Corsa-B.uk - Vauxhall, Opel and Holden Corsa B Owners Club

Hi all a bit new to the corsa scene. Have just bought a 1999 1.2 16v automatic 5 door for my wife. all seemed fine when we tried it. now, when started it has a very fast idle (1500) which isnt steady, it rises and drops by say 50 rpm about every second. I have spoken to the garage i got it from and they have said that they changed the idle control unit on the side of the throttle body and it was fine.
I have found that this unit was holding the throttle open a bit and spaced it away with washers to get the idle down to about 1000. only problem is that now when you put it into drive it drops to about 700 rpm and doesnt start easily in the morning. And also when driving along when the engine is at 1500 rpm the fluctuation in engine speed seems to return but only at this engine speed. I have tried to do this paperclip diagnosis thing but there aint enough pins as it needs to go between 5 and 6 but i only have 345 and one on the other row of pins. Any help or a point in the right direction would be great. thanks

ben

The idle control valve is is very finely controlled by the ECU and you will be confusing the ECU by spacing it out you should get rid of the washers.

A 1500 idle is high but does it drop down to 1000 after a few minutes when it has warmed up?

A fluctuating idle of 50rpm isn't too bad if there is a problem it will fluctuate alot more than that. Does it fluctuate while driving i.e. can you feel the engine accelerate the car by itself sometimes?

When I replace a part that is controlled by the ECU, like the idle control valve I dissconnect the battery for a few hours. This resets the ECU then when you start the engine again the ECU has to learn where the idle is so I will leave it idleing untill the revs drop when it has warmed up then take it for a drive.
WARNING: disconecting the battery will reset your radio so you need to know the code to get it to work again! electric windows may need to be recalibrated this is done by holding the up button for 5 seconds while the window is closed and the same with down. Aslo Check what it says in your manual in regards to the Auto box.

As for the paperclip test vauxhall decided to leave out the vital pins on the plug in some of the later corsas meaning the only way to check the fault codes is with a hand held machine, most garages have them but will charge for the use of them.