'03 wont start

[SDodge]

Hi guys, I have been dealing with a hard start/no start issue with my 3 rd gen truck for months now and I am hoping that someone here could offer some insight.



its an '03 250 hp automatic trans quad cab with 80 k. It has been seen by the dealer a few times for this issue where tests have been run per order of Star and parts have been replaced but the problem persists.



every time that a fuel flow test is done by removing the low side supply to the injector pump and re attaching the line the engine will start normally for a while (a couple of hours to a couple days. )then back to its old tricks.



the limit valve on the high side rail was letting fuel by and replaced. Then

the intermediate supply tubes that bring fuel to the injectors were replaced.

Then the Injector pump was replaced. And just yesterday the lift pump was retrofitted to the '05 in tank style pump.

late this morning after starting the truck and a half hour run and a 45 minute sit, she wont start, again !



the issue seems always to be low fuel pressure at crankover but we are running out of parts to replace.



any ideas out there?



Steve Dodge

Massachusetts.

 

[gjacobs]

My '03 is starting to do the same thing. Start ... stumble... die 3-4 times then start. Only does it every 2-3 weeks.

 

[blacksheep4x4]

So both pumps have been replaced. and the one thing between the two pumps is the fuel filter, maybe look in that area? Is it possible to have some type of blockage in that area? I don't know just a thought.

 

[rbattelle]

It'd be nice to get a pressure gauge at the CP-3. That would at least eliminate the LP fuel system as the culprit.



I assume it's not setting any codes. There are only 2 things the engine needs to run: fuel and air. If there's no codes, that suggests all the electronics are running. You've addressed fuel, what about air? Open the air box and make sure the filter hasn't been sucked into the turbo.



Your symptoms are just like a bad lift pump or clogged fuel filter. Why in the world did your entire fuel system go bad, anyway? Bad fuel? Are you running a pressure box?



Ryan

 

[MFalkinham]

I agree with Ryan, it sounds like a bad lift pump. The dealer replaced the original pump with the new in-tank version, but that one is still powered by the original lift pump wiring. It's possible that the lift pump power may have intermittant outages. I don't believe there is a relay, but that the LP power comes direct from the ECM (someone correct me if I'm wrong).

One way to test this would be to bypass the current LP feed with power direct from the battery through an in-cab switch.

 

[rbattelle]

I don't believe there is a relay, but that the LP power comes direct from the ECM (someone correct me if I'm wrong).

This is true. But I'd say it's highly unlikely the power is intermittent. Possible, but unlikely.



Best way to tell is with a pressure gauge.



Ryan