HKS F-Con V-pro Semi warm idle problem

[gareth001]

I had my car tuned last month at Eurospec, however following this the tuner and I are having problems with the idle - any thoughts on the following:

• From cold the car starts at around 2k and drops down to normal idle of 650 - so all good.
• If I blip the throttle to 2-3k and lift off, it will return to 650 but will hunt around +/-50-100rpm for a few seconds.
• If I get the car warmed up and park up for about 20 minutes and turn the car back on, first start will cause the car to stall, only with some throttle will it start. When it does start the idle will fluctuate +/-500rpm until it's back up to operating temp.

When the car was tuned it was found that the f-con already had a MAP sensor installed, but the MAF was still connected to the stock ECU. Since the tune the MAF has been disconnected with no ill effects that I can tell, but the above symptoms are still there. Any thoughts? Is there something in the stock ECU that's trying to take over from the f-con?

The f-con hadn't been plugged in since I got the car, so has been running on stock ECU (didn't know this until got to Eurospec). On stock ECU it was rich, but it did have a cone filter before the MAF, so I'm assuming this was the problem.

[Mark 4]

I had exactly same symptoms and it turned out that the idle stepper motor was sticking.

[gareth001]

Interesting that I didn't have this problem at all before the car was tuned.

That's not a cheap "does this fix it" - think will see if anyone has one of these going cheap.

[Mark 4]

You can take it out and clean it in about 10 mins. Do a search, I am sure thre is a "how to" somewhere.

[Ghost_2008]

The stepper is just under the air intake bend, about three screws and it will pull out, the tip gets oily and dirty. Give it a good clean and it should be good as gold.....

[Wodjno]

I too would point towards the ICV also.. Easy out n clean. And costs nothing except a little time. I know you said it didn't have this issue before, but things can go wrong coincidently.. Only way to say it isn't the ICV is plug the stock ecu in and MAF ? But i guess it would easier to give the former a clean

[Nutter_John]

I have a few idle control valves Gareth

[gareth001]

I have a few idle control valves Gareth

Thanks Jon, I'm going to give it all a good clean tomorrow evening - so I'll let you know how it goes if I can pop over at the weekend for a couple of mirrors?

[Eurospec]

The 3rd bit sounds like the idle stepper tgt vs engine coolant temp needs a tweak. I dont know how possible that is in FCON. Ryan will know for sure, but if you've mentioned it to him i'm sure he would have thought about that.

The second bit sounds like the gain settings in the pid loop for idle control. This is notoriously hard to get spot on. I would go so far as to say its very difficult to get right.

It will have an idle step control 'trim' for whether the air con is active or not. Try it with air con on (full cold) and off and see if there is any difference. If there is, then thats a good indication that its the setting in the map. Different ecus have different ammounts that you can adjust and i honestly dont know if you can do any of that stuff in fcon. In power fc, pretty much all the finer points like that you cant adjust.

Cheers,

Ben.