So I took my truck in to have the cp3 replaced with a LMM pump because mine wouldn't hold pressure. So i picked it up and after I got to the red light I noticed at idle it was surging. I thought maybe it just needed time to bleed out air or get used to having pressure again, I don't know. I have been through one tank of fuel and still the same problem....any ideas on what could have been missed during the installation procedure?

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btw! I still have the LB7 fpr all I did was shim it. As for the pump I figured the LMM was the same as the LB7. Correct me if I'm wrong!

 

what is your fuel and rail pressure

 

I figured it out! When I put in the lmm cp3 I left the lmm for on there and that's what's causing it to surge. But now I hear that since I have the lmm fpr then I can raise my max psi which I thought I could do even with the lb7

 

the port design on a lb7 fpr and a lmm fpr is different, your gonna have to get it retuned for the idle to keep it from surging. get ahold of phil and see when i have time to help both of yall out with efi live to fix that surge

hopefully they people who installed your cp3 were clean and tidy, dont dont any junk in your injectors