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MG TD TF 1500 - Dash Wiring-ammeter

For clarification. Does the wiring diagram as shown in the manual indicate the wiring as viewed from the front or as viewed from the back. Why I ask is because I think I've installed part of my new loom the wrong way round. Although I show the car charging at the battery (I'm still positive earth) my ammeter is showing a negative. As viewed from the BACK I've my brown and white wire going to the LEFT terminal and then on to "A" at the control box and the RIGHT terminal (Brown wire) going to the starter motor. SO I think I've wired it up in reverse.
SECOND question. The reading at around 2000 rpm AT THE BATTERY is showing around 15volts. Seems potentially a bit high. Comments please.
JK Mazgaj

Are you sure your car is positive ground and the + post is attached to the grounding cable on the battery box?

And also you have the gauge installed with the needle down?

What happens when it's not running and everything is off? Is the needle centered? And when you turn the lights on does it go to the negative (discharge) side?



Christopher Couper

Thank you Christopher. With others advice it would appear, as I suspected, that the ammeter connections are transposed. I'd assumed that the wiring diagram was as seen from the front of the dash rather than as is the case the rear.
JK Mazgaj

The diagram is indeed viewed from the front, but your response still bothers me because what you describe aligns with the view of the diagram and also the picture I attached.
Christopher Couper

Over the years different bits are added to the cars. My TF ammeter +/- are reversed to every other TF I know. Probably off a Y Type or a Morris of the same era.
I have seen YD's with up and down needles correctly marked with -20/+20.
74 years is time for all sorts of things to happen.
Ray TF 2884
Ray Lee

TD not YD
Ray
Ray Lee

Yesterday I reversed the two wires as suggested by others and the ammeter is now registering correctly. So in my case the diagram shows connections as viewed from the rear. Interesting point made by Ray.
JK Mazgaj

JK:

Don't know if anyone responded to your question about the charge voltage. I was curious as well, so I did a few checks. On two modern cars with alternators, one was charging at 14V. The other was charging at 14.5V. On my TF it was, like yours, charging at 15V. RPM was around 2K or so. If I went with a higher RPM it didn't' matter. It pegged at 15V regardless. As far as I know the voltage regulator is the original, and I've not messed around with it. I've never had a battery problem. I've used the OPTIMA AGM battery since I've owned the car. The multimeter I have is not digital, so the indicated voltage may be a bit different than the actual. I don't know if it makes a difference or not, but I had no load on the system other that the engines running. The regulator is adjustable, but not sure I need to tweak it or not.

Jim
Jim Rice

Jim, If you are a member of the Octagon club and if so view the problem I'm currently trying to solve regarding over heating ignition coils the cutout/regulator is part of the discussion. Cheers Jan
JK Mazgaj

This thread was discussed between 05/05/2023 and 13/05/2023

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