North American Turbocoupe Organization

Electrical Question
Gary S Offline
On the way back from Carlisle I noticed that my oil pressure gauge and my water temperature gauge were reading extremely low. However, my check engine oil light on the sentry board (the one under the radio) did not light up. Is the check engine oil light and the oil pressure gauge on the same circuit or a different circuit. I know I have a faulty IVR but I also don't want to scatter my engine all over the road. The IVR has been bad for a long time (the gas gauge, oil pressure gauge, and fuel gauge all peg on high when the headlights come on).
NATO Member
1987 Turbocoupe
168,000 Miles
5 Speed
Black w/Raven Interior

Pete D Offline
The "check oil" light on the sentry board relates to the amount of oil in the pan and is not related to actual oil pressure with the engine running. It gets it's information from the sensor in the driver's side of the pan, above the drain plug. I'm going to say that it has no direct bearing on the oil pressure gauge, they are not on the same circuit as they measure two different variables.

I have seen the oil pressure sensor fail in such a way that it reads lower and lower as it progressively fails. Try removing and replacing the wire lead on both the oil pressure sensor and the temp gauge sensor (driver's side of engine) a few times each to clean the connection. A bad (corroded) connection can cause low readings. If that doesn't fix it, I'd say change the IVR first to get past that issue. If the gauges still read low after that, it could be the sensor(s) or the gauges
Pete Dunham


Jeff K Offline
^^^^ +1

I have had poor / corroded connections at the OP and temp sensors in the past. I have also seen the OP sender start to fail and give low readings once many years ago on another Ford that uses the same OP sender as the TC does.
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.
11 Crown Vic Interceptor
14 Toyota Camry (wifes car)
95 Taurus GL Vulcan winter beater
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jmthunderbirdturbo Offline
Posting Freak
hmm, when the one on my 86 failed, it failed higher and higher, till it pegged. id start with IVR, but even if that fixes the issue, the factory gauges are awful. a decent 3 pod set with OP, WT, and voltage (amps is useless) can save you hours of questioning the factory 'guessing needles'.

my dad says the gauges in fords are as accurate as dousing rods.

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1988 TC 5MT-Blue/Blue check-off car. resto-project.
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