North American Turbocoupe Organization



Fuel Selector Switch troubleshooting?
G-Rage Offline
Junior Member
#1
Please don't flame for not searching, I did and found nothing.

Any tips on trouble shooting the fuel switch?
My 87 is set on premium but no light is on. possibly a dead led but I was hoping there were some tips on how to tell if its truly operating correctly or not.
Car with 45K miles basically sat in storage for many years until I picked it up in Nov '16 so there is no telling what all is hosed up....

87 Black 5 spd, 45K "original" miles, all original non modified survivor.
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Jeff K Offline
Administrator
#2
The indicator light is not an LED, it is just a regular very small light bulb, which can burn out.

With switch in regular position, max boost will be around 9 psi under WOT.Switch in premium will allow max boost of 14 psi.

Drop the glove box door. On the upper right, you will see a small blue relay. This is the premium fuel relay. With the key in RUN, and in a quiet environment, grab the relay and flip the switch from reg to premium. You should be able to feel the relay click, and maybe hear it click. If relay clicks, the switch itself is working correctly.
Jeff Korn

88 Turbo Coupe: Intake and exhaust mods, T3 turbo at 24 psi, forced air IC, water injection, BPV, Ranger cam, subframes, etc., etc.
86 Tbird 5.0 (original owner): intake, exhaust, valvetrain mods, 100 HP N2O, ignition, gears, suspension, etc., etc.
05 Taurus SEL Duratec daily driver
04 Taurus Duratec (wifes car)
02 Pontiac Grand Prix GT
95 Taurus GL Vulcan winter beater
67 Honda 450 Super Sport - completely customized
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G-Rage Offline
Junior Member
#3
Jeff can I put you on retainer ?
hell, how much to fly you in for a week ?
87 Black 5 spd, 45K "original" miles, all original non modified survivor.
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Jeff K Offline
Administrator
#4
Haha!

FYI, I misspoke....the blue relay is upper LEFT of the glove box opening, not the upper right! Sorry for the confusion.
Jeff Korn

88 Turbo Coupe: Intake and exhaust mods, T3 turbo at 24 psi, forced air IC, water injection, BPV, Ranger cam, subframes, etc., etc.
86 Tbird 5.0 (original owner): intake, exhaust, valvetrain mods, 100 HP N2O, ignition, gears, suspension, etc., etc.
05 Taurus SEL Duratec daily driver
04 Taurus Duratec (wifes car)
02 Pontiac Grand Prix GT
95 Taurus GL Vulcan winter beater
67 Honda 450 Super Sport - completely customized
Reply

G-Rage Offline
Junior Member
#5
How about lower left? The only blue item was there. No click heard.
Just installed Gillis valve.
Even at 15 +\- psi the engine seems to stumble at WOT
This is why I was wondering if premium switch has the timing advanced.
I’m running ethanol free 93 fuel.

87 Black 5 spd, 45K "original" miles, all original non modified survivor.
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Jeff K Offline
Administrator
#6
Switch has 3 terminals. Ground, +12 V hot in RUN, and +12 V when switch is in premium mode. The +12 V to switch is supplied by the same circuit that powers the speedo and tach. If speedo and tach work, switch should have power. Check with a test light. Use a DMM on ohms to be sure the switch has ground. All the ground does is provide a ground for the bulb in the switch. Check at blue relay to be sure one terminal has +12 V from switch with switch in premium position. One relay terminal should be grounded.
Jeff Korn

88 Turbo Coupe: Intake and exhaust mods, T3 turbo at 24 psi, forced air IC, water injection, BPV, Ranger cam, subframes, etc., etc.
86 Tbird 5.0 (original owner): intake, exhaust, valvetrain mods, 100 HP N2O, ignition, gears, suspension, etc., etc.
05 Taurus SEL Duratec daily driver
04 Taurus Duratec (wifes car)
02 Pontiac Grand Prix GT
95 Taurus GL Vulcan winter beater
67 Honda 450 Super Sport - completely customized
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