greenz2895

I just got a new auto meter electric fuel pressure gauge with a 1/8''NPT sender i was just woundering how you guys installed these on youre lt1.

94 NO TOP Z

I took the schrader valve out of the test port of the fuel rail and hooked a #4 hose into that port. I ran the #4 hose over to the driver's side where I installed a #4 male flare fitting and a adapater to fit the sending unit.

Injuneer

Its a "-4AN" connection on the Schrader valve. Here's a cut and paste from a writeup I did on installing a fuel pressure gauge sensor:

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You use the factory fuel pressure test port, on the hardline behind the intake manifold. Commonly known as the Schrader valve. The Schrader connection is a -4AN male. To attach a fuel pressure gauge or sensor:

Remove the black plastic cap. Use a tire valve core tool to remove the core from the Schrader valve. Start with a NOS part # 17535 "-4AN 90-deg swivel fitting". This provides the correct -4AN female to fit on the Schrader, a 90-deg bend to get the connection aimed away from the cowl, and the "swivel" feature that allows you to aim the connection in exactly the direction you want, then tighten it up. A non-swivel fitting can end up pointed in any old direction, and you can't just tighten it some more to change the direction.... the Schrader fitting can break right of the line.

NEVER over-tighten the “AN” type connectors, and NEVER apply any real pressure to the one attached to the Schrader valve. The Schrader fitting is only swaged onto the hard pipe. It is an expensive part to replace.

Run a short braided -4AN S/S hose from the 17535 fitting to a location where you want to tuck the fuel pressure sensor. Behind the PCM, its out of the heat and vibration frmo the engine, and there is the convenience of the big rubber grommet behind the PCM to route the wire through the firewall.

The S/S hose should have a -4AN female on one end to attach to the 17535, and 1/8" NPT male thread on the other end. NOS makes these hoses, but only in 24" length... I have seen shorter and custom lengths available on eBay for about 1/2 of what NOS charges.

Get a 1/8" NPT brass coupling, available in any hardware or auto parts store. Use that to connect the male end of the braided SS hose to the male 1/8" NPT connector on the pressure sensor.

This is Shobox's photo showing the location of the Schrader valve - covered with a black plastic cap on the passenger side rail hard line:



This is a pic of the back of the intake, with the NOS #17535 installed on the Schrader connection:

Z28_95RIDE

Fred, I am installing a wet nitrous system on my LT1. Your post here is helpful for the process and precautions. What I am wondering is if there is any reason I can't put a swivel T connection on this gutted schrader valve port?

The reason being, I need the fuel feed for the wet nitrous and I would also like to install a fuel pressure gauge. I guess I'm staying on topic and not hijacking the thread....

Injuneer

Do it the same way I outlined.... NOS #17535, -4AN hose with a 1/8" NPT male on the other end. Now get a 1/8" NPT brass tee - attach one end connection to the braided S/S hose, connect your fuel supply to the wet nitrous kit to the other end of the "tee" (with a 1/8" NPT to -3AN or -4AN fitting) and screw the fuel pressure sensor into the side connection on the tee.

green zr1

injuneer, can i just hook the pressure sensor to the 90 degree fitting instead of running the hose behind the pcm.

chevy94c

I need to hook mine up soon.

Injuneer

You can put a -4AN female to 1/8" NPT female adapter on the 90-deg swivel fitting, and attach the fuel pressure sensor with the 1/8" NPT male fitting there. The thing I don't like about doing it that way is the fact the extra weight is now hanging on the Schrader fitting, and that fitting is only swaged onto the hard line. Does not take much (e.g. - hitting sensor while working on the engine) to break the fitting off the hard line.

I had a 1/8" NPT bung welded to my passenger side fuel rail for the pressure sensor.

green zr1

thanks man, but it want just break off riding down the road would it? Also if i remove the core from the valve how would i releave the pressure if i had to later.

Brandon94Z28

I just hooked mine up last week. I didn't want any hose so here is what I had to do. I got a fitting that was -4an(female) on both ends. Then I got another fitting that was -4an male to go into female and 1/8 npt to go onto auto meter sending unit. Works flawless and cost me $10. I wish I could've found an adapter that ws female -4an and female 1/8 npt but I had no luck.

good luck
Brandon

green zr1

yea i didn't what a hose etheir i figured the more hoses and fittings you have the more places it could leak at.

green zr1

do you have any pics of your install, where did you get your parts i can't find a -4an female to -4an female.

Brandon94Z28

I don't have pics but I do have part numbers. They are Aeroquip brand from the local race shop. The first part is the blue/red anodized and the second is just brass. You can get them to match but the guy ordered the wrong color for me on the second part number. I installed these on my 95 IMP SS so the cowl spaced is different, I will go out and measure the heighth off of the shrader valve when I get off baby duty.
FCM2914 -4an female on both sides
FCM2721 -4an male to 1/8 female

later
Brandon

green zr1

thanks man.

cybern8

looking into installing a fuel pressure gauge, and found this thread. given the less than ideal location of this schrader, is there any reason why i can't simply splice a tee with a gauge into the fuel feed line? guessing if this isn't a good idea the reason is obvious to everyone but me... (?)