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igglez
New User
May 7, 2010, 12:43 AM
Post #1 of 2
(1582 views)
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Idle Speed Control Valve
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Hi,
I wonder if you could give me some advice. My car details are the following
Vauxhall Corsa B (1999)
1.2 16V
Mileage is around 75,000
The other day my engine management light come on, and my revs started playing up. When I’m stationary my revs are sporadic, rather than staying around 1000 they move up and down, making my engine sound a little crazy. If I put a little revs on and off this goes away, until I set off again and then it’s the same problem again.
Also, when slowing down, my car starts to stall forcing me to put the clutch down, and I basically can’t drive in high gears at slowish speeds, where before I used to drive in 4th its now 3rd and 5th 4th if that makes sense, or the car starts jumping about.
I put my car on one of those computers (don’t know what it’s called) and it came up with “idle speed control valve”, so I went and got a new throttle bay from a motor spares place (wasn’t new). I fitted this, but the problem is still there. When a guy put it back on the computer it come up with 2 faults found. Both the same thing, Idle Speed Control Valve, however 1 was not present 1 present. He said its running in “safe mode”? not sure what this is so he switched it off, and it seemed to fix it for a second but then it went straight back to how it was and when we tested it again it was back to this.
Now I’ve been told it could be the air flow sensor, but wouldn’t this come up as its own individual fault? I’ve been told mixed things about that, I was going to get one later to see if that fix’s it but I am very sceptical. I think it could also be the throttle bay I got also had the same fault but is that very likely?
Any help would be greatly, greatly appreciated!
Thanks,
Dan
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Loren Champlain Sr
Veteran
/ Moderator
May 7, 2010, 5:21 PM
Post #2 of 2
(1563 views)
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Re: Idle Speed Control Valve
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igglez; Can you post the exact code numbers? In most cases, the IAC (idle air control) valve can be cleaned. Very seldom does one have to be replaced, but it does happen. If you disconnect the MAF (mass air flow sensor) and the idle speed returns to normal, again, these can usually be cleaned, rather than replaced. Here, in the US, we have MAF cleaner available at most any parts store, which can also be used to clean the IAC. You could have a vacuum leak that is causing the idle speed problem, as well. Since Vauxhalls aren't imported to the USA, can't be sure of the computer's diagnostic abilities?
You may be shifting into a higher gear too soon. You should see about 2500-3000 revs prior to shifting into a higher gear. May be 'loading up' the engine, otherwise?
Loren
SW Washington
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