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GAWD! another issue arose yesterday


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Hey guys, yesterday i was getting on the freeway and i turned right semi aggressively and accelerated at the apex of the turn to 5500 rpms and hear this Hissing noise that grew louder as i accelerated....Now i hear it everytime i accelerate to 5500 rpms or when i turn right and accelerate alittle into the turn, I also hear it then.

The noise isnt a solid hissing noise like hiiiiiiiiiisssssssssssssssssssssssssssss..... Its more like hiss hiss hiss hiss hiss hiss hiss hiss hiss hiss, and as the rpms go up, the hissing gets more rapid.

Sorry, I dont know how to explain it any better.

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The noise isnt a solid hissing noise like hiiiiiiiiiisssssssssssssssssssssssssssss..... Its more like hiss hiss hiss hiss hiss hiss hiss hiss hiss hiss, and as the rpms go up, the hissing gets more rapid.

does it go up with RPM's, or with vehicle speed?

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The hiss you describe i suspect increases with speed not revs, it is likely to be either a stone stuck between the brake disk (think you call it a rotor in the US) and the steel backplate, or wear in the bearings allowing the disk to deflect excessively

When you stear to either side the disk deflects a little due to the forces acting on it and wear within the wheel bearings allow a little more movement, this does not mean your wheel bearings are shot, just lightly bend the back plate (splashguard) away from the disk a little.

All disks run out of line a little and the hiss, hiss, hiss you describe is spot on for this problem, it is common with the boxster to get small road chips stuck close to the disk

Glyn

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It definatly increases with RPMS, not vehicle speed. I've tested this twice. Update on the noise, I turned left kind of aggressively and some of the noise went away., also, i'd like to change what i said about the noise...its not so much a hissing, it sounds like apeice of metal chattering....

Edited by CJ_Boxster
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It definatly increases with RPMS, not vehicle speed. I've tested this twice. Update on the noise, I turned left kind of aggressively and some of the noise went away., also, i'd like to change what i said about the noise...its not so much a hissing, it sounds like apeice of metal chattering....

check your polyrib belt. if the belt is okay, while you have the cover off, see if you can locate the sound. the water pump can sometimes make noise like this if it's on its way out.

Edited by insite
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ok heres the current data that my ODBII scanner gave me while my 1997 boxster was idling

P0102

P0112 Intake Air Temp Sensor 1 Curcuit Low

Feul system 1 ========Closed Loop

Feul system 2 ========Closed Loop

Calculater load value ========1.1

Engine coolant temp ========87

Short term feul trim bank 1 ========3.1 - -0.7%

Long term fuel trim bank 1 ========1.5 - -0.7%

Short term fuel trim bank 2 ========-2.3 - 0.7%

Long term fuel trim bank 2 ========-1.5 - 0.7%

Engine speed ========814

Ignition timing advance ========4.5%

Intake air temperature ======== 45c

Air flow rate g/s ========2.93 to 3.40

Command sec. Air status ========off

O2s bank 1 sensor 1 ========present

O2s bank 1 sensor 2 ========present

O2s bank 1 sensor 3 ========absent

O2s bank 1 sensor 4 ========absent

O2 bank 2 sensor 1 ========present

O2 bank 2 sensor 2 ========present

O2 bank 2 sensor 3 ========absent

O2 bank 2 sensor 4 ========absent

O2s voltage bank 1 sensor1 ========0.165 - 0.0650

Short termfuel trim b1-s1 ========0.7 - -1.5%

Os2 voltage bank1 sensor2 ========0.095 - 0.675

O2s voltage bank 2 sensor 1 ========0.120 - 0.735

Short term fuel trim b2-s1 ========0.7 - -2.3%

O2s voltage bank2 sensor 2 ========0.700 - 0.645

---------------------------------------------------------------------------

Ok whats wrong with my boxster now...The P0102 I believe is from yesterday when I disconnected the MAF...Whats the P0112 mean? is that the root of all my troubles?

Edited by CJ_Boxster
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They are both from disconnecting your MAF.

P0102 is an open in the MAF circuit and P0112 is the MAF temperature sensor.

You MAF air flow looks a little low - it should be 12 to 24 kg/h (or 3.3 to 6.6 g/s). Are you sure you don't have an air leak on bank 2?

Dumb it down a bit for me....where or what is bank 2?

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They are both from disconnecting your MAF.

P0102 is an open in the MAF circuit and P0112 is the MAF temperature sensor.

You MAF air flow looks a little low - it should be 12 to 24 kg/h (or 3.3 to 6.6 g/s). Are you sure you don't have an air leak on bank 2?

Dumb it down a bit for me....where or what is bank 2?

your MAF measures the mass of air flowing past it. Loren is saying that the mass of air flowing past your MAF is lower than it should be. two basic things can be happening. first, something (dirty air filter) could be severely hampering flow into the motor. second, your motor is sucking some of its air from somewhere other than the air filter (a leak somewhere past the MAF). the latter is more likely.

given the hissing sound you describe, it's possible that you have a hose or gasket that's allowing air to slip past it, creating the hiss. bank 2, FYI, is the bank containing cylinders 4, 5 and 6. this is on the driver's side of the car. to find a leak, open your engine compartment. i use a propane torch (hand held, unlit of course). wave it around the engine compartment until the RPM's go up.

if i had to guess, even though it's not on bank 2, i'd go with the oil separator bellows. see pic below.

post-3131-1160753289_thumb.jpg

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They are both from disconnecting your MAF.

P0102 is an open in the MAF circuit and P0112 is the MAF temperature sensor.

You MAF air flow looks a little low - it should be 12 to 24 kg/h (or 3.3 to 6.6 g/s). Are you sure you don't have an air leak on bank 2?

Dumb it down a bit for me....where or what is bank 2?

your MAF measures the mass of air flowing past it. Loren is saying that the mass of air flowing past your MAF is lower than it should be. two basic things can be happening. first, something (dirty air filter) could be severely hampering flow into the motor. second, your motor is sucking some of its air from somewhere other than the air filter (a leak somewhere past the MAF). the latter is more likely.

given the hissing sound you describe, it's possible that you have a hose or gasket that's allowing air to slip past it, creating the hiss. bank 2, FYI, is the bank containing cylinders 4, 5 and 6. this is on the driver's side of the car. to find a leak, open your engine compartment. i use a propane torch (hand held, unlit of course). wave it around the engine compartment until the RPM's go up.

if i had to guess, even though it's not on bank 2, i'd go with the oil separator bellows. see pic below.

So if the rubber boot is the culprit, Would it be ok to just replace the boot and not the entire oil separator?

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So if the rubber boot is the culprit, Would it be ok to just replace the boot and not the entire oil separator?

nah. generally by the time the boot goes, the diaphagm inside the oil separator is probably shot, too. plus, the boot is the hardest part of the replacement process to install, so you might as well just replace the whole thing while you're at it. sunset imports has them for around $85.

this all assumes, of course, that the oil separator is indeed the problem. try the propane trick. my guess is that your RPM's will jump when you wave it around the oil separator.

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Hey guys, yesterday i was getting on the freeway and i turned right semi aggressively and accelerated at the apex of the turn to 5500 rpms and hear this Hissing noise that grew louder as i accelerated....Now i hear it everytime i accelerate to 5500 rpms or when i turn right and accelerate alittle into the turn, I also hear it then.

The noise isnt a solid hissing noise like hiiiiiiiiiisssssssssssssssssssssssssssss..... Its more like hiss hiss hiss hiss hiss hiss hiss hiss hiss hiss, and as the rpms go up, the hissing gets more rapid.

Sorry, I dont know how to explain it any better.

probably the engine mutated into turbo type and youjust didn't know it yet :) j/k....it's Friday, Sunny outside and this weekend, it's 74 degree..wohooo! i'm going for a drive

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ok, well $85 is better than $135 at the stealership. Well i dont have a propane canister...how about throttle body spray?

it should get the job done. just use a little spray here and there until your revs jump.

ok then, ill do that tomorrow...Think i cant goto Formula Drift if im going to be on my back along time.

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haha, I found a shop called Dutch Treat in lawndale, they work on nothing put porsche, i passed by and seen alot of new caymans and 911's there, they work on a $80hr labor rate and said to take my car in if i decide to give up finding the issue myself.

Why are the "working" on Caymans? Strange. They should be uder warranty and at the dealership.

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haha, I found a shop called Dutch Treat in lawndale, they work on nothing put porsche, i passed by and seen alot of new caymans and 911's there, they work on a $80hr labor rate and said to take my car in if i decide to give up finding the issue myself.

Why are the "working" on Caymans? Strange. They should be uder warranty and at the dealership.

my guess is probably oil changes. They were up in the air so they could have been draining the oil.

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Oh hissing cured, it was the heat shield attached to the engine cover...co-worker that was helping me reinstall the engine cover must have placed his fingers between the sheild and the cover itself causing to hang inside the engine bay rather than sandwich between the cover and the lip that it rests on....Some how everything he touches falls apart. LOL

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