LB7: Fuel Rail Pressure Sensor voltage/signal???

fastpunker

adrenaline junkie
Feb 7, 2012
215
1
16
Lake Havasu City, AZ
I have been trying to find documentation on the operation voltages/amperage output for the FPS.... either a scale of what the V or mV should be at x psi (i.e. @5000psi 1 wire is showing 1.35V and the other signal wire is 85mV). :confused:
The other thing I am looking for would be a FSM (full service manual) on how to diagnose a bad fuel pressure sensor... something like do an ohm check from this wire to that wire on the sensor itself. (I did this kind of chit to check the maf on my yota via the FSM)

So what I am after with all of this is to verify that wonderful :rolleyes: Autometer rail pressure gauge 2686 is off and not the actual factory sensor in the truck. The stupid gauge shows I am at 26,000+ psi at wot in 5th.... this with a factory LB7 CP3 and regulator with 250K on it lol. I am trying to get all of the accurate information to give to autometer when I send the gauge back to them to be fixed. (I know I know, over active enjuneeeer brain again lol)

Any help would be mucho appreciated:thumb:
 

JoshH

Daggum farm truck
Staff member
Vendor/Sponsor
Feb 14, 2007
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I believe there is a table in the LB7 and LLY tunes that sets the voltage to pressure of the rail pressure sensor. If you have EFILive if you don't have it already, you can download EFILive and a stock LB7 tune and take a look.
 

fastpunker

adrenaline junkie
Feb 7, 2012
215
1
16
Lake Havasu City, AZ
I believe there is a table in the LB7 and LLY tunes that sets the voltage to pressure of the rail pressure sensor. If you have EFILive if you don't have it already, you can download EFILive and a stock LB7 tune and take a look.

Thanks!! :woott: I found the table you are talking about finally. That was basically what I was looking for... at first glance it looks like I am seeing +.10V than I should be seeing given my prior measurements when I am at idle and 5000psi.

So my last question is if there is a PID to view the actual voltage as the truck is running so I can see what the ecm is seeing it as vs. what I am actually measuring?
Sorry, ran out of time to look for it last night. I figure there is, just wondering what it is labeled as.....
 

JoshH

Daggum farm truck
Staff member
Vendor/Sponsor
Feb 14, 2007
13,736
806
113
Texas!!!
Yes, there should be a FRP sensor voltage PID you can look at with EFILive or any quality scan tool.