182 revs dip when first applying throttle, air leak?

[Toggerman]

The alternator recently went on my 182. With the help of my lovely wife I managed to replace it myself. The battery was flat so I took the KTec IK off to remove the battery (also to use one of the jubilee clips around the aux belt tensioner). I put it all back on afterwards and replaced the clip.

I put the car back together and she starts and idles fine. However when applying throttle, the revs dip by about 500rpm for a second and there is a sound of air being sucked in by the IK filter which wasn't there before. It will then rev fine unless you drop it back to idle speeds and the sucking noise disappears.

I've checked the IK and hoses and can't see/feel any leaks. I also don't recall knocking anything when doing the alternator.

Any ideas?

 

[Toggerman]

Managed to get some time to have a look at this the other day. I can't see anything loose or disconnected. I removed the induction kit and cleaned out the plenum valve again (which was filthy again and I only cleaned it a little while ago).

The car still starts fine, although it now misfires when cold and there is a smell of fuel coming out the back. Applying throttle doesn't cause the RPMs to dip anymore but there is still a hesitation. When warm the misfire sounds like it goes away but the RPMs drop and raise again applying constant throttle.

Someone said to me yesterday that it sounds like the MAP sensor, could they be right?

 

[bloke]

Check lambda o. Live data they can be miles out but still not flag a fault code.

 

[Toggerman]

Thanks mate, I'll have a look at that too. I completely dismissed it just because there's no code.

 

[Toggerman]

Checked the live data, couldn't see anything wrong (however still learning how to read it all properly). Bought a new lambda sensor as the rear was kicking up a fault anyway, decided to try the pre-cat just in case, lo and behold it works. The misfire has gone and the car runs much better. Thanks Bloke!

But it is still making a loud sucking sound and has a slight hesitation when blipping the throttle from idle. The nice induction roar that existed before also sounds muffled in comparison to what it used to.

 

[Kazumz]

Checked the live data, couldn't see anything wrong (however still learning how to read it all properly). Bought a new lambda sensor as the rear was kicking up a fault anyway, decided to try the pre-cat just in case, lo and behold it works. The misfire has gone and the car runs much better. Thanks Bloke!

But it is still making a loud sucking sound and has a slight hesitation when blipping the throttle from idle. The nice induction roar that existed before also sounds muffled in comparison to what it used to.

I'm getting the same thing on my 200.

When I start it when cold, I can press the throttle just VERY slightly and it'll nearly stall out.

It runs like a bag of crap and splutters when cold. Rev matching is a nightmare at low revs because some times it won't even respond to my throttle tap and I end up nearly flying out the windscreen (lol).

Does that sound like the same thing you're experiencing? I'll get it looked at if it is.

 

[bloke]

I'm getting the same thing on my 200.

When I start it when cold, I can press the throttle just VERY slightly and it'll nearly stall out.

It runs like a bag of crap and splutters when cold. Rev matching is a nightmare at low revs because some times it won't even respond to my throttle tap and I end up nearly flying out the windscreen (lol).

Does that sound like the same thing you're experiencing? I'll get it looked at if it is.

checked exhaust manifold for cracks?

 

[Toggerman]

I'm getting the same thing on my 200.

When I start it when cold, I can press the throttle just VERY slightly and it'll nearly stall out.

It runs like a bag of crap and splutters when cold. Rev matching is a nightmare at low revs because some times it won't even respond to my throttle tap and I end up nearly flying out the windscreen (lol).

Does that sound like the same thing you're experiencing? I'll get it looked at if it is.

Sort of, although with mine I had to jab the throttle for it to dip. if I gently pressed it the car would be ok until you tried to maintain the revs and then it would splutter like mad.