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Tachometer not working properly.

Mon Sep 01, 2014 1:21 pm

The car starts up alright and idles fine, but the tach is reading nearly zero. I hadn't started the car since April but everything was alright then. Went to start it last Monday and the tach wouldn't read. I haven't touched anything under the hood or in the dash. Could it be a bad cluster? It worked fine up until the other day, never had issues with it prior.
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Last edited by RafaCalde on Tue Sep 02, 2014 2:31 am, edited 1 time in total.

Re: Tachometer to working properly.

Tue Sep 02, 2014 1:32 am

For the ST185 (and all 90-93 Celicas), the tachometer is tapped directly into the ignitor in the ignition circuit. So your possible failure points are the gauge itself, a bad connection, or a bad ignitor. The tachometer in my Celica ST went bad earlier this year. It would read about 1/3 of actual engine speed. It went bad after sitting for 6 months, and worked fine before that. So the gauges do go bad. If you get a used cluster, it's very easy to disassemble the cluster and swap the tachometer out. That way, your keep your speedometer and the mileage will still be accurate.

Re: Tachometer not working properly.

Tue Sep 02, 2014 9:25 am

Does it move at all when you rev the car? If it stopped working xompletely I'm not sure. But if it's works just reading low I had that and it was bad capacitors in the tacho

Re: Tachometer not working properly.

Wed Sep 03, 2014 1:21 am

It moves very very little. The car struggles to start as well, but once it does it's perfectly fine. I've to give a few tries before it'll idle normally. Maybe bad ignitor, bad capacitors? How do I check the capacitors?

Re: Tachometer not working properly.

Wed Sep 03, 2014 1:50 am

I do electronics repair as a hobby. You check capacitors by removing them from the circuit (de-solder them) and measure them with an ESR meter. Which isn't really practical...

There are 2 capacitors in the tach (At least in the GT tach I have here). They are 25 volt, 10 micofarad capacitors. The ones I have here are Matsushita (Panasonic) capacitors, which are usually very reliable. However, they are 20+ years old. If you feel like making a road trip to PA or shipping me the tach or cluster, I'm happy to solder in some new ones for you. If you want to make the repair, I'd order these as replacements:

http://www.digikey.com/product-detail/e ... -ND/356116

I'd say the easiest way to test it is to buy a used cluster and swap the tach over. A used cluster would certainly be cheaper than buying an ignitor.

Re: Tachometer not working properly.

Wed Sep 03, 2014 3:08 am

The one yyonline linked to above would be easy to swap in, but if it were mine I would upgrade to a better cap. This one:
http://www.digikey.com/product-detail/e ... ND/3248568
is not a drop in replacement and would require a little "rigging" to use but, being a ceramic cap, it will be more reliable long term.

Re: Tachometer not working properly.

Tue Sep 23, 2014 7:31 pm

I have this issue as well. Revving really high, it measures ~1'000rpm in the cluster. I have 2 gauge clusters so I will try to get some new capacitors in my current one, and be able to test between them all. I simply don't have much money right now so I haven't gotten around to looking into this.

Re: Tachometer not working properly.

Tue Sep 23, 2014 10:31 pm

Brad_91 wrote:I have this issue as well. Revving really high, it measures ~1'000rpm in the cluster. I have 2 gauge clusters so I will try to get some new capacitors in my current one, and be able to test between them all. I simply don't have much money right now so I haven't gotten around to looking into this.


That makes two of us. It's on the "to fix it" list. But since the car isn't on the road anyway, it's not a big deal at the moment. In any case, let me know how it turns out and maybe I could use some of your tricks to fix mine. Or just say screw it and save up for a stacks conversion :D.

Re: Tachometer not working properly.

Tue Sep 23, 2014 11:53 pm

I already said once, but I'm happy to offer my soldering skills to anyone trying to fix up an all-trac or any Celica for that matter. I have a nice Hakko rework station that I use for my side job. I even have the appropriate capacitors in my stash. So if anybody wants to replace capacitors, but isn't up to try it on their own, send me a PM and I'll be happy to help.

Re: Tachometer not working properly.

Mon May 15, 2017 12:39 am

My 1990 celica all trac tach meter is jumping and stuck at 0 to low rpm. I've cleaned out throttle body, replaced the egr valve, TPS sensor and put in new spark plugs with no success. Now that I found this thread, I think I'm running into the same issue. I have a other speedo I'll swap to test at some
Point but I think my tach caps are probably dead too :(

Re: Tachometer not working properly.

Mon May 15, 2017 2:38 am

Replace the caps in the spare cluster before swapping. No reason to risk swapping in another potentially failed one.

These caps are all hitting the end of their life. Its why this issue was unknown 5 years ago but seems to be happening to every owner today. Makes me worry about the other electronics on the system

Re: Tachometer not working properly.

Mon May 15, 2017 4:06 am

mx6er2587 wrote:Replace the caps in the spare cluster before swapping. No reason to risk swapping in another potentially failed one.

These caps are all hitting the end of their life. Its why this issue was unknown 5 years ago but seems to be happening to every owner today. Makes me worry about the other electronics on the system


Yup... I replaced the one in my Celica ST with a working one from a junkyard a few years ago. It worked for another year, then it started doing the same thing. I soldered in some new capacitors and it's good as new now.

Re: Tachometer not working properly.

Mon May 15, 2017 1:57 pm

yeah I've had to repair both of my tracs. The 90s cluster died almost exactly 2 years before the 92s

Re: Tachometer not working properly.

Sun Jun 25, 2017 10:09 pm

How-to with pics

viewtopic.php?f=49&t=48848
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