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turbopilot51

New rattle/knock

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I recently installed an Airdog FP-100 on my 2004.5 CTD. Right afterward I started noticing a rattle or knock around the 1300 to 1800 rpm range. It goes away when under under load. Any suggestions? :confused:

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When the 04.5's first came out, there were a bunch of threads on the forums, on what can best be called as a "gasser pre-ignition" type sound under light throttle at 1600-1800rpm. It seems to turn on and off depending on throttle position. Are you adding any cetane boosters???? Mine went mostly away after I put my GDP Walbro lift pump system and did the "tone ring mod". It's totally gone since I've been running the Smarty Revo. This leads me to believe it's timing, fuel related.Like Mike asked, what's you're idle fuel pressure. Doesn't really matter if it's pre-filter or pre-CP3 just so we get an idea. Right now with my Walbro, I'm seeing about 26psi pre-filters. With cold fuel, it's 30psi+. These Walbro pumps are incredible. The more stress you put on them, the better they like it!!

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I don't have a pressure gauge yet. Still looking for something easy to install. I wasn't to thrilled about the fitting that connects the fuel suction line to the suction tube on the tank. I may pull it off and stick the hose in a five gallon bucket of diesel and see if the fitting is leaking. I have checked all the other fitings at the Airdog and they're tight. I am open to other suggestions. Thanks to all!

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If you're handy, you can buy a good liquid filled gauge, get the appropriate tap,fittings and seal; and then tap the "hole" in the middle of the plastic nut on the fuel filter housing cover. Works like a charm. Don't use a NPT tapered tap, because you could crack the lid. You'll also need to drill a small hole or two in the bottom of the hole to get liquid fuel to the gauge. Here's a picture of something close. This is the gauge I had, but it was mounted in the machined aluminum block that took the place of the OEM lift that I got with my GDP Walbro lift pump kit. When I went to an "in cab" gauge, I gave this gauge to a friend and told him how to do what I just told you. He's been running it that way now for 1.5 years with no problems!!! I'll try to find the link for instructions on how to do this also!!!

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If you're handy, you can buy a good liquid filled gauge, get the appropriate tap,fittings and seal; and then tap the "hole" in the middle of the plastic nut on the fuel filter housing cover. Works like a charm. Don't use a NPT tapered tap, because you could crack the lid. You'll also need to drill a small hole or two in the bottom of the hole to get liquid fuel to the gauge. Here's a picture of something close. This is the gauge I had, but it was mounted in the machined aluminum block that took the place of the OEM lift that I got with my GDP Walbro lift pump kit. When I went to an "in cab" gauge, I gave this gauge to a friend and told him how to do what I just told you. He's been running it that way now for 1.5 years with no problems!!! I'll try to find the link for instructions on how to do this also!!!

My filter canister was removed when I installed the Airdog. I purchased the GDP filter eliminator bracket. http://www.glacierdieselpower.com/produ ... _id=0306FE. I would like to find something to work with my Quadzilla Commander.

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Sorry for the delay. I installed a fuel pressure gauge and it shows 30 psi at idle. Not much pressure change when I get on it. I called Richard at Glacier Diesel and he said the Airdog I have should run around 30 psi. Is this too much presure for the CP3? I just returned from a 800 mile trip pulling my 31' trailer and no problems. :confused:

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30psi is not a problem for the CP3. It takes what it needs, and sends the rest back to the tank. You've got the AirDog, so I assume you've canned the OEM fuel filter canister. The plastic cover will be fine on that up to about 60psi though. I see 24-28psi with my GDP Walbro LP.

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30psi is not a problem for the CP3. It takes what it needs, and sends the rest back to the tank. You've got the AirDog, so I assume you've canned the OEM fuel filter canister. The plastic cover will be fine on that up to about 60psi though. I see 24-28psi with my GDP Walbro LP.

I have deleted the stock fuel filter assembly totally. I have one of GDP filter housing eliminators. :thumbsup

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I just installed a new by-pass return spring from Richard at GDP. My fuel pressure is now 18 psi and the knock or rattle is much more quiet. Still looking for the reason for the rattle. :confused:

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