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RPM GAUGE IS OFF

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Old 11-18-2012, 05:02 PM
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Car: 1991 firebird
Engine: 305 tbi
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RPM GAUGE IS OFF

i NEED HELP MY RPM gauge is about 1300 off, i have no idea how to get it but when im idling its not rev-up high... sound normal but its holding at 2000, i am seeing 6000 when i shift gears when it should be what 3000?

somone help please

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Old 11-18-2012, 06:38 PM
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Re: RPM GAUGE IS OFF

Soudns like the gauge is wrong/bad, especially if the car runs well. How about when you're driving, doe the RPM gauge ever go over 2000?
Old 11-18-2012, 07:21 PM
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Re: RPM GAUGE IS OFF

When did this start? Was it reading correctly prior to replacing something? Did you replace anything before it started reading incorrectly? Gauge? Transmission? Rear end? Wheels/Tires? Do you know if it is actually reading incorrect?
Old 11-18-2012, 08:51 PM
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Re: RPM GAUGE IS OFF

If it's an electronic, rather than mechanical, tacho you'll probably find one of the capacitors had dies from old age.

Do a search, there are threads that explain how to repair it. Parts cost 50c.
Old 11-19-2012, 05:49 PM
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Re: RPM GAUGE IS OFF

I dnt know i just got the car, and it doenst rev high, but the tach reads 3000 when i start it, then it shifts in the 6000, when i turn off the car it stays at 2000, i have to turn the key back on to drop to 0, then once in the off position it comes back up to 2000.
Old 11-19-2012, 05:51 PM
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Re: RPM GAUGE IS OFF

where are these capacitors? i am new to this, ive had a few when i was younger, and always like the car.... just bought it off some kid, sunk 2400 into the transmission the 2nd day,.. but it was doing it before that. i thought it would be better since the trany rebuild but its not.
Old 11-19-2012, 06:06 PM
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Re: RPM GAUGE IS OFF

You'd need to remove the gauge cluster and replace a capacitor that is soldered into a printed circuit board on the rear.

Your transmission does not affect the tacho.
Old 11-20-2012, 04:48 AM
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Re: RPM GAUGE IS OFF

Originally Posted by peterc005
You'd need to remove the gauge cluster and replace a capacitor that is soldered into a printed circuit board on the rear.

Your transmission does not affect the tacho.


Or find a donor car in a junk yard and relieve it of it's cluster and tach and see if that fixes it.
Old 11-20-2012, 10:09 AM
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Re: RPM GAUGE IS OFF

Some types of capacitors just fail with age, so replacing an old cluster with another old cluster may not achieve much.
Old 11-20-2012, 11:18 AM
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Re: RPM GAUGE IS OFF

That is true, however, it may still work, and then he'll be better than he was.

Now, your saying the car doesn't REV high? When in idle, and you put your foot down, the car should roar...as the RPMS jump. Does the car do this or does it flat line/not rev high? Remember, 5K RPM is HIGH for these cars...
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