Lb7 no start??

[Mxz8002003]

Sry guys i just keep think of sh*t and want to be sure. So i know my fuel had is pumping good Threw test port. When i rebuilt the fuel head i also add the injectors direct cat filter adapter. Says no primer ball removal. Want to be sure if the fiter head will pump fuel then does that mean fuel is also able to flow through it??

 

[Bdsankey]

Sry guys i just keep think of sh*t and want to be sure. So i know my fuel had is pumping good Threw test port. When i rebuilt the fuel head i also add the injectors direct cat filter adapter. Says no primer ball removal. Want to be sure if the fiter head will pump fuel then does that mean fuel is also able to flow through it??

Does the truck have a lift pump? If not, you don't have a fuel pump on the truck other than the CP3. There is a gear pump on the back of the CP3 that is responsible for sucking fuel from the tank, through the filter, and then into the CP3 itself.

 

[Mxz8002003]

Sry if that came across confusing. Okay no lift pump.
Cp3 is gear driver. so no Electronic item like the Main computer could stop the pump from pumping fuel right??

And then my fuel Filter primer head. If it will prime and pump fuel manually when i pump it, which it does, then should it also allow for the cp3 to suck fuel threw it. Want to make sure the cat filter adapter is noT causing a prob.

 

[2004LB7]

If you can reliability get fuel to your fuel test port near the alternator then your filter shouldn't be an issue

 

[Mxz8002003]

I took the rubber supply line off at the cp3. Which from the outside looks fine. When i removed it fuel come out of the line. I then hit the primer a feel times and a full hose of fuel each time i pumped came out. Hooked the rubber supply line back up to cp3. next remove the Short high pressure metal line that comes directly off the cp3 to the distribution block at the distribution block side. Primed system up. Cranked over at least 10sec, no fuel out of high pressure line. None! Looks like ill be ordering a cp3. Any suggestions on who to order from and im feeling id should put a new regulator in as well??

 

[Bdsankey]

I took the rubber supply line off at the cp3. Which from the outside looks fine. When i removed it fuel come out of the line. I then hit the primer a feel times and a full hose of fuel each time i pumped came out. Hooked the rubber supply line back up to cp3. next remove the Short high pressure metal line that comes directly off the cp3 to the distribution block at the distribution block side. Primed system up. Cranked over at least 10sec, no fuel out of high pressure line. None! Looks like ill be ordering a cp3. Any suggestions on who to order from and im feeling id should put a new regulator in as well??

I can get you setup with a pump. I’ll shoot you a PM.

 

[2004LB7]

New cp3 should come with a regulator too. Please get one from a vendor here so at least the support is reciprocal

 

[Mxz8002003]

New cp3 should come with a regulator too. Please get one from a vendor here so at least the support is reciprocal

Absolutely!! Thanks 2004lb7

 

[Mxz8002003]

Okay so got the lb7 torn down tonight to be able to get cp3 out. 3 1/2hrs and 4 brewskis. Not bad i didnt think. (Tare down is easy right) I dont think it will be to bad going back together. No doubt my Previous Encounters with doing injectors on the lb7 helped me tonight. Although you take/remove many other parts that with injectors u do not.. Ended up going back with stock original through LDS. LDS is who i bought my injectors through when i had my first lb7 and was very new to the duramax. Was even contemplating on doing them myself. LDS emailed a very good pdf/DIY of lb7 injectors to me that made the job go off without a hitch. Did a little bullshi**ing with Brent today on our low milage lb7’s.. Pump should be here tomorrow.

 

[Mxz8002003]

Also BdSankey thanks For the quotes and input on different cp3’s.

 

[2004LB7]

If you have the pump out, would you be willing to remove the gear pump off the back and see if the drive shaft tab is intact? I had one break on my and the pump stopped completely.

I fixed mine but was curious if yours failed the same way. If course you will have to put it all back together if you need to send it back as a core

 

[Mxz8002003]

If you have the pump out, would you be willing to remove the gear pump off the back and see if the drive shaft tab is intact? I had one break on my and the pump stopped completely.

I fixed mine but was curious if yours failed the same way. If course you will have to put it all back together if you need to send it back as a core

Yeah i prob could do that.. im curious myself. With pump out and i spin gear by hand fuel only came out of return. I held finger over supply inlet, spun gear around few times the. Their was suction on my finger. Removed finger and Little bit of fuel shot up and out of return only. Obviously whatever fuel was remaining in pump after removal. But again nothing out of high pressure side. There was fuel sitting in the high pressure side port, just never come out

 

[Bdsankey]

Okay so got the lb7 torn down tonight to be able to get cp3 out. 3 1/2hrs and 4 brewskis. Not bad i didnt think. (Tare down is easy right) I dont think it will be to bad going back together. No doubt my Previous Encounters with doing injectors on the lb7 helped me tonight. Although you take/remove many other parts that with injectors u do not.. Ended up going back with stock original through LDS. LDS is who i bought my injectors through when i had my first lb7 and was very new to the duramax. Was even contemplating on doing them myself. LDS emailed a very good pdf/DIY of lb7 injectors to me that made the job go off without a hitch. Did a little bullshi**ing with Brent today on our low milage lb7’s.. Pump should be here tomorrow.

Also BdSankey thanks For the quotes and input on different cp3’s.

No problem, glad to help! Brent and the crew over at LDS are phenomenal to work with and you're definitely in good hands. Hopefully this fixes your issue (I can't really think of anything else it would be if you're not getting any fuel out of the high pressure side of the pump but have fuel at the inlet of the pump).

 

[2004LB7]

Yeah i prob could do that.. im curious myself. With pump out and i spin gear by hand fuel only came out of return. I held finger over supply inlet, spun gear around few times the. Their was suction on my finger. Removed finger and Little bit of fuel shot up and out of return only. Obviously whatever fuel was remaining in pump after removal. But again nothing out of high pressure side. There was fuel sitting in the high pressure side port, just never come out

Sounds like the gear pump is working but something else is busted inside.

 

[Mxz8002003]

Okay just got the truck back together, fired up after about ten seconds of cranking. Let it run for about ten mins, sounds good, shut it off and started it a couple times with no problems.. first initial look over my work, i see no leaks, everything looking good. Will do a better in spec tomorrow and a little rd test.

 

[dndj]

Glad you got it fixed. Thanks for posting up the resolution, for others in the future who may be facing similar issues with their truck as we try to keep our old LB7's on the road. :thumb:

 

[2004LB7]

:thumb:

 

[Mxz8002003]

So got about 100 miles on it, runs awesome. Ive own this truck for prob 8 plus yrs now and have put less than a 1000 miles on it. I think its time for the 29,000 miles to increase. These 100 miles i put on were very enjoyable. Motor is very quite for an lb7. But if im going to keep driving it for a weekend driver then i need a tune. Looking into that now. Thanks everyone who chimed in on this Thread.

PS. 2004lb7..... i packed the old cp3 up and going to send it out for core, i guess im just happy its running. thanks for your help!!

 

[TheBac]

Glad you got it repaired. :thumb: