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New MAF - boost held back.

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Old 11 October 2017, 09:38 AM   #1
Talking Dog
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Default New MAF - boost held back.

Hi all..

Should this cause and issue.. I replaced my MAF on my 02 sti which was mapped 5 years ago on the old MAF which I assume had never been replaced and had covered 80k back then.

With the new MAF installed Iíve noticed better throttle response and healthier sound in general. Initially there was some hesitation and small jerking when loading the engine and bring on boost.

Now after 70 miles and the engine being switched on and off a few times ( if this even matters) Iíve tried seeing how the cars performs on full boost. In the higher rev range Iím feeling a huge amount of ďholding backĒ the boost seems capped at 1.2/3 bar down from the 1.5bar. The engine will continue to rev but not strongly and with boost fading away / fluctuating.

The question running around in my head is, is the new MAF cleaner than the old at the time of the map and as a result throwing readings beyond the parameters of the ECU map. Does a new MAF require a tweak to the MAP.?
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Old 12 October 2017, 12:12 PM   #2
bludgod
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did you replace with a new genuine MAF sensor or just picked one up from your local motorfactors? I've found a few of the local suppliers here supplying MAF's that don't seem to match the scaling of the factory original (compared with a working/new MAF from Import Car Parts and Subaru direct).
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Old 12 October 2017, 02:35 PM   #3
john banks
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This is a potentially very dangerous situation for your engine. You should not boost it again until your tuner is sitting in it and controlling/monitoring the situation IMHO.
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Old 13 October 2017, 08:37 AM   #4
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RE- Bludgod – I got a replacement unit from ICP – the £114 Denso made in Vietnam module, the cheaper of the 2 available from them.. Not the Denso made in Japan that had Denso etched on the top which as around £194 .. Which I think is the issue.


RE- John B.. thanks for the concerns.. I’ve reinstalled my old MAF, and or though the engine sonds rougher at lower rpm and a rubbish dead sound around 2750rpm… the boost is cleaner and there is no choking sensation on the engine.

ICP have kindly spoken with me and will look a the unit for me.. However I think I need to dig deeper into my pocket and get the genuine stamped MAF.

Cheers
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