I recently installed an Autometer fuel pressure guage in my car. I just realized that I may have done something stupid when I installed it. I put it in the fuel send line rather than the check/relief valve on the fuel rail. Will this give me inaccurate readings?

 

I am not 100% sure on this but here are my thoughts, if it is installed on the fuel sending line, i would think that it would read the pressure of the fuel before it gets to the fuel rail, so in other words it is reading pump output pressure, I think for it to get an accurate reading of the fuel rail & injector pressure , it would have to be connected to the schrader valve on the fuel rail, also after installing my guage, i found out you have to pull the vacuum line off the regulator to get an accurate reading, also you didnt mention what motor you have or what psi the fuel pressure gauge is reading, i think this information could be helpful,

so its hard to say for sure, but im sure somebody else will chime in and correct me if im wrong,

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87 IROC-z 305 TPI
Borg Warner T-5 fresh rebuild
10-bolt 3.73 Richmond gears rebuilt GM posi,
formerly BW 9-bolt w/3.45 gears(broke it)
Ported Plenum and Runners Homemade AFPR
ACCEL 8.8 wires, High output coil,and cap & rotor
Bosch platinum + 4 plugs
Ram Air w/ K&N filters,
MAF sensor screens removed, TB coolant bypass
Polyurethane tranny and torque arm mounts
Dynomax catback w/custom tips
K&N oil filter,Mobil 1 synth, Futura GLS Super Sport tires 265/50/15 rear and 235/60/15 front mounted on 86 monte carlo SS rims ,

400 sbc and a 6 spd in the works

 

Along the lines of a fuel guage....My friend has a fuel guage that he doesn't want and it is used and already on his fuel rail. I wanted to know if we took it out and put it on my car if it would cause any problems, with my fuel rail or his?

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88 Formula 350
Upper and Lower SuperRam, 1000 CFM Accel Throttle Body, ZZ4 cam, 24# Motorsport Injectors, Larger Gutted Mass Sensor, Homemade Cold Air induction, Custom Burned PROM, MSD 6a box, MSD Distributor, Accel SuperCoil, Taylor 8mm wires, TB Bypass, B&M shift Kit, 160* Thermostat, Flowmaster Muffler,

 

JR4444, if the fuel pressure gauge is mounted on his fuel rail here is what you will have to do:
go to autozone or somewhere and get a tire valve removal tool, this tool allows you to pull the guts out of tire valve stems, and also lets you pull the guts out of the schrader valve.
Park the cars somewhere that u can get to both of them,
take off the schrader valve cap from the fuel rail and bleed off the pressure, now take the tool and unscrew the guts from the valve, now go remove the gauge from your freinds car
once it has been removed u will need to screw the guts from your valve into his schrader valve, once this is done it is time to put the gauge onto your car, put it on the way it came off, and there u have it,

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87 IROC-z 305 TPI
Borg Warner T-5 fresh rebuild
10-bolt 3.73 Richmond gears rebuilt GM posi,
formerly BW 9-bolt w/3.45 gears(broke it)
Ported Plenum and Runners Homemade AFPR
ACCEL 8.8 wires, High output coil,and cap & rotor
Bosch platinum + 4 plugs
Ram Air w/ K&N filters,
MAF sensor screens removed, TB coolant bypass
Polyurethane tranny and torque arm mounts
Dynomax catback w/custom tips
K&N oil filter,Mobil 1 synth, Futura GLS Super Sport tires 265/50/15 rear and 235/60/15 front mounted on 86 monte carlo SS rims ,

400 sbc and a 6 spd in the works

 

If you do decide to swap it like previously noted, you need to make sure of a few more things first. DO NOT swap them while the engines are hot!! I don't think you want fuel running down onto the manifolds. Second, you need to depressurize the fuel rails first. It is possible to crack the schrader valve a little and soak up the fuel with towels, but you are better off releiving the pressure another way.

 

Well my reading was 50psi at first. But I lowered it way down so that at idle its at about 30 and WOT its about 43-45psi I have an LO5 short block with stock 350 tpi heads.