how is a fuel pressure gauge ran?

motoking_1990

Active member
May 9, 2011
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Terre Haute, IN
I was wondering how a fuel pressure gauge is ran i think im going to buy one. I would assume a electrical connector somewhere but does it show before or after the cp3? Thanks
 

Noreaster

Active member
Jun 13, 2007
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Cape Cod,MA
fuel pressure is before the cp3 & rail pressure is after
fuel pressure uses a sending unit & rail pressure plugs into the sensor on the rail
 

BlkMax

Member
Sep 1, 2008
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Wasilla, AK
I was wondering how a fuel pressure gauge is ran i think im going to buy one. I would assume a electrical connector somewhere but does it show before or after the cp3? Thanks
Where would i get a fuel and rail pressure gauge
I do not see a lift pump in your signatures. With no lift pump, the fuel pressure will be at atmospheric or slightly below. Essentially zero.

PPE and others sell rail pressure gauges. Any electronic fuel pressure gauge will work, scale on that one should be no higher than about 30 psi.
 

jlawles2

Well-known member
Jan 28, 2010
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Danbury, TX
The differences in fuel pressure gauges are types. The less expensive ones tend to be mechanical while the more expensive are electronic.

Some people prefer the electronic version to keep from having to plumb a fuel line into the cab of the truck.

All of the rail pressure gauges that I have seen are electronic. I would not feel comfortable tapping into the rail pressure and having a 20,000 psi or more line running into the cab. The rail pressure gauge that I am running gets its signal from the factory sensor.
 

RedDmaxLBZ07

New member
Oct 16, 2009
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East TN
If you want to save your money you can log rail pressure with EFI Live. I dont know about you but its hard to watch gauges and drive especially when your sled pulling or drag racing...JMO
 

BlkMax

Member
Sep 1, 2008
743
4
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Wasilla, AK
X2 on logging the rail pressure with EFI. The actual rail pressure is only half the story, you also want the desired rail pressure from the ECU (not just what you have for rail, but what the engine wants for rail).

Also, I read a post that Pat had put up about some folks having issues with placing rail pressure sensors in the system. Not sure what the deal was, but I think it was throwing codes or something.

When I am not logging, I use an Aeroforce dual gauge system that plugs into the ODB2 port. There are 2 gauges, with 2 digital displays per gauge. Each gauge can be setup to read engine/transmission parameters that are built into the truck (rail pressure-actual and desired for instance). These also have analog inputs that you can setup for pressure or temperature transmitters (like EGT, fuel pressure, etc.). I wired the transmitters to also work with the analog inputs to EFILive. downside with these gauges is that if I want to log, I have no gauges.

Truth be told, I have a fuel pressure transmitter and never look at it unless I think the filter may be starting to become packed off. It is a nice diagnostic data point, but I do not use it on a regular basis once I figured out the lift pump can keep up with the CP3 and the tuning.
 

schulte

New member
Jul 31, 2010
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CT
I have an autometer fuel rail pressure gauge... it taps into the rail pressure sensor wiring. It's not really accurate, its often wrong by 5-10%.

Not really necessary, but it's cool to watch the needle sweep when you punch the throttle...
 

Righteyeblind

Member
Aug 29, 2008
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Fairbanks, AK
If you want rail pressure gauge to watch all the time get the Aeroforce or an Edge CS or CTS. You can see actual and desired rail pressure with this unit along with a lot of others. Also you can use it as an on the fly DSP5 switch.
 

McRat

Diesel Hotrodder
Aug 2, 2006
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Norco CA
www.mcratracing.com
For fuel supply pressure, any pressure gauge can do it, even a boost gauge. Problem with a cheap mechanical gauge is a leak in the cab if a fitting leaks. Digital is better, as only wires go into the cab.

You need to be careful with electronic rail gauges (ones that use the factory sensor, and have a gauge face in the cab). If they alter the factory signal, it can cause low performance, or other problems, because that's the same wire the ECM uses to control the Fuel Rail Pressure solenoid. I haven't had a problem, but I have heard of issues.

Devices that monitor the OBDII stream like EFILive or PPE or Edge or Predator, etc, are the immune to those problems.
 

Subman

Old Geezer
Jun 27, 2008
3,233
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80
Madras, OR, Pahrump NV
I have both but to be honest I really don't see the need for a fuel rail pressure gauge. It did come in handy this last week when I was driving back from Boise. Truck started missing like crazy and I didn't have my V-2 with me. Didn't have my fuel pressure gauge hooked up yet either but the fuel rail pressure was bouncing all over the place and would go almost to zero when I gave it just a little fuel. Lift pump wasn't working and obviously I had started to plug my 2 micron filter. All fixed now, loose ground wire on the FASS 260 and a new filter.:thumb:
 

jmaz268

Lead from the Front
May 20, 2010
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Springfield IL
For fuel supply pressure, any pressure gauge can do it, even a boost gauge. Problem with a cheap mechanical gauge is a leak in the cab if a fitting leaks. Digital is better, as only wires go into the cab.

You need to be careful with electronic rail gauges (ones that use the factory sensor, and have a gauge face in the cab). If they alter the factory signal, it can cause low performance, or other problems, because that's the same wire the ECM uses to control the Fuel Rail Pressure solenoid. I haven't had a problem, but I have heard of issues.

Devices that monitor the OBDII stream like EFILive or PPE or Edge or Predator, etc, are the immune to those problems.

Pat, care to elaborate on what you have heard? Or know what Brand of gauge had negative affects.

I have an autometer one at home i was going to install, but if it just makes things worse, then it will go back on egay.