Tach Reads High with the AEM tach output

[p5150]

Yes, I know that I can change the output of the AEM tach signal in the parameters window, but it still will not read accurately. It reads high.

I am running a 2jz AEM box (1100) in a 88 Turbo MA70 chassis.

Anybody have any input on this? Do I have to wire in a signal adaptor to the AEM tach output line?

 

[tissimo]

Mine read perfect.. are you using AEM to output the tach signal or using the ignitor like it is factory

 

[p5150]

Im using the LS7 output on the AEM. Are you using an ignitor output?

 

[tissimo]

yea, stock ignitor output (pin 1 on the small connector iirc).. no issues at all.. since ran in wastefire like stock 7m, its even accurate

 

[p5150]

I need more info - "small connector"? Are you talking about the connector that runs from the ECU to the speedo or a specific wire that runs out of the ignitor?

The speedo output seems to be about 500 high at idle when compared to the parameters window of the AEM. Im sure it gets worse with more revs.

 

[p5150]

Keep in mind also that I have a totally customized 2jzge harness and that I have wired in a 1j/2j ignitor. I may have to take one of the ignitor outputs and run it to the tach?

 

[tissimo]

those are the 2 ignitor plugs.. the smaller one (B) pin 1 (on a stock harness its Black) run that to the Tach wire in the dash.

 

[p5150]

Thanks bro - super helpful. I was trying to move your posted screenshot around with the cursor bar in the pic. Im a dumbass. ....

Doesnt that plug also go to a noise filter attached to the ignitor? I will check it out tomorrow and possibly wire it up.

I thought that the output of the AEM would be ok or that I could reconfigure the settings in it to properly control the tach but I guess that this tach cannot be controlled with the AEM. Good thing I left some extra wires in the harness I made!

 

[tissimo]

haha, np

you probably could use the aem output for it, but I dont know the setting to get it to work correctly.. the 1jz and 7m run like this (off ignitor) so easiest to just copy the design rather then playing with aem settings and trying to get something that works..

I'm not sure where the filter taps into to be honest..

 

[p5150]

Even with the AEM tach output settings adjusted, it is not perfect. The way I have it set now is as close as it is going to get. I will run a wire to the ignitor.