# screwed up tach

**URL:** <https://forums.speedlife.net/t/screwed-up-tach/104449>\
**Category:** SON240sx Automotive\
**Created:** [March 13, 2007, 8:28am UTC](https://forums.speedlife.net/t/screwed-up-tach/104449 "2007-03-13T08:28:54Z")\
**Posts on this page:** 1\
**Showing post:** 7

<div class="post-metadata">

**Author:** ![simplemind7](https://avatars.discourse-cdn.com/v4/letter/s/0ea827/32.png) [@simplemind7](https://forums.speedlife.net/u/simplemind7)\
**Post date:** [March 14, 2007, 11:31pm UTC](https://forums.speedlife.net/t/screwed-up-tach/104449/7 "2007-03-14T23:31:20Z")

</div>

> [@Free Axe Bodywash](https://forums.speedlife.net/t/free-axe-bodywash/9018/22):
>
> One thing I did notice is that it is getting a signal for Inst1 and that seems to be the RPM.

what is Inst1?

are you sure you connected all the same coloured wires at the body harness connector when you did the SOHC to DOHC swap? one of those is the tach wire so if you didn’t connect it then your tach won’t work.

the tach signal should come from the ignition coil.

if you’re sure that everything is in order then pull out your cluster and try to find the tach wire behind it, it will probably be the same colour as it is by the ECU. measure this wire and make sure it has the correct signal. if it does then your cluster is probably the problem.

hope that helps.

---

_[View the full topic](https://forums.speedlife.net/t/screwed-up-tach/104449)._