I am looking for the psi spec on the lift pump. I have gotten alot of different answers on the min and max pressure. The original pump put out 11psi and the brand new pump puts out 15 psi. The truck wont start and shows no codes. Dealer could not fix it and were only changing parts guessing. It has a brand new lift pump and a high pressure pump off of a running truck on it now but I still have no fuel pressure. As i'm sure you know these parts are expensive and I can't keep throwing parts at it. Thanks for any help.

 

Didn't they hook up the StarScan to it? Was it showing fuel pressure, rail pressure, throwing codes?

If it's not getting any fuel pressure, then the lift pump isn't working. May sound stupid but did they reconnect the wiring harness on top of the tank module when the new lift pump was installed?

As far as the pressure, you should be seeing 13 - 15 psi at idle from a stock pump. It should not drop lower than 7 psi under throttle.

If it drops lower than 7 psi, it's out of spec.....or you have some fueling mods.

Even with low pressure, the truck should start, the CP3 will draw it's own fuel once its primed. BUT, if the lift pump isn't working, it'll never get primed.

 

All the dealer said was it had no fuel pressure and the fuel in the tank looked dirty. We dropped the tank cleaned it out installed a new lift pump (the old one was putting out 11psi at the CP3, New one puts out 15psi). Installed a high pressure pump off of a running truck (however it was a 2006 5.9 pump). still wont start. I was told the high pressure relief valve in the rail may be stuck open returning the fuel. To check this we took the banjo bolt out of the return line and cranked it and we did get fuel out of this fitting so we plugged the return line and it still didn't start. Do you know what electrically could be shutting fuel off there is only the pressure sensor in the rail and the solenoid on the high pressure pump that I see and I would think we eliminated the solenoid as the problem when we changed the pump. When the truck shut down it showed 2 codes, one for fuel overpressurization and one for low fuel pressure. It will not throw any codes now. As a final not dealer also replaced TCM but neglected to tell me spare key would need to be relearned so i was getting a security code when I used this key but it has been relearned now. Thanks for any info I know its hard to troubleshoot over the internet but there are no competent diesel dealers around here and they are just changing parts in my opinion.

 

Okay, I hate to say this, but, the 6.7's are SUPER sensitive to fuel.

Did you get a sample of the fuel and do you still have the receipt? Please tell yourself that you did.

Here is why.....

Water in the fuel, which can make the fuel appear a dirty brown, is the THE number one cause of fuel system failure. Water damage IS NOT covered under waranty and the only way you'll get it covered is by insurance or going after the fuel station if it's found that it was bad fuel.

Here's what you need to do to see if you got water damage.

You need to remove one of the high pressure connector tubes and check it for rust. If there is rust on the inner side of the o-ring, you have trouble.

To do this, you need to remove the valve cover, one of the exhaust valves (number 3 is the easiest to work on), remove the high pressure fuel line going to that cylinder and then you can remove the connector tube.

You really need to get that fuel analyzed! That's gonna be your saving grace.

Replacing the components that ARE damaged due to water contamination comes in at the $18,000 range for a regular truck and $23,000 for a C&C.

I'm not trying to be the bearer of bad news, but I'm betting you have some significant water damage.

 

Thats most likely the problem and we are looking at going after the gas station now but still need to get the truck going . I can see the rust clogging the injectors but do you think it could happen all at once and shut the truck down then not even attempt to restart once most of the system has been apart and has new fuel in it? Can I send this stuff out to be cleaned or does it have to be replaced. I would at least like to hear the truck run a little before I tear all this stuff off and hope it works when i replace it. The connector tube you are refering to is is the one that goes through the side of the head to the injector right. I know this may sound harsh but after what the dealer did to me I may just do enough to get it going and trade it in so they can deal with it.

 

Yes, the connector tube is the one that goes through the head to the injector.

Water is EVIL in a high pressure system. Unlike the diesel fuel, which can be comprssed and is a lubricant, the water can't be compressed and it's an abrasive.

Put it under high pressure and it acts like a water jet.

It doesn't take long for a tank of bad fuel to do major damage.

 

Thanks for all your help. I have two more questions for now. Is there anyone you recommend that rebuilds these injectors and if not where can I get a good price on them? Thanks again

 

I just sent you a PM.