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Question regarding 1jz-gte idle   2013-09-18 18:45:00 <Dennis de Jong>
Hi all,

I have a question regarding the idle on a 1jz-gte. First a little bit of
background which might be helpful to others with weird electrical issues.

I discovered some strange electrical problems which involved the catalytic
converter light flickering on and off while the car was running and turning
off whenever I pressed the brake pedal. It turned out pressing the brake
pedal increased the voltage at the CCO pinout on the ECU, this pushed the
voltage above what was needed to switch the light on (low voltage means an
overheating catalytic converter). I thought this was odd since I don't have
a catalytic converter or a sensor. Furthermore, pressing on the brake pedal
also increased the idle speed by ~100rpm. It only did this when the brake
light circuit was intact, so it was not a vacuum issue.

Lots of reading on the interweb yielded little help, apart from general
confusion regarding the CCO circuit and whether or not removing the sensor
made a difference to fuel/air mixture. I can't say for sure whether the
ECU uses this value for any engine management, even with the manual! But
when there is no sensor, the ECU defaults to approximately 3 volts, which
is in the middle of the normal voltage range for the catalytic converter
(2.5 to 5.5 volts). Essentially the ECU only seems to care whether the
voltage in the CCO circuit is above approximately 2 volts as far as I can
tell.

After a lot of fiddling about testing the loom and learning a lot along the
way, a friend of mine who does a lot of work with electronics talked me
through the circuit and a bit about ECU operation. This led to
investigating the ECU which, 7M owners feel free to gloat here, had leaking
capacitors, these had been fixed before by someone else, but were leaking
again, I'm not sure why this was as the ECU was not the one that came with
the front cut.

Replacing these solved the above problems and some others which were more
subtle. The idle now stays at normal speed ~750rpm when the car is warmed
up, but still sounds quite "messy". I haven't heard many 1jz's idle, and
can't seem to find any on youtube that haven't been modified. Only
modifications for my car are the muffler, pod filter and aftermarket blow
off valve (came with the front cut from Japan). I've uploaded a video of my
car idling to (easier to hear with head phones):

http://youtu.be/zZJeVP5sNs8

Just wondering if this is normal idle for an unmodified 1JZ? The reason I'm
asking is that I want to make sure:

A) I'm not trying to create a problem when there is none.
B) Whether there's not another issue I need to attend to while I'm tinkering
C) Whether there's a possibility some other gremlin in the ISC system
caused the capacitors to start leaking.

Any thoughts would be much appreciated.

(html version)
Reply

Re: Question regarding 1jz-gte idle   2013-09-18 19:05:00 <Suzy W>
1jz ecus are very well known for crapping themselves :D

*gloat gloat* yw :)


On Wed, Sep 18, 2013 at 6:42 PM, Dennis de Jong <catingle1975@gmail.com>wrote:

> Hi all,
>
> I have a question regarding the idle on a 1jz-gte. First a little bit of
> background which might be helpful to others with weird electrical issues.
>
> I discovered some strange electrical problems which involved the catalytic
> converter light flickering on and off while the car was running and turning
> off whenever I pressed the brake pedal. It turned out pressing the brake
> pedal increased the voltage at the CCO pinout on the ECU, this pushed the
> voltage above what was needed to switch the light on (low voltage means an
> overheating catalytic converter). I thought this was odd since I don't have
> a catalytic converter or a sensor. Furthermore, pressing on the brake pedal
> also increased the idle speed by ~100rpm. It only did this when the brake
> light circuit was intact, so it was not a vacuum issue.
>
> Lots of reading on the interweb yielded little help, apart from general
> confusion regarding the CCO circuit and whether or not removing the sensor
> made a difference to fuel/air mixture. I can't say for sure whether the
> ECU uses this value for any engine management, even with the manual! But
> when there is no sensor, the ECU defaults to approximately 3 volts, which
> is in the middle of the normal voltage range for the catalytic converter
> (2.5 to 5.5 volts). Essentially the ECU only seems to care whether the
> voltage in the CCO circuit is above approximately 2 volts as far as I can
> tell.
>
> After a lot of fiddling about testing the loom and learning a lot along
> the way, a friend of mine who does a lot of work with electronics talked me
> through the circuit and a bit about ECU operation. This led to
> investigating the ECU which, 7M owners feel free to gloat here, had leaking
> capacitors, these had been fixed before by someone else, but were leaking
> again, I'm not sure why this was as the ECU was not the one that came with
> the front cut.
>
> Replacing these solved the above problems and some others which were more
> subtle. The idle now stays at normal speed ~750rpm when the car is warmed
> up, but still sounds quite "messy". I haven't heard many 1jz's idle, and
> can't seem to find any on youtube that haven't been modified. Only
> modifications for my car are the muffler, pod filter and aftermarket blow
> off valve (came with the front cut from Japan). I've uploaded a video of my
> car idling to (easier to hear with head phones):
>
> http://youtu.be/zZJeVP5sNs8
>
> Just wondering if this is normal idle for an unmodified 1JZ? The reason
> I'm asking is that I want to make sure:
>
> A) I'm not trying to create a problem when there is none.
> B) Whether there's not another issue I need to attend to while I'm
> tinkering
> C) Whether there's a possibility some other gremlin in the ISC system
> caused the capacitors to start leaking.
>
> Any thoughts would be much appreciated.
>
> ---
> Supra Club of New Zealand - http://www.supras.org.nz/
> Website sponsored by Alltech Diesel & Turbocharger http://www.turbo.co.nz
>
>


--
Cheers

Suze
7M POWAH! ;)
www.supra.co.nz

(html version)
Reply

Re: Question regarding 1jz-gte idle   2013-09-18 20:34:00 <Dennis de Jong>
Yeah, yeah, always something new to learn hehe. Enjoy the gloat! :-P
On 18/09/2013 7:02 AM, "Suzy W" <suprra@gmail.com> wrote:

> 1jz ecus are very well known for crapping themselves :D
>
> *gloat gloat* yw :)
>
>
> On Wed, Sep 18, 2013 at 6:42 PM, Dennis de Jong <catingle1975@gmail.com>wrote:
>
>> Hi all,
>>
>> I have a question regarding the idle on a 1jz-gte. First a little bit of
>> background which might be helpful to others with weird electrical issues.
>>
>> I discovered some strange electrical problems which involved the
>> catalytic converter light flickering on and off while the car was running
>> and turning off whenever I pressed the brake pedal. It turned out pressing
>> the brake pedal increased the voltage at the CCO pinout on the ECU, this
>> pushed the voltage above what was needed to switch the light on (low
>> voltage means an overheating catalytic converter). I thought this was odd
>> since I don't have a catalytic converter or a sensor. Furthermore, pressing
>> on the brake pedal also increased the idle speed by ~100rpm. It only did
>> this when the brake light circuit was intact, so it was not a vacuum issue.
>>
>> Lots of reading on the interweb yielded little help, apart from general
>> confusion regarding the CCO circuit and whether or not removing the sensor
>> made a difference to fuel/air mixture. I can't say for sure whether the
>> ECU uses this value for any engine management, even with the manual! But
>> when there is no sensor, the ECU defaults to approximately 3 volts, which
>> is in the middle of the normal voltage range for the catalytic converter
>> (2.5 to 5.5 volts). Essentially the ECU only seems to care whether the
>> voltage in the CCO circuit is above approximately 2 volts as far as I can
>> tell.
>>
>> After a lot of fiddling about testing the loom and learning a lot along
>> the way, a friend of mine who does a lot of work with electronics talked me
>> through the circuit and a bit about ECU operation. This led to
>> investigating the ECU which, 7M owners feel free to gloat here, had leaking
>> capacitors, these had been fixed before by someone else, but were leaking
>> again, I'm not sure why this was as the ECU was not the one that came with
>> the front cut.
>>
>> Replacing these solved the above problems and some others which were more
>> subtle. The idle now stays at normal speed ~750rpm when the car is warmed
>> up, but still sounds quite "messy". I haven't heard many 1jz's idle, and
>> can't seem to find any on youtube that haven't been modified. Only
>> modifications for my car are the muffler, pod filter and aftermarket blow
>> off valve (came with the front cut from Japan). I've uploaded a video of my
>> car idling to (easier to hear with head phones):
>>
>> http://youtu.be/zZJeVP5sNs8
>>
>> Just wondering if this is normal idle for an unmodified 1JZ? The reason
>> I'm asking is that I want to make sure:
>>
>> A) I'm not trying to create a problem when there is none.
>> B) Whether there's not another issue I need to attend to while I'm
>> tinkering
>> C) Whether there's a possibility some other gremlin in the ISC system
>> caused the capacitors to start leaking.
>>
>> Any thoughts would be much appreciated.
>>
>> ---
>> Supra Club of New Zealand - http://www.supras.org.nz/
>> Website sponsored by Alltech Diesel & Turbocharger http://www.turbo.co.nz
>>
>>
>
>
> --
> Cheers
>
> Suze
> 7M POWAH! ;)
> www.supra.co.nz
>
> ---
> Supra Club of New Zealand - http://www.supras.org.nz/
> Website sponsored by Alltech Diesel & Turbocharger http://www.turbo.co.nz
>
>

(html version)
Reply

Re: Question regarding 1jz-gte idle   2013-09-18 20:55:00 <Suzy W>
Driftmotion fixes 1jz ecu's daily, replacing the capacitors, not sure why
they take a dump when the ecu isn't that much newer than the 7m, why change
what worked :/


On Wed, Sep 18, 2013 at 8:31 PM, Dennis de Jong <catingle1975@gmail.com>wrote:

> Yeah, yeah, always something new to learn hehe. Enjoy the gloat! :-P
> On 18/09/2013 7:02 AM, "Suzy W" <suprra@gmail.com> wrote:
>
>> 1jz ecus are very well known for crapping themselves :D
>>
>> *gloat gloat* yw :)
>>
>>
>> On Wed, Sep 18, 2013 at 6:42 PM, Dennis de Jong <catingle1975@gmail.com>wrote:
>>
>>> Hi all,
>>>
>>> I have a question regarding the idle on a 1jz-gte. First a little bit of
>>> background which might be helpful to others with weird electrical issues.
>>>
>>> I discovered some strange electrical problems which involved the
>>> catalytic converter light flickering on and off while the car was running
>>> and turning off whenever I pressed the brake pedal. It turned out pressing
>>> the brake pedal increased the voltage at the CCO pinout on the ECU, this
>>> pushed the voltage above what was needed to switch the light on (low
>>> voltage means an overheating catalytic converter). I thought this was odd
>>> since I don't have a catalytic converter or a sensor. Furthermore, pressing
>>> on the brake pedal also increased the idle speed by ~100rpm. It only did
>>> this when the brake light circuit was intact, so it was not a vacuum issue.
>>>
>>> Lots of reading on the interweb yielded little help, apart from general
>>> confusion regarding the CCO circuit and whether or not removing the sensor
>>> made a difference to fuel/air mixture. I can't say for sure whether the
>>> ECU uses this value for any engine management, even with the manual! But
>>> when there is no sensor, the ECU defaults to approximately 3 volts, which
>>> is in the middle of the normal voltage range for the catalytic converter
>>> (2.5 to 5.5 volts). Essentially the ECU only seems to care whether the
>>> voltage in the CCO circuit is above approximately 2 volts as far as I can
>>> tell.
>>>
>>> After a lot of fiddling about testing the loom and learning a lot along
>>> the way, a friend of mine who does a lot of work with electronics talked me
>>> through the circuit and a bit about ECU operation. This led to
>>> investigating the ECU which, 7M owners feel free to gloat here, had leaking
>>> capacitors, these had been fixed before by someone else, but were leaking
>>> again, I'm not sure why this was as the ECU was not the one that came with
>>> the front cut.
>>>
>>> Replacing these solved the above problems and some others which were
>>> more subtle. The idle now stays at normal speed ~750rpm when the car is
>>> warmed up, but still sounds quite "messy". I haven't heard many 1jz's
>>> idle, and can't seem to find any on youtube that haven't been modified.
>>> Only modifications for my car are the muffler, pod filter and aftermarket
>>> blow off valve (came with the front cut from Japan). I've uploaded a video
>>> of my car idling to (easier to hear with head phones):
>>>
>>> http://youtu.be/zZJeVP5sNs8
>>>
>>> Just wondering if this is normal idle for an unmodified 1JZ? The reason
>>> I'm asking is that I want to make sure:
>>>
>>> A) I'm not trying to create a problem when there is none.
>>> B) Whether there's not another issue I need to attend to while I'm
>>> tinkering
>>> C) Whether there's a possibility some other gremlin in the ISC system
>>> caused the capacitors to start leaking.
>>>
>>> Any thoughts would be much appreciated.
>>>
>>> ---
>>> Supra Club of New Zealand - http://www.supras.org.nz/
>>> Website sponsored by Alltech Diesel & Turbocharger http://www.turbo.co.nz
>>>
>>>
>>
>>
>> --
>> Cheers
>>
>> Suze
>> 7M POWAH! ;)
>> www.supra.co.nz
>>
>> ---
>> Supra Club of New Zealand - http://www.supras.org.nz/
>> Website sponsored by Alltech Diesel & Turbocharger http://www.turbo.co.nz
>>
>> ---
> Supra Club of New Zealand - http://www.supras.org.nz/
> Website sponsored by Alltech Diesel & Turbocharger http://www.turbo.co.nz
>
>


--
Cheers

Suze
7M POWAH! ;)
www.supra.co.nz

(html version)
Reply

RE: Question regarding 1jz-gte idle   2013-09-18 21:02:00 <Looonie>
7M ecu's never really got much use because the engines were always killing
themselves in a variety of colourful, harmful and smokey ways.



1JZ ecu's on the other hand have a much harder job processing all that
superior power, torque and doing it on a daily basis, day in day out without
stop ;)



Che che

Looonie



From: bounce-101451-4880@list.supras.org.nz
[mailto:bounce-101451-4880@list.supras.org.nz] On Behalf Of Suzy W
Sent: Wednesday, 18 September 2013 8:53 p.m.
To: Supra Club of NZ Mailing List
Subject: Re: [sconz] Question regarding 1jz-gte idle



Driftmotion fixes 1jz ecu's daily, replacing the capacitors, not sure why
they take a dump when the ecu isn't that much newer than the 7m, why change
what worked :/



On Wed, Sep 18, 2013 at 8:31 PM, Dennis de Jong <catingle1975@gmail.com>
wrote:

Yeah, yeah, always something new to learn hehe. Enjoy the gloat! :-P

On 18/09/2013 7:02 AM, "Suzy W" <suprra@gmail.com> wrote:

1jz ecus are very well known for crapping themselves :D



*gloat gloat* yw :)



On Wed, Sep 18, 2013 at 6:42 PM, Dennis de Jong <catingle1975@gmail.com>
wrote:

Hi all,

I have a question regarding the idle on a 1jz-gte. First a little bit of
background which might be helpful to others with weird electrical issues.

I discovered some strange electrical problems which involved the catalytic
converter light flickering on and off while the car was running and turning
off whenever I pressed the brake pedal. It turned out pressing the brake
pedal increased the voltage at the CCO pinout on the ECU, this pushed the
voltage above what was needed to switch the light on (low voltage means an
overheating catalytic converter). I thought this was odd since I don't have
a catalytic converter or a sensor. Furthermore, pressing on the brake pedal
also increased the idle speed by ~100rpm. It only did this when the brake
light circuit was intact, so it was not a vacuum issue.

Lots of reading on the interweb yielded little help, apart from general
confusion regarding the CCO circuit and whether or not removing the sensor
made a difference to fuel/air mixture. I can't say for sure whether the ECU
uses this value for any engine management, even with the manual! But when
there is no sensor, the ECU defaults to approximately 3 volts, which is in
the middle of the normal voltage range for the catalytic converter (2.5 to
5.5 volts). Essentially the ECU only seems to care whether the voltage in
the CCO circuit is above approximately 2 volts as far as I can tell.

After a lot of fiddling about testing the loom and learning a lot along the
way, a friend of mine who does a lot of work with electronics talked me
through the circuit and a bit about ECU operation. This led to investigating
the ECU which, 7M owners feel free to gloat here, had leaking capacitors,
these had been fixed before by someone else, but were leaking again, I'm not
sure why this was as the ECU was not the one that came with the front cut.

Replacing these solved the above problems and some others which were more
subtle. The idle now stays at normal speed ~750rpm when the car is warmed
up, but still sounds quite "messy". I haven't heard many 1jz's idle, and
can't seem to find any on youtube that haven't been modified. Only
modifications for my car are the muffler, pod filter and aftermarket blow
off valve (came with the front cut from Japan). I've uploaded a video of my
car idling to (easier to hear with head phones):

http://youtu.be/zZJeVP5sNs8

Just wondering if this is normal idle for an unmodified 1JZ? The reason I'm
asking is that I want to make sure:

A) I'm not trying to create a problem when there is none.
B) Whether there's not another issue I need to attend to while I'm tinkering
C) Whether there's a possibility some other gremlin in the ISC system caused
the capacitors to start leaking.

Any thoughts would be much appreciated.

---
Supra Club of New Zealand - http://www.supras.org.nz/
Website sponsored by Alltech Diesel & Turbocharger http://www.turbo.co.nz







--
Cheers

Suze
7M POWAH! ;)
www.supra.co.nz

---
Supra Club of New Zealand - http://www.supras.org.nz/
Website sponsored by Alltech Diesel & Turbocharger http://www.turbo.co.nz
---
Supra Club of New Zealand - http://www.supras.org.nz/
Website sponsored by Alltech Diesel & Turbocharger http://www.turbo.co.nz







--
Cheers

Suze
7M POWAH! ;)
www.supra.co.nz

---
Supra Club of New Zealand - http://www.supras.org.nz/
Website sponsored by Alltech Diesel & Turbocharger http://www.turbo.co.nz

(html version)
Reply

Re: Question regarding 1jz-gte idle   2013-09-18 21:11:00 <Suzy W>
LMFAO

ok i'll let you have that one, it was well put :P


On Wed, Sep 18, 2013 at 8:59 PM, Looonie <supras@boost.org.nz> wrote:

> 7M ecuís never really got much use because the engines were always killing
> themselves in a variety of colourful, harmful and smokey ways. ****
>
> ** **
>
> 1JZ ecuís on the other hand have a much harder job processing all that
> superior power, torque and doing it on a daily basis, day in day out
> without stop ;)****
>
> ** **
>
> Che che****
>
> Looonie****
>
> ** **
>
> *From:* bounce-101451-4880@list.supras.org.nz [mailto:
> bounce-101451-4880@list.supras.org.nz] *On Behalf Of *Suzy W
> *Sent:* Wednesday, 18 September 2013 8:53 p.m.
> *To:* Supra Club of NZ Mailing List
> *Subject:* Re: [sconz] Question regarding 1jz-gte idle****
>
> ** **
>
> Driftmotion fixes 1jz ecu's daily, replacing the capacitors, not sure why
> they take a dump when the ecu isn't that much newer than the 7m, why change
> what worked :/****
>
> ** **
>
> On Wed, Sep 18, 2013 at 8:31 PM, Dennis de Jong <catingle1975@gmail.com>
> wrote:****
>
> Yeah, yeah, always something new to learn hehe. Enjoy the gloat! :-P ****
>
> On 18/09/2013 7:02 AM, "Suzy W" <suprra@gmail.com> wrote:****
>
> 1jz ecus are very well known for crapping themselves :D****
>
> ** **
>
> *gloat gloat* yw :)****
>
> ** **
>
> On Wed, Sep 18, 2013 at 6:42 PM, Dennis de Jong <catingle1975@gmail.com>
> wrote:****
>
> Hi all,
>
> I have a question regarding the idle on a 1jz-gte. First a little bit of
> background which might be helpful to others with weird electrical issues.
>
> I discovered some strange electrical problems which involved the catalytic
> converter light flickering on and off while the car was running and turning
> off whenever I pressed the brake pedal. It turned out pressing the brake
> pedal increased the voltage at the CCO pinout on the ECU, this pushed the
> voltage above what was needed to switch the light on (low voltage means an
> overheating catalytic converter). I thought this was odd since I don't have
> a catalytic converter or a sensor. Furthermore, pressing on the brake pedal
> also increased the idle speed by ~100rpm. It only did this when the brake
> light circuit was intact, so it was not a vacuum issue.****
>
> Lots of reading on the interweb yielded little help, apart from general
> confusion regarding the CCO circuit and whether or not removing the sensor
> made a difference to fuel/air mixture. I can't say for sure whether the
> ECU uses this value for any engine management, even with the manual! But
> when there is no sensor, the ECU defaults to approximately 3 volts, which
> is in the middle of the normal voltage range for the catalytic converter
> (2.5 to 5.5 volts). Essentially the ECU only seems to care whether the
> voltage in the CCO circuit is above approximately 2 volts as far as I can
> tell.****
>
> After a lot of fiddling about testing the loom and learning a lot along
> the way, a friend of mine who does a lot of work with electronics talked me
> through the circuit and a bit about ECU operation. This led to
> investigating the ECU which, 7M owners feel free to gloat here, had leaking
> capacitors, these had been fixed before by someone else, but were leaking
> again, I'm not sure why this was as the ECU was not the one that came with
> the front cut.
>
> Replacing these solved the above problems and some others which were more
> subtle. The idle now stays at normal speed ~750rpm when the car is warmed
> up, but still sounds quite "messy". I haven't heard many 1jz's idle, and
> can't seem to find any on youtube that haven't been modified. Only
> modifications for my car are the muffler, pod filter and aftermarket blow
> off valve (came with the front cut from Japan). I've uploaded a video of my
> car idling to (easier to hear with head phones):
>
> http://youtu.be/zZJeVP5sNs8****
>
> Just wondering if this is normal idle for an unmodified 1JZ? The reason
> I'm asking is that I want to make sure:
>
> A) I'm not trying to create a problem when there is none.
> B) Whether there's not another issue I need to attend to while I'm
> tinkering
> C) Whether there's a possibility some other gremlin in the ISC system
> caused the capacitors to start leaking.****
>
> Any thoughts would be much appreciated.****
>
> ---****
>
> Supra Club of New Zealand - http://www.supras.org.nz/****
>
> Website sponsored by Alltech Diesel & Turbocharger http://www.turbo.co.nz****
>
>
>
> ****
>
> ** **
>
> --
> Cheers
>
> Suze
> 7M POWAH! ;)
> www.supra.co.nz ****
>
> ---****
>
> Supra Club of New Zealand - http://www.supras.org.nz/****
>
> Website sponsored by Alltech Diesel & Turbocharger http://www.turbo.co.nz****
>
> ---****
>
> Supra Club of New Zealand - http://www.supras.org.nz/****
>
> Website sponsored by Alltech Diesel & Turbocharger http://www.turbo.co.nz****
>
>
>
> ****
>
> ** **
>
> --
> Cheers
>
> Suze
> 7M POWAH! ;)
> www.supra.co.nz ****
>
> ---****
>
> Supra Club of New Zealand - http://www.supras.org.nz/****
>
> Website sponsored by Alltech Diesel & Turbocharger http://www.turbo.co.nz****
>
>
> ---
> Supra Club of New Zealand - http://www.supras.org.nz/
> Website sponsored by Alltech Diesel & Turbocharger http://www.turbo.co.nz
>
>


--
Cheers

Suze
7M POWAH! ;)
www.supra.co.nz

(html version)
Reply

Re: Question regarding 1jz-gte idle   2013-09-19 19:47:00 <Jonathan Walker>
My 7M takes a daily beating and begs for more every day :P
----- Original Message -----
From: Looonie
To: Supra Club of NZ Mailing List
Sent: Wednesday, September 18, 2013 8:59 PM
Subject: RE: [sconz] Question regarding 1jz-gte idle


7M ecu's never really got much use because the engines were always killing themselves in a variety of colourful, harmful and smokey ways.



1JZ ecu's on the other hand have a much harder job processing all that superior power, torque and doing it on a daily basis, day in day out without stop ;)



Che che

Looonie



From: bounce-101451-4880@list.supras.org.nz [mailto:bounce-101451-4880@list.supras.org.nz] On Behalf Of Suzy W
Sent: Wednesday, 18 September 2013 8:53 p.m.
To: Supra Club of NZ Mailing List
Subject: Re: [sconz] Question regarding 1jz-gte idle



Driftmotion fixes 1jz ecu's daily, replacing the capacitors, not sure why they take a dump when the ecu isn't that much newer than the 7m, why change what worked :/



On Wed, Sep 18, 2013 at 8:31 PM, Dennis de Jong <catingle1975@gmail.com> wrote:

Yeah, yeah, always something new to learn hehe. Enjoy the gloat! :-P

On 18/09/2013 7:02 AM, "Suzy W" <suprra@gmail.com> wrote:

1jz ecus are very well known for crapping themselves :D



*gloat gloat* yw :)



On Wed, Sep 18, 2013 at 6:42 PM, Dennis de Jong <catingle1975@gmail.com> wrote:

Hi all,

I have a question regarding the idle on a 1jz-gte. First a little bit of background which might be helpful to others with weird electrical issues.

I discovered some strange electrical problems which involved the catalytic converter light flickering on and off while the car was running and turning off whenever I pressed the brake pedal. It turned out pressing the brake pedal increased the voltage at the CCO pinout on the ECU, this pushed the voltage above what was needed to switch the light on (low voltage means an overheating catalytic converter). I thought this was odd since I don't have a catalytic converter or a sensor. Furthermore, pressing on the brake pedal also increased the idle speed by ~100rpm. It only did this when the brake light circuit was intact, so it was not a vacuum issue.

Lots of reading on the interweb yielded little help, apart from general confusion regarding the CCO circuit and whether or not removing the sensor made a difference to fuel/air mixture. I can't say for sure whether the ECU uses this value for any engine management, even with the manual! But when there is no sensor, the ECU defaults to approximately 3 volts, which is in the middle of the normal voltage range for the catalytic converter (2.5 to 5.5 volts). Essentially the ECU only seems to care whether the voltage in the CCO circuit is above approximately 2 volts as far as I can tell.

After a lot of fiddling about testing the loom and learning a lot along the way, a friend of mine who does a lot of work with electronics talked me through the circuit and a bit about ECU operation. This led to investigating the ECU which, 7M owners feel free to gloat here, had leaking capacitors, these had been fixed before by someone else, but were leaking again, I'm not sure why this was as the ECU was not the one that came with the front cut.

Replacing these solved the above problems and some others which were more subtle. The idle now stays at normal speed ~750rpm when the car is warmed up, but still sounds quite "messy". I haven't heard many 1jz's idle, and can't seem to find any on youtube that haven't been modified. Only modifications for my car are the muffler, pod filter and aftermarket blow off valve (came with the front cut from Japan). I've uploaded a video of my car idling to (easier to hear with head phones):

http://youtu.be/zZJeVP5sNs8

Just wondering if this is normal idle for an unmodified 1JZ? The reason I'm asking is that I want to make sure:

A) I'm not trying to create a problem when there is none.
B) Whether there's not another issue I need to attend to while I'm tinkering
C) Whether there's a possibility some other gremlin in the ISC system caused the capacitors to start leaking.

Any thoughts would be much appreciated.

---Supra Club of New Zealand - http://www.supras.org.nz/Website sponsored by Alltech Diesel & Turbocharger http://www.turbo.co.nz





--
Cheers

Suze
7M POWAH! ;)
www.supra.co.nz

---Supra Club of New Zealand - http://www.supras.org.nz/Website sponsored by Alltech Diesel & Turbocharger http://www.turbo.co.nz---Supra Club of New Zealand - http://www.supras.org.nz/Website sponsored by Alltech Diesel & Turbocharger http://www.turbo.co.nz





--
Cheers

Suze
7M POWAH! ;)
www.supra.co.nz

---Supra Club of New Zealand - http://www.supras.org.nz/Website sponsored by Alltech Diesel & Turbocharger http://www.turbo.co.nz

---
Supra Club of New Zealand - http://www.supras.org.nz/
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