different fuses for pump and none of them read anything, the truck is wrecked in the front end , do these truck has a inertia switch or a shutoff for fuel pump.
He's talking about pressure at the injectors, not pressure to the CP3 pump. You need a scanner to test. There is no lift pump from the factory on the Duramax, the CP3 pump provides high pressure fuel to the injectors (more than 20,000 psi at times). The fuel to the CP3 is routed from the filter housing, so having that fitting off just ensures it will NOT start. Use the primer to build pressure to supply the CP3 pump, then hook up a scanner to see what your cranking fuel pressures are.
If the primer on the filter housing stays hard after pumping it, lol, than you most likely have fuel going to the cp3. Im guessing bad injector. You need something to check rail pressure like an edge cts or an autocal. Honestly, its worth the one hour labor time to pay a shop to diagnose it.
With the bleeder open cranking your not going to get fuel shooting out. The cp3 is in the valley of the engine and draws fuel through the filter housing/primer. No electric pump to push fuel from tank (unless aftermarket). If a bleeder or something (anything on the low pressure/suction side) was left open while cranking you havehave exacerbated your issue by sacking air. If the primer bulb will not stiffen up and stay that way by pumping you need to fix that with a rebuild kit. If it does, you may need to crank for a while to get air bled through the injectors and lines on the high pressure side. I generally don't recommend breaking anything loose on the high pressure side and cranking to bleed. Dangerous streams of high pressure fuel can hurt parts of the truck, or worse you. In fact, I have seen a wiring harness cut in half. Make sure the low side is good, then move to the high side. What's the history with this truck other than it has a wrecked front end?
That's all I know about the truck bought at a salvaged auction was supposed to run , I'm going to take it to a shopen and seek what they can figure out if don't know enough about these , this is my first duramax kinda downgrading from a 2012 cummins