weird poping sound

[tydon]

i have a werid poping sound coming from car on idle with a rough idle.

car is bd5a converted to single turbo v3/4 75 ecu.

no check engine light codes.

runs smooth on acceleration no boost cuts.

just a really weird poping sound sounds like it blows back through the air intake kinda.

[tydon]

the boost gauage also jumps up and down abit on idle.

also have a exhaust leak at mid section where down pipe joins up under car. (will have that fixed soon)

[gf8wagon]

Vac leak on intake side?

Split intake pipe

Afm packing a sad?

[tydon]

defintely not afm.

cant find any leaks although one of the breather pipes for manifold could be leaking. its a aftermarket underintake pipe. and the breather from metal pipe that goes to front of underintake pipe may not be in properly

[tydon]

Idle on cold car goes up and down frmm 1500 to 3000 till it gets warm. Still has bad idle bov doesnt leak. No boost cuts

[Marky]

 tydon said:

defintely not afm.

cant find any leaks although one of the breather pipes for manifold could be leaking. its a aftermarket underintake pipe. and the breather from metal pipe that goes to front of underintake pipe may not be in properly

Did you fix this yet

[ADIKT]

That\'s some big fluctuation on idle.

Get the exhaust leak fixed first (could be gasket making the noise?)

Then I would ensure EVERYTHING connected to INTAKE is connected properly and not leaking (maybe clean ICV at same time? another thing to eliminate)

Then go from there

Maybe a video of this said \'popping\' noise?

[tydon]

 Marky']

[quote name='tydon said:

defintely not afm.

cant find any leaks although one of the breather pipes for manifold could be leaking. its a aftermarket underintake pipe. b]and the breather from metal pipe that goes to front of underintake pipe may not be in properly[/b]

Did you fix this yet

nope aftermarket intake pipe doesnt have a metal bit to putblack pipe on tightly. Tryna jimmy something up. Gunna get vid tonight of weird idle

[tydon]

Fixed that pipe no diffrencene will post vid afterwork

[tydon]

View My Video

this was with car warmed up

[gf8wagon]

I cant see that video?shoulda done it on youtube lol

[tydon]

car when cold idle flactuates upto aroiund 2500 back down to 1000 not quite 3000 lol il do it for youtube now

[tydon]

[tydon]

forgot to mention also that brake booster still not fixed and has hole in it...

have done some research and apparently brake booster can cause bad/rough idle will fix and report back

[Koom]

For testing purposes, disconnect the hose from the brake booster and plug it up with a bolt. Then run the car. At least then you can get the leaking booster out of the equation. Just don\'t try driving it.

[tydon]

 Koom said:

For testing purposes, disconnect the hose from the brake booster and plug it up with a bolt. Then run the car. At least then you can get the leaking booster out of the equation. Just don\'t try driving it.

wont i need to block at maniflold and at the booster?

[Koom]

Once you\'ve pulled the hose off the booster its out of the loop. Then block the free end of the hose and that now means its not leaking from the manifold out through the hose.

[Marky]

If you\'re just trying to find the reason you have a bad idle, no just one end being blocked will answer the question

To all intents it just seems like any other air leak (what is that noise BTW?) and the vacuum flickering is the IACV trying to stabilise it and failling

One trick which sometimes works is spraying some CRC / etc around the place at possible causes - if it changes things for an instant start looking where you sprayed. Other way is if you have access to a compressor you can pressurise the whole thing and listen for the squeeeee of air coming out

Could be maybe a leak between manifold and block? I had similar on a VR4 once, drove fine but idled poos - was a gap you couldnt see between manifold and the gasket - mani must have warped ever so slightly

[Guest]

Any different with a filter on?

[tydon]

so ive blocked up the brakebooster hole with tape... to test it and its helped the idle issue considerably got brakes back aswell. but im sure i can hear another leak around the ICV somewhere going to test for leaks tomorow when its lighter. idle fluctuates up and down between 1000rpm and 1800ish rpm not as bad as before but obviously still a leak somewhere .

still no check codes or any boost cut

[tydon]

 evowrx said:

Any different with a filter on?

podfilter?

currently dont have one lol.. will get one this week

[tydon]

no longer getting that poping sound either

[Guest]

Brake booster line has the one valve in it and the right way round?

[Marky]

Randomly enough sometimes they hate having no air filter

Like it fcks with the idle a bit

aside from you should prob get one anyway hahaha

[Dvnt]

 tydon']

[quote name='evowrx said:

Any different with a filter on?

/quote]

podfilter?

currently dont have one lol.. will get one this week

can have mine for $30 if you want only done 10000km and comes with adapter, im going back to factory airbox