need help: how to increase idling speed on 4G93

[boyzone]

Guys,
Currently run with duratec 272 cam.
However, observed engine vibrate on stock idling speed. I did tried to adjust biss to increase..but, stepper motor will compensate back after 1,2 days.
Any good method to share how to increase idling speed without flash ecu?
Pls advise... Thx

 

[Tom]

Hi,

Which stepper motor is this? Does the 4G93 run on drive by wire?
Is there any way to adjust the throttle opening manually? such as a screw?

 

[boyzone]

Hi,

Which stepper motor is this? Does the 4G93 run on drive by wire?
Is there any way to adjust the throttle opening manually? such as a screw?

Hi Tom,

The stepper motor is from ISC, to step up the idling when cool start and air con turn on etc.
Our 4G93 is still run by cable as is from yr 92/93 technology.
On top of throttle body have a screw to adjust the idling. However, seem like not work as stepper motor will step down the idling as per ecu preset value.

 

[vr2turbo]

Hi Tom,

The stepper motor is from ISC, to step up the idling when cool start and air con turn on etc.
Our 4G93 is still run by cable as is from yr 92/93 technology.
On top of throttle body have a screw to adjust the idling. However, seem like not work as stepper motor will step down the idling as per ecu preset value.

The stepper motor should not compensate your normal idling right? Only with the aircon on. Mine is 1991 4G63, so the higher the normal idling, so is the idling with air con on or maybe yours not the same:hmmmm:

 

[boyzone]

The stepper motor should not compensate your normal idling right? Only with the aircon on. Mine is 1991 4G63, so the higher the normal idling, so is the idling with air con on or maybe yours not the same:hmmmm:

Hi vr2turbo,

I'm not sure. But, I did adjusted the screw without the aircon. However, will bring down to preset valve after few days run...

 

[^pomen_GTR^]

u sure? i thin the stepper motor not that intelligent on old 4g series engine...try adjust it again...this time adjust only after the engine hot.. (after a few minute drive).... and check the engine breather pipe as well as the oil filler cap seal...because last time my 4g92 weird idling sometimes low sometimes high untill i get mad and remove isc internal gear completely and use 2ficd... (1 for aircond and another one for engine warm-up) but ut turns out still weird idling...untill i put double oil seal/o-ring on the engine oil filler cap...then only it behave normally...

because on 4g series the engine breather hooked on maf sensor one before throttle body and one after throttle body...any leak between those 2 different area results weird idling (and maybe performance as well as fc)


best solution on breather area is to modify the breather pipe..remove the breather valve and put bigger pipe let it run open to normal air...plug the breather hole at intake...

 

[boyzone]

u sure? i thin the stepper motor not that intelligent on old 4g series engine...try adjust it again...this time adjust only after the engine hot.. (after a few minute drive).... and check the engine breather pipe as well as the oil filler cap seal...because last time my 4g92 weird idling sometimes low sometimes high untill i get mad and remove isc internal gear completely and use 2ficd... (1 for aircond and another one for engine warm-up) but ut turns out still weird idling...untill i put double oil seal/o-ring on the engine oil filler cap...then only it behave normally...

because on 4g series the engine breather hooked on maf sensor one before throttle body and one after throttle body...any leak between those 2 different area results weird idling (and maybe performance as well as fc)


best solution on breather area is to modify the breather pipe..remove the breather valve and put bigger pipe let it run open to normal air...plug the breather hole at intake...

Good input poman... I will check it up..
Btw, If I remove those breath pipes (In&Out) from ram pipe and intake manifold, can I replace with mini air filter and let it open to atmosphere?

 

[^pomen_GTR^]

Good input poman... I will check it up..
Btw, If I remove those breath pipes (In&Out) from ram pipe and intake manifold, can I replace with mini air filter and let it open to atmosphere?

can..but i prefer putting an oil catch tank...if filter alone aftraid got too much oil spilled from the hole...

 

[boyzone]

can..but i prefer putting an oil catch tank...if filter alone aftraid got too much oil spilled from the hole...

My engine just light mod, should not have such much oil spill out...kua ?

 

[Izso]

My engine just light mod, should not have such much oil spill out...kua ?

When fitting that plastic fuel filter, make sure the seal from the hose into the filter is tight but not overly tight until the plastic is crushed. At the same time don't make it too lose until there's a vacuum leak. Both suck, trust me. Been there.

 

[boyzone]

When fitting that plastic fuel filter, make sure the seal from the hose into the filter is tight but not overly tight until the plastic is crushed. At the same time don't make it too lose until there's a vacuum leak. Both suck, trust me. Been there.

Ok noted, thx for the input.

 

[Kopi]

Guys,
Currently run with duratec 272 cam.
However, observed engine vibrate on stock idling speed. I did tried to adjust biss to increase..but, stepper motor will compensate back after 1,2 days.
Any good method to share how to increase idling speed without flash ecu?
Pls advise... Thx

Duratec 272cam & stock throttle body or S90?

1. Are you experiencing throttle lag like you have to foot down the pedal more than usual to have the car going between 1000 till 2000rpm?

2. What's your fuel pressure setting?

btw... on most 4gx engine without fuel/ignition management hack and trims, and using cams 264°+, idling between 500-800rpm is NORMAL. Use S90 summore... lagi normal.

 

[6UE5t]

The stepper motor should not compensate your normal idling right? Only with the aircon on. Mine is 1991 4G63, so the higher the normal idling, so is the idling with air con on or maybe yours not the same:hmmmm:

It's the same. I owned 4G93, 4G63, and 4G67 before and they all exactly the same with regards to the stepper motor. Even 6A12 also use the same.

 

[boyzone]

The stepper motor should not compensate your normal idling right? Only with the aircon on. Mine is 1991 4G63, so the higher the normal idling, so is the idling with air con on or maybe yours not the same:hmmmm:

can..but i prefer putting an oil catch tank...if filter alone aftraid got too much oil spilled from the hole...

When fitting that plastic fuel filter, make sure the seal from the hose into the filter is tight but not overly tight until the plastic is crushed. At the same time don't make it too lose until there's a vacuum leak. Both suck, trust me. Been there.

Duratec 272cam & stock throttle body or S90?

1. Are you experiencing throttle lag like you have to foot down the pedal more than usual to have the car going between 1000 till 2000rpm?

2. What's your fuel pressure setting?

btw... on most 4gx engine without fuel/ignition management hack and trims, and using cams 264°+, idling between 500-800rpm is NORMAL. Use S90 summore... lagi normal.

It's the same. I owned 4G93, 4G63, and 4G67 before and they all exactly the same with regards to the stepper motor. Even 6A12 also use the same.

Last night spent 1.5 hrs to DIY my idling.
1st : I check my TPS voltage, observed unable to get 0.5v on idling regardless how I fine tune.
Suspected my TPS faulty.

2nd: I disconnect stepper motor to remove noise from stepper motor

3rd: I'm additional to install another FICD (2 in total) to step up my air con idling after disconnect stepper motor. Observed idling still unable to move up from 500~700 rpm

4th: Disable breathing pipe as per poman input... Still the same.

5th: Replace whole throttle body, connect back back stepper motor and remove all FICD.
Observation: Idling is at 900~950 rpm after adjust on BISS
When turn on the air con, step motor is step up to around 750 rpm.

6th: Activate one of the FICD to further step up my idling.
Observation: idling manage to step up to 950 rpm at initial stage. However, re-compensate back by step motor after 1, 2 min. Now idling at around 750~800 rpm.

7th: Breathing pipe is still disconnect as observed idling speed more stable compared with connecting.

8th: Further increase on FICD air pumping to increase to 950 rpm
Observation: To be continue today after work


Lesson learn:
-One of the factor to have bad idling is TPS faulty / calibration out
-Intake manifold's vacuum is draw out by something.. or leaking.
-Stepper motor will compensate the idling as ECU pre-set idling when air con turn on
-FICD only can step up the idling when the stepper motor is at minimum position (Almost full close)
-Compressor with heavy load will step the idling down badly. Stock stepper motor unable to recover the pre-set idling even though with full open. Then FICD can help immediately.

---------- Post added at 09:46 AM ---------- 6 hour anti-bump limit - Previous post was at 09:30 AM ----------

Duratec 272cam & stock throttle body or S90?

1. Are you experiencing throttle lag like you have to foot down the pedal more than usual to have the car going between 1000 till 2000rpm?

2. What's your fuel pressure setting?

btw... on most 4gx engine without fuel/ignition management hack and trims, and using cams 264°+, idling between 500-800rpm is NORMAL. Use S90 summore... lagi normal.

Bro Kopi,

No throttle lag as just running with 6A12 throttle body. Currently run with stock fuel pressure setting pair with e-manage

 

[Kopi]

ohho... 6A12 tb... psst dude... have you tried setting your TPS to 0.8v at closed throttle... and the stepper motor connected?

 

[boyzone]

ohho... 6A12 tb... psst dude... have you tried setting your TPS to 0.8v at closed throttle... and the stepper motor connected?

TPS from new throttle body is still with stock setting, will check once I free.
Now stepper motor is connected, and add in FICD to step up the idling a bit when air con compressor is kick in.