fuel pressure gauge query

[jlbeck]

I just received a fuel pressure gauge kit from Kirban's. Pretty straight forward but after reading the instructions I seem to detect a CYA tone by saying things like gauge is for tuning purposes or "if" you leave it connected after checking pressure be sure to check often for leaks. It is a liquid filled gauge and should be relatively vibration resistant I would think. I was wondering if any of you with rail mounted gauges have had any problems or have any tips.

 

[turbojay]

Mine became inaccurate after a couple of months due to the vibrations. I did not buy it from Kirban.

 

[Silver Fox]

Mine became inaccurate after a couple of months due to the vibrations. I did not buy it from Kirban.

Mine never was accurate. About 10 psi too low.

 

[1984 t-type]

I did a lot of searching on fuel pressure gauges before i bought mines and from what i read i decided to purchase a in dash unit. From my understanding its not a good idea to leave anything connected to the fuel rail due to weight and vibrations, also why leave it hooked up anyway its not like u can read an underhood gauge in the car. If you want to be able to monitor your F.P. you should go with a dash mount.

 

[jpratt]

I have been using an uderhood and a dash mount electric gauge together. The underhood one it direct mounted to a T at the end or the fuel rail and is used for setting pressure. The in car one is great for monitoring while driving.

 

[GNVenom]

Fuel pressure should only be checked occasionally, and only if you suspect a problem with the fuel pump, filter or regulator. Having anything attached to the Schrader valve indefinitely is not a good idea, and there is really no reason that I've ever found where you would need to constantly monitor fuel pressure. Also, having a gauge and fitting permanently attached adds additional weight to the fitting (it's brazed onto the thin brass fuel rail) which can lead to cracks and leaks...something you really don't need on your high pressure fuel system.

Using an electronic cockpit gauge would be the safest way to go if you must have fuel data at your dash. Some lower-cost transducers that attach to the fuel rail are very heavy and can stress the connection. Stick to the smallest electronic transducer you can find to minimize the effects of too much weight on the fitting. I've seen some large brass-bodied transducers sold which I personally would not put on my fuel rail fitting.

Your scan tool will give you most of what you need to know in terms of how the engine is running. IMO, fuel pressure should be checked and set initially, and checked only occasionally, just to be sure it's up to the chore.

 

[1984 t-type]

Hey John in your opinion what gauges should a street car have ? other than a scanmaster.

 

[GNVenom]

Well, it's just opinions, but here goes, in order of importance:

Boost Gauge (most important - you are always looking at it)
Scan Tool (too bad they don't put it in a gauge, hmm...)
Knock Gauge (my personal favorite ;-)
Coolant Temp Gauge (we always obsess on this one)
Volt Meter - see below
Tachometer - see below

And the least important: Oil Pressure. The only reason I am saying this is that the oil pressure on our turbo cars is almost non-existent at idle, and there is really NOTHING you can do to change that. There are no adjustments, all you generally do is look at the pathetic low pressure readings and wonder...

Seems the oil pressure increase is consistent and linear with RPM's; 1000 RPM=20PSI, 2000 RPM-40PSI, 3000 RPM=60PSI.

Volt meter: Gives you something to wonder about, but not much you can do with its odd fluctuations if you are certain the electrical system is up to par.

Tachometer: Another cool thing to look at, but really, you normally mat the throttle and it shifts where it's supposed to. You're never manually-shifting your car, so RPM's, who cares?

Opinions stated.......

 

[Bruce Urie]

I have Kirban's fuel pressure gauge, liquid filled, though I have a flexible braided hose running from the Schrader valve to the gauge mounted on the driver's side inside fender.

I do have to agree with John's assessment that having the gauge hooked up permanently is not a good idea due to the stress from extra weight on the valve. I thought by using a flexible hose I would eliminate the weight on the valve plus let the gauge last longer by eliminating vibrations.

Wonder if I should take the fuel pressure gauge out now? Do you think I should, John, or should I just leave it the way it is?

Your evaluation of the importance of what gauge to have is very good....it sure makes sense.

Bruce

 

[jlbeck]

Thanks for all your input. You have validated what I thought. I had an oil pressure sending unit, on another car, that the previous owner had mounted on a long brass pipe nipple and a 90 degree fitting and the nipple cracked causing a leak. When I went to replace it, it fell off in my hand. Lucky me. I think I will probably just remove it after I check the pressure.

 

[we4Mateo]

Scan Tool (too bad they don't put it in a gauge, hmm...)

Check this out...I had one on my GTP Grand Prix, it worked awesome, and I can't see why they can't be made to read our ALDL data...

AeroForce Tech Interceptor OBDC2 Scan Gauges: 3800 Performance