Tach issues

[Alphamacaroon]

Wired up my Gen II Coyote to the Autometer Coupe Platinum Gauges as per the Coyote install instructions— tapping into the blue/red wire in the #4 coil wire. At idle, the tach seems to twitch between 0-500 rpm, then when I rev the engine it actually stops twitching and holds steady at zero— almost seems like it's working backwards.

I checked the dip switches on the gauge and they are properly set for 8 cylinders. I also checked the wiring again— tapped into blue/red wire on #4 coil wire. I've read that maybe I need to buy the Autometer 9117 tach adapter, but it makes no mention of this anywhere in the install manual, so I'm hesitant to throw down $100+.

Any other suggestions? Thanks!

[FFinisher]

Yep, spend the $100, it won't work without it.

[Alphamacaroon]

Yep, spend the $100, it won't work without it.

That's what I figured— when in doubt, spend money! Thanks much!

[Alphamacaroon]

Installed it and doesn't seem to be working :(

I have it wired like so:

Red Wire -> Ignition switched 12V+ power
Red/Green Wire -> Tapped into Blue/Red wire in #4 coil
Black -> Chassis Ground
Gray -> Connected to SIG post on Autometer tach gauge

Does that seem right?

[FFinisher]

Oddly the wire that counts the pulses(Red/Green) has to go to the wire that feeds all of the coils. I attached it to the gray wire in the 16 pin connector by the computer, this wire changes color from Gray to Purple in that connector.

If you want to PM me your email I can work with you and send some pics of how its done.

you are not the first one to have issues with it. But it will work.

Look up Hawaii 35 ford pickup, He had issues as well I helped him through.

We will get it working.

[jdavis500]

Does it need to be calibrated first? I missed that detail with mine.

[Alphamacaroon]

Oddly the wire that counts the pulses(Red/Green) has to go to the wire that feeds all of the coils. I attached it to the gray wire in the 16 pin connector by the computer, this wire changes color from Gray to Purple in that connector.

If you want to PM me your email I can work with you and send some pics of how its done.

you are not the first one to have issues with it. But it will work.

Look up Hawaii 35 ford pickup, He had issues as well I helped him through.

We will get it working.

Found that other post— damn, this is starting to turn into much more of job than I thought... I've already tapped my #4 coil wire, and I'm really nervous about snipping wires in my computer harness. Is there no chance in getting it to work by tapping one coil wire? I may end up considering another set of gauges so I don't have to snip engine harness wires (I hear Speedhut might be compatible with single coil hookup). Just makes me super nervous.

[Alphamacaroon]

Does it need to be calibrated first? I missed that detail with mine.

The gauge or the adapter? As far as I know, the Autometer Platinum tach only has a setting for 4, 6, or 8 cylinder, but no other calibration. The tach adapter doesn't appear to have any sort of calibration either.

[freds]

Found that other post— damn, this is starting to turn into much more of job than I thought... I've already tapped my #4 coil wire, and I'm really nervous about snipping wires in my computer harness. Is there no chance in getting it to work by tapping one coil wire? I may end up considering another set of gauges so I don't have to snip engine harness wires (I hear Speedhut might be compatible with single coil hookup). Just makes me super nervous.

I went through everything exactly as you are, and came to the conclusion Speedhut was the simplest solution. I installed the Speedhut. It's bezel is very similar to the Autometer and I do'nt notice that it is not an exact match.

The Speedhut requires simple calibration. Driving over any 2 mile distance that suits you. You can even start and stop during the 2 mile calibration drive. Just follow the simple instruction.

I'm happy with that solution

fred

[edwardb]

I went through everything exactly as you are, and came to the conclusion Speedhut was the simplest solution. I installed the Speedhut. It's bezel is very similar to the Autometer and I do'nt notice that it is not an exact match.
The Speedhut requires simple calibration. Driving over any 2 mile distance that suits you. You can even start and stop during the 2 mile calibration drive. Just follow the simple instruction.

I'm happy with that solution

fred

I think you're confusing the speedo with the Autometer tach issue this thread is about. Also, Speedhut speedos from Factory Five for the last few years have been GPS based, so no longer require calibration. Just put it in and drive.

[freds]

I think you're confusing the speedo with the Autometer tach issue this thread is about. Also, Speedhut speedos from Factory Five for the last few years have been GPS based, so no longer require calibration. Just put it in and drive.

Yes indeed I am, thanks Paul. A senior moment. So ignore my second paragraph, which I have now deleted.

The Speedhut tach requires no calibration, and uses a one wire signal with a small "conditioner" which is supplied. It is a while since I installed mine and, frankly, don't remember the details exactly.

fred

[Alphamacaroon]

Thanks for the help everyone. I ended up taking the plunge and cutting into the engine harness, but instead of tapping into the underside of the PDB (I couldn't figure out how to get the darn bottom cover off), I ended up cutting into the purple wire near the engine harness connector and wired it per AutoMeter's "Coil Per Plug" instructions (which I think is the same way FFinisher recommended in that other thread). Tested it out last night and it seems to work.