Was it running at all with the last CP3 ?

CP3s are a 3 plunger cam operated pump. If the delivered fuel pressure was high enough, the shaft could be pounding out the bearing due to the high force pushing on the plungers. Or it could be flexing the CP3 body. I doubt it, but something to think about.

Bigblock: get in here.

I had a thought: if it isn't the lift pump, then put an oscilloscope on the FCA feed and watch the duty cycle, with your box on and at WOT. Maybe the FCA is getting the internal pressures up beyond 180 PSI. Is there a port on the pump housing that would allow one to hook a gauge up to check this ?

I'm spending way, way too much time on this stuff.

 

I am really disapointed in this pump problem. I wonder how many are leaking and people just don't know? I am crazy with maint. and checking things. I pop the hood more often than I drop the tailgate. I know alot of guys never check anything at all. Keep in mind I said it was just damp not a drip YET. I will ya'll posted.

 

FCA = fuel control actuator. It is the thing on the back of the CP3. It controls the internal pressure in the CP3, which controls how much fuel gets pumped, which controls the rail pressure.

High fuel volume being burnt = high internal CP3 pressure. But also a greater chance of CP3 starvation. So, it could be burning seals or starvation. I'd be careful with that box or the next CP3 could be on your dime.

Have you ever had a CP3 leak without running the box at all on it ?

 

The first one leaked winter of 04 box installed summer of 03. Second pump leaked fall of 05 replaced in December before Christmas. Now this one. FCA looks new it looks as it was part of the pump. I'll watch to see if leak gets bad. I thought the VA3.1 was agrevating the problem at first, then so many people saw similar issues on stockers I reinstalled the thing. I never hammer the truck If anything I baby it to sqeeze more mpg out of it.

 

You're on your next one leaking before my first one has even been replace dyet (3 weeks ago now it started)! Pump has been in, but "2 additional parts" have been on order since December 23. Service Manager doesn't know what they are.

However, when the new one DOES go in (maybe sometime this decade), if it starts leaking again, I'll look into the lift pump issue.

 

Mine was just replaced and I had the tech to check the lift pump because of the information on here and sure enough the lift pump wasn't out just "below speck enough to starve the cp3" according to the tech. They replaced both and he said he was impressed with the knowledge on this board, he wouldn't have checked the lift pump if I hadn't asked him to. LCH

 

I had ENOUGH trouble convining my dealer to replace the CP3, let alone the lift pump. I had to PHYSICALLY get under the truck and point to the leak before he called STAR. They certainly weren't going to do my lift pump. Wouldn't surprise me if it's out of spec.

 

My tech was really nice, it only took him a few minutes (like Superduty discribed in another thread). I told him I wanted to check it to hopefully prevent ruining a new cp3 and all the extra work, he said he agreeded totally.
I remember you posting about your trouble with the service tech, thats a shame.
I posted in another thread about my parts girl calling around and getting my parts shipped from other dealers that had them, they can do alot if they are the kind of people that they should be. Good luck LCH

 

Well, I think if it isn't in this week, I might have to try another dealer. But then I would have to start the process all over again.

 

Parts are FINALLY in. Going in for surgery on Tuesday.

Interesting, we have been having weather in 50s this week - and now it's hardly leaking at all.

 

how many miles a day do you drive?

 

During the week, about 25 (round trip commuting). On weekends, it can sit all weekend, or, like last week I did about 250 (high speed highway).

And it was dripping good last Saturday, but it was very cold outside.

 

I bit the bullet and purchased a FASS pump kit I'll install Sunday. So we'll see if my problems are gone. Its been mild here also & i have had box off since Monday.... to even the least bit damp and I prob. gone 200 miles in that time frame. So I feel SuperDuty is right on on the lift pumps not supplying enough fuel... worse when cold and fuel is thicker.

 

Keep us posted on what you find, Sawboy.

 

What is SPECK? Hold 5psi at WOT full load?