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Old 11-18-2002, 09:06 PM   #1
morgie
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Question How bad is it for the Engine ???

I changed my exaust for a 2.5" straight config... and was still experiencing some hesitation / lack of power probs in full throttle, from 4000 till 6000rpm..

Today, while doing some tests, i decided to disconnect the BOV from the "return/bypass" hose that goes back into the intake just in front of the turbo..

Disconnecting that hose prevent the BOV from pushing air back to the intake.. But, it also allows more air to enter into the intake, after the MAF (via that disconnected hose)... This Extra air is not calculated by the MAF, and the end result is that my engine is running Leaner air/fuel mix...

The result of that test ? WOW ! the car pulls real strong at 9-10psi and no hesitation anymore... On my Air/fuel meter gauge i get some Weird reading but a full throttle, i get like 2 leds orange, 4 leds green.. (so it is not so lean after all, but this is not so accurate i was told)....


My question is, How bad for the engine it is running with such a big "intake leak" ? could i melt a piston even if i dont get some 'not so bad' readings from the Air/Fuel ... ?


i should really get an EGT gauge... and an S-AFC i think... :\
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Old 11-18-2002, 09:57 PM   #2
HIHO
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I'm not sure of the negitive effects but I would think the air/fuel readings you are getting are false. I think the MAF would be missing some air?
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Old 11-18-2002, 10:06 PM   #3
ciper
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Maybe I mistunderstand, you are letting UNFILTERED air into the engine?!
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Old 11-19-2002, 07:49 AM   #4
morgie
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Ciper : ya, it was just for testing...

but you know, air is cleaner here in Quebec that in San-Francisco huhu


HIHO : yes that's the point, this non-calculated air leans the mixture and makes the car run well..


In fact, my question was not exactly what i wanted to say... i dont plan on running the car like that! but i want to know what's could the problem be, that without the bypass hose the car run great.... it's clear it a air/fuel mix problem, but what can control that ? what sensor can fail and make that mix to rich ?


with the mix leaner, it is less difficult to ignite.. so at high RPM, the explosion is quick and good... not the same as for the 'normal mix' ... wich seems to cause some .. missfire or ignition to late


like i said, i'll need a EGT and a S-AFC i think to control that mixture and make the car run clean... cuz now it doesn't.. (run clean/strong/constant)

Last edited by morgie; 11-19-2002 at 07:56 AM.
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Old 11-19-2002, 08:21 AM   #5
ScoobyHead1993
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I think the coolent temp sensor or the mass air flow sensor itself are the most obvious things that would make the fuel to rich. But I don't really see how you could adjust them either. AFC is the answer here.


Danny

EDIT~~ Your air fuel gauge is like looking at a Christmas Tree "Look at how pretty it is" In my oppinion it gives a general indication of what is going on but is not overall accurate.
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Old 11-19-2002, 09:31 AM   #6
subysouth
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a possible faulty O2 sensor.

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Old 11-19-2002, 09:52 PM   #7
morgie
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Thanx for the hints, i'll have a look at those two... and i will consider getting a EGT.
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