4.6 Running lean pinking

Hi i have 4.6 with 160k on it pinking like a

Its been on LPG all its life the pink is getting annoying for around 2000k now its been pinking particularly on first start up for a few minutes but even if the engine is warm it will pink until it gets red hot and when its red hot it sounds a bit tinny still and has a flat spot around 2200 - 3000 rpm were if you boot it if thinks about it before doing it and if you accelerate slowly through this it misses and splutters.

Now this happens both on LPG and Petrol but as always with faults worse on LPG so the LPG can be ruled out.

I have plugged in Diagnostics the only fault is the camshaft position sensor, i have reset it but it still comes back ( and funnily doesn't put the engine management light on???) so obviously i will change that BUT could this really be the fault ??? Come on its a P38 nothing is that simple is it ??

Any one shed some light on pinking ??? or running lean ?

remedave said:

Hi i have 4.6 with 160k on it pinking like a

Its been on LPG all its life the pink is getting annoying for around 2000k now its been pinking particularly on first start up for a few minutes but even if the engine is warm it will pink until it gets red hot and when its red hot it sounds a bit tinny still and has a flat spot around 2200 - 3000 rpm were if you boot it if thinks about it before doing it and if you accelerate slowly through this it misses and splutters.

Now this happens both on LPG and Petrol but as always with faults worse on LPG so the LPG can be ruled out.

I have plugged in Diagnostics the only fault is the camshaft position sensor, i have reset it but it still comes back ( and funnily doesn't put the engine management light on???) so obviously i will change that BUT could this really be the fault ??? Come on its a P38 nothing is that simple is it ??

Any one shed some light on pinking ??? or running lean ?

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Pinking is pre ignition were the fuel is ignited by heat rather than by the spark. Maybe **** petrol, cannot pink on gas it is far to high octane.

Not strictly true, pinking it caused by incorrect timing under fuelling and incorrect grade

Pre ignition heat pinking as you say used to happen in the olden days before inter web , in the days of carbs and manual chokes and stuff, when cars used to "run on"

This is pinking caused by incorrect fuelling and or timing a petrol version of diesel knock.

remedave said:

Not strictly true, pinking it caused by incorrect timing under fuelling and incorrect grade

Pre ignition heat pinking as you say used to happen in the olden days before inter web , in the days of carbs and manual chokes and stuff, when cars used to "run on"

This is pinking caused by incorrect fuelling and or timing a petrol version of diesel knock.

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Pinking is pre ignition were the fuel is ignited by pressure and heat. And not by the spark. Incorrect timing will cause heat, weak mixture will cause heat, glowing deposits in the combustion chamber can cause pinking and running on. Pinking is usually caused by using low octane fuel in an high compression engine. Octane rating is a measure of the propensity of fuel to compression ignite. Lower more chance, high less chance. LPG has an octane rating of something in the order of 115 and cannot be ignited by compression. Don't try to teach your granny to suck eggs.

Not to get of on the wrong foot here but i will teach Granny buddy

The fuel-air charge is meant to be ignited by the spark plug only, and at a precise point in the piston's stroke. Knock occurs when the peak of the combustion process no longer occurs at the optimum moment for the four-stroke cycle. The shock wave creates the characteristic metallic "pinging" sound, and cylinder pressure increases dramatically. Effects of engine knocking range from inconsequential to completely destructive.

Knocking should not be confused with pre-ignition. They are two separate events, however, pre-ignition is usually followed by knocking.

And to quote LPG octane is no were near 138 !! its between 100 - 110 normal industry 108

I i am not trying to be cleaver mate but there are the facts :fencing:

SO can we get back to causes of this P38 PINKING

Regards

for the record …..

Pre-ignition (or preignition) in a spark-ignition engine is a technically different phenomenon from engine knocking / pinking, and describes the event wherein the air/fuel mixture in the cylinder ignites before the spark plug fires. Pre-ignition is initiated by an ignition source other than the spark, such as hot spots in the combustion chamber, a spark plug that runs too hot for the application, or carbonaceous deposits in the combustion chamber heated to incandescence by previous engine combustion events.

The phenomenon is also referred to as 'after-run', or 'run-on' or sometimes dieseling, when it causes the engine to carry on running after the ignition is shut off. This effect is more readily achieved on carbureted gasoline engines, because the fuel supply to the carburetor is typically regulated by a passive mechanical float valve and fuel delivery can feasibly continue until fuel line pressure has been relieved, provided the fuel can be somehow drawn past the throttle plate. The occurrence is rare in modern engines with throttle-body or electronic fuel injection, because the injectors will not be permitted to continue delivering fuel after the engine is shut off, and any occurrence may indicate the presence of a leaking (failed) injector.[3]

You are good with Google aren't you. If you knew the answer why did you ask the question. Carry on smart arse. You will get no help from me.

As the post says, i am simply trying to find possible causes of the pinking, and by the way i didn't need to google that i know, i googled it to show you because you didn't believe me

I am not in the habit of knocking people, i am a master tech and have destruction tested engines and vehicles for a big company.

you don't need to be so sour but next time do your home work !

remedave said:

As the post says, i am simply trying to find possible causes of the pinking, and by the way i didn't need to google that i know, i googled it to show you because you didn't believe me

I am not in the habit of knocking people, i am a master tech and have destruction tested engines and vehicles for a big company.

you don't need to be so sour but next time do your home work !

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Are you having a laugh, i have told you the causes of pinking so obviously you don't bloody know do you. Master tech at what, bull****? Do me a favour go away.

remedave said:

As the post says, i am simply trying to find possible causes of the pinking, and by the way i didn't need to google that i know, i googled it to show you because you didn't believe me

I am not in the habit of knocking people, i am a master tech and have destruction tested engines and vehicles for a big company.

you don't need to be so sour but next time do your home work !

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ok,can i just ask you this.if you are a master tech,then surely you should be able to resolve this issue out by yourself i would have thought.After all you seem to know all the answers?

Sorry for the late reply Master tech yes but not Land rover !

remedave said:

Sorry for the late reply Master tech yes but not Land rover !

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ok,but this problem can be common to all petrol engines,so should still be within your capability's surely.

What does LR SV MT stand for??

In my eyes its Land Rover Special Vehicles Master Technician or Motor Transport....

Anywho, not gonna fuel any fires here, I was just curious!

Saint.V8 said:

What does LR SV MT stand for??

In my eyes its Land Rover Special Vehicles Master Technician or Motor Transport....

Anywho, not gonna fuel any fires here, I was just curious!

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LOL Land rover Service vehicles Master Tech !!! never thought of it as what you put, unfortunately it doesn't cover The p38 its MOD spec only i am afraid !

Still haven't sorted the F-ing thing though fitted a so called new secondhand sensor today but made no difference, un plugged it and run it unplugged its exactly the same as if it was plugged in, i have bench checked both sensors, the resistance are the same however i can't generate a pulse nor do i have any output Values i would have thought it would deliver a AC pulse but with it begin 3 wires ???

I have checked the crank sensor this seams fine and does generate a pulse on a bench test.

gemsdad said:

ok,but this problem can be common to all petrol engines,so should still be within your capability's surely.

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bloomin heck like, i explain summit and get ripped for it !!! i just like to have a chat about stuff for god sake lads chill out, yes i probably do know what is going on with it but i have been here before and someone has turned around and said

" oh yeah had that one before it just the connector under such and such " you see so its good to talk as test equipment can lead you up the garden path as i know too well

remedave said:

bloomin heck like, i explain summit and get ripped for it !!! i just like to have a chat about stuff for god sake lads chill out, yes i probably do know what is going on with it but i have been here before and someone has turned around and said

" oh yeah had that one before it just the connector under such and such " you see so its good to talk as test equipment can lead you up the garden path as i know too well

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Quoting manuals can get you up the garden path as well. time out everyone there must be an answer to the problem.

Possible induction air leak? Spray carb cleaner around all those nasty pipes and hoses on idle and see if rpm lifts. Just a thought, rubber splits and hardens with heat/age.

bloody ell..

lpg can "pink"..believe me...and octane of propane =108..=pink if timing to advanced..

and i would av to agree...master teck should be able to sort this..


think..cam sensor fault...so check timing!....not so easy, cos dont av timing marks...
check plugs...me would replace..

if does on lpg as well as petrol must be spark..so check timing..

though..lpg should be less "pinking" than petrol..

zen said:

bloody ell..

lpg can "pink"..believe me...and octane of propane =108..=pink if timing to advanced..

and i would av to agree...master teck should be able to sort this..


think..cam sensor fault...so check timing!....not so easy, cos dont av timing marks...
check plugs...me would replace..

if does on lpg as well as petrol must be spark..so check timing..

though..lpg should be less "pinking" than petrol..

Click to expand...

LPG needs timing to be advance more than when running on petrol because it takes longer to burn. Specially if the engine is the low compression unit and designed to run on 91 RON fuel. Timing on these engines is automatically set, regulated by the ECM from sensor information and cannot be manually set or changed. A good LPG system ECU should advance the timing when LPG is engaged and return it to the control of the engine ECM on switch back to petrol. Pinking on LPG on the low or even with the high compression engines with normal ECM controlled spark advance should be impossible because of it's much higher octane rating. This guy needs some decent diag live readings to look at.

I have changed the cam sensor it still throws code p0340 i have another cam sensor on the way to try again i have checked the harness and the crank sensor. the vehicle will run with cam sensor unplugged but not with the crank sensor unplugged so that would state crank sensor good.

With out even using live data i can tell you the engine is misfiring slightly not enough to be detected by the ECU, probably due to incorrect timing (cam sensor inop), this is causing the cats to work overtime and the O2 sensor's are clearly picking up excessive fuel and adjusting to lean causing the engine to run hot and produce a tink / pink. when i reset the Ad. values it loses the Pink / Tink for a few seconds.

Now i know that both cam and crank sensors are on the same CAN and that sometimes a failed Crank sensor will throw a Cam sensor code but this is not the case i suspect here, and i also know how robust the cam sensor should be and i bet none on here has had one fail ?

Zen .. its not that i don't know, i am just chatting about it !! throwing ideas around as i have said in previous posts its good to talk ….. you learn.