Tapping Fuel Line - Advice

[BQuicksilver]

Pretty soon I will be required to tap inot my fuel line to install a digital fuel pressure gauge i have purchased. At this point, i know nothing about doing this, and feel like it's time to start reading.

- What parts do I need to bleed off the pressure and do the job?
- Where is safe to tap? Are there any convenient areas? (i know close to ignition and close to headers is bad)
- Does anyone have step by step instructions, or any other advice?
- Is it okay to just tap one line? Is ther only one line, etc?

Thanks In Advance!

BTW: Please don't give generic advice to take it to someone else. I may do this, but I'll make that call if it's over my head.

[WayneE]

You'll just tap into the test port at the front of the fuel rail. You'll need to remove the shrader valve guts from the test port and get the correct fitting.

It's pretty simple.

[BQuicksilver]

Is that where everyone does it?

My instructions say to "not run any wires near the ignition wires b/c this will destroy the display"

[WayneE]

Oh yeah, don't be so lazy and use the search I typed in install fuel pressure gauge and got this thread that says you'll need a -4 fitting for the test port.

You're welcome!

[WayneE]

Originally Posted by BQuicksilver

Is that where everyone does it?

My instructions say to "not run any wires near the ignition wires b/c this will destroy the display"

What brand gauge?

You should have a sending unit that will mount near the test port somewhere and then run the wires under the cowl, through the firewall and into the passenger compartment to the gauge.

[BQuicksilver]

This is the gauge:
http://www.speedshop.org/store/Scrip...p?idproduct=19

It being an LCD may have something to do with the suggestion to keep it away from the ignition wires. It says this TWICE in bold on the one page install instructions.

[WayneE]

You shouldn't have any problem with it. Like I said, you should have a sending unit that mounts in the engine bay (to the test port) and then run the wires into the passenger compartment (remove the battery, poke through that grommet - do a search, you'll find more info).

[BQuicksilver]

Here is a photo I took of the entire setup in this kit.



I guess my primary questions left are:

1) Will the gold-colored fitting in the photo work with the test port/schraeder valve?

2) What sort of special protection will I need for the wire?

[BQuicksilver]

TTT

Any help would be greatly appreciated.

[badddrx7]

That unit looks very similar to the AutoMeter gauge I installed for my Nitrous system. Here is what I did, and my suggestion to you...

1. You will need to buy a -4N braided nitrous hose with the RED ends ( denoting fuel ) to tap onto the end of the fuel rail that is on the drivers side. Buy the hose long enough to get you over onto the Drivers side fender area. Mine was around 18" long. I mounted my sender on the back side of the Altenator area. You want to get the hose long enough and routed so that you can put the fuel rail cover back in place. This sounds complicated, but really it is very easy. So measure from the fuel rail over to where you will mount the sender and buy the hose length for that.

2. At the fender area end of the -4N hose you will need an adapter to take you to NPT ( national pipe thread ). Your picture looks like it's got a 1/4 to 1/8" brass adapter. So you will need a -4N male to 1/8" npt. Then to couple up the sender to this you need a simple 1/8" coupling. Now you have the fuel rail to the sender. Seal all threads with a dot of Teflon paste on the threads - no tape allowed. Make a custom bracket to hold your sender unit somewhere ( fender ? ).

3. Route your sender wire loom on thru the drivers side area up into the dash where your gauge will be. I routed mine thru an area near the driver side ankle area. I can find the exact spot if you need me to, but there is a flat panel in that area where I drilled a hole straight thru and routed my wire. It worked out really well and protected my cable. Took some fishing of the wire thru there, but worked.

4. Rest is hook up to ign power, ground and lighting circuit ( remember the Z06/c5 lighting is not 12v but milivolt ).

Tom

[BQuicksilver]

WOW, thank you for doing all that work, badddrx7!! That was one of the most helpful posts I have ever received!

I still have some questions, mainly because I don't have a mental picture of the different types of joints/connectors which you're commenting on.

1) Do I need to remove the schrader valve to connect the -4AN (female?) hose end? Or do I just attach the -4AN connector to the valve itself?

2) Exactly what connector do you use to hook to the schrafer valve, or fule rail if the schrader valve is to be removed? I assume -4 Female?

3) What's the best way to make the 180deg turn from the schrader valve toward the firewall? Just use a series of 90deg couplers?

4) When you buy the hose, do you need to buy the exact length or is it easy to cut? Also, does it typically come with -4 ends, or do you need to add them onto the hose ends separately?

5) It looks like the threads on the sender are 1/4" NPT, so couln't I just use a -4 to Female 1/4"NPT connector and then not bother with the brass adapter?

6) Or, since I'm just monitoring pressure, could i use the brass 1/8"NPT adapter and do the entire plumbing using smaller lines and connectors? If so, what size?

Thanks again for your help!

[badddrx7]

WOW, thank you for doing all that work, badddrx7!! That was one of the most helpful posts I have ever received!

I still have some questions, mainly because I don't have a mental picture of the different types of joints/connectors which you're commenting on.

1) Do I need to remove the schrader valve to connect the -4AN (female?) hose end? Or do I just attach the -4AN connector to the valve itself?

Yes, what you need is a simple tire valve removal tool. You can get one at Auto zone for a couple dolars. this little tool removes the inner valve from that schrader valve on the end of the rail. Retain the little valve for later use if you reverse things, along with the cap that you take off.

2) Exactly what connector do you use to hook to the schrafer valve, or fule rail if the schrader valve is to be removed? I assume -4 Female?

That is correct. BE SURE to vent off your gas cap of any pressure AND put a rag under the schrader when removing the inner valve as some gasoline will come out. And BE SURE to not work on this with a HOT engine. Be careful around gasoline. To recap, have your -4an hose ready, vent the gas cap, cold engine, ignition keys in your pocket, rags under the rail, remove shrader inner valve, and attach the -4an braided hose end. Once drained, no more gas should come out.

3) What's the best way to make the 180deg turn from the schrader valve toward the firewall? Just use a series of 90deg couplers?

No couplers, From the schrader valve connection you will have the braided hose. This braided hose is very high psi rated but will make sweeping 90's and 180 degree turns. Just get the hose long enough to make it to where you want to go. 18" will get you thru a couple turns and close to the fender. You need to measure, taking your turns into account.
4) When you buy the hose, do you need to buy the exact length or is it easy to cut? Also, does it typically come with -4 ends, or do you need to add them onto the hose ends separately?

5) It looks like the threads on the sender are 1/4" NPT, so couln't I just use a -4 to Female 1/4"NPT connector and then not bother with the brass adapter?

That is correct also. You can eliminate your adapter if you wish. This means you will need a -4an male to 1/4" NPT. You will then need a 1/4" coupling to mate up the sender to the -4an hose now. They make these couplings in aluminum also and anadized red so everything will match. Call Summitt Racing.

6) Or, since I'm just monitoring pressure, could i use the brass 1/8"NPT adapter and do the entire plumbing using smaller lines and connectors? If so, what size?

The -4an braided hose is your best avenue. It takes the abuse of vibration and wear very well. It should, it is used primarily for Nitrous pressures, which are well over a 1000#psi.

You could go with comprssion fittings, but I would not advise it. You will have more money in that and more fittings.

Take your time, plan out your work, and keep safety up front. Ask the forum more questions if you wish, there are a lot of helpful and knowledable folks here.

And don't forget to post pics afterwards...fourm loves pics.

Tom

Thanks again for your help!

[badddrx7]

I forgot to answer #4 -

You can get these in various lengths. They are high psi and already made up. Call Summit Racing and they will help you with what you need. Here is a 12" length below for an example.




http://store.summitracing.com/defaul...&Ntt=-4an+hose

Tom

[BQuicksilver]

Wow, thanks once again. One last question, who makes the best parts and where do you recommend I purchase from?

[badddrx7]

Summit Racing will have all you need.

If you have trouble getting thru that firewall - write back.



tom