Ranfurly

Hi

I finally pulled the trigger and got the S300 chips from Ken installed. Put in a new O2 sensor, cooler spark plugs, 24# injectors I felt that everything else was known and in good condition.

Firstly love the change, seat dyno is registering a change for the better with performance. Nothing empirical to offer as evidence just how she drives. Happy to have had it done and feel there's value from doing it. Ken is a fantastic vendor, patient and supportive. Absolutely provides service and follow up support for his customers.

Struck an issue with the install that I want to record for future reference. After the install the car wouldn't idle correctly and enable the adaptive learning with the new injectors. The tech battled a bit ran diagnostics and saw the idle switch wasn't activated (reporting secondhand and I'm non tech) swapped back in the old Ezk chip and idle occurred - felt that was a bit odd and looked further. Ended up finding that the earth from the idle switch wasn't registering correctly with the new chip - ok with the old but an issue with the new. He made a 'better' connection for the earth and voila it worked perfectly and has performed as intended. So long story short if there's an issue with idle post install of a S300 chip set look at the idle switch earth connection, it seems to need a stronger earth connection...?

Hope that helps someone in the future.

Cheers
Richard

Andre The Giant

Thank you Richard. I am about to install the chips myself on my 85, can't wait.

Don Carter

I lived with an occasional idle stumble with the S300 chips in my 86 for a couple of years, with the idle switch not working. When I finally got around to replacing the switch a few weeks ago, it made the idle perfectly smooth. Not sure if it had anything to do with the S300 chips or not. I didn't swap back to stock chips.

davek9

Richard can you please describe how/where the "grounding" was improved please?

"He made a 'better' connection for the earth and voila it worked perfectly.....".

Just wondering if the high idle issues w/ the S3's (85/86) cars is related to this issue too

Thank you,

Dave

Mongo

I have S300s for my S4 to install too. I would like to know this. I have also cleaned the LH and EZK grounds thoroughly at the back of the engine. I am not sure if I will have an issue because of this.

Ken are you out there seeing this?

Ranfurly

Hi

I've spoken to the service manager and quizzed him a bit more (local P dealership in Auckland and I'm finding them excellent to deal with) and will try to give better detail.

They removed the intake manifold to get access to the idle switch which is on the side of the throttle. They said they could hear the idle switch 'click' with the S300 chips in, but idle was not occurring, so they adjusted the switch 'forward' so that the switch had a stronger/more positive connection against the idle earth connection.

So remembering I'm non tech and not familiar with what I'm describing, it was a mechanical adjustment to ensure a stronger connection was made by the switch. Whether my idle switch just wasn't 'connecting correctly' due to age (probably most likely) and a new switch, as per Don's post, would have resolved the issue as well.

Hope that helps clarify what gave resolution to the issue.

Cheers
Richard

Speedtoys

Sounds internal to the switch itself..

PorKen

Thanks Richard! Glad you figured this out. It will help with other folks installs, I'm sure.

S4-up LH 2.3 has a variable input for both idle and WOT*. (IE. the LH is capable of throttle angle sensing.) The 928 TPS uses microswitch for idle and a sliding contact switch for WOT. Both are supposed to be on/off only but the voltage has to be a certain level, IE resistance has to be low, for idle or WOT to be true. If there was a bad ground it's possible that it may look like it's working, but the LH ignores it.

Perhaps an Achilles heel, but the S300s chips need the idle input to do some housekeeping. The stock chips can do without.


Note also that Richard had a late GTS TPS installed which also has a seperate variable pot for the fancy GTS kickdown relay. It's possible this TPS wasn't adjusted quite right.



*S3 LH 2.2 has a variable WOT input and a binary idle input.

FredR

Richard,

The idle switch is a micro switch device- if it clicks it works or so my tests have proved. The switch itself is adjustable to ensure the contact works correctly and that can be tested without removing the inlet manifold. None of this has anything to do with the chips I would politely suggest.

If everything was OK before you puts the chips in and after insertion it was not, then that would be somewhat strange. It will be interesting to see if Ken has any observations in this regard [he just beat me to it I see].

Rgds

Fred

PC-85-928S

How much did the "local" "excellent" p-dealership charge for all this?

Ranfurly

Hi

At the risk of being flamed for not being able to do it myself, 5 hours. I know they spent more than that problem solving the issue.

depami

Lots of things could be different including limits on analog inputs. In theory, a sensor that functions but is out of spec could easily cause high idle with one chip set but not another, even different version of what's supposed to be the same.

At work we are currently battling a compiler that does inconsistent strange things from compacting to fit code into a nearly full chip. Assembly language is less likely to present these issues but requires much more time, effort, and knowledge. Sometimes all it takes is a mishandled half carry bit to really mess things up.