Revving when braking?!

[ripp]

after I got my plenum painted and went for a drive couple of hours ago noticed that if letting the car glide in neutral and braking, the revs go up a bit, in the 1200-1700rpm zone, it's like pressing both (accel and brake) pedals at the same time. otherwise it drives fine.
also the idle takes longer to settle and seems a little higher, maybe 900 rpm.
all I did was to clean the TB and the other bits. looked under the bonnet and everything seems ok.
p.s: the revvin' thing only happens while at some speed, standing still with the engine running and pressing the brake several times nothing happens
cheers!

 

[Andyman]

Drawing in air / air leak mate. Check all your plugs are back on right first and make sure the plenum has a snug fit and all the gaskets are clean.

 

[ripp]

checked that, no joy

 

[ripp]

now a whine can be heard when revs drop down when blipin' the throttle. it seems like the car hates me these days lol

 

[Cooksport]

Check the brake servo vacuum pipe is on correctly!

 

[ripp]

take a look at this video. this sounds louder than I initially thought

 

[jinjur]

Im sorry...............but that is so ROFL its killing me

Definately air to be honest.

Jj

 

[ripp]

in this one you can hear how loud it really is. can't really source the noise unfortunatelly

 

[ripp]

Im sorry...............but that is so ROFL its killing me

Definately air to be honest.

Jj

ok, maybe I'm slower... light me up. already checked bolts, hoses, etc

 

[jinjur]

I mean the noise man, it is HILARIOUS.

Its probably something really small......what about spraying wd40 around hose joints etc while its making that noise to see if it stops

 

[sideways danny]

as said above. get it running, and spray something like brake cleaner or wd-40 at all the joins etc, one by one. If the revs change you've found your leak

 

[Jonny1*2]

^^ why would it be doing this while braking though Danny? When I had my air leak it just reved, not whistled :S Just tell people its got a charger on it mate

 

[jinjur]

Perhaps the braking oddity may direct the cause towards the servo pipework, im assuming that it connects to the intake somewhere like other cars..

First place to look imo.

Jj

 

[jinjur]

oh ffs......its still funny, i keep waiting for someone to announce "Captain on board"



lol

Jj

 

[sideways danny]

Perhaps the braking oddity may direct the cause towards the servo pipework, im assuming that it connects to the intake somewhere like other cars..

First place to look imo.

Jj

exactly this

infact, check for melted bits of the servo vac hose specifically

 

[ripp]

oh ffs......its still funny, i keep waiting for someone to announce "Captain on board"



lol


Jj

ok I admit it sounds funny

exactly this

infact, check for melted bits of the servo vac hose specifically

the servo hose is the one connecting to the plenum near the TB? I suppose the noise appeared somehow because I took out the plenum 3 days ago to paint it and something has changed when put it back

 

[ripp]

^^ why would it be doing this while braking though Danny? When I had my air leak it just reved, not whistled :S Just tell people its got a charger on it mate

to clarify this:
removed the plenum and painted last saturday. mounted back sunday.
monday went for a drive and noticed the revving when braking stuff, but no noise.
yesterday went out again and the whistle appeared, along with the revving thing.
today nothing changed ...

 

[Nickson]

Hahaha,
Im sorry but that is pretty hilarious!

No idea as to the cause though :rasp:

Sorry for being more of a pain than helpful

 

[ripp]

well at leas I made people laugh on my b-day

 

[sideways danny]

Ah ha! I bet that Is the teardrop shaped seal under the plenum not seated right

 

[ripp]

hmmm, that is sealed with some high temp silicone right? Odd as I removed the plenum when checked the plugs last spring and didn't get any noise even without repacking with silicone that area.

 

[sideways danny]

this seal

no silicon needed on it, just the rubber seal in the machined groove

 

[ripp]

yeah the seal is in it's place, but mine had some red silicone on it. you think it would be better to get rid of the red stuff and see how it goes?

 

[sideways danny]

the silicon is probably causing more problems really. Clean it all up, and while you're there make sure the upper to lower manifold sealing faces are clean and the gasket is flat

 

[ripp]

will do, maybe this evening. got to get myself a flashlight

 

[Andyman]

Thought 182s had the a rocker cover breather blanked off :S - everydays a school day lol

 

[ripp]

yes it is blanked, but there's a gasket on the plenum, that's what danny was about.
anyway, just got out and took out the plenum again, got rid of the silicone and put it back together. of course it's still the same...

 

[Andyman]

Yeah but that rubber seal show is the rocker breather gasket which 182's dont have?

your over gasket is between plenum and inlet. You could replace that? Roughly about 8 quid iirc

 

[sideways danny]

incorrect and it's nothing to do with a breather either

 

[Fred@BTM]

and its not blanked off either, there's a tiny tiny tiny hole

 

[jinjur]

Do the spraying thing.......get someone to rev and reproduce the noise while your at it but be careful of spinny bits etc....

As per dannys suggestion, try a wee toot under the plenum towards the above seal to see if that does anything.

Jj

 

[ripp]

got someone to rev the car while i tried to listen up closely. it looked like the sound came from the intake air temp sensor's area. I remember when mounting back this sensor it had one of it's lock pins broken, yet it still went in properly and won't come out easily. can this thing make that noise? it's freakin' loud, I'm also worried about some internal damage somewhere (although would be a strange coincidence to happen right after I played with the plenum..), hope I'm wrong though..
I'll try and do the wd40 thing tomorrow

 

[Jonny1*2]

to clarify this:
removed the plenum and painted last saturday. mounted back sunday.
monday went for a drive and noticed the revving when braking stuff, but no noise.
yesterday went out again and the whistle appeared, along with the revving thing.
today nothing changed ...

Think something is lost in translation there bud, not quite sure what you're getting at. Might just be me being thick though

 

[ripp]

LOL I wouldn't do that ) I'm not using google translate but maybe I should

 

[ripp]

I think I won't be able to get this problem sorted till the end of next week, you think this can get nasty? should I leave the car for the next couple of days?

 

[sideways danny]

i had a Trophy sounding a bit like this yesterday, although not quite so bad. Turned out one of the O-rings on the MAP sensor had been damaged when it was previously worked on. It's always safer to just unplug the sensors on the plenum and not try to extract them unless you really need to.

I wouldn't like to tell you it'll be ok, or say it's bad, but it's unlikely to drive right with a vacuum leak anyway

 

[ripp]

the map sensor has two tiny gaskets(maybe the o-rings you are talking about?), one of them was lightly damaged. but the thing is, as I said before, I listened closely and the sound gets louder in the inlet air temp sensor area.
anyway, I have a friend with a 172 ph2, are these sensors good to swap between them? maybe I'll get to the bottom of this doing so

 

[sideways danny]

the air temp sensor also has o-ring seals. That was my point really

 

[ripp]

will 172 sensors work? I wanna try what I've said above

 

[sideways danny]

yes, same sensor