Alright fellas...here is the deal.

Bottom line, my car is running between 15.2 - 17.8 AFR's on a cold start, and running 15.0 - 15.8 AFR at warm idle. You can hear the misfire and the P0300 random cylinder misfire code is really pissing me off.

Here is what I have done so far.

- New plugs
- data logged to eliminate twin disk as source of knock sensor irregularity
- wideband shows near perfect AFR at cruise and nice and fat (rich) at WOT
- No audible knock detected thru ecu scan (or minimal counts)
- We raised the idle to 950rpm thru ecuflash...did nothing but waste my gas
- Eliminated the front O2 sensor as faulty - no codes thrown
- Injectors are firing normally and within expected duty cycle

I am really getting frustrated by this. As far as I know, I cannot alter the idle control fuel maps and I need an alternative. I am ready to install my HKS 280's, but I am holding off until I can confidently continue. I do not want to compound my idle problem with some really big lumpy cams.

My mods are listed below.
Intake -
HKS Racing Suction intake, XS Power intercooler, XS Power IC piping, HKS SSQ BOV VTA (VER 2), HKS Upper IC pipe

Exhaust -
Maxford tubular racing manifold, 10.5 hotside (ported), Helix O2 housing, HKS downpipe, Helix Test Pipe, HKS Carbon TI Exhaust. ALL COMPONANTS HAVE BEEN CERAMIC COATED FROM THE MANIFOLD TO THE BACK OF THE CAR.

Engine Management -
HKS EVC V, HKS TT, HKS RS DB gauges with playback, Zeitronix wideband, ECU Flash, ECU Scan

So, what can I do to eliminate the misfire at idle? I am running way to lean and it is audible annoying and holding me back from modifying further.

-Vince

 

Anyone?

-Vince

 

What are your fuel trims in EvoScan?

 

When was the last time you changed your RS filter element?

Air sensor readings OK?

 

Check for boost leaks? Could be sucking in air from somewhere...

 

Hey,

I am having the same problems. I have everything worked out except the cold idle. It is very lean during warm up. Mine hovers at 14.5 to 16.0 during this period when it should be 13.0 to 14.0 . Unfortunately, it seems any change made, at this point, will be learned away when the LTFT is applied.

The only way we will get this issue solved will be gaining more access to maps in ECUFlash. I believe that there are some real discoveries going on this moment. Hopefully, we will be come privy soon.

HiVoltEVO8

 

HiVoltEVO8,

Cold idle is controlled by the upper left corner of your open loop fueling map in ECUFlash.

At startup, the car idles in open-loop until coolant temp comes up, etc. It isn't until closed loop begins where fuel trims are used. So, to alter your cold idle, just use the cells in the upper left of your map.

GreedMOTO,

You can use the same method for your cold idle issue. At warm idle, your fuel trims kick in and take over the correction to get to stoich. If you are still running lean, you may have maxed your fuel trims. It can be from your intake or any number of reasons, but currently in ECUFlash, the only way that you can tune this out is with the injector scaling and voltage latencies.

I don't want to get into a huge post here, but make changes while monitoring your LTFTs at idle and cruise. Keep in mind, that any changes you make will affect your entire map, so you may need to readjust your whole map once you get your idle running the way you need it.

Once we get control over closed loop idle better via new tables, etc, it will be much easier, but at this point, the method above is the only way to do it right now.


Eric

 

My car had was idling rough at idle too....turns out it was a bad 02 sensor.

 

I just recently got a p0300 code also while driving. I never got one before ecu been flashed plenty of times. After installing cams drove around and 2weeks later i see the engine light. Replaced plugs. Idle is a lil lumpy but not like hks 272's next i will replace wires. I can reset the dam code it will go away for a while and then comback while driving, but my car drives the same compression test shows good. Anyone know any other ways to combat this dam code.

 

I'm with djd24

 

Have you ever run leaded race gas?

 

The first thing you should check, anytime you're having problem with fueling, is boost leaks(post-turbo) and intake leaks(pre-turbo).

 

Why does it matter if you're lean at idle? It's not like there's any kind of load on the engine. Chances are it's done intentionally to improve tailpipe emissions.

 

It's not done intentionally, anything leaner than 14.7:1 on gasoline INCREASES emissions output.

 

Man you sound just like Big A...LOL