ArdWrknTrk Posted April 15, 2020 Share Posted April 15, 2020 If I buy a fuel pressure tester, is there a easy place to plug it into the fuel system? A cheap fuel gauge intended for carburetors is all you need. Mine cost under $10 Just disconnect the line to the carburetor and connect the gauge. Flip the switch and see what it reads. Unlike a stock system there's no safeties to bypass. Okay, i think i might have a fuel pressure gauge somewhere in my garage. I will look around and see if i can find it. Unfortunately I have to work today (from home) so I wont have time to pull the truck in the garage today. Will get back it to it tomorrow and see if i can find that gauge and a place to hook it up. Will report back then. I see the return line hooked up to the rear tank so you're going to have to connect where the carburetor is, to get a true reading. Most gauges today read to 100. Looking for 5 is not going to be accurate. A cheap 0-15 psi gauge is the *WTG. Link to comment Share on other sites More sharing options...
85lebaront2 Posted April 15, 2020 Share Posted April 15, 2020 I guess that is the pump relay! I'm seeing in the 1986 EVTM that there is no selector relay. Everything goes right through the switch. (This system morphed over the years, and I don't have the '85 document) Have a look here 1986 electric fuel pump control for how that's wired. Fuel tank selector on pg 97 Jim, you are correct in the fact that the system morphed, it changed several times. The 1985 system does have a fuel tank selector relay, that diagram can be found here: http://www.garysgaragemahal.com/electric-fuel-pump-control1.html It still uses the big tank selector valve, but the relay is for the pumps, red for front tank pump and brown/white for rear tank pump. The fuel pump cutoff relay is controlled by the oil pressure switch same as the 1986 system. Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted April 15, 2020 Share Posted April 15, 2020 Jim, you are correct in the fact that the system morphed, it changed several times. The 1985 system does have a fuel tank selector relay, that diagram can be found here: http://www.garysgaragemahal.com/electric-fuel-pump-control1.html It still uses the big tank selector valve, but the relay is for the pumps, red for front tank pump and brown/white for rear tank pump. The fuel pump cutoff relay is controlled by the oil pressure switch same as the 1986 system. Well, that's embarrassing! I didn't even see the 1985 EVTM when I went looking for a diagram... When they say 'upper left corner', where exactly is it? I feel better that I'm not going crazy when I think there's a selector relay for hot fuel in '85. Thank you for pointing out that page, Bill! Link to comment Share on other sites More sharing options...
85lebaront2 Posted April 15, 2020 Share Posted April 15, 2020 Well, that's embarrassing! I didn't even see the 1985 EVTM when I went looking for a diagram... When they say 'upper left corner', where exactly is it? I feel better that I'm not going crazy when I think there's a selector relay for hot fuel in '85. Thank you for pointing out that page, Bill! Always glad to help Jim, after all a 22" monitor is a lot better than a phone screen. Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted April 16, 2020 Share Posted April 16, 2020 Always glad to help Jim, after all a 22" monitor is a lot better than a phone screen. Bill, after owning a tune up shop all those years you're the one who could really help this man. Link to comment Share on other sites More sharing options...
85lebaront2 Posted April 16, 2020 Share Posted April 16, 2020 Bill, after owning a tune up shop all those years you're the one who could really help this man. Yes, but he needs to first get the fuel pressure issue resolved. I had already suggested getting it on an ignition scope and walked him through some of the tests needed. Link to comment Share on other sites More sharing options...
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