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Spent the morning hooking up a few gauges in my truck but for some reason the fuel pressure gauge is not working. It turns on and lights up with the key in the on position and/or truck running but it will not give a reading. Needle just stays at zero.

I purchased the Fuel Pressure Gauge Adapter from Merchant Automotive and used it to install the hookup on top of the filter housing for the Autometer Gauge.

Once I realized it wasn't working, I went back through the wiring to make sure everything was connected and wires were still in tact. Everything is fine.

Anyone have an idea on what I did wrong or what I should look for????
 

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Post a pic of were you installed the sensor. Also do you have a lift pump on your truck if not you will not get a reading at all.
 

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Post a pic of were you installed the sensor. Also do you have a lift pump on your truck if not you will not get a reading at all.
Here's a couple pics.....



 

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So do you have a lift pump on your truck ? If not you will not get a reading.
 

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Oh no kidding! Is there anywhere else I can hook it up to get a reading or is having a lift pump the only way? A lift pump is in the future plans, just not quite yet.
 

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The fuel supply line is negative pressure-- so if you have a vacuum gauge, it will show an increase in vacuum if the fuel filter is getting restricted.

If you want to show fuel supply pressure, you have to install a lift pump, as the Duramax vehicles do not have one.
 

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Kennedy Diesel sells a Vac gauge that plugs into the factory schrader valve to measure vaccum pressure. You can also measure positive pressure up to 7.5 psi for when you do your lift pump.
 

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so without adding a lift pump, even having the fuel pressure gauge there on top of the filter won't even show a reading? i just installed my egt and boost gauge today and was waiting to do my fuel pressure gauge until i found out some more info...
 

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so without adding a lift pump, even having the fuel pressure gauge there on top of the filter won't even show a reading? i just installed my egt and boost gauge today and was waiting to do my fuel pressure gauge until i found out some more info...
Correct, the factory setup uses negative pressure with the cp3 sucking fuel to it.
 
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