Sporadic tachometer jumping?

2008 TOYOTA COROLLA
297,444 MILES • 4 CYL • FWD • AUTOMATIC
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KIM NUTT JONES
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Tachometer wants to jump up and down when engine is first started and also while this happens, temp gauge does not work and if i turn A/C on while this is going on it blows warm air. This only happens for about two or three minutes then when engine warms everything starts working correctly. I checked under hood while it was happening and the only thing i see and hear that is out of ordinary is down where the A/C pulley is, the metal seems to jump in and out against the pulley that the belt runs on. It will click loudly and seems to create a friction that in turn makes my rpm's jump. Was wondering if A/C condenser clutch is sticking causing the other problems or if tachometer is bad or has an electrical issue somewhere? Maybe MAF sensor needs cleaning? This car has been a great vehicle. All i have had to do is general maintenance. Also, my check engine light came on three weeks ago. had it tested. O2 sensor needs replacing. Bank 2.

Well, tachometer has not jumped at all today. Why? Got me. Even turning on air conditioner did not cause anything. Here is a video of what it sounds like running today upon first start of day. Oh well, I did clean mass air flow sensor changed oil and air filter. Priced condenser and clutch assembly and o2 sensors. Haha just in case! Oh and also replaced a faulty headlight socket that was burned up.
Sep 1, 2017 at 12:15 PM
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STRAILER
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It sounds like the air conditioner system is over or under charged. Here is a guide that will help see if we are on the right track.

https://www.2carpros.com/articles/re-charge-an-air-conditioner-system

If the system has too much or too little freon it will cause the compressor to cycle or try and lock up. If the clutch coil is shorted will strain the electrical system and cause the problem you have described. Does it act normal when the ac is off?

Please let us know what you find.

Cheers, Ken
Sep 4, 2017 at 7:55 PM
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ARISLEONARDVENUS
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Good day! My Corolla GLi 1993 model EFi 4afe engine has a very low RPM gauge level 100 almost down to zero. When I turn on the a/c the rpm level is steady to 100 and the engine never stops even in full stop. I hope you can help me with this problem, Normally the rpm should be in 800 in normal idling condition but my corolla is down to 100. When I revolution the rpm hardly goes up. Thak you so much for your help.


https://www.2carpros.com/forum/automotive_pictures/271000_25022008257_1.jpg

Sep 11, 2020 at 1:42 PM (Merged)
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MMPRINCE4000
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Remove and clean the idle air control valve, and clean the throttle body.

It would be unusual for a car to idle steadily at 100rpm.
Sep 11, 2020 at 1:42 PM (Merged)
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ARISLEONARDVENUS
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[quote:24aef01433="mmprince4000"]Remove and clean the idle air control valve, and clean the throttle body.

It would be unusual for a car to idle steadily at 100rpm.[/quote:24aef01433]

Good day to you,

Thanks for answering to my queries, I just finished removing and cleaning the throttle body and the IAC valve attached to the TB. I removed all the dirts, carbon and oil with a 3M carb cleaner and it did a good job. My RPM had gone up to 600 but I feel like I have a high idling even if the rpm level only says 600. The engine is not idling normally. Please advise on what to do next.

Thanks again.
Sep 11, 2020 at 1:42 PM (Merged)
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MMPRINCE4000
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Normal idle speed would be 650-750rpm.

The IAC controls idle speed by moving a pintle in and out of the TB allowing more or less air into engine.

If you are using the instrument panel tach. to gauge RPM, your tach may be off.

Best thing is to find a scan tool and read what the ECM is seeing as the RPM.
Sep 11, 2020 at 1:43 PM (Merged)
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ARISLEONARDVENUS
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[quote:5a3a7cd345="mmprince4000"]Normal idle speed would be 650-750rpm.

The IAC controls idle speed by moving a pintle in and out of the TB allowing more or less air into engine.

If you are using the instrument panel tach. to gauge RPM, your tach may be off.

Best thing is to find a scan tool and read what the ECM is seeing as the RPM.[/quote:5a3a7cd345]


Thank you for your prompt response. I tried to test drive for an hour and observe the RPM, I observed that when the engine is thoroughly heated up, the idle speed is 800. Now I think I have to bring my car to a service center coz I dont have a scan tool and check the timing as well.

Is there a fuel injection cleaner? What would you recommend? please advise also on how to apply it.

You've been so helpful, I cant thank you enough for evertyhing but Thank you so much.
Sep 11, 2020 at 1:43 PM (Merged)
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MMPRINCE4000
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Most FI cleaners will do the job, added to gas tank according to instructions.
Sep 11, 2020 at 1:43 PM (Merged)
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ARISLEONARDVENUS
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[quote:43808fa030="mmprince4000"]Most FI cleaners will do the job, added to gas tank according to instructions.[/quote:43808fa030]

Hi Bob, Ken and all of the 2 Carpros team!

Thank you so much guys! I was able to save time, money and at the same time...learn more about my car! More power to y'all.

Best Regards.

Aris Leonard Venus
Sep 11, 2020 at 1:43 PM (Merged)
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AUNT1
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Replace the 2 pcs Capacitor on the tachometer circuit with value of 10uf/25V. That will solve your problem, done it also with my 1994 Toyota Corolla GLi 4AFE Engine manual Tranny.
Sep 11, 2020 at 1:43 PM (Merged)
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IAMJR200
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My car's rpm gauge stuck only on 800. If I turn on the key it will go to 800 but it will turn to zero if engine off.
Thanks in advance.
Sep 11, 2020 at 1:43 PM (Merged)
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STEVE W.
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That sounds like the stepper motor that moves the needle in the cluster has failed. There are places that will rebuild the cluster but it can cost as much or more than a used cluster in an older vehicle. Being a 1993 it will not interface with the cheaper scan tools that work on 1996 and up cars. You need the older system that Toyota used to be able to verify that the tachometer is getting the correct signal prior to removing it for repair.
Sep 11, 2020 at 1:43 PM (Merged)
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KEAHKINTANA
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I have a 1992 Toyota Corolla GLi with Engine 4AFE

totality of the car is good its just the stock tachometer or RPM not working. I needed the tachometer to monitor majority of my cars performance.

I don't know where to begin or how to end this problem. Please don't give Ideas like replace the whole console, put another TAch or replace the whole car.

can anyone help me on this . . . I've got a few knowledge in car electrical
Sep 11, 2020 at 1:43 PM (Merged)
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KHLOW2008
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First thing you need to to check is if the distributor is providing the signal to the tachometer.
If it is, then you need to check the continuity to the tachometer and if continuity is good and you are getting a pulse while engine is running, most probably you need a new tachometer.
Sep 11, 2020 at 1:43 PM (Merged)
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JNETT
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Hi, I have noticed that lately, the tachometer needle twitches randomly, during idle only (usually at stop lights, etc. so she's been driven and is warmed up). The twitch is usually only between 1,000-1,500; but sometimes jumps to over 2,500. I'm not noticing a big difference in how the engine operates when it's jumping up, but on a few occasions it sinks a little below idle, and the engine feels as if it might stall... So I'm keeping my foot gently resting on the throttle, and an eye on the needle. just in case! I've read it could be the igniter, sparks, battery, distributor? My veteran mechanic thinks it's just an electrical glitch and not to worry, but as I can't see him at the mechanic to try an alleviate the issue? Thanks in advance! Cheers! JS ;)
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Sep 11, 2020 at 1:43 PM (Merged)
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JACOBANDNICKOLAS
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Hi,

I recognize this car! LOL I hope you are well during these trying times.

As far as the needle, there is a tachometer drive module, but it isn't something that is serviceable. Is the engine at all affected when this happens?

Joe
Sep 11, 2020 at 1:43 PM (Merged)
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JNETT
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HI Jacob/Nicholas, we're doing okay over here in Australia. hope you're well in the US! Thanks for the reply. as mentioned in the original post.."I'm not noticing a big difference in how the engine operates when it's jumping up, but on a few occasions it sinks a little below idle, and the engine feels as if it might stall." As I'm not a mechanic, I would like know if there are easy checks I can make to rule out anything potentially disruptive? JS ;)
Sep 11, 2020 at 1:43 PM (Merged)
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JACOBANDNICKOLAS
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Hi,

The idea that it is erratic does seem as though it is an electrical issue. The only thing that could be checked would be the tachometer drive module, and in all honesty, I don't think it could be done at home.

I hate to say it, but I suspect you will need to wait until it gets worse to honestly determine what causes is. I don't feel it is anything to worry about at this time. Let me know if it gets worse or if yo have other questions.

Take care,
Joe
Sep 11, 2020 at 1:43 PM (Merged)
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DAVIDHEWES
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The indicator needle on my Toyota Corolla ( 5 years old ) is stuck underneath the pin it rests on so it cannot register the revs when I am driving. How do I put this right?
Sep 11, 2020 at 1:43 PM (Merged)
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KNIGHTRIDERKITT2000
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could remove the instrument cluster and disassemble to put the needle back in the right spot, or drill a small hole and use a stiff wire near the edge of the plastic cover to pull needle up and over
Sep 11, 2020 at 1:43 PM (Merged)
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KNIGHTRIDERKITT2000
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also its quite possible needle is broken by now also.
Sep 11, 2020 at 1:43 PM (Merged)