Cummins NTC-350

Yep, that is where you will want to pull your pressure reading from. If you want to do the dual line setup I can show you how I did mine, it's not the hard line setup that cummins uses on the N14 but it works as well and is less likely to leak.

They use the QSK block and maybe the rotating assembly, but use the older K series head, they did that because they pushed the idea that it was they same as the earlier K series, yet it is built heavier.
 
Dual line set up? You talking the dual line setup to plumb a field feed line up to the front of the head?

As far as my gauge, I am just going to run a hydraulic line from the pump to the gauge. I have a bulkhead fitting that I'm going to use to mount the gauges in the cab.
 
Yeah, that is the setup I was talking about. I switched over to AN fittings and braided stainless line, it's nice if I have to take it apart, I don't have to worry about the fittings corroding together like the old steel lines.
 
Yeah that'd be awesome! If you cold get me a list of parts and where I maybe able to get them.

Custom SS braided lines?
 
Everything I used came from jegs, the lines I used are just universal lines for gauge installation or brake lines. The ones I used are too long, so I need to measure for the proper length. I will figure out what all I used.
 
SmokinCAT said:
The guy I spoke with said that because people are going to the newer stuff that they dont get much call for doing older stuff so they are going away from the tooling that they need to do the work.
Click to expand...

I have seen this first hand it sucks
 
I have had good luck finding direct replacement parts, but places that do modified parts are scarce.
 
So I got my gauges installed today. My manifold pressure gauge works great. My fuel pressure gauge I am still skeptical about.

I plumbed it it and there was 0 pressure. So I cracked the hydraulic line right before the gauge until I got fuel. While I had the line cracked, it acted like it did when I first brought it home and the pump was sucking air. It would idle high and drop off, almost like a slow lope. I let it idle for a few minutes and the lope went away. I stepped on the throttle and the pressure jumped right up to over 100 psi. I put it flat to the floor and it jumped up to 200 psi and then cut out (free rev?).

I decided to take it for a ride. Every time I throttled on it the pressure would jump up and go back down. I had it in high gear and matted it and it slowly crept up to 200 psi of pressure before I was maxed out.

It idles completely fine and responds fine now. Even sittin there parked when I throttle on it the pressure will jump up and as soon as I let if the gauge will go to 0.

This doesn't sound right to me. I feel like there should be some kind of pressure at the gauge all the time. When I throttle on it, the pressure should drop then come back up, correct?
 
Nope, that is normal, mine is the same way I haven't ever had one that shows pressure at idle.
 
Is it that port that I have it plumped into them. Why not plumb the gauge in, in-line with the fuel supply?
 
I have mine setup to where the second fuel line comes out of that side port I put a tee in that spot before the AN fitting and pulled the reading from there.
 
Went pulling last nigh. I was first puller and tries 4th gear but track was very tight clay track. 4th gear was too tall so I came back last puller and pulled in 3rd. Truck I pulled pretty good. Started hopping a little bit at about 175' but I was able to stay right in it.

The only problem I had, was I think with my fuel gauge. I looked down about mid track I when I had the pedal flat to the floor and it was reading 200 psi. Which I was happy about, not I know how far I can go. But when I let off to get unhooked and the truck was idling, it was slowly loping, like it did before the pump was rebuilt and sucking air. Maybe there is air in my line to the gauge? Maybe one of my fittings aren't tight enough? But as soon as I throttled on it a little the lope quit and idles correctly.
 
So this afternoon I decided I was going to try another fuel plunger. Pulled the assembly apart and found the pump had a number 32 plunger in it already. With the no. 32 button it would make 200 psi before it free revved.

So I decide to go one button at a time. The next lowest button I had was a 25. So I putt that button in plus 4 governor springs. Now it makes about 230 psi of fuel pressure before it free revs. Took it out on the road and it smokes a little in every gear if I get after it a just little bit. I had it in high gear and couldn't max out the RPMs before I got to nervous and had let off. We have a pull this Wednesday so we'll see how it reacts. Hoping to get my pyrometer installed before then too. Need to weld a bung in the pipe.
 
The truck seems to run much better with the additional 4 governor shims and the number 25 fuel plunger. But when I was pulling I glanced down at my gauge and it didn't seem to go over 200 psi. Parked I, it will make about 230 psi before it free revs. But out on the road or pulling it doesn't get over 200 psi.
 
That's where a bigger button would come into play I think. Also check your fuel filter and feed lines, it might be starving for supply. I notice mine will loose power out on the road since I switched from a fleet guard to a napa filter.
 
I did go to one size bigger button than what was in it. The filter is a Napa gold filter that that was changed from the day we brought it home and really hasn't had any bad fuel put through it. Before with with number 32 button it would make 200 psi before free rev and it would also make 200 psi out on the road. That was also with 4 less governor shims. Maybe I see 230 psi before free rev with this number 25 button sitting still but never see 230 psi on the road or the track because I'm not reaching full RPM?

My other concern is, since I've installed my gauge, after I am full throttle going down the track and suddenly let off the throttle, the motor starts to lope. Is that a sign of starving the pump, or air in the system that has not bled out since installing the gauge?
 
I think the napa filter is too fine of a micron to flow a decent amount of fuel. I think that button is still not big enough for what you are doing, I have a working truck I tuned that is running a 10.
 
It also could be that the spring is not up to snuff, putting the shims in would help, but a week spring would account for the loss under power.
 
Well the pump was all rebuilt this spring before the truck was ever put on the road. So it should have a new spring. I'll have to look at the parts list to be certain but I don't doubt any of the work this shop does. The only reason I have not put the number 7 button in the pump is because of the clutch. I want to make it through this pulling season with this clutch. We have 4 more pulls and I'd like to make all of them.

When I took the back of the pump apart to change the button I noticed another spring and a screw in the assembly that the button is in. What does that screw do? Does that have any effect on fuel quantity or fuel pressure?
 
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