I had fun today...I finished up my gauge install. I did my best to do this on a budget, but still have a quality product when I was done, so I didn't cheap-out on any important details. First off, a couple weeks ago I purchased a 3-gauge dash-top universal pod off ebay, for a whopping 88 cents (and a couple bucks shipping). I was prepared to receive a useless paper-thin material, but it was actually very rugged black plastic, easily paintable to match the gray of my dash (which may happen at some point in the future). At the same time I purchased a Hoyt pyrometer off ebay, for around $90 shipped including the sensor. I used my dremel to slightly contour the bottom of the gauge pod to match the left side of the top of my dash, installed the gauge, and ran the wiring. I skipped the backlight at the time because I knew I'd be installing more gauges very soon.

A couple days ago I received my Isspro boost and fuel pressure gauges, and went to work gathering up parts to install them. I skipped the expensive install kits, and used tubing left over from another gauge I had for the boost gauge, and I already had a 48" length of braided line and some fittings for another project. Last night I got the gauges put in the pod and the in-pod wiring done. Today I planned the rest of the install, and went to Napa for some fittings and a length of rubber fuel line.

The boost gauge was easy. I just removed a 1/8" pipe plug from the intake and installed a 90 degree elbow (to relieve pressure from the plastic line), and attached the plastic line.

The fuel gauge was a bit more involved. After considering several possible ways to tap into the fuel line, I ended up removing the banjo bolt at the injection pump and drilled and tapped the end of it to take a 1/8" npt elbow. Because the braided line I had wasn't long enough to reach the pump, I used the braided line from the gauge through the firewall, hooked to an adapter then used high quality rubber line from there to the banjo bolt. I ran all lines and wiring through the firewall, out through a small hole next to the fuse panel cover on the side of the dash, and up the side to the gauge pod. At some point I'll probably replace the rubber hose with braided line, but for now at least the section in the cab is high quality stuff.

I fired it up and went for a ride, and was a little surprised at the readings i got. I took it easy for a while because the roads around here are filled with potholes from the wierd weather we've had. While driving easy I had between 0-10 psi of boost and around 10 lbs. of fuel pressure. EGTs stay around 300-600 during easy driving.

Once I got to a better section of road and could beat on the truck, I had max readings of 36 psi of boost, fuel dropped to 4-5 lbs., and egts never got above 900-1000. In the past couple weeks I've had the egts get to 1100 under certain conditions, but never over that.

I have the #10 plate slid slightly forward of the stock position, and the wastegate line is blocked off for now. I'll be changing my fuel filter tomorrow to see if it helps my fuel pressure. Any other opinions or suggestions are appreciated.

Jim

 

Glad you got them installed and working write, to me 4-5 Lbs of fuel preasure sounds realy low especially on a 12 valve.

 

whats your fuel pressure at idle?

 

It was around 10 at idle. I pulled the delivery valve and stretched the spring a bit, and got around 28 at idle. I don't know what too much pressure will do (probably wouldn't hurt anything with just a few lbs. over, but I played it safe), so I pulled it again and compressed the spring. Now I'm at 22 at idle, just at the high end of the rated pressure (found the specs for it) at idle. Tomorrow I'll road test it and see what I have under load and at higher RPMs.

Once again, the advice of this forum has saved the day! It also helped me prove to my wife that the money I spent on the gauges was well spent, since I was able to fix this before it became a real problem. Its just a band-aid fix for now, but I'll buy a new delivery valve soon...or maybe modify mine to use a different spring, and maybe tap the end of the bolt to accept a set screw so i can adjust the pressure. I don't really see an advantage of having it adjustable though, other than saving me a few bucks...and even I'm not THAT cheap.

Jim

 

To much pressure will blow the seals in the injection pump. Forget about stretching the spring and get a new overflow valve. The spring that you stretched was the overflow valve spring wasn't it? You should never see 5 psi on a 12 valve.

 

Yes, it was the overflow valve spring. I'm just using this to get by for a few weeks until I have the $$ for a new overflow valve. Cheapest I've seen them is tst, and its nuts that something this simple is $60+. There is nothing wrong with the valve other than the spring...someone should sell springs for $5 or $10 so we can replace just the spring.

Jim

 

True enough Jim - but youll never be able to source just the spring.

 

You won't find a better OF valve price than here

Precision Diesel Injection and Turbo Inc.
Marty Tompkins
888-734-7349
$35 + $7 shipping and handling.

Stretching the spring is a very short term fix. You'll find once the the spring loses it's springiness that changes in fuel temperature cause big swings in fuel pressure.

 

Thanks for that info! I'll be ordering it this coming Friday. During the road test, I fouond huge pulses in fuel pressure, so that the gauge is constantly "ticking", swinging up and down 5-7 psi constantly. Apparently the spring fix is a very butch solution (as I expected), and will only be used until the new valve arrives. Once again this forum has come through and given me helpful info! Thanks Bill.

Jim

 

If you can't get the old OF valve out don't bend the return line, you'll have a rough time getting it to line up again. Best to grind or file the spot on the intake that is keeping the valve from coming out.
A rag under the OF valve before removal will save you a lot of time searching for the sealing washer when it drops.

 

I had it out twice last night and didn't have any problem. I was able to catch the washer with my fingers while I pulled the valve out with my other hand. It was a tight squeeze, but I didn't have any problem. I just want to get it fixed asap. I don't like the pulses that are getting to my gauge. The pulses in fuel pressure are so much that I can feel them through the ss braided line. When I'm at higher rpms, I can actually hear the gauge making noise from the needle moving so much. I hate to think about what the pulses are doing to the injection pump.

Jim