fuel gauge on schrader valve.

zennx · 08-10-2004, 10:23 PM

Hi guys, i'm trying to diagnose a problem with my mustang. Car seems to have a lack of fuel in 3rd gear. I thought it would be beneficial to run a fp gauge on my schrader valve to monitor the amount of fuel thats coming in. Basically to monitor the strength of my fuel pump.

I found this one online so far...

The only thing that bothers me is that it says it will remove the schrader valve in connect to the fuel line in place of it. I don't want to get that extensive with it. Is there one that can just connect to the schrader valve?

Thanks, Ted

roundman · 08-11-2004, 02:51 PM

This gauge installs down on the fuel line before the fuel pressure regulator and you won't be able to see it while driving the car, so I would think twice about getting it. You could get a good fuel pressure gauge from Autometer and with a hose kit, install it on the cowl area where you can see it while driving the car to better diagnose you fuel problem.

zennx · 08-12-2004, 02:03 AM

Well..... I was thinking about it. The gauge on the schrader valve kind of scares me because they say you have to re-thread it or something and it could possibly leak. If there was one that just connected to it, instead of replacing it, it would be worth it to me because they are only like 20 bucks. I guess it would probably be better in the end just getting a dual gauge pod and getting a FP gauge in there. I already have a really nice air/fuel gauge still I used to have on my camaro.

roundman · 08-12-2004, 01:24 PM

I removed my Schrader valve once when I installed my adjustable fuel pressure regulator and it removes easily with a wrench. the valve has standard tapered pipe threads, forget which size but might be 1/4 or 3/8". My regulator has a pressure gauge port on it and I hooked up my fuel pressure gauge from it rather than the Schrader valve since the hose lenght is shorter from the regulator to the gauge this way. I wouldn't worry about creating a leak, all you need to do is put some teflon tape on the threads when you put the valve back into the block in the fuel line and carefully tighten it down securely. If you choose to get a gauge and want to mount it inside the car, be sure to use a gauge isolator so that you don't have gas running into the interior of your car as this is a big safety hazard.
If you really think you need more fuel, then I would suggest you get an adjustable fuel pressure regulator and gauge so you can play with the pressure while using you air/fuel gauge to see how rich/lean your engine is running. You can get a regulator for $80-$110 and a gauge with SS hose for another $80 or so. Autometer sells a high pressure isolator for about $95 in the Summit catalog.

zennx · 08-13-2004, 02:39 AM

Thanks a lot roundman! Good info. For some reason my car bogs down in 3rd a little bit like it's not getting enough fuel, and lately it's been feeling kind of sluggish. I havent had a chance to do a plug/wire change on it yet but I'm getting ready to, i been so busy with parting out my old car. I also have a walboro 255lph pump from my old car I could use in this one but I think it might be a little too big. I don't want the regulator to work over time to send all the unused fuel back, plus am I wrong when I say that with more fuel returning all the time it could carry some crud back to the tank? Anyway just wanted to keep a check for now on the FP level to make sure everything is good. Thanks for the help again.

Ted

roundman · 08-13-2004, 12:04 PM

Do the plug and wire change as soon as possible before you do anything else. you might also check/replace the distributor cap and rotor also. use some silicone di-electric grease on both ends of the plug wires too to seal out moisture from the connections and prevent corrosion too. then see if it still feels sluggish in 3rd gear. the bigger pump you have will not be a problem for the fuel pressure regulator and there shouldn't be any crud in the lines to flush back into the tank since the in-line fuel filter is in place between the pump and the fuel rails and injectors. if anything plugs, it will be the injectors as they have the smallest orifice (hole) in them. and a higher flow through the lines will help keep the lines cleaner too. it wouldn't hurt to change the fuel filter when you change the plugs either.

Fishhawk · 08-14-2004, 01:09 AM

I don't now if your problem is similiar, but after finishing the mods on my GT I installed a higher flowing mechanical fuel pump, 7.5-8.5 psi. at 120 GPH. Took the car to the track and found that first and second gears ran throught the RPM's fine. Shifted into third and the car bogged at around 4000 RPM. I believe that the stock fuel line from the gas tank to my fuel pump is to small (5/16th). I think the high flow pump was sucking the line dry in the first two gears and by the time I climbed the RPM's in third there was nothing left. After I came to the end of the track the motor was running fine. My plan now is to increase the size of the line to 1/2".

roundman · 08-14-2004, 02:07 PM

http://www.barrygrant.com/bgfuel/default.aspx?page=81

Check out this web page and read the section entitled fuel can test, it is very good information and will help you decide how big a pump and lines you really need to supply the fuel to your engine.