Fried Ammeter Part 2

[archigator]

Previously I posted a problem with my electrics, in that my engine does not turn-over (no spark) when I turn the ignition key. I previously had some Lucas smoke escaping from my dash in the area of the ammeter, and subsequently replaced a lot of the wiring in that area that had overheated and was swollen. Still doesn't work. (I know for a fact that my ignition switch, coil, etc. are good.)

I got a reading on the input side of my ammeter, but none on the output side. So I clipped a jumper wire from the input side of the ammeter to the output side... and the car starts! My fuel gauge now works too!

The problem... I turn off the ignition switch and the engine won't stop running! I unclip the ammeter jumpers, and the car keeps running. I disconnect the output terminal wires from the ammeter, and the car keeps running. I finally pulled the main coil wire and the car stops.

Can this still be a bad ammeter, or is something rewired wrong? (The previous owner replaced many wires with non-Lucas coded solid colors, I found that he even spliced two wires of different colors at either end of the loom, so rewiring was a challenge.) If I replace the ammeter with one that is a 30 amp or 60 amp unit, does that make any difference as to its operation, 50 amp units are hard to find. (I won't think so, as it's only a gauge.) Thanks.

Gary
'71 Elan Sprint
Miami, FL

[Emma-Knight]

Hello Gary,
working through my wiring loom I was reading wiring diagramm in extenso:
the ammeter normaly is between voltage control box and the batterie feed/return terminal at the starter solenoid. So excessiv plus is fed through a brown cable via the main plus solenoid batterie terminal back to the batterie - or taken from the batterie ( when no generator output). . Its just a through device, showing in or out.
If no problem before, melted insulation could be the cause.Maybe the white ignition wire is now in permanent contact with an unswitched plus line and so always connected to generator plus. (the car would be running until fuel empty)When the red white starter solenoid wire is ok, it would only work with an intact feed via ammeter/controlbox/ignition switch.
So start only via ammeter/bridging - run even with ignition swith off!

Things to look for: a working ammeter and an illegal connection between white ignition and unswitched plus.
And a full loom check...

The original Lucas wiring is not so bad if unmolested by DPO's...
It needs understanding and a little care.



Anna

PS II: had a look at Your first post so a failed voltage control box might have been the cause or some wiring that got in contact at some point -
behind the dash is quite a bit of sharp metall: heater and bracket that might scrap insulation; lost wires in the engine bay (like with my car), suddenly in contact with ground.