aollaku

Active Member
Hi folks. I have a range rover P38A 4.0 SE automatic 1996. When i start the car in the morning or when is cold down he have diffuculties to start and after start go to high RPM 1600 or 1900 RPM and i cant move gear selectore because i can break the gearbox in that RPM from position "P" to "D" position. There is no error on dashboard :( :( or in diagnostic tools :( :(. Is an LPG conversation with multipoint injection "Lovato".
 
You have already been advised what could be the cause. As your engine is throttled by air. You either have a faulty idle control valve or an air leak in it's piping circuit. Also check that the throttle linkage is adjusted correctly and not sticking.
 
I understand but i clean the idle control valve and the throttle with a cleaner and work better but there is no leak.
 
I understand but i clean the idle control valve and the throttle with a cleaner and work better but there is no leak.

It has to be getting excess air from somewhere. Is this constant or does it settle back to normal when hot? If it is constant check throttle linkage, there MUST be slack in throttle cable and cruise cable must be adjusted correctly if fitted.
 
no the linkage i checked and is ok. The RPM move they are not costant. Dose not move to much but move. For example from 1700 to 1800 or 1900 RPM or 1200RPM. Most of time they move with 100 RPM+-
 
no the linkage i checked and is ok. The RPM move they are not costant. Dose not move to much but move. For example from 1700 to 1800 or 1900 RPM or 1200RPM. Most of time they move with 100 RPM+-

Well it's getting excess air from somewhere. Should be idling at 700 RPM. Cold start RPM of around 1100 RPM rapidly dropping to 700 RPM on warm up. Diagnostics may show something.
 
Ok. Can i give you a pic of my engine and tell me what you can see??? And if there is something worng????
 
Obviously you were working on it and have several parts disconnected in the photos. Can't get anything from that looks like a plumbers nightmare. I would say somewhere in that lot you have an air leak. Where, is any ones guess. Make sure venturi is closing properly. Try some diagnostics on it to make sure idle value is correctly set and to pick up any faults. Sorry but that is all i can tell you.
 
I checked and diagnostic and there is nothing wrong :(. Mechanic change idle control valve, throttled, MAF, throttled sensor and nothing, We could not find any problem or air leak somewhere :(. Is very frustated :(.
 
Either the idle control valve is set incorrectly or you have an induction air leak there cannot be any other explanation.
 
how can i test for air leak??? because the idle control valve cant be set incorrectly i mean the wire plug.
 
how can i test for air leak??? because the idle control valve cant be set incorrectly i mean the wire plug.

The idle speed can be set (raised or lowered) by diagnostics. But if that has not been changed then it is either a malfunctioning idle control valve. The throttle valve is slightly open. Or you have an air leak.
 
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how can i find an air leak is any method around???

Check ALL the pipe work around the throttle valve and the manifold. Anywhere the engine can suck air other than through the idle control valve or the venturi.
 
i have seen but i cant find nothing :(. There is any method to check or test the pipe for air lake
 
Hi wammers i have changed everything. pipe, idle control valve, throttel position sensor TPS and now there is another problem the rpm are not high but when it start go to 800rpm and then go to 0 and after 1 seconds go to 800rpm this do 3 or 4 time then is more stabilized and move a llittel 50 or 70 rpm. Could be the spark plugs????
 
Hi wammers i have changed everything. pipe, idle control valve, throttel position sensor TPS and now there is another problem the rpm are not high but when it start go to 800rpm and then go to 0 and after 1 seconds go to 800rpm this do 3 or 4 time then is more stabilized and move a llittel 50 or 70 rpm. Could be the spark plugs????

It would have made more sense to change one thing at a time to sort your problem. You have upset something get it on diagnostics. Sounds like idle control valve. Won't be spark plugs.
 

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