Matell

I know there have been many posts on strange leaking/suction/wooshing type noises from the engine bay so here is mine. It may be the same as the others or it migh be unique....

In the past 2-3 days my car has developed a leaking noise (metallic whooshing of air sound) and it's getting progressively more obvious. The engine now sounds like a rice burner when it revs up from 3000 to 4000rpm, and feels a little slow. (But throttle response is still snappy)

I have an Injen CAI, DC Sports Header (which has had replacement flex pipe welded in), Random Tech Cat, Hondata IMG. The cat has seen about 25000km, the header has seen 35000km, the intake and IMG have been on for about 50-60000km.

When the engine is unloaded ie at idle or speed with the clutch depressed everything sounds normal. However when the engine is loaded most notably between 2500-3500rpm and I depress the throttle by even a small amount I hear a leaking or sucking noise coming from the engine bay. With the cabin windows closed it sounds like the intake, or a some other form of gasket leak on the intake side. But with the windows ajar it sounds like the noise is on the header/exhaust side.

When I first heard it I though a bit of plastic had been sucked against the intake filter, and later found by inspection that the rocker cover vent hose had come away from the intake. This made sense for the sucking noise under throttle. I reattached it and the noise remained. I next proceeded to replace the pod filter with a spare, disconnected and reconnected tightly all hose clamps and silicone connecting hose and boots and the problem was still there.

I later had an assistant operate the throttle from 2500rpm slowly to 3500rpm slowly while I looked for the source (car was static). I couldn't hear the noise very obviously at all (if at all) but all intake fittings seemed fine, I looked at the Hondata IMG and surrounds and could see no signs of leaking, and the same went for the header to block, and primary to secondary joint. No wisps of exhaust smoke or odours at all. I'll have a better look at the cat tomorrow. The fact that there are no abnormal smells at all has left me at a loss as to what's causing it.

Maybe it's the same noise many of you guys have reported, but just took 79,000km to manifest itself in my car. I'm going to try to have it's 80,000km service done next week and will have them try to identify and rectify the cause/source.

I'll give the car a compression test tomorrow (more money spent on car bits and inspect the coolant) to make sure it isn't a blown cylinder head gasket, and also take a recording of the noise so hopefully it'll be easier for you guys to offer any advice.

Based on the above do any of you guys have some thoughts?

Cheers,

Matt

jlukja

So you hear it under load but not when stationary? That is strange. I can't think of any air movement related items that would differ whether moving or standing still.

Paging Dr. JTso...

Matell

Right well I took several videos today trying to capture the sound but it's not very obvious unfortunately.

The last one I had recorded was external and it revealed something unsettling. As I depressed the clutch to prevent the engine stalling the odd noise went. In neutral I then raised the rpm of the engine with the clutch engaged and there is a distinct metallic whooshing/induction sound. Depress the clutch and it's gone. (Yes it almost stalled but I saved it (sister sniggers – bitch lol).

http://209.245.59.244/Gimme/85542820...57/2/Test2.avi
I recently had the clutch master cylinder replaced under warranty as it was creaking and the gear changes had become very poor, so I have a feeling the clutch throw out bearing or similar may be severely worn. I have a feeling this won't be a warranty fix.

As positive a find as this sounds I'm still not 100% convinced it's the cause. With the doors and windows closed it really does sound induction/exhaust related. As expensive as the fix may be, I hope I have correctly localised the problem as its been driving me nuts.

I also did a compression test today (removed fuel injector wiring plugs - obviously I don't have a Honda PGM to shut them down via the ECU as per the manual) and with the exception of a soon to be mention brain fart it went well.

Cyl 1 = 215psi
Cyl 2 = 220psi
Cyl 3 = 217.5psi
Cyl 4 = 220psi

So the cylinders are compressing very nicely with no leaks so that's a head gasket ruled out.

Now here's the stuff up...I didn't realise there was an extension that was screwed to the end of the tester hose (it was a brand new tester)

I screwed it into the spark plug hole on cyl 1, did the test, unscrewed it and moved to the next cylinder with no problems. I didn't realise this extension had remained threaded into the spark plug hole. So I went and installed the spark plug in cyl 1 and as I was torqueing it to 13lb.ft I felt something give, then cracking. I backed the plug out to find I'd f**k'd it up. The electrodes were sandwiched together and bent, the point was stuffed, also the ceramic electrode insulator was cracked into four pieces.

A quick call around confirmed that no one had our plugs in stock (why am I not surprised - thanks Honda).

So with some pliers and a screwdriver I reformed the gap, and having no choice reinstalled the plug. So far it's running ok, but I'm not sure how wise it is to drive on a stuffed plug. Monday I'll drop into a Honda service centre, surely they'll have a new plug in stock (at a premium price) and book in the 80,000km service making a point of the noise.

Still open to advice/suggestions if anyone has them.

stewie20068

I too have the sucking noise. someone described it as having a faint turbocharged sound to it. it just whistles. comes and goes. I have injen intake. no fix yet and I too have tightened all the clamps.

JTso

iTrader: (2)

The video link doesn't work. This type of problem requires a test drive in person.

Btw, a tip on future compression test. Just get a regular copy of your key and use it to crank the engine. The lack of transponder on the key will not engage the main relay to energize the fuel pump.

Matell

Hopefully this will work.
http://video.google.com/videoplay?do...78740047670979


Good idea!. I hadn't realised a copied key would work just as well. That removes a few steps in the process and sppeds things up

curls

You are too smart.

Matell

Over the past 2 days the worsening of the noise has allowed me to track it down....once again it's that damn P.O.S DC Sports Header!. The design is not flexible enough and as a result the new section of double braid flex pipe I had installed earlier this year to replace the cracked original DC flex section, has failed.

This time its at the aft of the flex section, which is about 2inches further away from the primary A/F sensor which died as a result of the first flex failure.

Somehow I don't think Honda will be as gracious this time around if that sensor fails, so until I can get the car to the shop to have another flex section installed (not sure if it's worth it) I'll hope an exhaust bandage wrapped and clamped over the flex section will prolong or prevent the onset of a sensor issue.

Three lessons to be learnt.

1) Just because you've had a prior problem fixed with something better, don't think it won't fail again.

2) Yes there may be some loss of power from the extra flex pipe, but on the K24 you can never have enough flexibility in the header design.

3) As possibly having the highest mileage on a DC header in a CL9 here's some advice. DON'T by DC (Dirt Cheap) Sports.

As for the noise in the video that seems transmission related....I'm still not sure, but now I have time to plan a clutch replacement.

matvey

I have a DC Sports header and I also get this annoying noise when stepping off the gas while cruising at 2500-3000 RPMs.

I think that the lower gasket on the header may be leaking (The one connecting the header to the stock piping).

Any suggestions on what I can try?

Thanks!

matvey

Does anyone know what can I use as a replacement for the gasket between the header and the cat?

Thanks!!!

- Matvey