20V engine idle speed

[me2kimi]

Hi to all sifus, bros and ZTH'ers.

It's been a long time that my engine running at low idle speed. It's not a problem before, but recently I can feel the engine shaking at idle.
So how am i gonna increase the idle speed?
From the picture, I think my engine idle not more than 800 rpm.
It's irritating when the engine shake while the injector cycle from rich to lean (it shake when at lean condition).

What have I done so far is increased ignition timing, but what I get only engine pinging.
Then increased the fuel pressure, got better response but still got engine pinging.
So I retarded back ignition timing and decreased the fuel pressure.

Felt so uncomfortable coz has to Q at sunway toll twice daily.
Please advice. Thanks in advance.

 

[jackisblack]

silvertop 4age 20v rite?..you can check ur throttle body,AFM.clean it n check it.svtop got 2 place to idle setup.1.AFM,2.at the back of the engine..foreman know it(toyota foreman commonly)...you also can diagnose ur engine first(done it with people u know that can do it or find somebody in here to help u hands on)...to increase idle speed,u can adjust it at the back of the engine..under the intake plenum..(foreman know this)..gudluck...

 

[me2kimi]

thanks bro for reply.
BTW, it's svt with map sensor already. no more using AFM.

 

[chinozie]

adjust your ISCV...

if adjust to the max...still the same...
check your ignition timing, then adjust it again...

still cannot...try to clean your ISCV...

if wanna DIY it, refer here :

:: [DIY] How to clean 4age 20v ISCV :: March :: 2008


if not..ask your mech to clean it...best result...
clean-up your TB also...

 

[imoloq]

Short term solution: increase engine idle speed

However I think there may be an underlying problem. Your temp gauge looks a bit on the high side. Last time my 4AGZE has idling problems too...turns out the radiator fan relay is spoilt and one day my engine just siezed because overheat. Now my fan is always on (jumped the relay contacts) and no idling problems so far.

Try using coolant in your radiator and use thicker oil (20W-50).

Also try cleaning throttle body. This shud be the easiest step.

 

[jackisblack]

i see...has been convert to MAP..ok..the rest of it still the same...give a checkup..

 

[me2kimi]

adjust your ISCV...

if adjust to the max...still the same...
check your ignition timing, then adjust it again...

still cannot...try to clean your ISCV...

if wanna DIY it, refer here :

:: [DIY] How to clean 4age 20v ISCV :: March :: 2008


if not..ask your mech to clean it...best result...
clean-up your TB also...

Sifu chin, can elaborate how to adjust the icsv?

Short term solution: increase engine idle speed

However I think there may be an underlying problem. Your temp gauge looks a bit on the high side. Last time my 4AGZE has idling problems too...turns out the radiator fan relay is spoilt and one day my engine just siezed because overheat. Now my fan is always on (jumped the relay contacts) and no idling problems so far.

Try using coolant in your radiator and use thicker oil (20W-50).

Also try cleaning throttle body. This shud be the easiest step.

Radiator fan is working and also use a coolant. High speed on hiway also didn't get overheat.
I'll monitor the temp as well.

 

[chinozie]

Sifu chin, can elaborate how to adjust the icsv?

Based on the link given...
here is a photo, marked in yellow as "ISC" :

Loosen just a little bit those 2 screws allowing you to slide the ISCV.
Then adjust the ISCV , if not mistaken clockwise it will increase it and anti-clockwise it will lower it.

Try to adjust it until desired RPM idling...make sure you doing it on normal operating temperature...

 

[alex_khoo]

silvertop 4age 20v rite?..you can check ur throttle body,AFM.clean it n check it.svtop got 2 place to idle setup.1.AFM,2.at the back of the engine..foreman know it(toyota foreman commonly)...you also can diagnose ur engine first(done it with people u know that can do it or find somebody in here to help u hands on)...to increase idle speed,u can adjust it at the back of the engine..under the intake plenum..(foreman know this)..gudluck...

can i know how to adjust AFM( adjust the screw by feeling?) and another place is which part at back of engine got pic to show? i oso had idiling problem

 

[levin818]

Actually its not recomended to adj the ISCV. Its been fix at the factory and not suppose to touch it. For eg, factory setting is somewhere in the middle, ie: 50% open 50% close. Altering it to say, 60% open 40% close might temperorily resolve your idling problem but will also alter your ECU compensation curve which will lead to another problem.
At idle, engine breath through ISCV and 4 throttle bypass passage. If ISCV clogg then you will get low/irritating idling. Usually after clean up the ISCV you will be able to resolve the problem. If you want to slightly increase the idling, it can be done by adjusting the 4-throttle's bypass passage but it need a Carburator balance to balance up the air flow once you have adjusted the bypass screw. One of the easier way is to slightly increase the Throttle Openening Screw's position (to slightly open up the butterfly at idle). But if doing this way, you need to retune your TPS's position.

 

[levin818]

Also, the bypass screw at the AFM is for emission adjustment NOT for idling adjustment.
You will just add problem into your list if you adjust the screw out from factory setting.

 

[me2kimi]

Hi sifu, since I got this kind of air regulator in my hand so I did not performed as what sifu chin advice.

I replace this air regulator with aircon vsv (this valve not function anymore).
As for the result, it can allow more air entering the intake without adjusting throttle body butterfly or TPS. As same concept as "air compressor".

Idling speed is increase a bit but still need more air to increase to desired speed. Thinking to find ball valve type to replace current one. But I donno my method is correct or not.

 

[levin818]

Yes it will works like slightly lifting the butterfly. You are brilliant man!

 

[me2kimi]

Thanks mr wong

 

[feipepe]

hi mekimi,
can u upload DIY ur OEM air regulator valve photo where is locate? and some more, need to know is it OEM valve can be install as well in AFM system? (silvertop)

 

[me2kimi]

Hi feipepe.

Here is the picture where I installed the air regulator. I think it cannot implement on AFM system coz AFM is sensitive to vacuum leak. It measure how much air entering the combustion chamber while map sensor measure pressure inside the manifold.

Slightly vacuum leak at AFM system also can make rough idle.

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[D7zul]

my SVT also have idling problem..

will clean AFM & ISCV 1st

thanx 4 d info guyz

 

[levin818]

can i know how to adjust AFM( adjust the screw by feeling?) and another place is which part at back of engine got pic to show? i oso had idiling problem

Alex, you just need to put back your original trumpet, and tighten up both end of your ram piping.
Please buy a new tightening clips. Your existing clips already worn out. When tightening, make sure both joining part is align.

 

[alcyon]

Thicker oil like 20W-50 will actually increase engine resistance and temperature. I recommend to stick to 5W-40.

 

[sweelt]

When come to isc/iscv and air bypass screw. Don simply adjust. Idle will go crazy and u are cathing own tail.
I have bad experience. lol....