Having strange issue with f/p guage after install...HELP!

[GTA_V6_Mustang]

I put in the gauges I ordered yesterday. Now when I put it KOEO the gauge reads 40psi, which seems fine enough no fluctuating obviously because its not running. now the problem begins when I start the car. At first it seems fine, it will be around 38-40. But then it starts like going nuts. will go as high as 60 and then stay at 100 pegged. Wondering if anyone else who put in an electric f/p gauge has had this problem also when the sender is direct to the fuel rail because I am starting to think the ignition wires may be causeing EMI in the sender seeing as it only acts up when it is on. I have the wires run under the intake manifold to the firewall, signal str8 to guage and other to independent ground on chassis. Any suggestions

 

[sleeperstang199]

almost sounds like the wires going to your sender and intermitently being shorted to ground. just a thought. good luck maybe make sure all of your wiring is correct

 

[Stanger007]

I'm using Autometer 2246 sender into my datalogger, it is steady as a rock.

+1 on checking your wiring and make sure it is not grounding out.

Wes

 

[GTA_V6_Mustang]

hehe found the problem. "Dirty ground" is what they call it(not actually dirty as in dirt) I was sharing the ground I was using for both a/f ratio guages with the f/p gauge and it was causing interference in the circuit. So I seperated it and now I am good. around 32 to 36 psi sitting and 42-43 WOT. Seems about right to me no?

 

[Danman765432]

I think 38 - 39 is stock for WOT, if you have an adjustable FPR then yours could around 43ish and how the car is tuned and running.

 

[GTA_V6_Mustang]

I think 38 - 39 is stock for WOT, if you have an adjustable FPR then yours could around 43ish and how the car is tuned and running.

hehe well my car is 42ish at WOT and 36-38 normal driving and like 32-34 idle.