Leyland Car Owners - Electrical problem

Subject: Here we go again
: Date: Sun, 30 Nov 2003
: Just as I thought i had my deluxe all sorted, this comes up.
: From day one the car has been an electrical nightmare.

: The alternator was not working, so I thought I would change it with one that I knew was working. When I got it on, it was putting out low charge and you could not turn the
: engine off with the key.

: I had another one sitting there that looked like it had been sitting on the ocean floor, but a wire brush soon got rid of all the corosion. I put this one on and it works great, putting out 13.5 volts.
: But I still have the problem of the engine not stopping.
: Everything is normal when you go to start the engine, the ignition light comes on and all the gauges and the engine starts ok.
: Once started the ignition light goes out completly, all as it should be.
: Then, all that happens when you when you turn the key to the OFF position, is the ignition light comes on dim. It is lucky that the holley is adjusted to idle very slowly, and a sharp jab of the accelerator gives it too much fuel to handle, therefore stalling it.
: Has anyone else had this or a similar problem?
: Any ideas would be much appriciated.
: Adam

: From: "David"
: Date: Mon, 1 Dec 2003
: The alternator charging light circuit is feed straight from the ignition switch, ignition supply [white wire].
: The resistance of the bulb is supposed to stop the feed back.
: I have experienced this with electronic ignition fitted cars as the often get a voltage supplied from elsewhere, also electric fans radios etc starter motor/resister bypass circuit.

: Power coming from the alternator balances the light power flow, no charge, the currect flows and light comes on. [for those that didnt know]. It was common practise to put resistors across the bulbs to stop that anoying glow at night. [for cars with voltage earth woes] also diodes.

: Unless the bulb is to big not all the oil,brakes, direction indicators, igntion 2.2Watts
: high beam and dash ilumination lights = 2 candle power.


: I thought there was diodes in the alternator [IND] circuit to stop this problem.

: From: "Force7"
: Adam.
: Before you go and unwrap all the wiring from your engine bay try this.
: I need more information about the symptoms.
: If you stall the motor and put the key to the off position and disconect the alternator wiring does all the ignition lights go out.??
: If they do then the problem is with the alternator. If not you have other problems.

: With the key in the off position , motor not running does the ignition lights come on.??

: If it does come on then check the fuse box to see if there is a white wire (ignition) plugged into a brown wire (battery) somewhere on the fuse box. If there is then put the wires back to where they belong.
: If not then go the coil and locate the white wire that comes out of the harness and goes to the ballast resistor as well as the coil (+) Disconnect this wire from the ballast resistor and also from the coil.
: Place a jump wire between these two terminals. Start the car and see if this fixes it. If
: so then there is a stort like Stuart says somewhere down the harness.
: If this doesnt fix it let me know



: From: "Mark"

: Hi Adam.
: First thing to check is your ignition switch contacts to make sure it is not 'sticking' when you turn it off. There may be just enough residual current to keep the motor going if the contacts are not moving freely as they should inside the key switch assembly.
: Easiest thing to do is try another ignition switch assy.
: If all your other electrics work well, and you can't find a solution, consider inserting a relay, activated by a + out of the ignition switch, to feed power to the + coil contact thru the ballast resistor) to the coil, only when the ignition switch is turned on.
: If you felt adventurous you could also adapt this into an immobilizer.
: All the best
: Mark


: From: "Stuart"
: Date: Mon, 01 Dec 2003

: There are two things that cause this.
: You either have a wire melted together somewhere in your wiring loom and are also close to an electrical fire. Unfortunately this is not trivial to fix.
: You will need to unwrap all the wiring in the engine bay and find where the two wires are touching and rubbed through.
: It is most likely in the bit running from the fuse box to the starter.
: Alternatively there is a short in the starter.
: We burned out the entire wiring loom with this style of problem once.

: Stuart

: From: "Andrew Kloot"

: Date: Tue, 2 Dec 2003
: How about booking it in to your local auto electrician and let him deal with it all this un wrapping of wiring looms sounds like a disaster waiting to happen.
: Andrew


: From: "Mike"
: Date: Thu, 4 Dec 2003

: It's always difficult to identify an electrical fault, especially when the car is elsewhere. There are three places where ignition (white) and power (brown, and the power cable from the battery to the starter motor) are in close proximity.
: They are the fuse box, the starter motor, and the rear of the ignition switch.
: My first choice is with the starter motor solenoid cover. Check that all wiring is well insulated at that location, but most of all, that the bottom(white) wire and connector on the solenoid does not touch anything live connected to the battery positive, e.g. the main battery/starter lead or the brown wires that are normally attached there.
: This white wire normally provides 12volts to the coil while the starter is being used,
: to facilitate starting. If the white wire touches a live battery lead,
: then you could have a continual 12 volt supply to the coil, rendering the ignition
: switch out of circuit (and the ballast resistor is also out of circuit), making it ineffective when turning off the engine. Check the temperature of the coil before starting the car from cold: if it's warm then it probably has a continual voltage supply going to it while the engine is still and the ignition is turned off. You may also have noticed that the engine seems to go quite well - if I am right, it could be because the coil that normally
: runs on a ballast resistor receiving approx 8 volts, is actually running between 12 - 14 volts, giving a bigger spark. Do you still use points, or is your ignition electronic? If points, check their condition, and the condenser.
: You say that the ignition light glows dimly when this problem occurs. This could be because of the slow idle speed causing insufficient output from the alternator; this can be checked by increasing the engine speed up to see if it disappears. But if not, the dim light can also indicate the presence of low voltage in the ignition wiring behind the dashboard, perhaps even when the engine is stopped. As this voltage has to flow through the ballast resistor, the ignition light will be dimmer than when starting the engine because the voltage is reduced.

: I hope this helps a little. Always check that your earthing is good.

: Mike.


: From: "Adam"
: Date: Thu, 4 Dec 2003

: Well, what can I say.
: From melted wires to light bulbs to relays.

: In a sense, everyone was right.
: The light bulb in the dash was to big, and it is strange because it is the dash that I put in
: (when I converted the layout from Deluxe to Super).
: This did not fix it however.
: I then found a relay under the radiator (I could only see it from the underside of the car)
: wired into the coil wires.
: I removed this, and still it did not help.
: I did some investigating with a multimeter and found the fault to be somewhere under the radiator in the loom. Upon inspection, I found some shocking discoveries.
: I removed all the external tape of the loom from the temp wire round to the other side by the Inhibitor switch.
: On the right hand side, the wires for the balace resitor and for the lights had been twisted to-gether and taped up with masking tape!
: The big brown one to the alternator had also had the same treament.
: Over the years the tape had worn off leaving the wires exposed.
: The brown + wire had earthed to the body and melted into 2 pieces, along with
: fusing into the white balace resistor wireing.
: With the altenator not working, this was not noticable.
: But when the new one was fitted, + energy was fed directuly into the ignition system
: and could not be stopped without stopping the engine, which in turn was hard due
: the the supply of energy.
: I have replaced the white wires and joined them properly with solder and shrink wrap.
: Instead of leaving the wiring in the same positions, I decided to re-route them while they were exposed.
: I now have the big brown wire coming up from the left side, near the battery, to the alternator.
: I have done the same with the Temp wire and the brown and yellow one for the alternator.
: I will hopefully include photos and information on the car, as the restoration is going well.
: Thank you all for the feedback, it was very much appreciated,
: Adam

Leyland P76 Owners 2005

Technical Information

Adam and his electrical harnes problem

Some answers

Problem solved