Don't Believe Everything You See

[dynoman]

In the process of trying to solve my backfire problems I decided to fix my in-car FP gauge. I found a cut wire to the sender, fixed it and tried it out. The in-car gauge reads 33lbs. and the one on the rail reads 42lbs.,crap the in car guage readings are off, the sender must be bad. I decide to hook up a temporary gauge from the rail to watch FP during boost. After hooking up the 3rd gauge it reads the same as the in-car gauge , soooo I remove the LIAR and replace it with a known good gauge . Now all 3 gauges agree my FP was too low!!!! After adjusting FP to the RIGHT pressure I took it for a ride , yes the FP rises 1 to 1 with boost , no backfire , and HOLY CRAP THIS CAR IS NASTY . I can't wait for my son to come home from FT Knox with his Cobalt SS to show him a real turbo car :biggrin:. Thanks everyone for pointing me in the right direction !!
Thanks Sam

 

[pacecarta]

rail gauges suck
i'll never use the but I see so many in use at shows
few want to listen when i tell them those rail gauges go bad fast and that what they see probably isnt correct , but they look cool i guess

 

[dynoman]

I assumed that nice Autometer gauge was right , could have caused some real damage. I've heard that it might be a good idea to mount the sending unit off of the motor to the fire wall for less vibration. Any thoughts on that?

 

[pacecarta]

sender isnt designed the same as a bourdon gauge

gauges shouldnt be on the motor , the fender is a better place for them

 

[Bruce Urie]

sender isnt designed the same as a bourdon gauge

gauges shouldnt be on the motor , the fender is a better place for them

Paul, are you suggesting that I take the rail gauge, hook it to a braided fuel line, then run it from the end of the rail, and bolt the gauge to the fender on the driver's side under the hood?

Would this improve the lifespan of the fuel pressure gauge? Would appreciate your opinion, Paul.

Bruce '87 Grand National

 

[pacecarta]

i use a gauge on end of a braided hose , caspers used to sell them ,
for the racer i use an autometer 2 5/8 on a braided hose in a cup style gauge holder

its also good to keep a test gauge around to check any gauge for accuracy

 

[Roger]

My sending unit for my in cabin electric gauge is on a braided line over 10 years now - so far it appears to work.

 

[Bruce Urie]

Paul and Roger, thank you kindly for your help here. I feel confident now to switch to this configuration. Appreciate it very much. I knew I could count on you for the right solution.....best to you and your family.

Bruce '87 Grand National

 

[dynoman]

It was a real eye opener when I hooked up the "test" gauge only to find out the rail gauge that I was setting my fuel pressure to was 9 psi off !!

 

[Bruce Urie]

It was a real eye opener when I hooked up the "test" gauge only to find out the rail gauge that I was setting my fuel pressure to was 9 psi off !!

Thus the whole point of your thread....and a good one, I might add. Shows you can't trust things in this world today, always good to have a check unit, or back-up unit. Good thing that rail gauge wasn't used on the Space Shuttle.

Nice post and a real eye opener for us.


Bruce '87 Grand National

 

[Mathias]

Good suggestions. Don't leave gages mounted on the engine. Also, a liquid filled gage can give inaccurate readings. Mechanical gages can eventually leak fuel or ?.. Keep away from heat source and vibration. Use a quality sender to safely mounted gage. Don't burn your car down.

 

[GNRick]

I had a mechanical autometer gauge go bad a couple months ago. It was mounted on the hood. it showed the symptoms of a bad fuel pump- worked fine at idle but didn't increase with boost. I thought crap, my 1 year old fuel pump went out on me. Changed the gauge and fixed the problem.