len73

I was towing pretty heavy and ran the rail presure down to the point where it stumbled a bit. I backed out of the throttle and it was ok. My question is does that do any damage and if so what it the best upgrade to fix the problem? Buy heavy I mean 25000lbs up about a 8% grade .

JJPage

How low did your pressure drop?

Not likely to damage anything, just is not normal.

Are your fuel filters plugged? This is the easiest cure if that's the problem.

Check your rail pressure relief valve, you can remove the banjo bolt from your pressure relief valve, located on your rail, start the engine and check if any fuel is leaking through it, it should be dry. If it is leaking, either replace it, or cap it, there are kits available, I just matched and replaced the banjo bolt with a solid bolt and a neoprene washer.

If your relief valve is solid, intact, you need CP3 upgrades. Which upgrades depends on the current condition of you CP3 injection pump. If you have low to medium mileage on your truck, and have always fed it clean fuel, one of the upgrade kits will work well, otherwise you may need a new CP3, with upgrades.

Ace

I'm voting for this option, just based on the list in his sig.

len73

I didn't see how low it went when it spudered but i did see it below 6000, my pressure from the lift pump never went below 10 psi. My filters are going to be changed soon but only have maybe 10 000 km on them. I'll check the pressure relief as soon as I get time. The truck only has 27 000 km on it and I alway run good diesel and howes so I would think the cp3 should be ok. I reading about the arson kit and floor it's bag of parts, would you recommend either? Thank you for your responses.

JFlory

When you check the relief valve, make sure you put the line that is removed into a cup, or something. The return for the injectors and cp3 will flow back up and out of it. Makes a good mess.