MR2 just got LOUD!! - Update: CAT Failure

Sam · December 20, 2003, 21:40

Went shopping on Friday night - car running perfectly normal. On the way back the intake/exhaust note was louder than normal - it seemed to increase in volume on the motorway. By the time I was close to home it was over twice as loud as normal. (Think TVR loud).

I managed to get out for another drive tonight and so far can say that the problem only occurs when the engine is under load - increasing acceleration = increasing volume. The car also appears noticeably slower accelerating. I have driven with the passenger seat forward and cubby hole cover open to get a better idea of where the noise is coming from and it does sound like the intake area.

I have had a strained look (in poor light) over the HKS Induction Kit - and everything appears normal - and firmly attached.

I havent had a chance to fully examine the car in daylight yet - which I will be able to do tomorrow - anyone got any ideas in the meantime?

I have only had the 2 back for a couple of weeks after it being with MR T for 31 days getting half the gearbox replaced and hoping this isn't a serious engine problem s:roll: :roll: s:roll:

zud · December 20, 2003, 22:18

I had something similar on a previous car... and it turned out to be just a loose bolt on the exhaust manifold. Putting the engine under load opened up a gap. The mechanic I used at the time just put in a new bolt and didn't even charge me anything! Good luck with yours... I hope its something as simple!

Slacey · December 21, 2003, 08:52

I agree, it sounds like the exhaust is blowing.
When you say TVR loud, are we talking TVR sound too? I'd be tempted to leave it... s:wink: :wink: s:wink:

Anonymous · December 21, 2003, 09:24

Boy racer you!

Slacey · December 21, 2003, 12:22

Quote from: "cstevens"Boy racer you!

As I have said before, I think I'm becoming the club hooligan! s:lol: :lol: s:lol:

Sam · December 23, 2003, 12:20

So far have checked the exhaust and the intake - all in good condition - nothing obvious. I went down to Toyota garage and got the mechanic to take it for spin - he claimed the Intake filter was disintegrating! I had already checked this and it isn't. To be on the safe side I replaced it with a new one today and the noise is still there. Next up I have been advised to clean the MAF. Failing that I guess I 'll have to put the stock box on and then try it again. s:roll: :roll: s:roll:

Sam · December 31, 2003, 13:09

Things have taken a turn for the worse s:cry: :cry: s:cry:

I have cleaned the MAF (which was filthy) and reset the ECU.

I have now started to replace the HKS induction kit with the stock airbox. After I took the HKS kit out I noticed a scuff mark under the heatshield where it looks like something has been rubbing against it and actually worn a couple of millimetres into the shield. I looked inside the pipe connecting the filter head to the inlet manifold and it was also pretty dirty, I noticed some small lumps in with the general dirt build up and after getting one out I discovered it is a small piece of metal!

Oh no! I might just jump to the conclusion that the heatshield has been rubbing against something, disintegrating and flying straight through the filter and into the engine s:cry: :cry: s:cry:

Does this sound plausible? Could the metal sharpnel get through the filter? Could it have come from somewhere else? I dread to think if this is true what sort of damage it may have caused.

I will try to get some photos done tomorrow of it for all to see.

Help!!! Anyone got any ideas on this?

Slacey · December 31, 2003, 13:11

Yes s:(

s:( , it does sound plausible s:shock: :shock: s:shock:

I'm not sure what to suggest next though, one of the more technically minded members can jump in now....

Anonymous · December 31, 2003, 14:06

wash the inside of the engine to slush the metal out !!!!

Fairys good for grease s:wink: :wink: s:wink:

Na realy try taking the rocker cover and cleaning it by hand

markiii · December 31, 2003, 14:39

not sure about the metal, but the HKS is iknown to be the worse one on the market for filtration so I wouldn't be surprised if stuff gets past it, I'd have thought shrapnel would be too biug to make it past though, un;ess we're talkign about filings here?

Sam · January 1, 2004, 16:20

Yes it is shavings although there are a couple of larger pieces in there ( I guess a couple of mm across). I will borrow a digital camera and get some pictures done tomorrow.

I am in the process of putting the stock airbox back on but have managed to lose the top cover - so once I get a new one I'll try the engine again. Maybe it is nothing to do with the metal shavings altogether - does seem a bit of a coincidence though.

I am wondering what sort of damage they could do if they did get sucked into the inlet manifold?

Anonymous · January 1, 2004, 16:31

Quote from: "Sam"I am wondering what sort of damage they could do if they did get sucked into the inlet manifold?

A lot, I hope you get things sorted ok s:(

s:(

Sam · January 1, 2004, 16:36

Cheers WD - Me too!

Tem · January 1, 2004, 17:21

Quote from: "markiii"not sure about the metal, but the HKS is iknown to be the worse one on the market for filtration so I wouldn't be surprised if stuff gets past it, I'd have thought shrapnel would be too biug to make it past though, un;ess we're talkign about filings here?

Yeah, you might wanna consider getting rid of the HKS...it might be good at sucking air and it might look nice, but it sucks at the main job of filtering.

Pictures say more than words, so here goes:
m http://www.mkiv.com/techarticles/filter ... index.html m

Sam · January 2, 2004, 13:18

Yeah I have seen that article before Tem (after I got the HKS). I think what has happened here though is not really down to the filter itself (although it does let more dust in than others) - but the fact that when Toyota last had the car for a gearbox problem and belt tensioner noise. For some reason they decided they needed to install a stock box to eliminate the fact the noise wasn't coming from the HKS kit. They did this and found it wasnt the HKS and was in fact the V-Belt Tensioner (as I had suggested to them). I think that when they re-installed the HKS they didn't do it correctly and hence the vibration and heatshield eroding away. I was hanging on with the HKS becasue it did sound great and I thought it was only a matter of time before I got a turbo installed and ditched the current intake system anyway.

Now I am stuck because Toyota wouldn't look at this latest problem until I had the stock airbox back on, and I havent got all the parts! Anyone want to part with their old stock box?

Slacey · January 2, 2004, 14:15

Quote from: "Sam"Anyone want to part with their old stock box?

If no-one wants to part with theirs, maybe someone local to you could lend you one?

Sam · January 2, 2004, 14:35

Quote from: "Slacey"If no-one wants to part with theirs, maybe someone local to you could lend you one?

Sure that would be great also - I just need to a) try it with the stock box to see if that cures the problem, or b) if the problem isnt cured just present the car to Toyota with a stock box on.

Anyone up for that?

I have been phoning around breakers/Jap spares places and have had no luck so far. I phoned a local Toyota and they were insisting that the Air Box cover comes with the MAF and cant be sold seperately which bumps the price up a lot. I then spoke to my original Toyota garage and they recognised the part numbers I provided from the Spyderchat parts list but wont be able to give a price till Monday.

Liz · January 2, 2004, 14:45

I have got a stock box in my garage for a lend, I am in Essex so not too far away to travel? I am around most of this weekend and also off on Monday. Maybe if you came down you could clean my MAF for me as I don't poke around in engines!

Sam · January 2, 2004, 15:03

s:D

s:D Thanks Liz - you have PM!

Anonymous · January 6, 2004, 14:13

Depending on how loud this sounds exactly like my car, eventually this was tracked to blockage in the lower exhaust, possibly bits of pre-cat (manifold replaced 18th Nov). The dealer changed the vvti gear and exhaust and problem is now resolved. I believe vvti gear was secondary damage, as initially power was OK just noisy, but it very quickly got worse.

Depending on how loose/rattly the debris is you might be able to check this by removing the exhaust and shaking it, failing that not sure how you could check this other than trying another exhaust which is a load of hassle.

Sam · January 7, 2004, 10:06

Yeah to be honest I have now started to suspect the precats causing some trouble. Well I should soon find out - the car is disappearing to Toyota again on Friday (Lets hope for not as long as last time - 31 days!).

Sam · January 15, 2004, 17:39

Update:

I collected my car today. The problem was pre-cats disintegrating and blocking the main cat. All 3 cats have been changed although I am still waiting for the copy of the claim put into Toyota by the garage to confirm this was all that was changed.
They tried to blame the HKS induction kit - saying that fitting this altered the compression ratio! (I can't see how this could be true in any way at all).
I said that other MR2 owners had had problems with the pre-cats failing and they said this was the first case they had seen or heard of.

Anyway car is running perfectly now so I think I'll keep the stock airbox in place and extend the warranty. Just have to be patient now and wait for the TTE turbo s:roll: :roll: s:roll:

aaronjb · January 15, 2004, 18:29

Quote from: "Sam"They tried to blame the HKS induction kit - saying that fitting this altered the compression ratio! (I can't see how this could be true in any way at all).

PMSL! You're right to disbelieve them... Given that compression ratio is a function of bore size/piston stroke/squish area etc (basically engine internals), there's no way an induction kit could alter compression ratio..

If by some miracle you managed to create enough of a ram air effect, you might raise cylinder pressure a tiny weeny bit - but no more than driving on a cold day increases the density of oxygen in the cylinder.

Just another example of a garage saying anything that comes to mind to try and get rid of you, I'm afraid...

(Someone correct me if I'm wrong!)

Aaron

Anonymous · January 15, 2004, 18:35

Quotesaying that fitting this altered the compression ratio!

I would agree with your sentiment on that although I can't say why the fault occured. I thought compression ratio was a fixed aspect i.e. the ratio of the space above the piston from when it is at it highest point of its travel, to the space above it when at the bottom of its descent. To change it you would need to alter the head, piston or connector rod in some way I would have thought.

Some of the turbo owners can probably give us a more experienced view.

They didn't say why the pre-cats had fallen apart? Was it age? Overheating?

aaronjb · January 15, 2004, 18:38

Thinking on it a bit more (you're right on the definition of compression ratio btw Lusaka), the only reason I can think that an induction kit could cause the cats to fail is this (and it's a very slim chance);

If the induction kit pipework modifies the crankcase breather arrangement, it could increase the ingestion of oil fumes to an extent that the oil content contaminates, and then breaks down, the CAT element.

But that really is a slim chance, and purely conjecture until someone comes along who knows the ins and outs of the 1zz-fe breather arrangement (I don't, but I've seen similar problems on other engines).