P38 4.6 hse wont rev up

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skippy22

New Member
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170
Location
bedfordshire
Hi i just bought a hse it had becm fault, i replaced the becm and key now its starts and everything works, it now wont rev very well it will rev to 2000rpm and thats at a struggle, the diagnosis says cam sensor and another one but i replaced them and still same, someone say the green circle thing near the ignition could be at fault, the car has had £1000's spent on it completly rebuilt engine with 4.0 block as the 4.6 in it was cracked, does anyone have idea what it could be
Thanks
 
What else is diagnostics saying? What's the background info? New engine or ex-scrapper? LPG or just petrol? Engine ECU changed by T4 to 4.0 from 4.6 spec? More info please.
 
Hi i just bought a hse it had becm fault, i replaced the becm and key now its starts and everything works, it now wont rev very well it will rev to 2000rpm and thats at a struggle, the diagnosis says cam sensor and another one but i replaced them and still same, someone say the green circle thing near the ignition could be at fault, the car has had £1000's spent on it completly rebuilt engine with 4.0 block as the 4.6 in it was cracked, does anyone have idea what it could be
Thanks

The green circle is the light to guide you to ignition key. Try the throttle position sensor.
 
its just petrol, as far as im aware thats all diagnostic says and ecu is origonal,

has had full engine over haul, cylinder heads were removed suspect head gasket! but found leaking linner in block, used a 4.0 ltr block, 4.6 crankshaft used new big and main bearings,new camshaft bearings with new camshaft and followers new timing chain and oil pump. cylinder heads were skimmed and valves recut. new pistons with rings, new water pump new spark plugs and coil pack.
it only done about 100 miles after engine was rebuilt, then it had the becm fault the becm was done then this problem accured
 
Your original Engine ecu is set for the 4.6 and has adapted itself to that spec. and your old engine characteristics. You have suddenly replaced the engine with a different animal. Firstly, you need to get the engine ecu put into adaptive learn mode in order for it to self teach to the different engine. If that fails, try swapping the engine ecu with one for the 4.0 litre, again getting it put in to adaptive learn mode (Default..Factory).
Bear in mind that the fuel delivery/mapping requirements for the 4.0 are different to the 4.6. If your old 4.6 ran ok on the ecu settings, the 4.0 is a different animal as far as the mapping is concerned.
 
apparantly the ecu is done but it still has the fault
the bloke who is looking at it has asked if the fly wheel on the 4.0 and 4.6 are thepick ups the same (havnt a clue what hes on about), he said when he done a rover once the same prob seemed there and it was that any ideas
 
mine had the same problem,it was the crank sensor. Also check the flywheel as the pickups for the sensor can get damaged when swapping engines.
 
Not sure,would think so. Its called a reluctor ring i think and is fitted to the flywheel. You can see it through the crank sensor hole if you take it out. The sensor was about £70 from the dealer and it ran fine straight away.
 
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