Is it possible for two cp3's to fail within 50 miles of each other?

duramax hd

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Feb 27, 2009
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Quick rundown on this. I had my dual CP3 fail and blow a freeze plug out of the side a month back. Since mileage is unknown to me, and the guy I bought my motor from can’t seem to give me a straight answer on this kind of stuff, I decided instead of throwing a new CP3 at it, I would test the CP3 in the valley. I put the stock belt back on, capped off the high pressure and low pressure side, and ran the truck. It was running pretty good on a single pump for a around 50 miles. Cruising to work last Friday, noticed the oil pressure was low, and dropping fast. The low oil pressure light came on and the truck stalled within the matter of a mile of noticing this. Got it pulled off a main street and tried to restart, wouldn't even crank over one turn. So I thought maybe the battery? Got a new battery and it had enough juice to crank it up. Oil pressure was sitting at 10psi, so I shut it down and check the oil. Way over filled, so I took a clean paper towel and did a fuel test. Lots of fuel in the oil. I couldn’t leave the truck on the side of the road so I drove it a mile down the road to a parking lot where I had it towed.

My buddy and I did a lot of digging through old threads, and are thinking the valley CP3 has failed and is filling the crankcase with fuel. What are the chances that two CP3's at almost the exact same time? Its almost to coincidental. There’s nothing else in the fuel system really. Is there a restriction somewhere that I’m missing? I’m almost positive everything was put together right. What is causing the pumps to blow up in the first place? I’m running out of patience for this damn truck
 

Chevy1925

don't know sh!t about IFS
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Oct 21, 2009
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unless the front of the CP3 blew out just right to only go into the front main cover and not dribble fuel down the valley of the motor, its not the CP3 putting fuel into your crank case.

Id start looking at return lines and injectors Kris.....

Sorry to hear about all your issues man. it can drive a guy nuts but keep at it! you will get her goin good soon!!
 

duramax hd

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unless the front of the CP3 blew out just right to only go into the front main cover and not dribble fuel down the valley of the motor, its not the CP3 putting fuel into your crank case.

Id start looking at return lines and injectors Kris.....

Sorry to hear about all your issues man. it can drive a guy nuts but keep at it! you will get her goin good soon!!

I talked to Tim, and he's thinking the same thing. My gut is CP3, and Tim had a good idea to take the oil fill tube off and see if I can see the CP3 leaking fuel into the crankcase that way. If there is nothing, the valvecovers have to come back off and ill be chasing leaks

im leaning towards injectors or return lines. :(

Really dont want it to be this!
my little brother had a shaft seal blow and fill his crank case with fuel on his 01.

Yea I heard its rare, but I know it is possible.

Bad fuel can take out a cp3 & they get there fuel from the same place...
Maybe this casued it. Ive been on the same tank for a little while now come to think of it. I have an airdog with a water seperator, but maybe shit got past the filters?
 

Ne-max

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Nov 15, 2011
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I talked to Tim, and he's thinking the same thing. My gut is CP3, and Tim had a good idea to take the oil fill tube off and see if I can see the CP3 leaking fuel into the crankcase that way. If there is nothing, the valvecovers have to come back off and ill be chasing leaks



Really dont want it to be this!


Yea I heard its rare, but I know it is possible.


Maybe this casued it. Ive been on the same tank for a little while now come to think of it. I have an airdog with a water seperator, but maybe shit got past the filters?

You can check return lines without taking off the covers.