ECMlink Will ISC cause WOT or cruise tuning issues

[AWD-Tony]

I can't get my ISC set to 30 and I've tried everything so I plan on leaving it as is. Will this cause an issue with WOT and/or cruse tuning?

 

[steve]

No.

 

[AWD-Tony]

That's great news. Does it matter which gets tuned first between cruise or WOT?

 

[steve]

I don't claim to be a tuning expert but I wouldn't even consider going WOT until I had the cruise tuning dialed in.

 

[AWD-Tony]

I would have guessed the same. Thanks again, Steve!

 

[Vegas Smith]

I believe it's only for idle.

I don't claim to be a tuning expert but I wouldn't even consider going WOT until I had the cruise tuning dialed in.

I've talked to multiple tuners that will do WOT tuning first because they'll use Global fuel adjustments, then move onto cruise and idle. The reason being if you tune idle and cruise perfectly, then do your WOT tuning, you may change your global fuel and then have to redo everythuing

 

[AWD-Tony]

I've talked to multiple tuners that will do WOT tuning first because they'll use Global fuel adjustments, then move onto cruise and idle. The reason being if you tune idle and cruise perfectly, then do your WOT tuning, you may change your global fuel and then have to redo everythuing

Ugh!! Another item to research. My mind is being overloaded, severe KNOCK!!!!

 

[19gsx91]

What Nick @Vegas smith said

I tune WOT first and dial in cruise/idle last.. so does every other tuner I know that knows what they're doing.

 

[chrysler kid]

It would probably be easier if you called the isc the iac, or idle air control valve as it is the proper name.

The position of the plunger is determined by the voltage draw from the alternator or from accessries like the fan, or headlights. Each one of those draws clicks the iac motor open a little further

 

[91talonts1]

^Mitsubishi calls it an ISC.

Tuning cruise or wot first is personal preference really. As everyone else said if you do cruise first you will more than likely end up going back and making changes but shouldn't be anything drastic. Sometimes you gotta do a little cruise/idle tuning first to be able to comfortably drive to where you're doing pulls .

 

[steve]

The Mitsubishi FSM calls it both an ISC and a IAC depending on which year book your looking at. The 90 DTM called it the Idle Speed Control Servo as did the 90 and 91 FSM. I didn't see it called a IAC until the 95 DTM and FSM came out but I note the later 92-94 FSM I have used the IAC name.

So depending on when and where you started one is going to be the "right" one to you but both are correct.

I'm always interested in what others do and why. Usually more interested in the second part since it validates the first.

 

[bling5tatus]

I can tell everyone reading from personal experience that usually tuning WOT is pretty easy when compared to getting the cruise/idle figured out. The reason is the conditions at WOT have many constants in the equation where as the idle and the cruise do not have as many. This is not to suggest that anyone should bolt their car together and go out and floor it. You still do mid throttle boost to work your way up to a safe WOT tune.

All of this is easier on a car that is using a MAF. SD is what complicates things and requires you to have a laptop in the car all the time.... and this is coming from someone who used SD since I first got my DSM (happened a year or two before my registration date here). The reason SD is difficult to tune at cruise is because varying throttle positions cause varying amounts of intake vacuum/pressure at a given RPM range which reads a value from a table of arbitrary numbers. Part of the gas law constant is set by the user (VE Tables). The VE is the "model" for the air that the motor can ingest at any given load and rpm and this isn't something that usually is able to be changed for a motor. Engineers at OEMs determine what the VE of a motor is and then they program the software accordingly because it matches what their engine production is producing from the manufacturing plant. Fastforward to people converting MAF to MAP and now you have the ability to change these "hard coded" VE values to try to compensate for things like CR changes inside the engine, cams that are not stock, exhaust that is not stock, etc.

A MAF doesn't care about all that stuff, it just reads air going into the motor and knows how much fuel it takes to explode that amount of air. The ONLY disadvantage I can think of to using a properly tuned MAF that is sized for the amount of air your turbo can suck in is that if you have boost leaks you have a "big" issue for your tune. My counterpoint to that is that you shouldn't have boost leaks on your turbo car. An SD setup will allow your car to "run normally" with huge boost leaks and while some people think this is a good thing because it won't leave you stranded, if you're lazy about checking your car or ignorant about making sure it's in tip top shape then you shorten the service life of your turbo by overspinning it trying to produce the pressure the wastegate is set at and having to make more boost than the setting to overcome the leaks in the intake. This is especially harmful if you already are running your compressor at the edge of it's ability to produce efficient boost (determined by studying the compressor map).

 

[ishnish]

Bringing this back up. I'm highly considering tuning for WOT first now because tuning my injectors for idle has been absolutely miserable and I notice I'm always having to mess with global and dead times.
Would it be wise to time WOT first and then do cruise and idle?

Also, having huge issues with my ISC not budging from 70. I wonder if this is something I can move on with. Im a perfectionist with my car functioning as it should be mechanically but this isc issue has me stumped