160 pump 4k problem

bna5017

bna5017

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Joined
Jan 15, 2008
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I just put a set of Pacbrake 4k springs in my pump and seem to be having a hard time getting them tuned very well. First I had them at 1 soft and 3 hard clicks- didn't run much different than it did with my stock springs. then I tightened them up one click at a time and took it for a drive each time. Anyway, they are at 6 hard clicks right now, and it runs pretty good. But I cannot get it to idle. It takes a little pedal to get it started.

I read BgBlDodge's thread, it seems like I might need to try putting the shims back in under the idle springs. But I am not sure if this will cure my problem on a 160 pump, or if someone may have any other suggestions.

thanks,
Brett
 
So will it not idle, or will it not start without fuel? Do you have to hold the pedal down to keep it idling? Maybe the idle needs to be raised? When the springs are a little tight, it takes a little fuel pedal to start them, but it should idle fine. Mine starts fine with the 4k's, just cranks a second longer if i dont tap the throttle. If i back the springs off a click on each side, it starts right off without pedal.

Eric
 
It will not idle or start without pedal. The starting without pedal does't bother me, but I can not get it to idle. I adjusted the idle every time I tighten or loosened the the springs.

I am going to try to put the idle shims back in it, but my new spring seats are not large enough in diameter for the shims, seems to me that it would be ok to put the shims on the upper spring seat.
 
Not enough room between the idle spring and the others. Idle shims will help. I've seen on some spring kits that the spring heigth are not the same. I mic all the ones I install. Makes for a smooth operation of the gov. This is food for thought.
 
On my 95' Junker, I installed Pac Brake 4K springs. I initially went 1 soft, 4 hard clicks. Truck started normally, idle raised about 50-100 rpm just like Pac Brake claims in the instructions. Truck would only free rev to 3800 rpm and it seemed to start to lose full fueling around 2600 rpm.

I then tightened both sides to 1 soft, 6 hard clicks. Startup is normal, idle is high at around 1050-1100 rpm. Free revs to 4100 rpm and starts to lose full fueling around 2800 rpm.
 
I just put 2 idle shims (equal to .042") in on the upper spring seat, and set the stud protrusion to .045" on each side. Idle is good, but it doesn't seem to run as well as it did when I had the springs at 6 hard clicks. I don't have valve springs yet so I am not worried about getting it to 4k just yet. But I would like to get it to run a bit better.

I have a mack rack plug to put in it, but I doubt that it will gain me anything as I don't feel like I am bottoming out the rack on the stock plug at all, no changes to the AFC net much difference at all at full throttle. I think that something is keeping the rack from traveling very far. Any way to measure the rack travel without taking the pump off?
 
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