MKII 16v engine problems??

[TIM20]

I have got a 1991 golf 16v

When i start the car some tiimes the temperature light continues to flash (longer than normal) and the rev counter rapidly fluctuates between idle and about 2500rpm.  the engine just ticks over as normal and sounds fine. 

This is really anoying me now and i cant think what is causing it

 it continues while driving but it has no effect on the cars performance etc

Any ideas???

Tim

[Purple Monster]

Give the isv a clean

[vwsystems]

yeah give the isv a clean,

if your car wont idle once hot and has the revs all over the place the throttle switches may be at fault!
theses tell the ecu when the throttle is shut and to put it in idle mode! there are 2 switches 1 for throttle shut and 1 for full throttle!

sometimes the wires from the switches snap and this will have the same effect, or the switches go all together! to check if the wires have snapped or are at fault get a multimeter and unplug the connector from the switches and cross the terminals you should get a few volts, but keep the ignition switched on without the engine running! if you dont get any reading it will apear that the wires have snapped somewhere probibly either inside the connector or inside the vw plasitc sleaving!

if the wires are ok then it will be the throttle switches!

there is only too things which make the temp led flash this is water level too low or water temp too hot!

so your water level may be low.....!

hope this helps

[Veedubgt18v]

this applies to an 8v more than a 16v cos the 16v is mechanical injection. make sure your base settings are right (timing etc) the onkly 'ecu' on a 16v is the one controlling the igniton.

[Gambit]

i would check the throttle switches. especially the one that the throttle arm rests against when idling

if you look at the throttle body you will see the switch. you should hear this click when you move the throttle yourself from under the bonnet

[vwsystems]

mine clicked but it didint work..........

to test them just unplug them.............

if theres a difference then they work but if the engine runs and idles the same theres the problem!

mine kept doing it on and off! coming and going!
i kept thinking the isv was at fault!!!

been like that for well over a year! only in december did i find out it was theses!