Blacktop ECU - missing info in the service manual

olskool

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High idling? Could it be your TPS too advance? I guess if a vacuum hose left unplug will afect the idling as well, even though its running with MAP.
Yeah but when I switch A/C off and the water temp goes to 84-86C the idle will drop to 900rpm, perfect. Switch A/C on temp drops to 76C plus idle 1.1-1.2k rpm. Hoses replaced and checked, no leaks :banghead::banghead:
 

me2kimi

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Is it that idling during aircon compressor on or off? AFAIK, when aircon compressor turn on, iscv will work to allow more air for the engine.
When both fan running, there will be slightly low temp for the water.
 
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olskool

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I don't know bro...It's been like that since I swapped to MAP.

I've been recently informed by a BT 6sp user who changed his thermostat to 78/76C that his idle is at 1.2k all the way but only after the change. Prior to that it was idling at 900rpm a/c on or off...

makan petrol!!!! :bawling::bawling::bawling:

Pls see table below...
 

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levin818

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Yes thats the one. If turn anti-clockwise 45 deg each will move the idling up from 800rpm to ~900rpm. If you want to tune down your idling, it should be clockwise direction.
Usually we adjust this with the aid of carburator balancer. If you do not have it, makesure all 4 screws turn at a similar angle.
 

olskool

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Thanks Levin818, but mine looks like the below pic and does not have individual vacuum outlets. So I wouldn't know how to use the carb balancer if I had it.

Also, if I tune it idling down when a/c is on to RPM900, would it affect the idling when the a/c if off?

cuscostrutbrace: Is all 20v water temp at 82C when a/c is on? I thought it should be lower since both fans are on...


 

levin818

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I ever borrow a Carb balancer from Ah Ngah long time ago. It is a thing with analog needle that move according to the airflow. By placing it on top of individual throttle, you can monitor/adjust the aif flow at each throttle. According to BT service manual, at correct airflow you should get 850rpm at idle with all electrical load OFF. So you should not measure the airflow with A/C ON.
 

cuscostrutbrace

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Thanks Levin818, but mine looks like the below pic and does not have individual vacuum outlets. So I wouldn't know how to use the carb balancer if I had it.

Also, if I tune it idling down when a/c is on to RPM900, would it affect the idling when the a/c if off?

cuscostrutbrace: Is all 20v water temp at 82C when a/c is on? I thought it should be lower since both fans are on...


Well,the water temp sensor and water temp switch position are different.The water temp switch is at the cold side(before cold water enter the engine/before thermostat),the temp switch will switch the fan on at 93deg and switch of at 83deg,so where it is positioned doesnt matter because the thermostat will open at 82deg,water temp will rise eventually.

The water temp sensor positioned after the thermostat,where the water circulates. Means before 82deg,the water inside the block just circulates inside the engine,and this temp sensor can measure the variation in temp from cold to hot..

Let see,thermostat full open at 82,at this time the fan is off,so after a driving while temp will raise to 93,then fan kick in,temp goes down to 83,fan switch off,but since the fan is off at this point,temp will raise again after driving for a while..by theory,the water temp should not fall below 82deg,because the fan will be off at 83deg so there will be temperature build up after that as there is no cooling air for the radiator....unless the fan does not switch off at 83deg,still running until temp drop lower than 82deg.
 

me2kimi

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I make the converter by myself. It allow me to plug and play BT ECU and run with MAP in within 5 min. I have try resolve the O2 problem by supplying a 1V to OX+ so that the ECU can read the signal at OX. It works very well at low load but not at high load/WOT due to difference in HT signal between SVT and BT. So my car now, sometimes fast, sometimes slow... To resolve this problem, the only way is to handle the HT signal seperately. I am now working on it... very close to the solution hehe..
Bro wong, can I use SVT ecu as a secondary ecu just to supply signal to O2 sensor?
 

levin818

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Wah you are brilliant man! Yes i think it will work :biggrin:
1) Connect HT, OX and OX+ to SVT ECU.
2) Parallel BATT, +B1, E1, E01, OX with BT ECU

Pls keep us update on your result man!
 

me2kimi

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Ok, I'll try it once got a time
 

levin818

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Opps the BT ECU may flag in an error code 21 (Open/Short in heater circuit of O2 sensor for 0.5s or more). Try place a 1k 0.5W resistor across +B and HT to cheat the BT ECU.
 

me2kimi

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BTW, which area you think is most suitable to place the 2ndary ecu? the space look tight already.

Are still continue designing PWM circuit or you will use this method?
 

pcmoddingmy

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Guys, what's the purpose of having 2 ECUs just to run the O2 sensor properly? Hehehhe...
Btw, sifu Wong regarding the exhaust temperature pinout (CCO & EGW) will only work when the exhaust temp sensor is installed right?
Any difference after installing this EGT sensor?
IIRC, there was a thread previously by scottwrx where he installed the EGT sensor and claimed that the engine pinging/knocking was eliminated due to the EGT feedback to the ECU.
However, its very hard to find the EGT sensor as this is usually attached on the catcon which is usually dismantled in japan itself.
 

levin818

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me2kimi,
Yes the PWM circuit is already in progress. Just had it simplify from 3 ICs to 1 IC so next will be prototype construction.

pcmoddingmy,
We just want to have some fun with the silvertop O2 :biggrin: The overall idea is, we want to retain svt O2 sensor, with the resources that we have now.
And regarding the EGT sensor, I am using it since day one i bought the car. I don't feel any significant diff when i test drove other 20V which running w/o the sensor. Perhaps it only works when the engine reach certain level of conditions.
 

me2kimi

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Wah you are brilliant man! Yes i think it will work :biggrin:
1) Connect HT, OX and OX+ to SVT ECU.
2) Parallel BATT, +B1, E1, E01, OX with BT ECU

Pls keep us update on your result man!
hi wong, E2 no need to connect or not?
 

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