Tachometer not working properly.

RafaCalde

New member
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.
 

yyonline

Member
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.
 

aus jd 2703

New member
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
 

RafaCalde

New member
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?
 

yyonline

Member
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.
 

Brad_91

New member
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.
 

RafaCalde

New member
Brad_91":3m1ydrzz said:
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.
 

yyonline

Member
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.
 

GT4ZBoy

New member
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 :(
 

mx6er2587

New member
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
 

yyonline

Member
mx6er2587":1c88o803 said:
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.
 
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