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MG TD TF 1500 - another start up question


Again, I am electrically challenged. OK, I run power to the fuel pump and coil directly from the battery, right? I also run power to the starter from the battery with a cut off switch? The battery will keep the fuel pump and coil running but I use the cut off switch to activate and deactivate the starter, correct?

Rob Welborne

rob, i am not sure what state of repair/disrepair you car is in, but yes, what you write will work..just as when you turn the key to on..walk around and use the jumper switch to provide a circuit to energize the starter. you are just by passing the mechanical starter switch. you could use a screwdriver jumper across the starter switch terminals. the switch is better.
make sure the car is out of gear. regards, tom
tom peterson

I used the stock starter switch; you can operate it without the cable.

I had a solenoid type switch at the ready but I found the original in a box of parts.

I second the neutral check.
J E Carroll

Rob - Are you trying to test everything without using the ignition switch? If so and if you are concerned that something might short when you switch the ignition on, start by putting a 10 amp fuse inline with the battery cable, turn the ignition switch on and see if the pump is running and the fuse doesn't blow. You can even turn the headlights on and step on the brake pedal to see if the lights are working and again, no blow fuse. Turn the ignition off, remove the fuse and reattach the battery cable on the battery terminal, the turn the ignition on and see if the engine will start up. Using the fuse in line for the initial tests, will protect the wires from being fried if there is a short somewhere while checking out the rest of the circuits. Caution, only leave the ignition on for a few minutes at a time so you don't fry the points in the distributor or overheat the coil. Also, if you try to start the car with the fuse in line, you won't even get a bump before the fuse blows. Cheers - Dave
David DuBois

Sorry I did not give enough information about the state of my car. The complete body is at the painters so of course there is no wiring harness attached to anything. What I have is a complete chasis and rebuilt engine needing its first start up since rebuild. Once I have a successful start up and the body is done at paint I will of course hook up the harness and probably need more help for my feeble electronicless brain.

Rob Welborne

Hmmmm....I don't understand the point of putting the cut-off switch in line to the starter....
I use a cut-off to do just that, cut off the battery from the entire car, without having to disconnect the terminal.
If you are testing circuits, use a VOM, and/or a 12V test lamp, and just leaving the ignition switch in the "on" position will do it...(even without current, using the ohm meter). Every circuit in the car can be done this way.

Edward Wesson 52TD


I am just trying to get a first start up on a fresh rebuild. I just want to make sure I hook the power up to every thng correctly. There is not wiring harness in use so no circuits to check, just proper pawer.

Rob Welborne

Its the most basic set up you need!
Heres how ive done it in the past!
You will need 1 very good battery.
1 set of good jump leads.
A few mtrs of wire.
Should work for - and + earth cars!
Connect neg on batt to some point on the engine with black jump lead.
Connect 2 wires to fuel pump and to batt,so it runs.
Distributor wire to coil,then coil to batt,HT from coil to distributor.
You should put both of these onto an inline switch to turn on/off.
Flick open points to test for spark/power.
Make sure pump is actually pumping fuel to carbs,and float chambers are full.
Clamp red jump lead to starter,and when you touch it on the + on batt starter should turn.
I turned engine over for approx 1 minute before starting to get the oil pressure up.
Turn on switch with pump and coil wire,then turn over engine,remembering to activate the choke by hand or wedge it open.

I hotwired my TF before activating power through the loom,as I wanted to check its circuits before powering it up.
Hopefully ive remembered the sequence I used!
If anyone thinks its wrong or missing something,say so!!

My Youtube video of this procedure might give you some confidence. Sounds sort of like what you're trying to do:

I also have a crude wiring diagram I could send as well. Search for "efhask" when on Youtube and you will see it.
efh Haskell

You probably already know this but, what ever you do, make sure the engine gets oil pressure as soon as possible! I pressure pre lube a rebuilt before cranking it up, fill the pump and filter also. I take the plugs out and crank it until oil pressure is evident. Put the plugs back in and fire it up. IF YOU INSTALLED A NEW CAM, once it starts, take it immediately to 2000/2500 RPMs and keep it there for a good 20 to 30 minutes or more. Naturally the cooling system has to be hooked up. I've never ruined a new cam doing it this way. PJ
Paul sr

This thread was discussed between 11/04/2013 and 13/04/2013

MG TD TF 1500 index

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