cletus

I'm in the process of installing a mechanical fuel pressure gauge inside my car. I am trying to find out a good way to get through the firewall. It is a pretty big sized tube (I'll say roughly 1/2" at the biggest point (endpiece) being conservative). I'm hoping someone here may know of a good hole I can use that is pre-existing or any other helpful knowledge. I got lucky installing a boost gauge in my other car and there was a random unused penetration with a grommet in it that all we had to do was cut a hole in that. It was cake. Hoping to get lucky twice.

Here's kinda the trick though. I'm mounting the gauge in the center console under the radio. Due to the fact that you do not want fuel inside the cab of the car, the gauge setup is a little complicated (in retrospect, the extra $100 for an electrical gauge might have been worth it had I known ). The tube running to the gauge is a 4' steel braided tube that is sealed and contains a liquid. This runs out into the engine bay to a device that actually gets fuel run to it. But because of this, I only have 4' of cable to work with. On top of that, the device in the engine compartment must be mounted at the same height as the gauge in the cockpit (fun, huh?).

So it makes kinda a nice puzzle. If anyone happens to have any decent places, I'd appreciate it. Gauge manufacture gave me a grommet for a 1" diameter hole. 1" metal drill bits go for about $30 a pop though. But it would still be that much easier if I didn't have to drill at all.

Thanks guys.

4ohfour

I just took a look at the firewall of my 84, and it seems as though the only way to get a 1/2 inch pipe through it is to make yourself a hole.

cheers'

Felix Wankel

Buy a 1'' hole saw, it should be cheaper than a 1'' drill bit. I doubt 4' of hose will make it through where the stock wiring goes, and then to the console.

cletus

It's probably going to end up being relatively difficult to get a drill in there unfortunately. This will be intriguing.

mar3

iTrader: (8)

Just out of cuiousity, does the sender use an oil-based medium to get the pressure signal to the gauge in the car or does it, God help you, use the actual fuel pressure?! In either case, it's a real bad idea to send any fluid into the cabin unless it's in hard line like the coolant in the heater core. Oil or fuel emits fumes and is flammable....

Directfreak

iTrader: (2)

Cletus, for an extra $100, do it right and do it once. You're gonna end up with a "Rig" job that you will not be happy with - period.

Return the gauge, spend an extra 100, and get the right gauge, and place it where'd you'd really like.

Most Mechanical gauges are used for "under the hood" uses while tinkerin' (nice)
or for Race Cars out in front of the windshield. (ugly on street cars).

REVHED

"Firewall penetration"... sounds like a porno flick.

cletus

It's actually a set up made to be put inside the car. There is something under the hood that basically translates the pressure over to a sealed tube with a different fluid so there is no fuel/bad material inside the actual car. I'm not sure what the fluid is but they said if you spill it, replace it with a 50/50 water/alcohol mix or something. It is a steel braided line. Doesn't bend too well. It isn't going to leak. But if it does for some reason, it really isn't much fluid to spill (4' long and probably 1/4" ID isn't really much) since there is something under the hood that doesn't allow fuel in that tube.

Generally I prefer mechanical gauges over electric ones which is why I went with the mechanical. The electric one would be a PITA too since there is a pretty big box that would have to be mounted somewhere under the hood. The only real pain about this one is that tube is kinda big and the length is fixed. But yes, it is actually designed to be put inside the car and everything needed to be done was included, so it's not really a "rig" job. The only thing that would have made the electric easier is the smaller hole in the firewall just needed to run the wires.

peejay

Ah. Fuel pressure isolator.

I prefer the gauge-on-the-hood trick, that looks SO race But then it's easy to steal... oh well.

cletus

Yeah, that's the stuff.

Well, considering the fuel problems I've been having lately, I wanted to be able to monitor my fuel pressure while driving to see if I had a fuel problem or a carb problem. So leaving a gauge under the hood does nothing since I can't see it while driving. Leaving it on the hood was an option, but considering I drive it on the street and live in a city, I'm doubting that set up would last.

Welp, back to "work"