truck runs but question!

blackcoal

blackcoal

New member
Joined
Jan 2, 2011
Messages
515
Got my truck to start and run, but have a question.

I have the idle set at just under 800 rpms which it seems to run smooth at. But when you bring the RPMs up when it comes back down to idle it will drop down to about 500 rpms sound like its gonna stall but then it will come right back up to the normal idle at about 800rpms, what causes this? Any ideas?

160 pump
CPP SAC 7x12
65cc haisley delivery valves
0 plate
4k springs (i was told, in the pump when i got it)
60+ fuel psi
.120 fuel lines
.093 crossover tubes



Would the big lines have anything to do with it? Any ideas? Havent got to drive it but im thinking it will be difficult to drive if it is doing that, like my guess is it will stall.


video of it:

[ame="http://www.youtube.com/watch?v=0ZxHAjBj3QA&feature=plcp"]http://www.youtube.com/watch?v=0ZxHAjBj3QA&feature=plcp[/ame]



[ame="http://www.youtube.com/watch?v=r_QWLWVYiP0&feature=channel&list=UL"]http://www.youtube.com/watch?v=r_QWLWVYiP0&feature=channel&list=UL[/ame]
 
Last edited:
Those are huge lines, try smaller lines. I run stock lines and .093 tubes. No issues.


Posted to CumminsForum via autoguide for iphone.
 
Try loosening the governor springs a click or two. My 12v will do the same thing, but only when the engine is cold in sub-zero temperatures.
 
okay ill give the springs a try. the lines i got for next to nothing, so thats the only reason im using them
 
Its going to be a bear to drive.


Posted to CumminsForum via autoguide for iphone.
 
okay thanks for the help guys. ill get the radiator and the rest of the front end on and get it out on the road and see how it drives. might have to go with some smaller lines?


Tate, is that a common thing for them to act weird if the govener springs arent adjusted right?
 
Loosen up the springs then try one soft, 3 hard clicks on each side. That should help if they are set tight.
 
If the springs are too tight, the bottom end gets weak, it can't compensate by adding more fuel if the RPM gets too low. With my ****ed up 12mm pump with 5k's, it wouldn't idle below 1200 rpm, and if you rev it up and let off the throttle it would drop below the 1200 rpm and just die.
 
Ill finish this up so if some one else runs into the same problem sometime. I reset the govener springs which deffently helped and bumped the idle up to about 900rpms and it took care of it dropping down to 500rpms before it goes back to idle.

It isnt to bad driving with the .120 lines, it will lope if your in gear driving slow at a idle or letting out on the clutch. You just have to give it a little throttle and its perfectly steetable. Planning to get a smaller set of lines sometime because it does get anoying.
 
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