Fuel Pressure
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Senior User
Joined: Jan 2006
Posts: 304
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Fuel Pressure
In order to not hijack Brad SS' thread I'll start another on fuel pressure.
My fuel pressure gauge usually reads 75psi cruising at 60 mph. Now at times I check it is reading 100psi, which is as high as the gauge goes. From there if I go WOT or slow to a stop, it does not cause a change. When it is reading 75 psi the gauge falls to 60-65 psi at WOT. I have an ITP RR and AD 2. All connections seem to be good. This was going on before my clutch fan issue, which I posted earlier.
I checked with a pressure gauge under the hood and the highest I've read is 70 psi. Is there another port for checking fuel pressure? Unless someone has a better idea, I am going to get a TEE and mount a manual gauge (duct taped to the windshield or something) so I can compare while cruising. The in truck gauge is an ISSPRO Performax. The Boost and EGT Performax gauges seem to be accurate.
My fuel pressure gauge usually reads 75psi cruising at 60 mph. Now at times I check it is reading 100psi, which is as high as the gauge goes. From there if I go WOT or slow to a stop, it does not cause a change. When it is reading 75 psi the gauge falls to 60-65 psi at WOT. I have an ITP RR and AD 2. All connections seem to be good. This was going on before my clutch fan issue, which I posted earlier.
I checked with a pressure gauge under the hood and the highest I've read is 70 psi. Is there another port for checking fuel pressure? Unless someone has a better idea, I am going to get a TEE and mount a manual gauge (duct taped to the windshield or something) so I can compare while cruising. The in truck gauge is an ISSPRO Performax. The Boost and EGT Performax gauges seem to be accurate.
Elder User
Joined: Sep 2004
Posts: 821
Likes: 1
From: Nashville
I had the exact same thing happen with my EV2 fuel pressure gauge. It turned out to be a bad sensor. Isspro has had a few of them go bad recently (they don't make the sensors). There's a troubleshooting sheet for the EV2 gauges on the Isspro site. I used it to determine that my sensor was bad. Not sure if the Performax sensor is the same but I suspect it is.
http://www.isspro.com/TROUBLESHOOTIN...leshooting.pdf
You should call Isspro and speak to Mike about it before you bother with your tee setup.
http://www.isspro.com/TROUBLESHOOTIN...leshooting.pdf
You should call Isspro and speak to Mike about it before you bother with your tee setup.
Hotshot
Joined: Dec 2003
Posts: 15,369
Likes: 121
From: Stuttgart, Ar
If you're running pressure that high then you can easily adjust it. The underhood gauge that comes with the RR kit from Strictly Diesel (ITP) isn't the most accurate or reliable thing. I had two manual and two electric gauges in my posession this past summer and none read exactly the same although 3 were really close.
You should be able to check the fuel pressure in 2 places under the hood. One is in the fuel pressure test port on the secondary filter housing (picture 57) here: Page 30: Fuel Supply System OR in the RR system regulator. They should read virtually the same pressure at idle.
Balancing the AD2 and the regulated return fuel systems is a little tricky. The AD2 has to return some fuel to the tank to work and separate properly. I've found the best way is to crank the underhood regulator virtually closed and then adjust the AD2 for desired fuel pressure so that it can return as much fuel as possible to the tank. A properly functioning AD2 can pump a LOT more fuel than your truck can use unless you're running some very large injectors.
You should be able to check the fuel pressure in 2 places under the hood. One is in the fuel pressure test port on the secondary filter housing (picture 57) here: Page 30: Fuel Supply System OR in the RR system regulator. They should read virtually the same pressure at idle.
Balancing the AD2 and the regulated return fuel systems is a little tricky. The AD2 has to return some fuel to the tank to work and separate properly. I've found the best way is to crank the underhood regulator virtually closed and then adjust the AD2 for desired fuel pressure so that it can return as much fuel as possible to the tank. A properly functioning AD2 can pump a LOT more fuel than your truck can use unless you're running some very large injectors.
