Club 80-90 Forums

The wires to short would be the plug that you are testing from.

One way goes to switch that you have been testing to. The other way if looped out tricks the ECU to think switch is closed.

The switch can be adjusted on the throttle body too. 
Take it off and see if it is actually the switch faulty, or just mis-adjusted?

Here's an old vid of me playing with one:

[youtube]https://youtube.com/shorts/cL6sK-mQNjA?feature=share[/youtube]

it's to the left of your expansion bottle. Below the rear air vent

"will try and short wires to ECU next - where is the ECU?"



 

you use a piece of wire to jump the two pins on the black plug that plugs into the white socket; as Andrew says that is the same as the microswitch on the throttle body being closed, ie telling the ECU to release control to the idle control unit which runs the 'dls' retarder and air bypass valve and runs fuelling at idle

you should download the 2.1 manual from Syncrosport website (or Sir Adventure) it has all the diagnostic information and pictures showing all the components and detailing how to adjust

Bingo - connected the two pins, fired her up and she ticked over lovely on idle.

My next challenge is to investigate the throttle switch now! Is there a chance the adjustment is incorrect, or does it need replacing as no resistance was detected?

I appreciate all your help guys still - sorry for the numbty questions!

Ashwood wrote:Bingo - connected the two pins, fired her up and she ticked over lovely on idle.

My next challenge is to investigate the throttle switch now! Is there a chance the adjustment is incorrect, or does it need replacing as no resistance was detected?

I appreciate all your help guys still - sorry for the numbty questions!

Yes. They can be adjusted.


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If it's not closing at full throttle either the chances are the switch is mullered. I'd whip the throttle body off to have a proper look.

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Be aware the adjustment is made with small allen headed machine screws that can be seized well solid so you need decent tool and some plus gas or Wurth rost off to free things up before going at the adjustment
Once you have removed the throttle body remove the cover for the switch which is on the bottom first then you can manually operate the switch directly and test it again - sometimes a little contact cleaner in the switch is all that is needed, sometimes the switch is goosed beyond repair but they can be had and replaced, though finding a new switch may take a bit of research to find the correct size

Got it off, hurrah!

The tester now gives 0.5ohms on full throttle on the click, but then the switch goes back and does not the click for the idle setting. Assume it just needs a mm of adjustment. I’ve tried to loose the securing screw - the screw top wobbles slightly but will not loosen. Only got WD 40 in workshop so sprayed with that, but little concerned as the screw wobbles but still stuck fast.
Normally a stuck screw is rigid?

This vid will help with adjustment

I am intrigued as to what is the adjusting screw and compression spring that is fitted where the throttle cable normally attaches, not something I am familiar with.



Usually if the screw wobbles then the threads are damaged, either on the screw itself or the part it is screwed into

Here is another angle, I just unscrewed it from the rod.

so I could be up a certain creek without a paddle on the locking screw!!

Doh, the head has just sheared off the locking screw - what would you do now? Try and drill screw out and re thread?

I’ve searched online but cannot find any replacement switches - hmmmm.

Wait... The locking screw on the switch plate doesn't look sheared off.

Do you mean the head of the screw that acts as the mechanism to stop the flap in the throttle body carrying the force of the spring?

You alter the idle switch as per vid I posted in earlier.
( Apologies if I have mis-read something. )

my bad, I see now it's Auto so different linkage to the manuals I am used to

The locking screw is made out of monkey metal that corrodes badly, same thing has happened to mine - drill out 3mm then 3.3mm be careful not to drill through the plastic plate the and it should re-tap at M4 so you can fit a new screw - I plan on using the M4 hex head screw (7mm head with a blade screwdriver slot too, that we use in the syncro gearbox to secure the one way valve, cut down to length), I have had to order a 3.3mm drill bit though as I haven't got one in stock. M4 thread pitch is 0.7mm. I have M4 tap obviously

I can let you have a couple of the hex head screws