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wyatt_erp

New Member

• Dec 2, 2011

• #1

First P38 purchased today, and it seems to have a metallic "knock" when under load under normal driving conditions. It does not do it when idling or when revving freely. When this happens, the engine is up to running temp but no signs of over heating occuring. No management lights on etc.

Does anyone with familiarisation with the P38 4.0 have any advice or pointers to places for me to begin a search. I dont really want to be replacing end shells if its something simple that may just be a trait to this model of Rangie.

Any advice gratefully received.

Thanks in advance.

 

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Stoneytd5

New Member

• Dec 3, 2011

• #2

is it knocking or detonating ( pinking) as plug leads break down under load on these very often

 

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wyatt_erp

New Member

• Dec 3, 2011

• #3

Stoneytd5 said:

is it knocking or detonating ( pinking) as plug leads break down under load on these very often

Click to expand...

Definitely sounds more like ends - either little or big. As soon as you take load of the throttle, it goes quiet again.

Its definitely not pinking/detonation.

 

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Stoneytd5

New Member

• Dec 5, 2011

• #4

wyatt_erp said:

Definitely sounds more like ends - either little or big. As soon as you take load of the throttle, it goes quiet again.

Its definitely not pinking/detonation.

Click to expand...

does it sound like its knocking thru the inlet manifold??????

 

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dirtydiscov8

New Member

• Dec 6, 2011

• #5

If it worsen under load its usually mains and if it worsens when not under load big ends...or is that the wrong way round!!!

Easy way to check for sure if you think it's a bearing knock is to take of the sump and pull off a big end and main cap and have a look to see if they are worn down and showing copper coloured wear marks.

 

vougese39

Well-Known Member

• Dec 7, 2011

• #6

Sticking valve worn valve train,slipped linner,worn little end or big end or even a badly unbalanced crank or a rebuilt engine put together incorrectly all option to consider

 

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wyatt_erp

New Member

• Dec 13, 2011

• #7

Hi - Just an update, I think the problem lies with a faulty knock sensor which is causing over fuelling down one bank of cylinders. Im trying to get someone to let me know what the resistance should be on the sensor when removed from block and unplugged.

Anyone?

 

vougese39

Well-Known Member

• Dec 13, 2011

• #8

whats the feed back of the sensor in live data with a diagnostic tester if it is overfueling on one back then you need to see the sensor feedback for the lambdas and the afm and the coil charge times and the injection pulse width timing too

the knock sensor is a peizo crystal that flexis though vibration of the misfire so you need to see what all the sensors are doing