inaccurate tach reading

[raybugarin82]

Good day everyone
I have a small problem regarding a tach imstallation.
I know i cant imstall an autogage tach directly that i need a tach adapter.
So i got an msd tach adapter 8920. Does anyone have installed the same tach adapter or do i need something else to make my tach work....
I got it working but it does not match the stock tach....
Can anyone have the wiring diagram for imstalling the tach with the adapter..

Thanks a lot

 

[95gstnate]

If you say you got it working but just doesn't match your stock tach did you make sure you set the tach for 4 cylinder operation?

 

[sillycon]

There is a margin of error on the stock tach (and your aftermarket tach as well).

When you say it's not reading the same, are you talking a few hundred RPM or a few thousand? A few hundred RPM difference (100-200) wouldn't be off the mark.

 

[raybugarin82]

If you say you got it working but just doesn't match your stock tach did you make sure you set the tach for 4 cylinder operation?

I clip the brown and orange wire if that's what you mean...i saw it on autometer site 4cylinder....my friend told me that i need to have it calibrated for dsm...

There is a margin of error on the stock tach (and your aftermarket tach as well).

When you say it's not reading the same, are you talking a few hundred RPM or a few thousand? A few hundred RPM difference (100-200) wouldn't be off the mark.

No not by couple of hundred rpm.....on idle stock tach reads 1000 rpm on the autometer its 500rpm..
Rev it up to 2000rpm, autometer tach reads 1000..
Rev at 3000, reads 1500.....
Its like half of the reading...
I already installed a tach adapter from msd
tach adapter 8920...... I also tap straight to the ignition pack......
Any ideas what im doing wrong???

 

[dsmpat95]

Set the tach to 2 cylinder, and should fix your problem. The car uses a wastespark system and it can throw off the aftermarket tach.

 

[talontd92tsi]

Set the tach to 2 cylinder, and should fix your problem. The car uses a wastespark system and it can throw off the aftermarket tach.

This is correct. The way the dsm works is on a 2 coil system, therefore you have to set the tach to 2 cylinder on most tachs to make it work properly.

 

[raybugarin82]

Thanks ill try it tomorrow and let you know what happens...
Happy holidays !!

Okay so thers 4 wire loops at the tach... Already cut all 4 wires.....is this wrong? Can i do anything else after this....i dont know how to calibrate it for 2cylinder engine coz its not in the manual.....anybody that can guide me step by step...?? thanks

 

[raybugarin82]

Guys i cant find any instructions on setting the tach to 2 cyl.....i have an autogage 233904 and a tach adapter msd 8920.....

 

[raybugarin82]

My tach cant be calibrated to 2 cylinder....does this mean i have no use for my tach?

 

[1G Eclipse94928]

My tach cant be calibrated to 2 cylinder....does this mean i have no use for my tach?

Have a professional install it. hopefully you havent broken anything. WTF

http://www.msdignition.com/assets/0/1281/1282/1283/7b75c16e56154df68728c9ec1630f058.JPG

 

[raybugarin82]

Lolz....thanks but no thanks......thats why i joined so i can DIY....

 

[autocrossn]

Did you ever figure this out? i have the same adapter and plan on running ls1 coils