LLY: New Cp3 leaking

[frankenstien]

I replaced my cp3 in my lly about 3 weeks ago with a Sportsman LBZ pump. I have contacted the company i bought it from and waiting for them to contact me back, it was purchased from a reputable company. I just want to make sure there's something i didn't check for that maybe i don't know about

I am getting fuel in the valley of the engine, maybe 3-4 tablespoons when i drive it from home to work, which is about 8-10 miles.

It is leaking from the bottom of the cp3 as far as i can tell, i have taken it apart 3 times, cleaned the fuel up and tried to see where it came from, I did do some searching, and tried some of what i found but no dice.

I replaced the supply/return rubber hoses when i replaced the cp3
my factory fuel filter is deleted and line is looped off the bottom of the FICM

1.all the fittings on top of the cp3 are dry
2.checked the main fitting from cp3 to rail fitting
3.checked from drivers rail to passenger rail fittings
4.Does NOT leak just sitting with lift pump running at 12psi
5.unplugged the regulator, NO leaks from high pressure fittings didnt see any filling the valley
6.small rubber line that connects hard lines above bridge is dry

I was able to get a camera in under the cp3, very hard to see, but the freeze plug looks intact, couldn't see any drips

bought some leak dye today, need to get some more and a light, but even then if its under the cp3, what else is on the cp3 that could leak? I do not appear to have any diesel in the oil

if anyone has any other ideas id be interested, I just want to make sure i have checked all there is before i send it back

 

[2004LB7]

O ring on the gear pump on the back?

 

[frankenstien]

O ring on the gear pump on the back?

This what your talking about? I got my hand down there with the y bridge tube pulled, as far as i could grab, and get my fingers under it it was all dry.

 

[2004LB7]

Could be. Under the gear pump there are two o rings and one in the two halves of the pump. Make sure the screws holding it on the to body of the CP3 are tight.

 

[frankenstien]

ill give it a try, might have to pick up some short torx bits

 

[Burn Down]

Those seals should leak with the lift pump running, they are on the inlet side of the cp3. I would command rail with a scan tool/v2 or unplug the regulator and let it idle. Be very careful with the rail up and cking for leaks. If you don’t see the leak that way, swing by NC and get a small bottle of fuel dye. Put the dye in your fuel tank and run it, watch for the glow.

 

[rfletes79]

Had this same issue last month with a brand new 10mil pump. Narrowed it down to the pump as everything else was dry except for the valley, slowly would start filling the valley. Pulled the pump, sent it back, found the leak. Was the front pump seal?? Or at least that’s what was relayed to me. They fixed it, overnight shipping back, installed and back on the road. Customers truck is already in florida doing some camping....

 

[frankenstien]

Those seals should leak with the lift pump running, they are on the inlet side of the cp3. I would command rail with a scan tool/v2 or unplug the regulator and let it idle. Be very careful with the rail up and cking for leaks. If you don’t see the leak that way, swing by NC and get a small bottle of fuel dye. Put the dye in your fuel tank and run it, watch for the glow.

just making sure im reading that right, those seals SHOULD leak with the lift pump running? or SHOULDN'T?

I already did the disconnect the regulator and let it idle for a few, no leaks, all my fittings are tight and dry.

yeah no one wants 26k psi of fuel in the face, haha

 

[frankenstien]

Had this same issue last month with a brand new 10mil pump. Narrowed it down to the pump as everything else was dry except for the valley, slowly would start filling the valley. Pulled the pump, sent it back, found the leak. Was the front pump seal?? Or at least that’s what was relayed to me. They fixed it, overnight shipping back, installed and back on the road. Customers truck is already in florida doing some camping....

this is kinda where im at, at least i think. im going to get some dye and see what it looks like

 

[Burn Down]

just making sure im reading that right, those seals SHOULD leak with the lift pump running? or SHOULDN'T?

I already did the disconnect the regulator and let it idle for a few, no leaks, all my fittings are tight and dry.

yeah no one wants 26k psi of fuel in the face, haha

Sorry, if bad they will leak with the lift pump on.

 

[frankenstien]

Sorry, if bad they will leak with the lift pump on.

gotcha :thumb:

 

[frankenstien]

alright, well i got some dye, put it in and drove it for a while and ran it pretty good. removed the air intake , y bridge horn and found.....there is fuel in the valley of the motor.....I am suspect of the inlet hose clamp, as i could turn the hose very easy when it is hot, not so much when the motor is cold, so im going ot get some real clamps and put them on

also, how hot does a cp3 run? that thing was cookin.


The dye is supposed to make it glow orange, when i put it together i had a coolant leak, the O ring on the heater pipe at the T stat housing broke when i put it in, and i didnt see it so i got coolant on the cp3, I cleaned it up when i did it, but i missed some and it cooked on and glows under the uv light, so i brake cleaned everything off, had to go to work so ill put everything back together tomorrow, add more dye as it seems the recommended amount is pretty weak. give it another run and see what it looks like

I also pulled off the oil fill tube to see if the front seal was leaking, didnt see any fuel in there

 

[Burn Down]

Use some yellow glasses with that black light and dye. If it's leaking you'll see it, glows brightly.

 

[frankenstien]

Use some yellow glasses with that black light and dye. If it's leaking you'll see it, glows brightly.

yeah, i was rocking those cool guy glasses, im going to give it another try tomorrow, no work so ill have more time

 

[Burn Down]

How much dye did you put in the tank?

 

[frankenstien]

I wasn't able to get the UV dye from NC they didn't have any for fuel.

The stuff I got says 1oz dye per 5 gallons.

My fuel gauge was half way between 1/4 and 1/2 and I put in 3 oz, maybe I should have put in more?

 

[frankenstien]

Today, i put all the dye in the fuel and drove it. I attached some pictures, i tried looking further back with a little mirror, but couldn't see more than an inch or so under the cp3, the cp3 is dry the very bottom center of the valley is not. everything else is dry. Looks like I'm going to have to pull it to see the exact leak, i put the UV lift on some oil off the dipstick, and it did not glow.

LDS got back to me after they contacted S&S for some diagnostic ideas, before i pull the pump. i have not called them back to tell them the results, going to call them tomorrow.

S&S did say that if i have a fuel restriction on the return side of the system, there is a weep hole in the pump that will leak.

I modified the supply side of the fuel system, I have a fass 150 adjustable lift pump, so its the pump only, it is a 1/2 inch suction line to the factory sending unit to a quick connect adapter to 1/2 '' fuel hose.

On the supply side, it comes out of the pump into 1/2 hose into a double filter set up under the frame, a cat water seperator and cat fuel filter on Baldwin fuel filter heads threaded together on a custom made bracket, from there it goes straight to the factory inlet on the drivers side back of the engine and is connected with another quick connect to 1/2 fuel hose barb.

factory fuel filter head is deleted, 1/2'' hose used to loop from the bottom of the FICM up to a 1/2'' push lock Tee, where i have a bleeder and pressure sensor threaded in, then to the factory location.

I will grab some pics of it all and post them later, could changing that fuel line size cause an issue with being fed too much fuel and not being to return it fast enough?

When i did this i did it because i didn't want to cut into the factory fuel line, so i removed it and replaced it with soft line. I figured the restriction would be at the fitting on the engine, so it would be a minimum increase? but maybe i was wrong? maybe its just bad luck on a cp3 pump with a defective seal, S&S sounded pretty confident there's nothing wrong with the cp3

im going to look at it some more and see what else i can see

 

[Burn Down]

Use a mirror to look back along the bottom sides of the cp3. There are freeze plugs in the side that I have seen blow out from cp3 failures, maybe one is seeping?

 

[DAVe3283]

Do you have a flow-through lift pump? If so, unplug it and see what happens.

Still leaks = CP3 or return line leaking
No leaks, runs fine = supply side leak under pressure when hot
No leaks and it dies = bad supply side leak (sucking air)

That's how I'd go at it next. Should help you narrow things down a bit at least.

Sent from my Cat S60 using Tapatalk

 

[frankenstien]

Use a mirror to look back along the bottom sides of the cp3. There are freeze plugs in the side that I have seen blow out from cp3 failures, maybe one is seeping?

I got a mirror in there and a bored scope camera, I think its coming up from where the pump meets the block, I was able to see one the 1st or 2nd time had it apart, its right above one of the pump to adapter bolts, it was dry.