17 replies to this topic

[HUBBA.HUBBA]

My alternator died yesterday. Prior to it dying, the ignition light was staying on when idling (fan belt was tight). Tested outuput - 11volts.
Now the Car will not start, engine turns over but no ingnition light. Would a knackered alternator cause this? Im have presumed that this is the issue, but until my alternator arrives on Tuesday im going to be constantly thinking about it.
Oil pressure light comes on ok.

Edited by HUBBA.HUBBA, 12 December 2015 - 11:46 AM.

[David128]

Looks like the Alternator is the problem. Looking at the wiring diagram seems  to point to that

[Stevie W]

Hi,

 

From memory, if the "field" windings inside the alternator go open circuit, you'll get no ignition warning light and no charging, which is what you have! I believe that this will also stop the engine from starting.  

You could check for 12v at the LT side if the coil to confirm this...hope this helps!

 

Cheers, Steve.

[dklawson]

Both the OP and IGN warning lights are powered off the same connection to the ignition switch.  If the OP light works that suggests that the IGN light should also be getting power.  The next test would be to unplug the alternator (WITH THE ENGINE OFF) and use a jumper wire to connect the small wire in the alternator plug to earth.  Turn the ignition on.  If the IGN warning light turns on, that says the bulb is OK, that the circuit has power, and that the problem is in the alternator.  If the bulb does not turn on, put a new bulb in the holder and try again.  With the jumper wire earthed a known good bulb should light up.  A working IGN warning lamp is mandatory for the alternator to start charging the battery... it is more than an just an indicator lamp.

 

A reading of 11 volts is for a very discharged battery.  Try a battery charger on it.  If you can get the rest reading up close to 12.5V after charging, the battery is still good.  You can start and drive the car short distances each day if you charge the battery again at the end of the day.  This will allow you to use the car until the new alternator arrives.

[HUBBA.HUBBA]

Thanks for the replies. I'll do that test. Its not my daily car so no immediate hurry, Was looking to upgrade the alternator to a lightweight one anyway, but will still do the test out of interest really.

[dklawson]

If nothing else, the test will confirm whether the IGN warning light works or not.  Remember, even with many aftermarket alternators, the warning light is more than an indicator.  It is part of the charging circuit that must work for the alternator to charge the battery.

[HUBBA.HUBBA]

Did the test and the light circuit is fine. Got the new alternator on. Still not starting. Getting a spark. Fuel coming through. Tested compression. One thing I have noticed is the oil pressure gauge not moving when turning engine over. Does that normally really move when the engine is running?

[GraemeC]

You're unlikely to be get oil pressure up on the starter as the engine isn't turning fast enough for the pump to build up pressure.

[dyshipfakta]

Engine turning fast enough to start? Does it bump easily?

[dklawson]

Did the test and the light circuit is fine. Got the new alternator on. Still not starting. Getting a spark. Fuel coming through. Tested compression. One thing I have noticed is the oil pressure gauge not moving when turning engine over. Does that normally really move when the engine is running?

 

How are you confirming there is spark?

How do you know fuel is getting into the cylinders?

 

Is the ignition light turning on and off with the key with the new alternator fitted?

[HUBBA.HUBBA]

Plugs out, hold against block and turn over for spark test.
Couple of the plugs seemed to have some moisture on them.
Ing light is turning on and off with new alternator.
Just wiggled lead off oil pressure sender and strangely the oil light is now not coming on!

[monkey]

If the wire is disconnected from the oil pressure switch on the engine block then the oil light won't come on at all - the switch earths the circuit to light the light

[HUBBA.HUBBA]

If the wire is disconnected from the oil pressure switch on the engine block then the oil light won't come on at all - the switch earths the circuit to light the light

Given it anothet wiggle and crimped it a bit and the oil light is now working.

Edited by HUBBA.HUBBA, 15 December 2015 - 05:58 PM.

[HUBBA.HUBBA]

Right, put more fuel in. Supply getting to carb. Took dash pot, piston and needle out to expose jet and no fuel comes out when I switch fuel pump on. Blockage in float chamber valve?

[dklawson]

Fuel is not supposed to come out of the jet tube on its own.  If it does, the float level is a bit too high or the jet set to low.  It is the vacuum created by air passing through the carb venturi that "sucks" the fuel out of the jet tube.  

 

However, you should be able to use a flashlight and look down into the jet to see fuel.  If you don't, then take a look in the float bowl and make sure there is gas in it.  On an HS series carb the bowl should be 1/2 to 2/3 full.

 

Your spark test is good.  Cars do not go badly out of ignition time on their own but points can wear to the point that the spark is weak and timing off just enough that the engine has trouble starting and running.  If your car has points, I would go completely through the valve adjustment process and give it an ignition tune up before you spend more than a cursory exam of fuel delivery and float level.  Do not touch the mixture until you have gone through the ignition.

 

Remember that a quick test is to tip a thimble of gasoline down the carb throat and try to start the engine.  If it fires, runs briefly, then dies, you have a fuel delivery problem to sort out.