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Soarer Central Mechanical - TT General Mechanical Fuel consumption just got worse

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Michael Sztyk
Tinkerer
Victoria
1JZ-GTE Soarer TT

Posts: 79
Reg: 12-2005

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Tuesday, September 19, 2006 - 06:48 pm, by: Michael Sztyk (Sli1)

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Just curious on what else can go wrong from buggered coilpacks...

So far im sure my cat has been gutted as the notes a bit deeper and suspecting the o2 sensor since my fuel consumption has gone pretty bad... Just got 374k's from a full tank.

I have done a search by the way but couldnt find exactly the answer...

I have patched cracks on the packs with silicone for now till i get new ones. Seems to have fixed the problem for now.

I tried one place for second hand packs, but when i looked at them they already started to crack LOL....

So yeah, what else can go wrong from buggered packs from everyones experience?

Callum Finch
Goo Roo
WA
Soarer TT & Corolla

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Tuesday, September 19, 2006 - 10:27 pm, by: Callum Finch (Sigeneat)

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I am getting about 350kms to a tank at the moment, very rich!

It seems the main killer with my fuel economy is more so my coilpacks causing misfiring.

I'd say work on replacing them asap. 'Patching' them doesnt really work from what i can understand as the same cracks just come back again through the stuff you stick on.
Of course, dont even think about second hand coilpacks =P

Check your plugs as well, they may need regapping or replacing ;D

...and stop flooring it everywhere! >.<'''

Toan Nguyen
Tinkerer
VIC
TT

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Wednesday, September 20, 2006 - 02:48 pm, by: Toan Nguyen (Soarer_gt)

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Sounds like you also have a boost leak.

Cihan Aday
Goo Roo
Its stock i swear.
JZZ30

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Wednesday, September 20, 2006 - 03:46 pm, by: Cihan Aday (Cihan)

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Callum 350 to a tank??
Must be some kind of problem there buddy. Coilpacks wont actually make a difference to fuel economy unless you have to accelerate harder to overcome the sometimes debilitating shudders. ECU fuel delivery won't be effected by coilpacks unless its very consistent.

I would look into the ECU itself being a problem, or look at the sensors the ECU bases fuel delivery on. That would include, water temp sensor, intake temp sensor and the oxygen sensor.
If you have any means of diagnosing injector duty cycle or pulse width at part/light throttle and idle the numbers will tell a story and it would be a good idea to have them looked at.

Coilpacks in general either stuff up completely and don't fire, or crack around contact areas and allow contaminants (and lack of contact) to interfere with the discharge, creating a misfire under load because of the weaker spark. The problems usually under boost.

As a reference, driving sedately and smartly around town (no highway work) I achieved 226kms from 23.1L of fuel (10.2L/100kms). Driving on boost and spirited'ly occasionally, this 22L fill im doing about 11.1 litres per 100kms. Im at 97kms with a little under 15% (~11.7L) of the tank to go (not including reserve).

Great Ocean Rd cruise day a few months back, I spent 12.2L/100kms including the drive along the GOR to apollo bay, and back again. We didnt take that easy at all.

Tuning the timing maps and fuel maps in that area (properly) helps ;) So does watching how you drive generally and how and when you brake. Maybe i've been lucky so far, but somethings right for sure.

Luke Nieuwhof
Goo Roo
WA
Soarer TT

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Wednesday, September 20, 2006 - 05:16 pm, by: Luke Nieuwhof (Luke_nieuwhof)

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We'll swap the ECU this weekend Callum, see if that helps. If you want I can bring around the original one too and you can use it for a while to see if it makes a difference to the economy.
I agree 350 is pretty shocking! Even with the way mine is piss farting around at the moment I am still getting about 600-650 a tank, though I was getting 10L/100km before the problems...

Michael Sztyk
Tinkerer
Victoria
1JZ-GTE Soarer TT

Posts: 81
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Wednesday, September 20, 2006 - 08:58 pm, by: Michael Sztyk (Sli1)

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Wow, 600 to 650 to a tank...
That would be nice.

Cihan Aday wrote on Wednesday, September 20, 2006 - 03:46 pm:
Coilpacks in general either stuff up completely and don't fire, or crack around contact areas and allow contaminants (and lack of contact) to interfere with the discharge, creating a misfire under load because of the weaker spark. The problems usually under boost.

Yeah the issue that started this whole problem was initially jerking on boost at around 13 to 14 psi. I had then resealed the cracks on the packs and that stopped. During that time the cat must have been gutted since the note got deeper and the economy went downhill soon after that

:-(

Got it booked in for a checkup at sports and luxury with Doug next week but not sure how much they can really diagnose.

Anyone know someone in melb that actually knows these cars and can diagnose accurately? LOL

Dean Carsen
Tinkerer
SA
JZZ30 vvti 5 speed

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Wednesday, September 20, 2006 - 09:23 pm, by: Dean Carsen (Deano)

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As Cihan mentioned , faulty O2 sensors are a common cause of poor fuel economy. They dont last forever, yours could be 15 years old.A good mechanic can check it out with a multimeter.

Callum Finch
Goo Roo
WA
Soarer TT & Corolla

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Wednesday, September 20, 2006 - 10:11 pm, by: Callum Finch (Sigeneat)

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It was 350kms doing lots of city driving and with the aircon going.. but i like to use that example as a drastic case! =P
Usually ~7km/L, which is still bad.

It could be the ECU, or the tune on my SAFC. It was touted as a "conservative tune" when i bought the car. A majority of my driving these days is highway and main roads if that changes things.

This sat im having new plugs (~60,000kms platinums) and coilpacks installed. Ill also get my mechanic to have a look at the mentioned sensors.

These days with the car sitting at home for 90% of my driving (new daily driver) i can get quite spirited in the ol' Soarer, so that wouldnt help! ;D

I did just find out that there may be a slight exhaust leak after the dump pipes, however im told that shouldnt cause any problems other than noise pollution?

Ill get my mechanic to check those sensors this w/e. Cheers for the tips!

Luke Nieuwhof
Goo Roo
WA
Soarer TT

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Thursday, September 21, 2006 - 07:06 am, by: Luke Nieuwhof (Luke_nieuwhof)

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Got a spare O2 sensor if you need it also

:-)

Michael Sztyk
Tinkerer
Victoria
1JZ-GTE Soarer TT

Posts: 82
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Thursday, September 21, 2006 - 09:09 pm, by: Michael Sztyk (Sli1)

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Thanks for all the replies guys.
Ill keep you posted once i find out what it could be.

Thanks again...

Michael Sztyk
Tinkerer
Victoria
1JZ-GTE Soarer TT

Posts: 83
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Saturday, September 30, 2006 - 03:46 pm, by: Michael Sztyk (Sli1)

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Seems i didn’t have a vacuum valve on the standard BOV.
Not sure what its called but i think its EMU valve?
Please correct me if im wrong...

As the boost built up it was letting boost escape too easily without the valve there. That explains why i had the sound of an after market BOV...

Also replaced the fuel pump ECU and seems to be sounding a bit quieter.

Still yet to check the exhaust but im leaning towards a definite cat blown out...

Getting back to normal

Michael Sztyk
Tinkerer
Victoria
1JZ-GTE Soarer TT

Posts: 84
Reg: 12-2005

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Saturday, September 30, 2006 - 03:47 pm, by: Michael Sztyk (Sli1)

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Now just gotta do a few tanks to test consumption before trying a replacement ECU...

Heshan Jayawardena
Tinkerer
WA
JZA80 Supra

Posts: 22
Reg: 10-2006

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Wednesday, March 05, 2008 - 01:54 pm, by: Heshan Jayawardena (Apophis)

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Hey
I was wondering if any of you guys could tell me the parts number for a genuine 02 sensor for an early model TT (jzz30)

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