LeftTurn1LE

I was installing my 100 psi electric fuel pressure guage from Autometer today. Has anyone done this before? It seems I need an adapter between the NPT sender and the schrader valve. I think I need part 3280(the one on the right) from Autometer, but I'm not sure. Its a 91 TPI. Also, has anyone had trouble with clearance between the sender and plenum? It looks like a tight fit. Thanks.

Ed Maher

You need one of the things on the left.

And you also need to make a tube with flares on both ends to hook to the port and the adapter. And you need a NPT sleeve to connect the adapter to the sender.

And you decore the valve with a regular valve decoring tool or small screw drivers.

There are pics of how i mounted my sender on my webpage.

LeftTurn1LE

Hmm. Its hard to tell in your pictures. The one on the left is for a mechanical gauges right? Does the sender replace the Schrader or are they both used? Can I get all that stuff from a local hardware store? Its getting too late to think, I'll have to look at it again in the morning.

LeftTurn1LE

Okay I contacted Autometer and they gave me two bogus part numbers for Summit.(923104 and 991001) I can't find a piece like that at any automotive or hardware stores.

Someone correct me if I'm wrong. The fitting on the right would go directly in the fuel rail replacing the Schrader valve. Then the sender would just go into that fitting and the Schrader would no longer be needed.

I know there are more people with this guage in thier cars. I'm sending an email to Summit tonight to see what they say I need.

MikeT 88IROC350

I am going thru this same ordeal. Just that I have a little 1.5" mech Autometer gage to install.
I found some brass adaptors from work to install mine. One just like your left pic, except it has a female 1/8" NPT. I put that right on the little gage. Now I need to make a very short tube with 1/8" flares on both ends. The flare will mate up directly with the schader valve. Just have to de-core it like Ed says. I going to try and make a short tube out of 1/4" (OD??) tubing at work. We got a nice bender so I hope I can make it clear everything. The schrader valve should not be replaced. It has some odd threads going into the fuel rail.

Ed Maher

Just to make sure you're clear on the parts needed:

There are exactly 5 pieces of hardware between the fuel rail and my sender

1/4" brass tube, bent to fit

2 x 1/4" flare nuts (for the ends of the tube)

1/4" flare to 1/8 NPT male adapter (the piece on the left in that pic)

1/8 NPT femle-female collar

All of which can be purchased for a few bucks at home depot. If you don't have a tubing bender and a flare tool, you'll need those too. Don't forget thread tape on the pipe fittings, and the flare fittings are left dry/clean.

MikeT 88IROC350

Okay, got my AM fuel pressure guage installed tonight. Came out real good. Basically did like Ed described. Here it is:

Used about a 2-2.5" by 1/4" copper tube, with the 1/4 flares (brass) on both ends. Bent tube slightly so guage faces front of car, near runner.

Used a 1/4" flare TO 1/8" NPT FEMALE (brass) adaptor to connect to the guage. My AM 0-60 guage has just a male 1/8" NPT on it.

That's it!! Looks great, no leaks so far. Easily clears everything, made it so it doesn't even hit the vac line. Should be a snap to make FP changes. The guage did read about 1 psi lower than my portable test guage read, at least the last time I used it.

I will try to snag a digital camera and take some shots, and post here.

LeftTurn1LE

Okay I was getting confused on why all the extra parts were needed, but I think I understand now. I still think that one fitting is all I need, but at $7 plus shipping and about a week of waiting, its cheaper and faster to use the other parts.

MikeT 88IROC350

Okay here is a picture of my gauge installed. I think it came out ok.

By the way, the gauge cost was 29.99, and the hardware was free, borrowed from work!

LeftTurn1LE

The guy at Summit figured out what those other P/N's were for. One was a swivel fitting that costs $20. No way I'm buying that!

MikeT, thats a nice clean looking install.

BOTTLEDZ28

iTrader: (9)

i went through all that crap when installing my little fuel pressure gauge as well. i went to my local peformance shop and the guy just ordered me some Russel fittings and it looks great. well, yesterday I bought a 2 5/8 Phantom mechanical fuel pressure gauge and it already has a 4AN fitting on the gauge. I just used a NOS 4AN line to connect it to the shrader valve. I guess automter now sells gauges with AN fittings on the back of them. there was a sticker on the box that said " new design requires AN fitting and line"

89 Iroc Z

How did you mount it on the fuel rail? Did you replace the stock check valve with an adapter that doesn't have a valve or did you drill out the valve in the stock connector?

Also is that just copper pipe?

BOTTLEDZ28

iTrader: (9)

Drill?? there aint no drilling required to mount a fuel pressure gauge. take the black cap off the shrader valve and then remove the valve stem inside the valve. the stem is removed the same way you remove a valve stem on a rim. go to autozone and see if they have the tool to do it. DO NOT put pliers in there to try and remove it. you will end up ruining it.Once the stem in out you are going to need a 1/8NPT to 4AN adapter to mount the gauge. Accell sells the perfect elbow for this job and they put it in there kit when you buy there gauge.

here is the ad for the Accel gauge at Jegs:
For use with OEM or aftermarket multiport fuel injection systems. Reads to 60psi in one-psi increments for periodic inspection or regulator adjustment. Easily mounts to pressure checking valve on GM TPI fuel rail with supplied fittings
part #310-74726 1990-92 TPI $ 59.99
part #310-74745 1985-89 TPI $ 49.99

MikeT 88IROC350

Yep, just 1/4" copper tubing. I bent it up and made the flare ends at work, since we had all the tools. The fittings are brass. But now I am thinking about those made up Russel fittings. I have a fuel leak now with this gauge. I didn't think it was the flares, so I pulled it off today and re-did the seal from the 1/8"NPT male on the gauge, to my female brass fitting. I used just Teflon tape the first time. Maybe it don't like high-test fuel. So I put some gooey Napa teflon thread sealer on it, and now it leaks worse!!

I wonder if I damged the gauge just tightening it down? Can't really tell where it is coming from. Fuel was running down the copper tube steadily, after car was shut down. I pulled the whole thing. I might take it to work and put some air pressure to it just to fine out the leak. I will have to put the valve core back in before I run the car!!

BottleZ, can you get just the elbow from the Accel gauge? My gauge had no hardware with it.

Bort62

The key with that Thread sealer, weather it be The Goop or tape, is you Cannot turn it back...

Meaning, As your tightening, if you back it off ( loosen ) it a little to get the gauge to point the right way or something, its going to leak.

The Pipe Dope has always worked well for me, I don't like the teflon Tape.


TFE pipe thread compound.

MikeT 88IROC350

I installed the flare fitting to the 1/8"NPT on the gauge first, then adjusted the postion with the flares. They don't need any sealant, and kind of act like swivels. Maybe when I tightend down the fitting to the gauge (second time), with the thread dope, I hurt the gage somehow?
I know the teflon thread dope is good stuff!

Bort62

did you tighten it by the gauge, or with a wrench under the gauge on the little nut it should have ?

It you just muscled the gauge till it was tight, I would say you have a 99% chance of causing a leak

89 Iroc Z

so what is the size of the fitting on the fuel rail?

Ed Maher

You can wear out a flare when you tighten it down too much (or too tight) Basically you're relying on the compression of the tube in the flare part to act as your seal. Once you tighten that too much, or too many times, it's flattened and can't do it's job. Thats why double flare is also around, since it has 2 layers of metal to compress/seal with it's more serviceable than normal flare.

Ed Maher

The nipple is 1/4" flare

MikeT 88IROC350

NO, I used a 7/16" box end wrench to hold the gauge when tightening the fitting to it. But after what Ed said, maybe I need to make a new copper flare tube. I am going to put some air pressure to it, to look for the location of the leak. I'm not an expert at making up the flare ends, so maybe it just wasn't perfect to begin with.

BOTTLEDZ28

iTrader: (9)

Ed Maher,
89 iroc z asked what size the fitting is on the fuel rail. you say 1/4" flare but its a -4AN fitting. when ever you get a nitrous kit it always has a AN hose to tap into the shrader valve. some pipe threads and an threads are very close and fell like they fit but there not right. i have a 2 5/8" auto meter gauge hook up to mine with a 4AN braided NOS line.

Mike T, I an not sure if you can just buy the elbow from Accell, try emailing them or calling them and se what they say. tell them you bought a gauge and the elbow supplied leaks. they may just send you a "replacement" free of charge.

Ed Maher

Hmmm, a normal 45' flare works perfect for me, if it wasn't right, it would not seal, and it's been on there for well over a year now, and has even been removed once. Are you sure those nitrous kits aren't including an adapter end to put the 4AN line on a 1/4 flare?

BOTTLEDZ28

iTrader: (9)

the line has an AN fitting on it with no adapters. i have put many AN lines on the shrader valve and have had no problems or leaks at all

MikeT 88IROC350

My gauge is an Autometer SportComp. It came with no hardware or fittings. I made up the adaptor from pieces at work. I don't think it leaked near the Schrader valve. I am going to rig up and adaptor to put air pressure to the whole assy, to try and locate the leak.

I actually hope it is one of the flares leaking, that way I could easily make a new tube with new flare ends.

IROCZZ3

BOTTLEDZr28 is correct...the schrader valve fitting is -4 AN. Most likely your leak is at the flare. AN fittings are flared at 37*...normal flares are at 45*. You can easily see the potential for leaks with the mismatched flare ends. When properly flared and matched you should not need any sealants except on pipe thread fittings. IIRC, the proper AN flaring tool is expensive but is the way to go if you want to use hard line. Otherwise, you could use a short length of -4 AN braided line and attach the gauge to the firewall.

The setup I had a long time ago was what I described above (gauge mounted on firewall). The ONLY adapter I used was a female 1/8" NPT to -4 AN male adapter for the gauge. Then I used about a foot long -4 AN braided hose (courtesy of the Air Force) from the schrader valve to the gauge. Never had any leaks.

LeftTurn1LE

Man this has been nothing but trouble for me. You were right Ed, there is no way around using all that stuff. I searched all day again today and only found one place with the 1/4" flare fittings. I also bought a crappy flare tool for $8 that already fell apart twice. Its going back to the store tomorrow. The 1/4" flare seems to fit fine on the schrader valve but not on the sender. I still need the 1/4" flare to 1/8" NPT adapter, and I'll be ready to go. The people at Autometer are crazy to think those two parts were all I needed.

BOTTLEDZ28

iTrader: (9)

leftturn1le, DO NOT put the 1/8 fitting on the shrader valve!!!!it does not work right. you will end up with leaks!!!!dont you have any performance shops in your area that can order you an AN line. i am in the middle of hooking up my custom nitrous kit and I am sure of what size the shrader valve is.

LeftTurn1LE

Hmm, you mean 1/4? Yes, theres a speed shop in Muncie, but it wasn't open today. They probably have the fitting there without ordering it. I'll give it a try since I won't be finished til tomorrow anyway, and whats one more fitting after everthing I've bought so far right.

LeftTurn1LE

Okay, what exactly is the sender, I mean which fitting goes on there. The 1/8" NPT only threads about half way on. Is this right or is the sender a -4 AN thread too? If its 1/8, where can I get a -4 AN to 1/8 adapter. You guys are using some fancy stuff that I just can't find in hardware stores around here. Even the speed shop doesn't have some of these.

89 Iroc Z

This is probably a stupid question but is Teflon tape fuel safe? As in will fuel eat away at Teflon?

BOTTLEDZ28

iTrader: (9)

dude stop messing with all the fittings and just call Accell and get the one they put in the fuel pressure gauge kit. I am sure tey sell it sepertaly if you tell them you need it. by the time you get the right fitting and adapters, you will end up spending $50 and have a speggetti mess

Desert86Roc

I found it much easier just to use a NPT to AN 90* adapter for the fuel rail, then put whatever you want on the AN end.

In the picture below...the 1st is what I used when I wanted to have both nitrous lines and fuel pressure gauge attached at the fuel rail. You would only need the 90* fitting and then whatever line you were using.

Also...you dont use teflon or any sealant on AN adapters... just the regular threaded portions (as in the fuel rail log below).

MikeT 88IROC350

Well glad to see that I am not the only one with problems. Tonight I found the source of my fuel leak. Rigged a male 1/4 flare to my air line, then did a soapy water bubble leak test. Found more than one leak. At least my gauge is ok. Big leak coming out the 1/8"NPT between my gauge and the female brass adaptor. Guess I didn't seal it good enough with the Teflon thread dope. Also looked like I got a poor flare, so I cleaned it up a bit.

I gooped up the threads real good this time, and I'm letting it set a day before sticking it on the fuel rail. Does the Teflon need to cure? I will do another bubble check before install. If it still leaks, I'll have to make up another copper tube with flares.

I also wonder about Teflon tape on fuel lines, is the dope better? The tape works good on air lines.

Desert86Roc

Liquid Teflon? What kind are you using? Teflon tape is much much neater.

LeftTurn1LE

I'm using an electric guage with a sender. The sender is 1/8" NPT. I would need the adapter anyway.

MikeT 88IROC350

Well I still got fuel leaks with my homemade adaptor. I made up a new 1/4" copper tube with 45' brass flares. I thought I had it sealed, did a water leak test. But when I mounted it up on the rail, and fired the moter, got some fuel dribbling down. So I gave up on it for now.

Need to get purpose-built adaptor purchased I guess. Anyone know a good source, IE Russel, Aeroquip, or other?

89ProchargedROC

www.anplumbing.com

cheapest parts around that i can find and just about anything you'll ever need

89 Iroc Z

Wow, this site sells some nice stuff are great prices.

MikeT 88IROC350

Yep, great site for an adaptors. I found at least 2 pieces that will work for me. Got to get an order in now.