Mitsubishi step motor (ISC ) question

[boyzone]

All Masters,

I would like to ask some about our Mitsubishi ISC ( step motor ) function, hope can help.
Besides step up air con idling and warm idle, does this step motor will provide additional air during cruising and acceleration as well ??
Pls advice ... Thanks.

 

[phat7]

not sure if its the same as Mazda's but its primary function is to regulate idle thru input on tb. apart from this there is no function. ISC - Idle Speed Controller

 

[ecupro]

boyzone,
You quote :

"I would like to ask some about our Mitsubishi ISC ( step motor ) function, hope can help.
Besides step up air con idling and warm idle, does this step motor will provide additional air during cruising and acceleration as well ?? "

Em.......may be damping effect, ( instead using mechanical, like toyota 4AGE, 20V )
So, the isc will "hold" the rpm for a while and the rpm will drop to say 950 rpm, in order you engine would not stall. ( Honda also have this kind of effect )

Ah.... and when you park your car and turn the wheel, the power sterring switch will active the isc too.

Good Luck.

 

[boyzone]

Hi, Master Leow ..
thanks for the advice .

I'm plan to install FICD from AE86 into my mitsubishi engine to get safety drive ( I'm encounter engine stalled intermittent in junction/ traffic light when car slow down )
After understand from some experts expriance, this due to my step motor not working well related.
So, before I step to FICD, need to understand on step motor working function.
Let's say this motor will provide additional air during crusing and acceleration, that mean after I'm install with Toyota FICD, I might lose on this function and advantage right ??
Pls advice ... Thanks.

 

[phat7]

if you have an aftermarket ecu you can tune in the idle speed and remove the isc.

 

[boyzone]

After market ecu is too expensive for me ....

 

[140dB]

yup, after market ecu too ex to just do that. there is a screw above the tb u can try adjusting. as for air con, try the FICD. for cold start, u can always wake all the neigbours wif ur revving...hahah...

afaik, the isc or ficd is not solely provide additional air during cruising or acceleration, unless the a/c is on, or the ecu is in cold start mode. its there for a stable idle...

 

[boyzone]

Hi Bro 140dB ,

Thanks for the answering my question ... Think I will step into FICD modification soon in my Mitsubishi engine ...
another question is , after install in FICD, do we need to disconnect original mitsubishi's step motor wiring ?? Pls advice ... Thanks

 

[ecupro]

boyzone,
Are you using turbo charge engine like 4G93T ?
Did you modify the BOV and brow the air "outside" ( Bi...Si...si )?
If yes, even you modify or add the FICD, it would not help you.
Because, the Mitsubishi air flow is a "Close Box" design, so the injector will inject more fuel while you close the throttle.
Nissan like RB-20, the air flow also a "Close Box" design. The engine also stall is they modify the BOV ( blow the air outside..Bi...Si..si )

Good Luck.

 

[jswong]

For Mitsubishi throttle bodies, if you're getting a bad idle, it could be the idle compensator at the throttle body is worn out. It's just a bunch of gear wheels near the ISC stepper motor assembly. I think it costs only around 30 to 40 bucks or so. Check this one first before plugging in anything to overide the stock ISC stepper motor.

 

[boyzone]

Mr. Leow,

My engine is 4G92 mivec.. actually my idling is good .. the only problem is it can be stalling intermittently when slowly / press in the clutch in traffic light / junction.

Bro jswong,

my throttle is control with step motor one.

 

[kennethfong]

hi boyzone!!

y r u having this prob with ur mivec though i've forgotten where did i read it b4 on mivec stalling issue esp after high rev on the road....

though if u plan to change, could u sell to me ur mivec throttle body?

 

[boyzone]

Hey kenneth,
nice to meet u here ..
I'm not planing to sell my throttle body ..la, because Mivec throttle body is the biggest in Mit's family ,furthermore is quite hard to get . : )

 

[kennethfong]

awww, looks like i still have to keep on pestering my mech.... :)