So i got a ricer autometer tach (hey shut up, it was cheap as hell ) and found that the higher my stock tach goes the more inaccurate it is. from 1000 to 3000 they are both at the same RPMs, but after that, the higher i rev the more inaccurate the stock tach is. If im at the redline (6500) on the autometer tach, my stock tach is at about 7200rpm! Anyone experience this too? I dunno if its the autometer thats inaccurate or the stock one. The autometer one is attached directly to the blue wire coming off one of my distributor plugs. I remember reading a post a very long time ago on here that said something like the crx tachs are grossly inaccurate at higher RPMs...is that true?

 

where did you tap your rpm signal... my friends been having problems like this cause they had bad grounds and tap in to the blue wire of the dizzy.. i tapped mine off the ecu

 

I tapped mine into the blue wire coming off my distributor plug (the plug that only has 2 wires, the blue one and the black one). So you tapped into the ecu wire? is this in a CRX or wat? Is it accurate then or nah? Oh yea, about the tapping. I also tried plugging the signal wire directly to the stock tach and its still the same... so i guess the stock tach IS off then.

 

I wouldn't be surprised if its like that on purpose. To try to prevent people from harming the engine as much as possiable. I've known that the stock tachs were inacurated but never had any comparison #s, wow.

 

crud you know what though? I asked my brother (he used to have an 88 crx way back when) and he said that his stock tach was off by quite a bit too... crud i wish there was a definate way of finding out...on a dyno maybe? i dunno...

 

I've noticed that too. After installing my Autometer tach and comparing it to the stock one, there was a 300-400 rpm difference.

 

ihave the same prob with my auto gauge tach. at idel my stock one reads 300 and my auto meater reads 850. i tapped in right off the blue wire going into the tach its self. but it redlines where its suppose to and threw the whole power band is about 600rpm's off the stock one

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ThE bEe GuY &raquo;</TD></TR><TR><TD CLASS="quote">So i got a ricer autometer tach (hey shut up, it was cheap as hell </TD></TR></TABLE>

So how big is this tach?

 

its the 5 inch one

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by dirty-t &raquo;</TD></TR><TR><TD CLASS="quote">ihave the same prob with my auto gauge tach. at idel my stock one reads 300 and my auto meater reads 850. i tapped in right off the blue wire going into the tach its self. but it redlines where its suppose to and threw the whole power band is about 600rpm's off the stock one</TD></TR></TABLE>

on the back of the autometer tach theres 2 wires, a brown one and a orange one, did you cut both of them like you should? if you only cut one it might be on the V6 calibration setting

 

All of the 4th gen tachs i've had experience with are inaccurate once they get around 4k. Im pretty sure they are made to read high, since they all read the same amount over.

 

man i wish i knew they were that off a year ago. i was designing a digital tach with like 50 leds (like the S2000), and i got it working up to about 4krpm, but after that it would always be off. here i thought it was my circuitry maybe i'll re-start that project sometime after all. thanks for sharing the info.

 

yeah you aught to see it compared to the vafc its funny how it will be off by almost 1000 rpms, but then again i have a b16a, redlines at 8200