Range Rover P38. 4.6 litre, Rough idling......IAC valve?

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Dan Meulebrouck

New Member
Posts
35
Hi everyone
Im new to Landyzone and want to say hello to everyone and hope that someone can help me.....
My 2001 P38 '4.6 Vogue' has recently developed a fault that the dealer cannot seem to find.
The car runs normally but when idling, both hot and cold, the engine feels a little rough, it is idling around 850rpm but just feels throbby and course, you can actually feel it turning over through the seats. The dealer (franchised) can find no fault but a recent trip to a none franchised specialist found a fault code indicating that the IAC valve was faulty...... I have not got a clue what this is and do not know whether this valve could be causing the problem......
Does anyone have any advice or experienced a similar problem. The garage also suggested a faulty injector or even an engine mount. Not being mechanical at all, and disabled to boot, so unable to crawl under and over the car I have no clue!
Great site, great threads......
regards.
Dan
 
Hi everyone
Im new to Landyzone and want to say hello to everyone and hope that someone can help me.....
My 2001 P38 '4.6 Vogue' has recently developed a fault that the dealer cannot seem to find.
The car runs normally but when idling, both hot and cold, the engine feels a little rough, it is idling around 850rpm but just feels throbby and course, you can actually feel it turning over through the seats. The dealer (franchised) can find no fault but a recent trip to a none franchised specialist found a fault code indicating that the IAC valve was faulty...... I have not got a clue what this is and do not know whether this valve could be causing the problem......
Does anyone have any advice or experienced a similar problem. The garage also suggested a faulty injector or even an engine mount. Not being mechanical at all, and disabled to boot, so unable to crawl under and over the car I have no clue!
Great site, great threads......
regards.
Dan

I can tell you the IAC is the Idle Air Control, it's used by the ECU to maintain the correct engine idle speed. It's operated by a solenoid that moves the valve in and out, fine controlling it by sending electrical impulses to it, for example for half open it would be energised for fifty milliseconds if it was a 100Hz frequency circuit.
If you follow this link:
Help!! Looking for IAC on 4.6 - Land Rovers Only - Land Rover Forum
there is a picture of the IAC (with a green label on it)
Just buy a new IAC and replace it.
Hope this has helped.

Landygirl87
 
Hi everyone
Im new to Landyzone and want to say hello to everyone and hope that someone can help me.....
My 2001 P38 '4.6 Vogue' has recently developed a fault that the dealer cannot seem to find.
The car runs normally but when idling, both hot and cold, the engine feels a little rough, it is idling around 850rpm but just feels throbby and course, you can actually feel it turning over through the seats. The dealer (franchised) can find no fault but a recent trip to a none franchised specialist found a fault code indicating that the IAC valve was faulty...... I have not got a clue what this is and do not know whether this valve could be causing the problem......
Does anyone have any advice or experienced a similar problem. The garage also suggested a faulty injector or even an engine mount. Not being mechanical at all, and disabled to boot, so unable to crawl under and over the car I have no clue!
Great site, great threads......
regards.
Dan

I can tell you the IAC is the Idle Air Control, it's used by the ECU to maintain the correct engine idle speed. It's operated by a solenoid that moves the valve in and out, fine controlling it by sending electrical impulses to it, for example for half open it would be energised for fifty milliseconds if it was a 100Hz frequency circuit.
If you follow this link:
Help!! Looking for IAC on 4.6 - Land Rovers Only - Land Rover Forum
there is a picture of the IAC (with a green label on it)
Just buy a new IAC and replace it.
Hope this has helped.

Landygirl87
 
Hi landygirl87

Thank you so much for the explanation!

The car is booked in and is to have a new IAC unit fitted. Will let you know if this cures the problem!
Best regards, and grateful thanks.
Dan
 
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