TBI Throttle Body Injection discussion and questions. L03/CFI tech and other performance enhancements.

Tach problems

Thread Tools
 
Search this Thread
 
Old 11-30-2011, 05:56 PM
  #1  
Member
Thread Starter
 
Badrs2810's Avatar
 
Join Date: Jun 2010
Location: Nc
Posts: 264
Likes: 0
Received 0 Likes on 0 Posts
Car: 91 camaro rs
Engine: 305 (350 vortec in dec.)
Transmission: Wc-T5
Axle/Gears: 3.08 (3.42 in dec.)
Tach problems

I just bought my 91 rs 4'months ago never thought bought it bc I know where to shift. Now, it's starting to annoy me.... When at idle, my tach reads between 2500-3000 rpms and thee car is probably running 500-800 rpms, idk what normal is. Would this be a busted tach, bad wire, fuse? What could fix this? Any help would be great, thanks
Old 11-30-2011, 06:16 PM
  #2  
Member
 
bigreed91's Avatar
 
Join Date: Jun 2011
Location: Columbia, TN
Posts: 384
Likes: 0
Received 0 Likes on 0 Posts
Car: 1990 camaro rs
Engine: 5.0L 305 tbi
Transmission: 700r4
Axle/Gears: 2.73
Re: Tach problems

From what ive read a lot of peoples tachs are off and i dont think its an easy fix from what i read, mine sits at the redline all the time, i just got a autometer tach im gonna use instead. Do a search in the electronics section i believe
Old 11-30-2011, 06:16 PM
  #3  
Member
 
platynumx's Avatar
 
Join Date: Mar 2005
Location: orange county indiana
Posts: 123
Likes: 0
Received 1 Like on 1 Post
Car: 89 rs vert/88 t/a GTA
Engine: 355 tbi/350 tpi
Transmission: 700r4 w/megashifter/700r4
Axle/Gears: 3.73/???
Re: Tach problems

I have the same problem in my 89 rs.I just figured something wasn't hooked up properly when the previous owner swapped an l05 in or he replaced the tach with one out a v6 car.
Old 11-30-2011, 06:41 PM
  #4  
Senior Member

iTrader: (2)
 
camarorsssss's Avatar
 
Join Date: Aug 2006
Location: LONG ISLAND, NY
Posts: 548
Likes: 0
Received 11 Likes on 10 Posts
Car: 1991 camaro rs convertible
Engine: Built ls1
Transmission: T56
Axle/Gears: 3:42
Re: Tach problems

An aftermarket tach such as autometer would be a good alternative and are more accurate then the stock tach. I had the same problem with my original tach and a swapped out the entire guage cluster for a working one and put in an autometer tach as well.
Old 11-30-2011, 07:01 PM
  #5  
Supreme Member
iTrader: (1)
 
UNCLE TOM's Avatar
 
Join Date: Dec 2006
Location: ms. gulf coast
Posts: 2,403
Likes: 0
Received 3 Likes on 3 Posts
Car: 91 R/S , 89 dodge p/u
Engine: L31 GM crate re-cammed , 318
Transmission: T-5 , 4 speed auto
Axle/Gears: 3.42 , ?
Re: Tach problems

a common problem with 90-92 camaros . (mine has it) there are fixes , try a search for the problem (90-92 tach fix) . i just live with mine , i'm a cruiser , not a racer . good luck .
Old 11-30-2011, 09:07 PM
  #6  
Supreme Member

 
zenish's Avatar
 
Join Date: Dec 2000
Location: stallings,n.c.
Posts: 1,271
Likes: 0
Received 1 Like on 1 Post
Car: 1989 camaro rs convertable
Engine: 305 tbi
Transmission: 700r4
Axle/Gears: 7.5"3.42 gears forth gen 2000 camar
Re: Tach problems

Originally Posted by platynumx
I have the same problem in my 89 rs.I just figured something wasn't hooked up properly when the previous owner swapped an l05 in or he replaced the tach with one out a v6 car.
all the third gen tachs go bad.i have a two"tach and unplugged the dash tach.there are people on tgo that have posted repair solutions but its over my head.
Old 11-30-2011, 09:31 PM
  #7  
Member
Thread Starter
 
Badrs2810's Avatar
 
Join Date: Jun 2010
Location: Nc
Posts: 264
Likes: 0
Received 0 Likes on 0 Posts
Car: 91 camaro rs
Engine: 305 (350 vortec in dec.)
Transmission: Wc-T5
Axle/Gears: 3.08 (3.42 in dec.)
Re: Tach problems

I found the article, it's located in the electronics section, it's a simple fix.... Read it. I haven't tried it yet, I will very soon though.... It's between two pins on your tach board. I believe it's 4 and 10, it has pics if you don't understand. Clip 4&10 and solder an in series of @197k ohms from pins 4 to 10... Should fix prob... That's a brief, but read the article.
Old 12-01-2011, 11:50 AM
  #8  
Member
 
bigreed91's Avatar
 
Join Date: Jun 2011
Location: Columbia, TN
Posts: 384
Likes: 0
Received 0 Likes on 0 Posts
Car: 1990 camaro rs
Engine: 5.0L 305 tbi
Transmission: 700r4
Axle/Gears: 2.73
Re: Tach problems

Yeah im more of a mechanical type, i can do basic wiring but whe it comes to that kind of stuff i dont even bother. If i had the right tools like a multimeter and sodering gun i could probley figure it out. But when i bought my car there was an autometer tach in the back seat so i'll just use that lol
Old 12-01-2011, 11:57 AM
  #9  
Member

iTrader: (2)
 
L98wit's Avatar
 
Join Date: Jan 2010
Location: CT
Posts: 107
Likes: 0
Received 0 Likes on 0 Posts
Car: 91 rs
Engine: 350 tbi with EBL
Transmission: t56!
Axle/Gears: 2.733
Re: Tach problems

its very simple, solder between the two pins a resistor u can buy at radio shack. just look up the thread as this has been discussed and has very clear pictures tells u the pins and the resistor needed. its simpler than how it sounds believe me!
Old 12-01-2011, 02:40 PM
  #10  
Member

iTrader: (2)
 
TheGr8erG00d's Avatar
 
Join Date: Jan 2011
Posts: 191
Likes: 0
Received 0 Likes on 0 Posts
Re: Tach problems

Do a forum search for tachometer fix. They have a thread on here with a full tutorial on fixing your tach. These guys posting above me have the right fix, but the thread goes into detail and has really helpful pictures to help you along. I used it to fix my tach that was off by several thousand rpms like yours.
Old 12-02-2011, 10:42 AM
  #11  
Supreme Member
 
torque_is_good's Avatar
 
Join Date: Sep 2010
Posts: 1,438
Likes: 0
Received 2 Likes on 2 Posts
Re: Tach problems

Originally Posted by Badrs2810
I found the article, it's located in the electronics section, it's a simple fix.... Read it. I haven't tried it yet, I will very soon though.... It's between two pins on your tach board. I believe it's 4 and 10, it has pics if you don't understand. Clip 4&10 and solder an in series of @197k ohms from pins 4 to 10... Should fix prob... That's a brief, but read the article.
I did that but eventually ended up buying another tach. What I ended up with was a tach which worked great showing the idle rpm's up until 1500 and then it was way off.

When I first started fixing it, my idle was at "1500" per the original tach and at 1500 (external meter) my tach showed 5000

If you want accuracy, buy an aftermarket tach
Old 12-02-2011, 01:02 PM
  #12  
Supreme Member

 
zenish's Avatar
 
Join Date: Dec 2000
Location: stallings,n.c.
Posts: 1,271
Likes: 0
Received 1 Like on 1 Post
Car: 1989 camaro rs convertable
Engine: 305 tbi
Transmission: 700r4
Axle/Gears: 7.5"3.42 gears forth gen 2000 camar
Re: Tach problems

Originally Posted by L98wit
its very simple, solder between the two pins a resistor u can buy at radio shack. just look up the thread as this has been discussed and has very clear pictures tells u the pins and the resistor needed. its simpler than how it sounds believe me!
its a little harder on a 1989.the circuit board is fastened to the tach.i went ahead and ordered the capacitor that moreley?suggested and will try replacing that.it was only nine dollars with shipping.
Old 10-23-2014, 08:45 AM
  #13  
Member

iTrader: (2)
 
Blue_IROC_86's Avatar
 
Join Date: Mar 2005
Location: Killingly, CT
Posts: 140
Likes: 0
Received 0 Likes on 0 Posts
Car: '82 Camaro Z28 (Former Pace car)
Engine: 85 5.7L Small Block
Transmission: WC T5
Axle/Gears: 96 disc LT1 3.23 Auburn 10 bolt.
Re: Tach problems

Excellent, i can finally have a decent working tachometer. I don't care if it's perfectly accurate. I just don't want a goofy racing tach.

And on a side note... Why is it that when people step into a thirdgen for the first time they think the tach is the speedometer... "Ohh it only goes up to 70?"
Old 11-16-2017, 04:42 PM
  #14  
Junior Member
 
cwpdist's Avatar
 
Join Date: Aug 2009
Posts: 2
Likes: 0
Received 0 Likes on 0 Posts
Re: Tach problems

There is now a replacement for the 1982-89 Chevy Camaro V8 Tachometer Circuit Board. Any body try this yet.
https://www.wc-autoparts.com/1982-89...t-replacement/
Old 11-17-2017, 04:43 PM
  #15  
On Probation

 
sonjaab's Avatar
 
Join Date: Apr 2007
Location: Syracuse NY
Posts: 1,588
Received 18 Likes on 18 Posts
Car: 84 Z-28
Engine: 305 HO
Transmission: r-700
Axle/Gears: 3:73
Re: Tach problems

Heres a thread on a guy who fixes them and/or sells the board cheaper.
https://www.thirdgen.org/forums/elec...-tach-fix.html
Old 11-17-2017, 10:42 PM
  #16  
Member
 
LiveIt!'s Avatar
 
Join Date: Nov 2016
Location: Florida
Posts: 348
Likes: 0
Received 0 Likes on 0 Posts
Car: 1988 Camaro Sport Coupe
Engine: The All-Powerful 2.8l!! :P
Re: Tach problems

Originally Posted by Blue_IROC_86
Excellent, i can finally have a decent working tachometer. I don't care if it's perfectly accurate. I just don't want a goofy racing tach.

And on a side note... Why is it that when people step into a thirdgen for the first time they think the tach is the speedometer... "Ohh it only goes up to 70?"
It's funnier when they think you're going 70 on a slow road
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
GeneralIesrussi
Carburetors
5
01-20-2020 01:06 PM
Hotrodboba400
Firebirds for Sale
3
12-10-2019 07:07 PM
andy74
Electronics
2
09-03-2015 08:41 AM
Hotrodboba400
Firebirds for Sale
0
09-02-2015 07:28 PM
greenyone
TPI
3
09-02-2015 03:39 PM



Quick Reply: Tach problems



All times are GMT -5. The time now is 10:46 AM.