Chevy and GMC Duramax Diesel Forum banner
  • Hey Everyone! Enter your ride HERE to be a part of this months Ride of the Month Challenge!
1 - 20 of 37 Posts

·
Registered
Joined
·
124 Posts
Discussion Starter · #1 ·
2002 gmc 2500 hd 305k

going to replace injector pump. I have the injector pump, I have never done the job although I have read tutorials and watched a couple videos. my mechanic skills are decent.

What gaskets or parts will I be needing for this job?

Will getting air out of the system be difficult?
 

·
Registered
Joined
·
71 Posts
I have not changed an injector pump but I don't believe it will be too hard. I know from experience that getting air out of the system is easy. Crack your fuel filter head bleeder screw and hand prime until fuel comes out of the bleeder. Close the bleeder and hand prime until the primer button is too hard to push. Now the truck should be ready to start. It may take a little cranking and sometimes you have to hand prime a couple more times. Just be careful not to do too much cranking without resting the starter or it will overheat.
 

·
Registered
Joined
·
124 Posts
Discussion Starter · #3 ·
I have heard of loosening the injector ports up until fuel starts to emerge. Just wanted to know what gaskets may be needed
 

·
Registered
Joined
·
71 Posts
I personally would not loosen the injector lines. These trucks can be primed by the method mentioned above. If you took the injector lines off and saw the rust that typically falls into the injector, you wouldn't mess with the injector line. I had this happen on my truck when I replaced the head gaskets. As far as gaskets, I reused the intake gaskets and banjo fittings. These would be removed to get to your pump. As far as the pump itself, I haven't changed one so I don't know for sure if it has any gaskets.
 

·
Registered
Joined
·
124 Posts
Discussion Starter · #5 ·
I was thinking of just cracking them open, but thanks for the heads up. Never heard of reusing the same gaskets. While I am there, replace the thermostats.
 

·
Registered
Joined
·
372 Posts
I also wouldnt mess with the injector lines.. should start ok after priming a couple times.
 

·
Registered
Joined
·
124 Posts
Discussion Starter · #7 ·
Thanks for the input. Appreciated!
 

·
Registered
Joined
·
372 Posts
Also will need new thermostat/ coolant crossover gaskets
 

·
Registered
Joined
·
124 Posts
Discussion Starter · #9 ·
about removing the gear on the existing pump: is this a normal thread? loosen counter clockwise? What type of puller/installer, or will I need to hit it with heat?
 

·
Registered
Joined
·
372 Posts
Must have a new pump with no gear? I believe it is reverse thread but its been a while sorry.. the gear nut, i just lightly rattled with a impact. Used a small puller tapped again with impact and came right off.. i was very surprised how easy mine came off.. put a little loc tite going back on
 

·
Registered
Joined
·
124 Posts
Discussion Starter · #11 ·
Yes. New pump with no gear. I'll stare at it, hit it with impact. Thanks again
 

·
Registered
Joined
·
372 Posts
Good luck.
 

·
Registered
Joined
·
124 Posts
Discussion Starter · #13 ·
Thank you and cheers
 

·
Administrator
Joined
·
16,862 Posts
DO NOT crack open the injector line, our fuel systems operate at 4300 - 26000 PSI.

This is a quick example of what can happen.

 

·
Registered
Joined
·
124 Posts
Discussion Starter · #15 ·
I will make sure of that. Thanks for the input
 

·
Registered
Joined
·
40 Posts
Yeah I just got done replacing mine last week. It's a pain if you've never done it before which was my case but you remove the AC compressor lay it back toward passenger side. Remove alternator, bracket, turbo horn, Y bride, wiring harness from glow plug box on drivers side all the way to passenger side and lay it over. Coolant tube and a few other small items. Replace all the rubber fuel lines while youre at it. Chunk the bastard clamps use real ones!! 4 bolts hold CP3. I got an upgraded LBZ pump same price... Remove gear and adapter and put on new pump. Standard threads RH. No need for loctite. It's a dry taper on pump make sure you get all oil off gear and taper and hit with impact a little then torque to 52 ft lbs. then reinstall all the parts. That's the easy way. All the other stuff can stay on unless you wanna spend all day putting it back together.
 

·
Registered
Joined
·
124 Posts
Discussion Starter · #17 ·
rubber fuel lines to and from injector pump? dealer item, or typical auto part item?
 

·
Registered
Joined
·
40 Posts
No they can be made with common fuel hose. Most are 7/16 and one or two were 3/8. The check valve was 5/16. Be sure to replace the insulating rubber that is on some of them. And one more expensive item that you better check is the Bosch fuel block mounted behind the CP3. It splits the fuel equally to each rail can't miss it. Got a FPR in it and one end has a Alan screw inside it that has a spring and plunger valve behind it. Mine was full of rust and the plunger was pitted from this bio-hippy-fuel they are selling and it doesn't get driven everyday. It was a smooth $1000 but it can cause a new injection pump pressure to blast injectors straight to hell. Replaced CP3, fuel block, and all rubber lines and filter base with a new one. About $2800 but it runs better than it did the day I got it off the lot in 2002. I would also recommend adding a little synthetic 2 stroke outboard oil to your fuel for a few tanks to live the new CP3. Just my 2$ but it works
 

·
Registered
Joined
·
40 Posts
While your at it... Turbo horn can be mod by removing around 1/4-3/8 " inside diameter on turbo end add a little more hp and faster spool time. I also got a rubber screw plug and plugged my resonator off. Check your waste gate hose and make sure your waste gate will open with a pair of pliers gently. Mine was stuck. Lubed it up with some PB blaster and it popped loose when I started it. U will notice there are several things that will need to be cleaned or fixed after you get down into the engine... And my truck was taken very well care so it wasn't me. Any questions just holler man I don't mind helping after the cluster I went through getting mine back to purring. But like I said ... It was very well worth it!!!
 

·
Registered
Joined
·
124 Posts
Discussion Starter · #20 ·
That sounds like a good run down. I appreciate the help, and yes, I will probably message later
 
1 - 20 of 37 Posts
Top