Crazy Tacho and Missfire

[Stagless Steve]

The last couple of times I have taken the Stag for a run I have experienced some odd behavior from the Tacho. It will swing wildly from one side of the dial to the other. This is sometimes accompanied by a sudden loss of power, but not always. I have checked the tightness of all connections to the coil, dist cap etc, and cleaned the spark plugs but it is still happening. Any ideas as to what might be causing this this?
Thanks
Steve

[JASL]

If you have a separate ballast resistor I would check the connections to that. You may be wise to seek the assistance of an auto-electrician, but supply him with the wiring diagram suitable for your model year.
Good Luck

[davidf]

Do you have electronic ignition?

if Lumenition, the sockets in the 3-pin connector plug can expand, so the pins don't connect securely.

[richardthestag]

Could be lots of things

i had this and about 30 seconds later the leccy ignition module shat itself and I was left stranded.

If you still have points fitted check that the nut that secures the LT wire to the points is tight and insulated properly

Make sure that the earth wire is still in place between the rotating plate and the fixed plate inside the distributor.

Lastly if you have the Mk2 ballast wire in the loom pink/white?!? Mine started to breakdown and this caused a chronic misfire. I went solid state ballast resistor and bypassed the loom ballast wire. That fixed that.

Good luck

[bullstarz]

If you have electronic ignition (no points) then your ignition amplifier is slower braking down. If you have Lumenition then thats the black box.

If you leave it to long it will just stop working, replace it.

[Stagless Steve]

Thanks for the responses so far. I do have electronic ignition and I'm pretty sure there are no points in the distributor. The system was fitted by the previous owner who only had the car for 5 years, so it's no more that 7 to 8 years old. I'll have to check the documentation to find out what make it is. Is it normal for these systems to start breaking down that quickly?

[stag8manod]

Hi Steve, +1 for a faulty Lumention. Just replaced mine for .similar reasons,struggled to get home. each time it faulted the rev counter dropped to zero only to pick up again.
Cheers Ian A

[davidf]

Is it normal for these systems to start breaking down that quickly?

Not so common for the amplifier to fail, but not unknown. But with Lumenition, lots of reports on here of problems with the 3 pin connector between the amplifier and the distributor.
Common problem, simple to check/fix, so must be first thing to check/eliminate.

[DJT]

Not so common for the amplifier to fail, but not unknown. But with Lumenition, lots of reports on here of problems with the 3 pin connector between the amplifier and the distributor.
Common problem, simple to check/fix, so must be first thing to check/eliminate.

Replace that troublesome connector with a Superseal or waterproof connector. 3-way ones are available on eBay for a couple of pounds and they are easy to fit.

[Stagless Steve]

I think I have found the miss-fire problem, a chaffed low tension lead, so I have put some tape round it and so far the car seems OK. Fingers crossed.

Steve

[Mike J]

I have had the same problem with the three point connector. Just soldered mine. with shrink tubing over the top.

Mike