CP-3 (Injector Pump) Replacement Poll

[rbattelle]

A simple CP-3 replacement poll. Please answer "yes" if you've had at least 1 CP-3 go bad.



Please note: INJECTOR PUMPS ONLY (not lift pumps).



-Ryan

 

[WoodChuck]

142k miles on stock CP3. No problems at all but being a horsepower junkie I need more and have a Dragonslayer on the way.

 

[dhoward]

no injection pump 120,000 mi. only bad injectors

 

[JCasper]

89K and no problems

 

[jbucha4]

160k miles but the actuator acts up when i bring the vehicle to a stop. The rpms stay at 1000 and i have to shift it back into first to drop the rpms to 800

 

[jman]

The FCA doesn't seem to be the cause of the 1000rpm idle sticking. Mine has done this for a long time and I haven't found anything to fix it. Rebuilt injectors did nothing, new FCA did nothing. It seems it is electronic related because a few have said loading a Smarty program cured it, but haven't heard if when they go back to stock it returns. It annoys me, but is tolerable I guess.

 

[JBallou]

Yes I have had a failure, mine leaked fuel between the pump halves.



I think that your poll is flawed, I don't think that a pump failure has been traced back to a lift pump, the truck just will not run, or run poor.



Second is you need another option for FCA issues that were poorly diagnosed.



Third is that you need a garbage can "other reasons".

 

[hcole]

You know, I own a 2nd gen and was curious about this poll's results so I had to choose one choice to see poll results. I chose the first one - no so I guess I and others like me could skew your results. Sorry

 

[rbattelle]

I don't think that a pump failure has been traced back to a lift pump, the truck just will not run, or run poor.

This poll is over 3 years old. It's original purpose was to check whether there's a causal relationship between lift pump failures and CP-3 failures.



Ryan

 

[WoodChuck]

This poll is over 3 years old. It's original purpose was to check whether there's a causal relationship between lift pump failures and CP-3 failures.

Ryan

I noticed the date when I voted, our trucks were pretty new back then. Based on the results it looks like lift pump failures do not affect the CP3 or do they? The CP3 has a built in lift pump and the early Dmax didn't have an external LP.

I had the relay fail on my FASS and the truck started and idled fine so I drove it about 20 miles and even got on the freeway and it didn't miss a beat.

I have read that if the OEM LP fails it doesn't start or run too well.

 

[rbattelle]

Based on the results it looks like lift pump failures do not affect the CP3 or do they? The CP3 has a built in lift pump and the early Dmax didn't have an external LP.

I don't think we can say definitively from this poll that LP failures don't cause CP-3 failures. However, in light of more experience since this poll was started, I'd say it's pretty consistent that a failed LP will NOT cause a failed CP-3. This may be because most trucks whose LP fails don't run for very long (they stall out).



It's a bit of an exaggeration to say the CP-3 has a built in "lift pump". True, it does have an internal intermediate pump between the high pressure chambers and the inlet. I believe it outputs somwhere between 100 and 150 psi.



But there's been much debate about just how much that little guy could suck. I think the general consensus is that it's not strong enough to suck all the way from the tank, through a failed LP, and then through a filter. At least, not usually (occasionally someone has an experience like yours, where the truck will continue to run with a non-functional LP).



As far as I know, no one has ever tried removing the LP entirely and trying to run the engine with only the CP-3 internal pump (like the Duramax does).



Ryan

 

[TCDiesel]

Thought I would add this Picture. .

 

[rbattelle]

Good photo, TWest. Some day I'd love to acquire a junked CP-3 to dismantle and "play" with. So many projects... so little time.

Ryan

 

[Bachant]

replaced the lifit pump at 200K just as a precaution. I now have 306K.

 

[LFarmer]

CP-3 replaced at 19000 due to external leak

 

[cerberusiam]

As far as I know, no one has ever tried removing the LP entirely and trying to run the engine with only the CP-3 internal pump (like the Duramax does).



Ryan

Someone has and they will. The efficacy of the setup is hard to measure, but, it is not adequate for even stock fueling based on running characteristics. Unscientific tests but a good guide.



The Dmax guys add pusher pumps for reliability and better performance, with lines that are twice the size of what the Dodges have. The fact that the low pressure pump of a CP-3 is capable of drawing means very little.



The low pressure side is regulated to provide 180 psi to the high pressure circuit for optimal performance. If the fuel is not available it will cavitate and cause sporadic pressure issues in the high side that impact the pump all th eway to the injectors. Throwing air bubbles into a HPCR system is just not a good thing.



There have been a few failures that needed complete fuel system replacements due to metal thru the system. Invariably, an under performing LP was found to be a contributory factor. While not conclusive, it is suggestive that a failed\failing LP can have a direct impact on IP failure.

 

[desertbull]

Lost the CP3 on Mexico Highway 1 100 miles north of La Paz pulling a race truck trailer in the middle of the night... got towed by a FORD towing a 35' flatbed race truck trailer loaded with a Trophy Truck prerunner strapping us at 40 mph all the way to La Paz arriving at 4:30 a. m... . about 130 feet of trucks/trailers attached with a tow strap in the middle of the night...

Turbo Tom with Action Turbo in Santee was with me and tried every diesel trick he knows until we gave up and figured it was the CP3... and ain't no CP3's in Baja...

Flatbed tractor/trailered the truck/trailer to the Tijuana border and tow strapped it across to to Tom's shop where he swapped out the CP3 and all good again...

It was a long 4 days of hell...