Stewart Warner tach problem

[Hanny87]

Well I've installed my Stewart Warner 5" tach and am having a problem with it. Tach works great from idle to 2k, seems accurate when compared to what my scanmaster says, but as soon as soon as I get above 2k the needle just goes back to zero. If I shut the car off and restart it, it works again. Anyone else have this problem? I have the tach lead plugged into the green connector behind the alternator. Any help would be appreciated!

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[TurboTdr3.8]

Did you select it on 6 cylinders ?

 

[Hanny87]

Yes, the dip switches are selected for the 6 cylinder setting. Double checked it.

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[gnxparts]

First step is try it in another car to confirm it works

Next step to follow

 

[Hanny87]

I'll try that later tonight or tomorrow morning. I don't have another v6 car to try it on, but I'll try it on my 84 hurst/olds and see what happens.

 

[Hanny87]

Update! I got to thinking today while I was on a little road trip... my factory tach abd boost gauge have been malfunctioning since I got the car, and was thinking maybe it was sending a bad signal through the tach wire. I pulled the dash apart and unplugged it, and the Stewart Warner tach worked perfectly! Whew! Thanks for the help guys!

 

[Hanny87]

Ok, so I've got another update here. When I tried the tach last night I had the instrument cluster taken out to unplug the factory tach and boost gauge, and the Stewart Warner tach worked perfectly. This morning I put everything back together and the tach started doing the same thing. So I pulled the instrument cluster back out, and the tach worked fine again, put it back in, and does the same thing. Apparently there's something in the instrument cluster that interferes with the tach signal... does anyone know what this might be? And how to fix it? I really want to use this tach because it matches the rest of my gauges. If anyone could point me in the right direction I would appreciate it!

 

[GNRick]

When I installed my VDO tach I just tried different dip switch configurations until it worked.

 

[Hanny87]

I tried that, and even tried a vdo tach converter from Caspers. Nothing worked. Ended up putting the Stewart Warner in my Monte SS and put an Autometer in the GN. All is well now, both tachs working fine.

 

[GNRick]

Good to hear.