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#1
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Strange problem with tach
Having a weird problem in my 6-speed swapped SVX. The tachometer reads low, sometimes around 2/3rds where it should be and more recently usually about half. (But it still seems to vary, even in the same driving session). Anyone ever experienced something similar?
I'm wondering if there could be a poor connection between the ECU and tachometer that's causing some of the pulses to be dropped? Either that or a problem in the circuitry of either the ECU or the tach causing some of the pulses to either not be sent, or not be received? Or maybe low voltage to some part of the tach causing the response to the pulses not to be as strong as it should? I don't currently have a spare tach to swap in, so any ideas for how it might be fixed or what to look at would be very much appreciated. I have multimeter/soldering iron/etc, and a non-working tach in a spare gauge cluster that might be usable as parts. Or, if anyone has a working one for cheap, that would be great, although it probably wouldn't ship very easily if removed from the gauge cluster, though I suppose I could send the rest of the gauge cluster back. Thanks
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'94 Laguna Blue LSi ~159k.......JDM ultra short-geared 3.900 STi Version 7 6-speed w/ Cobb shortshifter, ECUtune 244,8.1mm/256,9.1mm i/e cams, group N motor mounts, '97 grille, JDM clear corners, Momo JDM Legacy GT steering wheel, apkarian's LED tails, silver STi BBS wheels, PWR radiator, redstuff pads f/r, drilled/slotted rotors, bontragerworks rsb #18, Koni/GC 450f/375r coilovers, Megan Racing adjustable lateral links, KMac c/c plates, Stebro exhaust, ECUtune 1v5, Optima battery in the trunk where it belongs. Turbo project '97 Ebony LSi ~137k #036.......Power mode mod, JDM clear corners, BBS wheels. AUX/pocket mod Now a mod "over there" ............Photo album |
#2
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Re: Strange problem with tach
You have the ECU tuner or similar software don't you? Check the tach on there to see the signal it's getting.
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'92 SVX LS Pearl White - 6mt |
#3
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Re: Strange problem with tach
A couple of years ago, my speedometer failed. Soon after, the tach would struggle to go above 1500 RMP. Not being electronics literate, I replaced the gauge cluster with one with many less miles. All has been well since. I examined the printed circuit board but, could not detect any problems, except, the circuit board was warped. I recorded the difference in mileage and will always disclose the difference if the car is ever sold.
You are far better than me at this but, I took the old gauge cluster apart and could not see any easy way to replace the speedometer or tach. Gene
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Gene and Ben 1992 SVX LS AWD 110K - Liquid Silver 1994 SVX LSi AWD 128K - White Pearl (daily driver) 1994 SVX LSi AWD 95K - Emerald Pearl (sold) 1992 SVX LS-L AWD 115K - Dark Teal 4.44 swap (sold) Last edited by bwb3; 09-24-2013 at 11:44 AM. |
#4
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Re: Strange problem with tach
What is it with these cars clusters and cold weather? Replaced my speedo over a year ago when it started reading off especially in the cold. With these recent cold snaps we've had, now the tach reads nothing to very little during driving. Is it the capacitors or resistors that don't like the cold or what? Lucky I still have the spare tach to replace the current one, but sucks that I have to pull it out again.
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01- Impreza RS Original Owner 92- SVX LS-L |
#5
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Re: Strange problem with tach
What did you do with the yellow (?) cable which gives the erev signal to the TCU? The tach get its signal from the same source. Maybe there's something there.....
You can check the signal with a normal scope - I did, for a different reason, though . /T |
#6
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Re: Strange problem with tach
Hooked up every thing the way it was as I pulled it out. It has something to do with outside temperature, when it's cold it reads low when it's above 60, it seems to read normal.
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01- Impreza RS Original Owner 92- SVX LS-L |
#7
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Re: Strange problem with tach
You may want to check the lubricating grease on the speed sensor itself. It tends to get thick with age and cold weather makes it worse.
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"The things you own end up owning you. It's only after you lose everything that you're free to do anything." 92 Pearl White Ls-l (138k) Euro Headlights & Blinkers, 97 Grill, Euro Tail Lights, SS Brake Lines, Stebro Exhaust, Slotted Rotors, Classic Registration 96 Legacy Outback (206k) 5-speed 2.2 Lightweight Crank Pulley, Group N Trans & Motor Mounts SOLD Wanted: Steering Wheel |
#8
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Re: Strange problem with tach
Wouldn't that effect the speedo only? That part of the cluster is fine.
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01- Impreza RS Original Owner 92- SVX LS-L |
#9
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Re: Strange problem with tach
You're totally correct. My mistake
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"The things you own end up owning you. It's only after you lose everything that you're free to do anything." 92 Pearl White Ls-l (138k) Euro Headlights & Blinkers, 97 Grill, Euro Tail Lights, SS Brake Lines, Stebro Exhaust, Slotted Rotors, Classic Registration 96 Legacy Outback (206k) 5-speed 2.2 Lightweight Crank Pulley, Group N Trans & Motor Mounts SOLD Wanted: Steering Wheel |
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