North American Turbocoupe Organization



tach issues
jamman16 Offline
Junior Member
#1
i recently installed a autometer tach on the steering columb and it reads about half of what it should and never gets over 2k rpm, its wired to the green side of the coil
the stock tach usually takes about a minute before it registers close to the correct rpm and flutters occasionally and won't respond quickly to changes in rpm (rev to 2k or so and it might read 1200 if you hold it there for abit) and sometimes it works perfectly.

so do i have to take out the stock tach for the new one to work proporly or would it be a tfi/pip issue?
86 SVO 2R manual
85 T-Bird TC auto
88 tc auto
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Jeff K Offline
Administrator
#2
If the engine is running good, the problem isnt a PIP/TFI problem. Cound be the new tach is defective. Exactly where do you have the new tech input signal hooked to? Ignition coil negative?
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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5.0TurboCoupe1988 Offline
Posting Freak
#3
are you sure the tach is calibrated for a 4 banger? if i remember correctly, there are extra wires on the back that have to be clipped in order for the tach to be correct for a 4 cylinder.

a tach only counts sparks. if it is set up to divide the sparks by 8 to move the needle, it will show half the RPMS of a 4 banger.
1988 TC 2.3/5-Speed, 148K
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jamman16 Offline
Junior Member
#4
did hook it to coil negitive (green/yellow) dose run good just a concern.

looked up the install instructions, did come set for an 8cyl no wires to swap around just a start-up procedure

Thankyou haden't thought of that Smile
86 SVO 2R manual
85 T-Bird TC auto
88 tc auto
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Joe F Offline
Posting Freak
#5
You might need an Autometer Tach Adapter. I know I did but I also run an MSD ignition setup. If you get really stumped, call the tech support people at Autometer - they're *extremly* helpful in getting you up and running.

HTH
JR's Place - My '87 Turbocoupe
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