EVO I ISC/BISS Setup Routine

[ilwilton]

Good morning team,

 

I've done a bit of searching and chasing my tail in the past to find the correct and foolproof method of setting up the base idle set screw / isc position.

 

I've read quite a few posts for factory ecu setup, but nothing for a Link that has given good results.

 

So far, the idle set screw has been two turns out from fully closed, I've used the timing calibration menu to lock timing and adjusted the screw to desired idle rpm but doesn't give consistent results.

 

Have also gone through multiple times in open loop, setting the base idle position tables but get idle hunting when coming to a stop, jumping up multiple times above target before resting around idle RPM.

 

If someone has successfully done this procedure and had solid results, can you please clearly lay out your process for me to follow?

 

Dyno is in a couple of weeks and I'd like it to be as solid as possible before I get there.

 

One other question is, where should the ISC step count be ideally at operating temp and target RPM?

 

Thanks!

[Vaughan]

A log of the hunting idle might help show any issues.

I found Ignition idle control as well as idle position control (I'm using open loop) was required on my cammed v6 to hold it stable

[ilwilton]

Just now, Vaughan said:

A log of the hunting idle might help show any issues.

I found Ignition idle control as well as idle position control (I'm using open loop) was required on my cammed v6 to hold it stable

I'll go for a drive after work and take a log.

 

I've seen the ignition idle control menu before, and understand the centre column needs to be the idle timing number, but have been unsure as to how aggressive the number needs to be either side of centre value.

[Vaughan]

I'm using a G4X so my setup will be a little different but I am seeing it move between 15 and 7 degrees when at operating temperature with a target of 15 and allowable range from -5 to 30.

A few of the Link sample maps have it set up so those might be worth having a quick look through too

[Confused]

The BISC setting on a 1997-02 Galant VR-4 using a MUT / EvoScan locks the ISC at 22 steps from fully closed.

I'd hazard a guess that doing likewise on the Link, along with disabling any other variable idle adjustments, should yield similar results if the idle screw has been changed from the factory calibrated default.

I'm unsure if using the MUT also locks timing during this procedure, but you could temporarily modify the ignition table to give a fixed ignition angle, and then the combination of stepper plus idle ignition correction should help stabilise it for day to day use.