How accurate is the factory tach?

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musclecarmaniac

New Member

Apr 26, 2004

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Minny Soh Ta

Apr 6, 2005

#1

• Apr 6, 2005

• #1

I would like to know how accurate the factory tach is on our gt's because my car feels like it runs out of power by 5000 rpm. Either the Tach is way off or there is something wrong wih my car and i need to find it and fix it. My car has and AODE with 4.10's without a chip but that shouldn't matter because i shift it manually.

 

final5-0

Mustang Master

Apr 6, 2003

6,817

12

79

DFW Texas

Apr 6, 2005

#2

• Apr 6, 2005

• #2

I've seen others say anywhere from 200 to 800 rpm off.

Mine reads 300 rpm more than what it should.

Later
Grady

 

stprorolla49

Active Member

Oct 9, 2004

1,455

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Fairfield, CT/North Jersey

Apr 6, 2005

#3

• Apr 6, 2005

• #3

i find it to be very inaccurate.....i ahve an autometer 5" tach on the dash wired to the same wire as the stock tach, and the auto meter is about 200 rpms different than the stock one.....something to think about

 

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wytstang

Mustang Master

Mar 14, 2004

4,988

4

78

Summerville,SC missing South Fl. weather :(

Apr 6, 2005

#4

• Apr 6, 2005

• #4

Your car is dying because it can't breath. The lower stock intake is very restictive and needs help breathing aka porting. You can also just swap out your stocker for a cobra or the like and it will pull past 5g.

 

final5-0

Mustang Master

Apr 6, 2003

6,817

12

79

DFW Texas

Apr 6, 2005

#5

• Apr 6, 2005

• #5

wytstang said:

Your car is dying because it can't breath. The lower stock intake is very restictive and needs help breathing aka porting. You can also just swap out your stocker for a cobra or the like and it will pull past 5g.

Click to expand...

I agree with Danny and would like to add if you still got the stock vt and a good bit of miles on the clock then the springs are most likely weak or gone all together.

Its a common thing on stock Stangs.

btw ...... if you fix your settings so the sig will automatically show it will be easier for the nice members of this forum .......... like me to help you cause we will have some info when we reply to you

Later
Grady

 

M

musclecarmaniac

New Member

Apr 26, 2004

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Minny Soh Ta

Apr 7, 2005

#6

• Apr 7, 2005

• #6

My car has 86,000 miles on it. I live in Minnesota but my car came from California so it has 4 cats on it cause of the california emissions system. Im thinking it my have a clogged cat or cats. Tonight I am going to run a compression test and a vacuum test to see whats up. I'll post the findings.

 

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wytstang

Mustang Master

Mar 14, 2004

4,988

4

78

Summerville,SC missing South Fl. weather :(

Apr 7, 2005

#7

• Apr 7, 2005

• #7

If you don't have smog laws do away with the cats completly your car WILL thank you for it.

 

Venom351R

Founding Member

Apr 27, 2002

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MAINE

Apr 7, 2005

#8

• Apr 7, 2005

• #8

On the dyno my stock tach read about 300-400 RMP's off from the dyno tach in the upper RPM's

 

yellowstang1994

New Member

Sep 9, 2004

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Apr 7, 2005

#9

• Apr 7, 2005

• #9

I don't know about this situation. But some tachs could be calibrated differently then others. What I mean is, say if you run an aftermarket tach directly off the wire feeding into your stock tach (by the gauges). It might be getting the same reading but the aftermarket one may be calibrated differently. I heard it's a better idea to tap into the wire running into your computer or off the coil. I heard that doing it by the cluster wont' be a precise enough time. Which is maybee why some people experience a different rpm range? I run a shiftlight in my car but I tapped the wire directly off the coil and back into my car. My shiftlight is extremely accurate with my tach. I dunno

 

stprorolla49

Active Member

Oct 9, 2004

1,455

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39

Fairfield, CT/North Jersey

Apr 7, 2005

#10

• Apr 7, 2005

• #10

yellowstang1994 said:

I don't know about this situation. But some tachs could be calibrated differently then others. What I mean is, say if you run an aftermarket tach directly off the wire feeding into your stock tach (by the gauges). It might be getting the same reading but the aftermarket one may be calibrated differently. I heard it's a better idea to tap into the wire running into your computer or off the coil. I heard that doing it by the cluster wont' be a precise enough time. Which is maybee why some people experience a different rpm range? I run a shiftlight in my car but I tapped the wire directly off the coil and back into my car. My shiftlight is extremely accurate with my tach. I dunno

Click to expand...

the wire that comes off the coil that you are talking about, goes thru the harness in the dash and is the same wire that goes straight to the factory tach....i ripped apart the tape to retape it anyway, so in know that its only one wire

 

KingDiamond

New Member

Mar 9, 2003

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Chicago, IL

Apr 7, 2005

#11

• Apr 7, 2005

• #11

Isn't the rev limiter on the AOD-E about 5200? On the 5 speed it's around 6200.

 

dstanggt50

Founding Member

Sep 13, 2000

1,316

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Woodinville, WA

Apr 7, 2005

#12

• Apr 7, 2005

• #12

I have the stock tach on the 95, but I had an Autometer tach on my 87gt, and my stock tach read close to 1000rpms higher than the autometer. Maybe they are closer on the sn95's, or my 87's tach had something wrong with it.