VFSV6FORME
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My son's Statesman 6 cylinder with a 3.8 litre engine has an issue which I classify as dangerous and for the love of money I cannot find out what is causing it. I have spoken of this in my other thread about my son's Statesman but this deserves another thread by itself.
The issue is when the car is cold or the car has done only half a km from home the idle in neutral or in park after you put it in these two positions because you feel the car wants to go on, the idle goes up from 1200 or even up to 2500 rpm, yes you pick this whilst driving the car as you come to a set of lights, you put the foot on the brakes and the car wants to still go forward, so you put it in park or neutral and up the revs go from 1200 to 2500 rpm.
Now, I have spoken about a sticky throttle, but its not that because the car drove in my driveway and it was doing 2200 rpm in park so I lifted the bonnet, grabbed the throttle cable on the throttle body itself and slammed it shut, which it was shut, it was 100% shut. I grabbed the cable again and opened the throttle body more and slammed it shut again, I heard the thud sound, so it was 100% shut, but still the car was idling at 2200 rpm, so after this I suspect that either the idle control valve was getting a fake message from the ECU that was making the car idle that fast or was that EGR valve, I think its the EGR valve, that motorized unit that sucks exhaust gases ( from the Passengers side exhaust) , goes through this motor and then injects it on the manifold side of the throttle body.
Now, this exhaust gas to the manifold if they call it the EGR valve that looks like a windscreen wiper motor, I have blocked that now to test, but it still does it, but I will go back on the last paragraph when the car was idling on 2200 rpm. To get it to go back to normal, forget about slamming the throttle body , forget about the EGR valve, most of the time, I say most of the time, turn the engine off, then start it after a minute and the car idles on 900 rpm.
Now, it only leaves the Idle control valve and since I have changed two of these I don't think its the idle control valve that is causing the issue not unless it getting a FAKE message from the ECU. Now, I got my spare idle control valve and I wound it in so it allows more air flow in, I put it in the car, did not connect it and started the car and the car revved about 2700 rpm, so by this, you can see that the idle control valve can allow this car to idle at 2700 rpm in park or neutral, so the question is if the idle control valve is causing the issue, what can cause the idle control valve to fully or partly wind in (more air come in) that allows too much air in that makes the engine idle from anything from 1200 to 2800 rpm?
What else could cause this? Does this car have an intermittent power booster issue that is allowing vacuum in the manifold that allows the car to have a higher RPM when the throttle is fully closed? Or what do you think about that other valve (forgot what its called) the one that sucks the fumes from the petrol tank then goes through a solinoid and after this goes to the manifold side of the throttle body. So what happens if this is stuck occasionally open?
This issue with this Statesman has confused me because its not my car, otherwise I would have changed everything with a new throttle body, new EGR valve and new everything else, but I have a feeling if I did this the problem would still be there, something is occasionally allowing air to come into the manifold to make it idle to 1200 to 2800 rpm and as soon as you turn the ignition off or turn the ignition off again and wait for 5 minutes then turn the car back on its OK, it idles on its correct RPM, which is about 900 rpm.
Once again its not a stuck throttle cable, its not a Cruise control cable as its disconnected so what do you think I have missed.
The issue is when the car is cold or the car has done only half a km from home the idle in neutral or in park after you put it in these two positions because you feel the car wants to go on, the idle goes up from 1200 or even up to 2500 rpm, yes you pick this whilst driving the car as you come to a set of lights, you put the foot on the brakes and the car wants to still go forward, so you put it in park or neutral and up the revs go from 1200 to 2500 rpm.
Now, I have spoken about a sticky throttle, but its not that because the car drove in my driveway and it was doing 2200 rpm in park so I lifted the bonnet, grabbed the throttle cable on the throttle body itself and slammed it shut, which it was shut, it was 100% shut. I grabbed the cable again and opened the throttle body more and slammed it shut again, I heard the thud sound, so it was 100% shut, but still the car was idling at 2200 rpm, so after this I suspect that either the idle control valve was getting a fake message from the ECU that was making the car idle that fast or was that EGR valve, I think its the EGR valve, that motorized unit that sucks exhaust gases ( from the Passengers side exhaust) , goes through this motor and then injects it on the manifold side of the throttle body.
Now, this exhaust gas to the manifold if they call it the EGR valve that looks like a windscreen wiper motor, I have blocked that now to test, but it still does it, but I will go back on the last paragraph when the car was idling on 2200 rpm. To get it to go back to normal, forget about slamming the throttle body , forget about the EGR valve, most of the time, I say most of the time, turn the engine off, then start it after a minute and the car idles on 900 rpm.
Now, it only leaves the Idle control valve and since I have changed two of these I don't think its the idle control valve that is causing the issue not unless it getting a FAKE message from the ECU. Now, I got my spare idle control valve and I wound it in so it allows more air flow in, I put it in the car, did not connect it and started the car and the car revved about 2700 rpm, so by this, you can see that the idle control valve can allow this car to idle at 2700 rpm in park or neutral, so the question is if the idle control valve is causing the issue, what can cause the idle control valve to fully or partly wind in (more air come in) that allows too much air in that makes the engine idle from anything from 1200 to 2800 rpm?
What else could cause this? Does this car have an intermittent power booster issue that is allowing vacuum in the manifold that allows the car to have a higher RPM when the throttle is fully closed? Or what do you think about that other valve (forgot what its called) the one that sucks the fumes from the petrol tank then goes through a solinoid and after this goes to the manifold side of the throttle body. So what happens if this is stuck occasionally open?
This issue with this Statesman has confused me because its not my car, otherwise I would have changed everything with a new throttle body, new EGR valve and new everything else, but I have a feeling if I did this the problem would still be there, something is occasionally allowing air to come into the manifold to make it idle to 1200 to 2800 rpm and as soon as you turn the ignition off or turn the ignition off again and wait for 5 minutes then turn the car back on its OK, it idles on its correct RPM, which is about 900 rpm.
Once again its not a stuck throttle cable, its not a Cruise control cable as its disconnected so what do you think I have missed.
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