Aftermarket Tachometer, few questions

[spiff]

So the 88’ I purchased had some really JANKY wiring going on, and they basically were jumping fuse 21 and 27- so I have no dash lights nor a working tach… Fuse 21(the most important one which powers the tach and dash lights) has esploded a bit and melted itself into the fuse box.

Now, I’ve already found the solution to this, and my buddy who is a great electrical wiz says we can fix it the RIGHT way in the next weekend or so when he has time.

My question is, if I wanted to run an aftermarket tach, would it be possible to make it work without using Fuse 21?

Any direction or advice on wiring it up would be great.

Thanks

• Dan (upcoming socal’er)

[Ranger]

An aftermarket tach needs connection to switched 12V and the coil. Alternately the DME may have a wire that that will provide the tach signal. None of that has anything to do with fuse 21.

[mahoneyj]

While building a Lemons E30 we bypassed most of the stock harness. Mostly because my buddy hates dealing with old crappy cobbled harnesses. He pulled the switched power from a circuit associated with the ignition wires and got the tach signal directly form the DME harness. He used the Bentley to figure all of this out with pin out diagrams I think. Worst case you can run a wire from the tach directly to the coil for the signal. During some testing we ran a jumper from the tach to the coil and it came to life at idle. Its pretty cool if its the first time you have done it. We then used it confirm the lead from the DME. Then he permanently wired it in.

[cwbaader]

Push the easy button…power from switched power on the main relay. Ground to ground lug next to the steering column (left side, 10mm bolt). Run wire to coil. Win…Chuck

[mahoneyj]

[spiff]

mahoneyj wrote:

While building a Lemons E30 we bypassed most of the stock harness. Mostly because my buddy hates dealing with old crappy cobbled harnesses. He pulled the switched power from a circuit associated with the ignition wires and got the tach signal directly form the DME harness. He used the Bentley to figure all of this out with pin out diagrams I think. Worst case you can run a wire from the tach directly to the coil for the signal. During some testing we ran a jumper from the tach to the coil and it came to life at idle. Its pretty cool if its the first time you have done it. We then used it confirm the lead from the DME. Then he permanently wired it in.

Interesting.

My electrical buddy will be coming by this weekend- we tried to attack it the other weekend but left a vital part at my other friends house when we first tore into it (the wire that essploded had actually opened itself up and became exposed, so we disconnected that).

Hopefully… we can at least fix the tach issue this weekend. I could care less about the interior lights and right hand turn signal(at least the left one works). However, I have searched around an apparantely when your right-turn-signal makes an ERRRRRRR sound, it means the relay is bad.

Going to be freshening up suspension and brake bits this month, will keep ya’ll posted.