My Mk2 (16V ABF) was doing this with ever increasing regularity, pull up at lights or junctions and it would take it upon itself to sit and rev at anything up to 3K, go down the road a bit and was OK again. Very annoying. After cleaning out my ICV, Throttle body and associated bits and bobs for the umpteenth time, and it still did it, I decided to look for other possible causes. It didnt take me long to find something interesting......
There are 2 electrical connectors on the throttle body one on the lower front and a smaller one on the upper rear.....
Now, I dont know what they do but im sure they must be responsible for sending some sort of electrical signal with regard how far open your throttle is so the ECU can work out air/fuel mix, if anyone knows feel free to jump in!!
The wiring for these connectors runs along the back of the top of the engine block and is fastened directly to the cam cover by 2 clips. They are covered by a thin plastic cover. When I undid them and took a look I discovered something truly horrific!!
The heat from the engine block had more or less melted the plastic cover away on the smaller connector and the wiring as you can see is fried, KFC`s got nothing on these babys. The wires were so crispy one of them actually just snapped off while I was removing it.
I cut out the crispy deep fried length and spliced in some new bits, wrapped the whole lot in heat reflective sheet ( that`ll be tin foil then...
), and ran the wiring through an old bit of aluminium duct tube I had keeping it away from the engine block.
Since I did that nearly 2 weeks ago Ive not had one incident of random over revving at idle.Is it cured? Hey its a Mk2! anything can happen in the next half hour!!!
Could be worth checking if yours is doing this, Cheers TF
There are 2 electrical connectors on the throttle body one on the lower front and a smaller one on the upper rear.....
Now, I dont know what they do but im sure they must be responsible for sending some sort of electrical signal with regard how far open your throttle is so the ECU can work out air/fuel mix, if anyone knows feel free to jump in!!
The wiring for these connectors runs along the back of the top of the engine block and is fastened directly to the cam cover by 2 clips. They are covered by a thin plastic cover. When I undid them and took a look I discovered something truly horrific!!
The heat from the engine block had more or less melted the plastic cover away on the smaller connector and the wiring as you can see is fried, KFC`s got nothing on these babys. The wires were so crispy one of them actually just snapped off while I was removing it.
I cut out the crispy deep fried length and spliced in some new bits, wrapped the whole lot in heat reflective sheet ( that`ll be tin foil then...
), and ran the wiring through an old bit of aluminium duct tube I had keeping it away from the engine block.
Since I did that nearly 2 weeks ago Ive not had one incident of random over revving at idle.Is it cured? Hey its a Mk2! anything can happen in the next half hour!!!
Could be worth checking if yours is doing this, Cheers TF
