GolfGTIforum.co.uk
Model specific boards => Golf mk2 => Topic started by: aaand on 10 December 2005, 22:40
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how do i reset the idle? i am not mechanicly miinded and ned help, my idleing is rubbish,have replaced isv and not really any better, where is the blue sencer chip thing??? i have 8 valve 89 gti :cry:
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its on the front of the block on top of a black plastic housing with two water hoses going into it. check for any leaks round the crankcase breather bung (the flat, round thing on top of the rocker cover) it might well help to take off all the hoses connecting the ISV to the inlet and clean them out and possibly the throttle body with carb cleaner. then once everything is how it should be get the car running up to temperature (till the fan kicks in) then remove the blue plug from the temp sender, rev the car over 3k letting it drop to idle then you can adjust the idle speed with the little flat head screw in the throttle body. switch off, re connect the blue plug, wait a minute and start it up again. it 'should' be fine!
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nice one mate, will try this in the morning , im hopeing this is going to work, thank you very much :smiley:
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no worries! digifants are annoying when things like this happen as they rely on so many sensors etc unlike the mechanical earlier version....
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tell me bout it, its been driving me mad for ages ive read through the hayns man, ut some of it i just dont get, also would i need to adjust the co content screw?? would this help the idleing?
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not really and its easy to screw it up with out a proper way to measure the co2 levels.
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CO and idle should be both adjusted together, not one without the other(well thats the theory :laugh:).I think i am right in thinking the early digifant systems are adjustable.
Basically get all the basics checked, idle, co, ignition timing, check for vacuum leaks.
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did all that and still idles really rich, i was messing around with some switches at the back of the throttle body ( think it is the chock) and when pulled the wires it idled fine, so seems to be somethig to do with this, can i just disconect it, will it make a diference ??
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Try replacing it.
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yeah will tomorow,
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I did have this problem on a passat fitted with a 9A engine (2L 16V). it used to die intermittently but not completely, the revs used to bounce back up. But if i restarted the engine the problem went away.
I changed the throttle valve switch, the contact points had worn right down, and my problem was solved.
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im convinced that its to do with the choke because ive replaced the isv and checked fro leaks every thing, its getting me down now lol
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If it idles with the switches unplugged then it sounds to me like the idle switch is either broken or not being closed when the throttle is closed. The switch you need to check is under the throttle body and you can't get to it without taking the inlet boot off. Even then its a right mare as there isn't much room to get to the screws! If you unplug it the ECU will basically think your car is idling all the time so I imagine it'll run really badly, and it wont be able to enrichen the mixture at full throttle either!
Once you've sorted the 2 switches, the Idle/CO procedure on Digifant MK2 is as follows:
1. Get the engine up to temp, at least 80 degrees on the MFA oil temp display
2. Turn the engine off and remove & plug the intake side of the breather pipe between the rocker cover & air intake
3. Hold the MFA button in and turn the ignition on, off and on again, then start the car. This puts the MFA into a 'secret' mode. Put the MFA switch to setting 2 and press the button till you get the digital rev counter, position 2 I think :)
4. Unplug the blue temp sender and rev the engine cleanly over 3k rpm 3 times, letting it return to idle between each rev.
5. Check the rev display, adjust the idle with the idle screw on the throttle body to about 850-900 rpm. Clockwise to decrease, anticlockwise to increase
6. If you have a CO meter, block off one of the talipipes (i use a load of duck tape) and shove the probe up the pipe. Follow the manufacturers instructions, and set the CO to about 1.8ish using the allen screw on the MAF, clockwise to increase, anticlockwise to decrease.
If you don't have a CO meter, turn the screw in until the engine starts to sound rough then back it out gradually till the idle sounds smooth & even. Check the aerial or bonnet stay for vibration, you want it smooth as possible. This will get you close, then take it to a garage to get it set properly :)
7. Reset the idle to 850-900 rpm if it has changed, and adjust the CO accordingly, repeat till you get about 1.8 at 850ish rpm :)