Using Air-Con after high life cam install

**CHB** · 18-07-2009, 11:04 PM

guys,
how do you guys get the engine idle smoothly if your engine has high lift racing cam?
mine is 3T-C with 284* degree cam. it idle at 1000RPM at 60kpa, 20 more kpa than a stock cam. if i switch on my air-con, the idle get even worst. the whole engine jerks like hell and i don't like that specially at traffic lights.. haha..
any tips to improve the idling with these condition?

**river** · 18-07-2009, 11:09 PM

Hi,

Hasn't your air-con got a centrifugal clutch?

The air con on the 18R-G, which idles around 1000-1200rpm, has a centrifugal clutch and the air con won't switch in until approx 1500-1600rpm. So, at idle the air con is not working, which can be annoying in real hot weather when in start-stop traffic.

Other air-con units (I think the AE71 had this type... or maybe it was the Mitsubishi Colt) have some switch or whatever that ups the revs by a couple of hundred rpm when it was enabled while idling.

seeyuzz
river

**CHB** · 18-07-2009, 11:22 PM

mine does not have one, when ever you switch on the A/C, the A/C pump kick in immediately and pull my idling RPM way too low (around 600-700RPM). my intake throttle has been modified and it now does not have the vacuum pulling action when ever the air-con is turn on. normally our air-con system has a valve the is open and allow more air to be suck into manifold, some sort like a bypass valve and i don't have that at the moment. is that what cause the problem?

**river** · 18-07-2009, 11:32 PM

Hi,

Did your previous manifold have this? And it connected to your air-con, or air-con switch?

seeyuzz
river

**CHB** · 19-07-2009, 01:00 AM

it is 2TG-EFI manifold and the throttle body is from another Toyota model, not sure which model but it has 60mm throttle plate.

**X kyle X** · 19-07-2009, 09:39 AM

Most of the systems I have had, have a vacuum effect, I.e when you turn the AC on the idle raise' slightly to keep the car smooth...

Id be looking at that for your issue

**matty12** · 19-07-2009, 11:47 AM

you need idle control.That will fix it.If you have aftermarket ecu most have a a/c request output to connect to.

**CHB** · 19-07-2009, 03:57 PM

currently my engine idling at 60kpa, which is some where around -300mmhg and that already quite high for an engine to idling smoothly. if i add another idling control will it get even worst?
what kind of idling devices i can use? i'm using Megasquirt at the moment and i have a spare output handy. bare in mind that 2TG manifold does not has any of these idling control which means i need to come out with my own DIY route.

**MWP** · 19-07-2009, 06:50 PM

Have you read the megasquirt manuals?
It has plenty of suggestions for idle air control.

**CHB** · 19-07-2009, 06:58 PM

yes i did read the manual but most of them are stepper motor type. what type of idle valve that 4AGE using? may be i can adapt the idling control into mine 3T..

**MWP** · 19-07-2009, 11:33 PM

No they are not...
Look at the control for the 2 and 3 wire non-stepper (PWM) types.
Common options are the Falcon 2 wire and Hyundai 3 wire (bosch style) solenoids.

I went through all this in the last two days fitting one up to my 3SGTE.
I went with the Falcon solenoid, as the 3 wire is a tad harder to control and has huge in/out hoses.

See here: http://www.msextra.com/manuals/MS_Ex...nual.htm#Fidle