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**MN6WS6** · 07-06-2004, 05:02 PM

I don't know why they are so much more, but I'm going to try an electric oil pressure gauge in my car. They are half the price of electric fuel pressure gauges. I already know that an air compressor gauge works, because I have one on my car now. I want the electric one though so that I can actually mount it in the car instead of on the cowl.

**Injuneer** · 07-06-2004, 08:22 PM

Definitely go electric. With a mechanical gauge, by the time you buy a high pressure isolator ($110) and the braided S/S lines to run inside the car ($20-30), you are looking at a total cost very similar to the cost of the electric gauge. And the electric gauge will be INFINITELY safer.

The "isolator" can be a problem. You have to fill the line inside the car with a glycol solution, and somehow keep it "fiiled". Lose a little glycol and your fuel pressure gauge loses its accuracy. I also have first-hand experience with the AutoMeter high pressure isolator, and it FAILED, allowing fuel into the lines inside the passenger compartment. AutoMeter recalled that particular isolator (PN5280), and the next one (PN5281).... and they are now up to model PN5282.... who knows how long before those start to fail and cause problems?

But I still like the AutoMeter products... I've been running their full-sweep electric fuel pressure gauge for 4 years..... left gauge in the 3 center vents:

**xxRillixx** · 07-06-2004, 10:37 PM

I went with the electronic fuel pressure gauge & also did the oil pressure guage (extra $45)

. I also went with the AutoMeter brand. I just cant believe how much it costs for gauges!! Checker wanted $275 for the same fuel pressure gauge as above

!! I ended up around $300 for the Fuel, oil, and dual holder

. Still need to pick up the fuel pump & fuel regulator.

**Injuneer** · 07-07-2004, 06:46 AM

Summit has as good a price as anyone on the AutoMeter products.... the full-sweep, 0-100psi electric fuel pressure gauge in the Sport-Comp series is $195. I think I paid about $180-185 from T. Byrne Motorsports, but that was at least 5 years ago and AutoMeter has changed from a 3-piece to a 2-piec design.

If you need any help in hooking up the pressure sensor, I have some suggestions.

I have the electric fuel pressure, oil temp and tranny temp, and mechanical oil pressure and nitrous pressure.

**xxRillixx** · 07-07-2004, 08:30 PM

Originally posted by Injuneer

Summit has as good a price as anyone on the AutoMeter products.... the full-sweep, 0-100psi electric fuel pressure gauge in the Sport-Comp series is $195. I think I paid about $180-185 from T. Byrne Motorsports, but that was at least 5 years ago and AutoMeter has changed from a 3-piece to a 2-piec design.

If you need any help in hooking up the pressure sensor, I have some suggestions.

I got mine for $185 n some change. I would greatly appreciate any help on how to do the pressure sensor.

**Injuneer** · 07-07-2004, 10:37 PM

This is a "cut & paste" from an install writeup that I never got around to posting on my website:

How do I install it?

The typical fuel pressure sending unit has 1/8” NPT male threads on it. You need to be able to connect the 1/8” NPT threads to the –4AN male connection on the Schrader valve. That’s the whole problem.

I'll try and walk you through it. The Schrader valve is the "test connection" on one of the hard fuel lines behind the intake manifold. It will have a black plastic cap screwed onto it (at least that's the way it left the factory), like one of the A/C recharge connections.

This picture shows the fuel line, with the test connection. However, my setup already has one of the correct fittings screwed onto the test connection:

http://members.aol.com/Fredrick518/Photos/bkofint.jpg

When you remove the plastic cap, you will find the top of the connection has a "tapered" (sort of conical) end on it. This is a "-4AN" connection.... a system of fittings that is used widely to contain high pressure fuel and nitrous. You will also see a "core" inside the opening.... that is identical to the "core" in a tire air valve, and will have to be removed with a tire valve core removal tool. There is typically some pressure in the line, and a little bit of fuel will squirt out at you, so make sure the engine is not hot, and hold a cloth around things when you start to unscrew the core. Just press the core in, with the tip of your finger, with a rag wrapped around the valve to relieve the pressure.

Now that you have the core of the valve out, you have two choices on connecting the pressure sensor to the Schrader:

� (Not Recommended) Use a hard fitting – an elbow from Earls - that changes the –4AN to 1/8” NPT male, and then add a 1/8” NPT “coupling” from Earls to hook the elbow to the pressure sensor. If you decide to mount the sender directly on the Schrader valve, get and Earls 90-deg adapter:

EAR-923104.

Then just get the 1/8" NPT coupling, or a similar fitting from Earls:

EAR-991001.

The thing I do not like about connecting the sensor directly to the Schrader connection is... 1) when you tighten the -4AN fitting on the Schrader, you have no control over which way it will be pointing when you are all tightened up. An -AN type fitting seals very well with minimum torque. Too much torque, and you damage the seal, or worse yet, you break the Schrader connection off the fuel line... VERY expensive to repair. I believe the Schrader connection is only “swaged” onto the fuel line. And 2) now you have the weight of the sender on the connection, and possibly very close to the cowl, which it might hit if the engine torques over on acceleration.

� (Recommended) Use a swivel fitting to get the connection away from the cowl, and easy to position. Then run a braided S/S hose to the pressure sensor, in a remote location. The sensor is away from the cowl, and can be positioned away from the heat.

I suggest the NOS part # 17535 -4AN 90-degree swivel fitting. - that is what you see screwed onto the Schrader connection in my photo. That lets you tighten the fitting and point it in any direction, and gets it angled so it is parallel to the cowl, rather than point up into it. Then run a short -4AN braided hose to the sensor, which can be located out of the way. NOS makes a 24" -4AN hose with 1/8" NPT threads on the other end. Use a brass coupling to connect it to the sensor. Or, use a brass "tee" for multiple connections, as described below.

NOS-17535 for the 90-deg swivel fitting.
NOS-15230-1 for a red fitting 24" -4AN hose, or
NOS-15230-2 for a blue fitting hose.

(Update - you can get these hoses in various lengths on eBay, at about 1/2 the price of the NOS hoses)

Now, with the hose in place, you can tuck the pressure sender out of the way, say behind the PCM, which is where the rubber grommet is that you are going to route the wires through, to get them inside the car.

Some people want to connect two or more devices to the Schrader connection.... a fuel source for a wet nitrous system, or a fuel pressure safety switch for a nitrous system, or a small extra pressure gauge that will be visible under the hood while you are adjusting your pressure regulator. If you want to connect two devices to the hose, just get a brass 1/8" NPT "tee" with 3 female 1/8" NPT connections... screw the hose into one end, the pressure sender into the other end, and the extra device into the remaining opening.

You can get the fittings direct from NOS by calling them, or from Summit or JEG's online. All you need is the part #'s, and you put them in the "search" field on Summit with the NOS or Earls vendor code in from of it, and it will give you the price and allow you to order online.

� For the ultimate install, take your fuel rails off. Have an aluminum 1/8” NPT female ferrule welded into the rail. Screw the sensor directly into that… very clean, very neat. That is the way I have mine installed currently.

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