10 replies to this topic

[iwatkins]

Hi All,

 

Came to start the car this morning. "Turned on" the battery (we have a kill switch in the boot) and key in ignition, turned to position 2, fuel pump starts, then past position two on the spring to start. Starter turns then doesn't stop turning.

 

Key back to position 1, starter still turning. Key back to off and key removed and starter still running. Fuel pump stopped as it should when key moved back past position 2.

 

Used kill switch in boot to isolate before flattening battery.

 

Went back to it a while later, turn on kill switch, starter runs, turned off again. Key "feels" right in the ignition switch barrel, i.e. it turns fine through all positions and springs back nicely from the start position.

 

Where to start to diagnose this? At the ignition switch, then the relay, then the starter solenoid?

 

Ignition switch is about the only thing that hasn't been replaced on the interior. 

 

Car is a 1990 Studio2 with a 1991/92 1275cc engine. Starter and solenoid coexist, so a pre-engaged one. Relay is behind the dash somewhere I guess as the fusebox was moved by previous owner to behind the dash rather than in engine bay.

 

Cheers

 

Ian

 

 

[WiredbyWilson]

try unplugging the ignition switch along the column - this will tell you if its the switch or not.

 

Failing that try the relay - but not sure there is one for starter?

[iwatkins]

Ok, with power off via the kill switch, I've unplugged the ignition switch from the loom under the steering column.

Working on the ignition switch mini loom I have four connections at the pins on the connector. Using a multimeter on continuity mode, I've held the positive probe to the brown wire and the negative probe against the other pins.

With the key at OFF, I don't get anything. Good.

Key at position 1 I get continuity between the brown and light green/white. Good.

Key at position 2 I get continuity between the brown and light green/white and between the brown and white. Good.

Key at START I get continuity between the brown and light green/white and between the brown and white and between the brown and red/white. Good.

So I'm guessing that rules out the ignition switch?

With the ignition switch disconnected, turning the power on via the kill switch turns the starter still.

So does that rule out the ignition switch and the starter relay and that I should be looking at the solenoid or even the starter itself?

Cheers

Ian

[Dan]

  All you really had to do was unplug the ignition switch and turn the isolator back on to see if the starter still ran!

 

  Is the starter engaged in the flywheel, or just running retracted?  I'd tend to suspect the solenoid at the moment.  With the ignition still unplugged try the isolator again. If the motor still runs isolate it again and go around and unplug the small brown/red from the solenoid.  Then try the isolator again.  If it still runs it's definitely the solenoid.

 

  The relay should be on the inner wing by the master cylinders.

[lrostoke]

I think there is a starter relay on that sort of age car.

Look for a relay with a brown wire and a red/white, brown/red and black...

If brown/red is live with ignition off and red/white isn't suggests relay sticking

[iwatkins]

Thanks Guys.

 

Yes, with the ignition switch unplugged the starter still runs as soon as the isolator is switched on.

 

If I pull the connector with the brown/red wire off the spade on the solenoid, the starter doesn't run when the isolator is switched on.

 

When the starter is running, it is engaged with the flywheel, i.e. the engine itself is turning as the fan belt/alternator pulley/fan is all moving.

 

Lrostroke, I'll pull the dashboard out shortly and trace the the wiring to the relay and test that.

 

Cheers

 

Ian

[Ethel]

Brown/red on the starter's operation terminal would indicate a relay, I think it would be located under the bonnet.

[Dan]

If I pull the connector with the brown/red wire off the spade on the solenoid, the starter doesn't run when the isolator is switched on

 

 

 

  It's the relay or the relay wiring.  If it's been moved the previous owner could have made a mistake with it.

[iwatkins]

Thanks everyone for their help.

Sure enough, the relay was stuck open. Relay was just inside the bulkhead drivers side where the loom runs through to under the bonnet. Probably moved there when the fuse block was moved inside too.

Relay looked original, took it out, cleaned the connector on the loom, fitted a new 12v 30amp relay and everything was fine, car started, starter stopped etc. Sorted.

Tested the old relay on the bench and sure enough, stuck open. Gave it a whack and it closed again. Chucked it in the bin.

I've learned a lot about the ignition circuit today, not something I've had to worry about before. Dash can stay out for now (always a bind to do) as I'm converting from 2 to 3 clock gauges next week and making a better dash to suit.

So again, thanks again everyone. Not sure what I would do without you.

Cheers

Ian

[iwatkins]

All you really had to do was unplug the ignition switch and turn the isolator back on to see if the starter still ran!

Yep, well I know that now. Didn't know that before today. So another bit learned.

[Carlos W]

Well done for sorting it!

You were logical and methodical in your approach which made it easy for people to give advice