haltech 4agze idle stability (big cams).

**nb86** · 23-11-2005, 10:44 PM

ive just picked up a sprinter with a haltech e6x running a 4agze with 255 cams @10mm lift, also 6kg flywheel. not exactly a recipe for smooth idling i know but the car is cycling the idle up and down constantly and often stalls when stopping even though it sits at around 1000rpm normally. its not a mechanical fault and the tps etc. is working fine, is there some trick or tuning adjustment i can try to get the thing to idle better?

**The Witzl** · 23-11-2005, 11:40 PM

is the haltech controlling the idle speed control motor at all??
if so, get the idle control retuned

otherwise.... increase idle speed

**Hen** · 24-11-2005, 12:35 AM

The problem with the ZE idle is the uber-long post-throttle inlet tract. The key to tuning the idle is to make the valve adjustments SLOW. Basically you'll need to start with a highish valve opening value, then use slow tracking rates depending on engine revs.

Unsure if this is how Haltech runs it, but I have played round with this on a Wolf and got it working well... eventually.

Those cams aren't hugely long either, but that lift is massive. Do you have documentation for them?

Hen

**EVOSTi** · 25-11-2005, 04:59 PM

the haltech CANNOT run the factory 4A idle valve. you need to get the idle valve from a commodore (VN or whatever) and mount this to a plate and this replaces the factory valve.

**TA22-3SGTE** · 25-11-2005, 10:07 PM

With larger cams the vacume at idle is unstable which sometimes make it hard to tune with the load points moving around with the unstable vacume , Try enabling and tuning the Zero throttle map .

Trevor

**The Witzl** · 26-11-2005, 06:57 PM

yeah good point Trev - the haltech should have a TPS/MAP crossover engine load sensing function.... where it tunes against the TPS at low RPM and then switches over to the MAP sensor at higher RPM/TPS points.
I know a megasquirt can do this

**nb86** · 27-11-2005, 03:09 PM

im not sure how its runnning currently, i have a feeling its not using the idle valve. the car is running rich on all they low load mapping so im going to get it dyno tuned, the top end mixtures seem rich as well. ill have a bit of a play as the haltech software is so user freindly but im no tuning wiz.

**EVOSTi** · 27-11-2005, 07:46 PM

Originally Posted by nb86

im not sure how its runnning currently, i have a feeling its not using the idle valve.

no its not. the haltech can only control a stepper type motor for idle.

**nb86** · 28-11-2005, 11:14 AM

in that case how is the computer cycling the idle up and down like this?

**nb86** · 28-11-2005, 06:06 PM

i had a shot at connecting the laptop at lunchtime today, but the program kept telling me to "reconnect to haltech". does the igntion need to be on or something?

**Ben Wilson** · 30-11-2005, 08:04 AM

You need the ignition on.

If you don't have a manual, you can download one from www.haltech.com.au

**nb86** · 01-12-2005, 03:30 PM

sorry my tuning skills have had to evolve very quickly now. using the zero throttle map the car now idles sweetly at about 950 rpm when hot and doesn't drop with the AC or thermo fans, nor does it stall after heavy deccel. to stop. thanks for the advice fellas