Tachometer RPM's Reading Low

elemgee · #1 01-11-2018, 01:47 PM

My 94's tachometer recently started reading low RPM's. At idle, for instance, it reads around 300 rpms. When accelerating, the highest it will read is around 1,400 rpms. The engine runs and sounds fine.

Thought it might be due to the very cold weather we're having here in the northeast but its around 60 degrees today and the problem persists,

Any ideas?

Thanks.

Larry

oab_au · #2 01-11-2018, 02:45 PM

Quote:

Originally Posted by elemgee

My 94's tachometer recently started reading low RPM's. At idle, for instance, it reads around 300 rpms. When accelerating, the highest it will read is around 1,400 rpms. The engine runs and sounds fine.

Thought it might be due to the very cold weather we're having here in the northeast but its around 60 degrees today and the problem persists,

Any ideas?

Thanks.

Larry

Hi Larry, the taco gets it's signal off the ECU, so does all the other units, engine, gearbox, etc, so that should be OK.
It does have a separate ground up behind the dash, or it is seizing up.

gwynethh · #3 01-12-2018, 06:44 AM

Mine is doing the same a bit intermittently. I have a replacement unit ready for install during car work season (July1 to Aug 30 here in New England). Here is a proof of issue video. https://www.youtube.com/watch?v=JMQ1apL_uC4. Keep us informed of your solution.

Levoi · #4 02-01-2018, 07:10 AM

Yes I have the same issue, and also the speedometer is off (to low). 1 speeding ticket as a result so far..
Idle is a very convenient 0 RPM according to the tachometer...I have the idea that this does become somewhat better when driving for a long distance, so bad voltage / ground may be to blame? I don't see how the engine could run fine with a bad ECU, but honestly i'm don't really have a lot of knowledge in that department.
Please keep us posted!

Mike621 · #5 12-23-2021, 12:18 AM

Anyone resolve this issue? I'm having the same symptoms and thinking its something in the cluster.

calisvx · #6 03-03-2024, 04:10 AM

*bump* anyone ever resolve issue Sam having the exact same thing and I have no idea as its intermittent =(

Noriyasu · #7 03-03-2024, 07:47 AM

This is probably a capacitor issue. The life of the electrolytic capacitor on the printed circuit board of the tachometer is about 4000-8000 hours.

I saw a similar topic on this forum recently.