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Discussion Starter #1 (Edited)
I installed a set of EV2 gauges about 9 months ago - fuel pressure, boost pressure, and pyro. Everything was great for a few months...gauge readings were in line with where they should have been.

After a few months, my boost gauge would periodically get jumpy, with pressures jumping around seemingly randomly, from about 0 to 25 psi, regardless of whether I was at idle or driving at higher RPMs. I figured it was probably just a loose wire or something, so I didn't worry about it too much.

A couple months ago, I noticed that my fuel pressure had jumped up about 4 psi, from an average of about 17 psi to 21 psi. I was a bit worried at first. Then I realized that when I turned the key to power the gauges (before bumping the starter), the "baseline/zero" reading was at 4 psi. I figured this meant that my actual fuel pressure was about 17 psi, which is where it should have been.

Today, I was driving home for lunch and I noticed that my fuel pressure was steadily increasing at the rate of about 1 psi per minute or so. When I got home, the fuel pressure gauge read about 32 psi. I tested the baseline reading by powering the gauges without bumping the starter, and it read 14 psi, which would give me an actual fuel pressure of 18 psi (about what I would expect). On my way back to work the fuel pressure gauge reading kept climbing and it maxed out at 40 psi.

My pyrometer seems to be working normal, although the "baseline" reading is about 380 degrees, even though it's below freezing here.

Each of the gauge dials go to zero upon receiving power, before going to the "current readings" (before starting the engine).

The wires all seem to be making good connections. My truck seems to be running just fine (smooth, no error codes, good mileage, etc).

What else should I check? What could possibly be going on with my readings? Bad sensors? Bad gauges? Wiring problems?
 

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The boost gauge sounds like an intermittent connection, probably the ground wire to the sensor. Please try the following: Use the plastic wire insertion tool (that you used to push the wires into the orange connector when installing) with a pair of pliers and squeeze the wires in just like the original installation, then while holding the connector and tool with the pliers, grab the wires and pull them towards the orange connector, forcing them deeper into the "V" of the connector terminals. Also, make sure you did not strip the wire ends before putting them into the orange connectors. The wire insulation helps holding the wires into the connectors, both by grabbing on the sides of the connector plastic portion, and by holding the wire conductor strands into a circle so they don't flatten out.

For the fuel pressure gauge, it sounds like the sensor is failing. Please PM me your address and where you bought the gauges originally, and I will have a replacement sent.

For the pyrometer, is it showing 380 with the key on but the engine off and cold?

Regards,
Michael Pliska
 

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Discussion Starter #3
You seem to be right about the boost gauge wire. It's been too cold to mess with my truck too much, but I jiggled the wires in back of the boost gauge a little more and it's obvious that it's a wiring issue.

The pyrometer is showing about 100 degrees when cold, and I'm guessing that's about where it should be.

I will PM you my address. FYI, I have been using a needle valve barely cracked open to block the fuel pressure spikes, and also have the gauge at the end of a grease gun hose to limit vibrations to the fuel pressure sensor. Neither of these would be negatively affecting the sensor...would they? Is there anything else I should be doing?
 

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The needle valve and hose are a great way to limit the fuel system pulses that are inherent on a VP44 truck, they should not affect the gauge aside from smoothing out the displayed pressure. Do you have the needle valve on the VP44 side of the hose? That is the best arrangement for damping the pulses.

Just let me know if you need a replacement for the orange connector &/or wire insertion tool. Sometimes the orange connector can get boogered up from messing with it too many times, and it's easier to start with a fresh connector.

Regards,
Michael Pliska
 

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Discussion Starter #5
Yes, the needle valve is on the VP44 side of the hose.

A replacement orange connector and tool would be appreciated. I'm not sure that the current connector is bad, but I don't know that it isn't bad. Better to be safe than sorry I guess.

Thanks for your help Michael. I will pull off the existing sensor this weekend and send it to you.
 

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Discussion Starter #6
I connected the new fuel pressure sensor tonight and I had a reading of 16 psi when I started the truck. Absolutely wonderful... :party018:

Thanks for your help, Michael. I can't imagine ever going away from ISSPRO gauges, thanks to the great service!

I haven't messed with the boost gauge wiring yet...I'll wait until it gets warmer over the weekend to do that.
 
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