Surging started last year and before I could figure out problem it started having starting issues. Soon it would not start at all. Replaced lift pump, no change. Replaced injector pump,no change. Replaced all injectors, started right up yay. But still surges. Returned injector pump as it was 1800 bucks and put original back on. Replaced apps with one from timbo , no change. Runs good under load but when cruising at a steady speed you can hear motor surge and it feels like brakes are being applied on and off on and off. More pronounced at pre overdrive speeds. Truck is a 2003 3500 quad cab auto trans. Any help greatly appreciated. Thanks Bill.

 

Did the new injection pump come with a FCA or did you have to use the original? If it's the original I would try swapping out the FCA.

And do you have a performance tune or box on your truck?

MikeyB

 

It came with fca but I actually took the new inj pump off before putting in injectors so i never had it running with anything but the original pump. So you think it could be the fca. Truck is all stock other than k&n filter

 

Might have a look at the wires described here.. http://www.cumminsforum.com/forum/3r...rt-solved.html

 

Have checked that wire loom several times amongst others and all seems good. Removed and cleaned cov and purged ports before replacing. Tried to do same with fca but torx capscew at 6 o'clock position is to close to fca body for a .250. Socket holding the torx bit to gain proper alignment. Fearing I'd strip it I decided to remove the hole pump for better access if cleaning cov didn't work. But that's just what it did. Truck is running and sounding perfect for first time in 13 months. Thanks to all who posted on this and my other thread (2003 won't start). Here's hoping I only give help here in future and never need help again. Ya right!