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Open in new windowArchive through November 15, 2006Neil Griffiths25 
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Mark Paddick
Goo Roo
ACT
UZZ31 V8 Soarer , JZZ30 TT Soarer

Posts: 2853
Reg: 07-2005

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Wednesday, November 15, 2006 - 10:07 pm, by:  Mark Paddick (Sparks) Quote hilighted text Edit Post Delete Post Print Post   View Post/Check IP (Moderator/Admin Only) Move Post (Moderator/Admin Only)

But the diags won't tell you !

It's interesting that some of the more mundane Toyota ECUs (Corolla, Camry etc) always get this right. An airflow meter fault code means exactly that; the AFM is crook (usually the inlet hose to the engine has come off or is leaking rather than the AFM itself being faulty). Maybe the Karmann Vortex variable frequency Soarer one is harder to monitor correctly.

Oh, and I figured out why a V8 will run OK with the AFM disconnected. The AFM output frequency is used to modify the frequency of an internal oscillator. With the AFM disconnected the oscillator still outputs its' unmodified frequency so the AFM signal is still there, just doesn't change from near its' max output.
Michael Hutton
Tinkerer
SA
soarer v8 limited

Posts: 26
Reg: 01-2006

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Wednesday, November 15, 2006 - 11:55 pm, by:  Michael Hutton (Lexual) Quote hilighted text Edit Post Delete Post Print Post   View Post/Check IP (Moderator/Admin Only) Move Post (Moderator/Admin Only)

So more than likely this is something in the ecu? And it should be pulled out and examined?
Mark Paddick
Goo Roo
ACT
UZZ31 V8 Soarer , JZZ30 TT Soarer

Posts: 2861
Reg: 07-2005

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Thursday, November 16, 2006 - 08:37 am, by:  Mark Paddick (Sparks) Quote hilighted text Edit Post Delete Post Print Post   View Post/Check IP (Moderator/Admin Only) Move Post (Moderator/Admin Only)

Most likely a coil pack or igniter but the ECU can do it too.
The easiest way to diagnose ECU faults is to replace it with a known good one.
Michael Hutton
Tinkerer
SA
soarer v8 limited

Posts: 27
Reg: 01-2006

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Thursday, November 16, 2006 - 03:34 pm, by:  Michael Hutton (Lexual) Quote hilighted text Edit Post Delete Post Print Post   View Post/Check IP (Moderator/Admin Only) Move Post (Moderator/Admin Only)

Cool, I had the igniter and coil packs out and tested and they were okay. I might try and source an ecu and slip it in, see how that goes
Michael Hutton
Tinkerer
SA
soarer v8 limited

Posts: 29
Reg: 01-2006

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Friday, November 17, 2006 - 10:34 pm, by:  Michael Hutton (Lexual) Quote hilighted text Edit Post Delete Post Print Post   View Post/Check IP (Moderator/Admin Only) Move Post (Moderator/Admin Only)

Mechanic pulled off the cats - found out the are pretty much stuffed and blocked to the proverbial s...house, so he's gonna clear it out and se how it goes from there - fingers crossed!
Harry Lemmens
TryHard
Victoria
V8

Posts: 243
Reg: 11-2004

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Monday, November 20, 2006 - 12:23 pm, by:  Harry Lemmens (Wombat) Quote hilighted text Edit Post Delete Post Print Post   View Post/Check IP (Moderator/Admin Only) Move Post (Moderator/Admin Only)

Question is: What caused them to overheat in the first place ... Although it is usually a stuffed coil, all of the items mentioned in this (and another?) thread will need to be checked.

There must be a reason that the cats overheated in the first place. The usual reason is unburnt fuel. This gets down to the cats and the reaction there is essentially to burn the fuel. Except ... theres about 1000% more fuel (and AIR) there than should normally be the case. Little wonder the converters get hot enough to melt down the guts!
Michael Hutton
Tinkerer
SA
soarer v8 limited

Posts: 30
Reg: 01-2006

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Friday, December 01, 2006 - 08:56 pm, by:  Michael Hutton (Lexual) Quote hilighted text Edit Post Delete Post Print Post   View Post/Check IP (Moderator/Admin Only) Move Post (Moderator/Admin Only)

well, 45 days later, got my car back, good as new. Turns out one of the new coil leads was crap, and shorted out, leaving only 4 cylinders firing. Thanks for your help guys, now I have to relearn how to drive it :-)
Brian Timms
Tinkerer
New South Wales
180sx DET

Posts: 12
Reg: 12-2006

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Monday, January 01, 2007 - 02:23 pm, by:  Brian Timms (Turbo_brian) Quote hilighted text Edit Post Delete Post Print Post   View Post/Check IP (Moderator/Admin Only) Move Post (Moderator/Admin Only)

I had similar issues with my own car (a Nissan 180sx), took it to be detailed, got it back and was sweet.

Next day, runs like a mofo, nasty, horrible, running on 3 cylinders instead of 4, sounding like a wrx and running pretty much like one as well.

Anyway, it threw a Cat warning light while trying to drive it to a mechanics to get looked at, and it turns out there was water in the cylinder heads around the spark plugs, causing the plug lead to short to the head, thus not spark, no combustion, and unburnt fuel going into the exhaust and cat converter.

It melted the cat converter, and threw a code on my car.

Anyway, got the water removed, and it drove ok, but wouldn't boost past 4psi (usually set at 19PSI), I went to the point of removing the wastegte hose completely, and it didn't fix the issue.

So after due consideration, I removed the Cat Converter completely, took it for a spin without the cat and exhaust, and she boosted up and hit 19psi, and boost cut-off within 2,800rpm, it was back.

After checking the cat converter, it was clogged up like a public toilet at a concert, so I took to it with a hammer and pinch-bar, and it's now the world's highest flowing cat (but not a cat converter, because it converts NOTHING!!)

Needless to say, New cat converter, and a nice cleanout fixed my issue, but it's good to see that your issue is also fixed up now as well.

B.
Daniel Clarke
Goo Roo
NSW
TT 2.5L 6 cylinder

Posts: 1081
Reg: 03-2006

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Monday, January 01, 2007 - 03:03 pm, by:  Daniel Clarke (Dieseltrain) Quote hilighted text Edit Post Delete Post Print Post   View Post/Check IP (Moderator/Admin Only) Move Post (Moderator/Admin Only)

45 days later? Worlds slowest mechanic maybe? SHoulda been done in no more than 3 days .

Glad you got it sorted though.

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