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Engine knock at high revs when accelerating hard, Apexi ECU

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Old 27 August 2009, 10:57 PM
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wildfire
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Default Engine knock at high revs when accelerating hard, Apexi ECU

Getting engine knock at high revs when accelerating hard, only thing that has been changed is the plugs which are now 7b instead of the 6b that the car was mapped on. Think they were set to 0.65, could this be causing the knock? The old plugs were causing the car to misfire as they were knackered, last resort will be to get some new 6b plugs. Other option is the car has Apexi Power FC ECU, is there any settings that i should adjust? Not able to get the map checked/tweaked at the moment.

Any advise apreciated.
Old 27 August 2009, 11:12 PM
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bluerigster
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Are you currently using a lower octane fuel to what the car was originally mapped to use?.
Old 28 August 2009, 08:32 AM
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wildfire
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Using V Power, was mapped a couple of years ago before Shell changed their fuel to Vpower, think it used to be 98Ron. Car is MY00 UK turbo with TD05, decat, FMIC, Walbro 255. Never had any trouble last year, car was left unused for a couple of months, when i came to use it the car would judder and misfire on boost which i found to be well knackered spark plugs, car had run fine before being left for the couple of months so found that a bit strange.
Old 28 August 2009, 08:37 AM
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RA Dunk
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Could be just a dodgy batch of fuel, have seen this happen before, run the tank almost dry then refill up using a different fuel station just too see
Old 28 August 2009, 08:51 AM
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jasonius
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^^^
could be, try adding some octane booster (NF of millers) if you have some, see it that helps..?

The mapping for optimax shouldn't make any difference as v-power is better.

Fuel pump isn't getting tired is it..?
Old 28 August 2009, 11:34 AM
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JohnD
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Are you able to measure the knock count or is it audible?

JohnD
Old 28 August 2009, 11:38 AM
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Mus
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could be fuel pump or plugs?
Old 28 August 2009, 12:01 PM
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Originally Posted by jasonius
^^^
could be, try adding some octane booster (NF of millers) if you have some, see it that helps..?

The mapping for optimax shouldn't make any difference as v-power is better.

Fuel pump isn't getting tired is it..?
Believe it or not, I got more activity on the knocklink when my local garage switched from Optimax to Vpower. I took the car to Bob to check the map and, If I recall, he said that the car needed a bit more fuel added to the map. It may have been that the car was making slightly more boost on the higher octane petrol....I don't remember.

It's good advice to add a splash of octane booster to the mix though, if the knock dissappears, chances are it was just a dodgy batch of fuel. Running cooler plugs should make knock less, not more, likely if I understand it correctly.

Ns04
Old 28 August 2009, 01:03 PM
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wildfire
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Tried a couple tanks of fuel and still the same.

Kncock varies from 24-36 on the Apexi Power FC commander and have knockling fitted which flashes up.

Fuel pump is only a couple of years old and only done a few thousand miles, does whine a bit tho.

Did not want to reisk putting octane booster in as Vpower has slightly higher octane than the optimax it was mapped on.

I can adjust some of the setting useing the Apexi Power FC commander.

Spark plugs have only just been changed so could be due to changing them from 6B to 7B or maybe the gap is wrong. Not got round to checking the gaps yet.

Cheers for the responses.
Old 28 August 2009, 01:18 PM
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m@t STImulation
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hope you work it out
Old 28 August 2009, 02:38 PM
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Pavlo
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maf sensor?
Old 28 August 2009, 02:42 PM
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JohnD
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Not knowing too much about the Apexi Power FC, what is considered too high a knock reading? Is it the big red that flashes on the Knocklink or both orange?
Plug gap should not be an issue as det. would only be spark initiated if the ignition was too far advanced, and thats not the fault of the plug.

JohnD
Old 28 August 2009, 07:55 PM
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wildfire
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Checked the air flow Maf sensor reading when it started and it looked ok on Apexi hand comander.

Have seen the first 3/4 leds on knockling sensor light up, not the Large clear led. Only used to get the first 2 to light up and max reading on the Apexi was upto around 20.
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