taromilk

Hi all,

I recently just put in a new clutch (new OEM clutch disc with ACT HD pressure plate) , After installing the clutch my s2 would stall almost everytime when idle(not in gear).
This only happens when the car is warmed up. The RPM drops to about 500rpm and the engine just dies. Then it is hard to start up after. Sounds similar to a bad battery kind of sound where the crank will chug.

I traced it on flashpro and I can see the rpm dip below 500rpm and engine stalls. Volts coming from the battery looks to be ok.

My mechanic said the battery is fine. He believes it may be a "Crank Walk" . where the crank shaft is moving and is causing the low RPM and idle stall.

I tried tuning the flashpro to make the idle RPM for higher temperatures to be 1500+ , but it took no effect. The idling rpm still went down to 500s.

I have an '08 , and it's wasn't in the best condition when i bought it. Tried my best to fix it up and put a lot of money and effort into it. But now it looks like the engine is going... possibly.

From what I read in the forums, the symptoms of a crank walk is very similar to this... however I did not pull the oil pan to check for metallic materials. But my mechanic did say he was able to move the crank about 1cm outwards... so he believes the engine is bad ...

Any suggestions anyone? Is this salvageable or if i were to sell as-is, what would I get around for this car? '08 with 66,000km clicks on it.

Thanks and appreciate the input. any is good at this point, even a pat on the shoulder

R3AL-STATUS

ACT pressure plate, assuming you didnt do the no clutch start bypass? Anyways, if your crank is moving forward when applying the clutch pedal then yes you could possibly have crankwalk. If so, trying to salvage the bottom end would be useless, you better off finding a used bottom end.

XxMerlinxX

Get a dial indicator and measure it, unless of course you can clearly see it moving. Or drain your oil and inspect for flakes. Or clean your IAC Valve and see if that remedies it.

taromilk

Not sure if the crank moves when pressing on the clutch but the RPM does change when i press on the clutch. thanks for the input. I only need to find a used bottom end? or would it be more practical to replace with a whole new engine?

Thanks for the info. I will try to clean the IAC valve. i see a DIY on it here.

Any idea why the flashpro idle RPMs don't take effect according to the temperature range i set it to? or is there somewhere else i need to change in the flashpro manager other than the Idle section.

R3AL-STATUS

Drain the oil, remove oil pan, if you find the thrust washer sitting in the pan regardless what the bottom end look like just replace it. Save yourself some money and the headache. Now, if you didnt attempt to keep driving the car with the issue your having then your head should be fine. Mutiple cranking, attempting to drive the car, and clutch load puts stress on the timing chain which transfer to the head which in term causes broken cam caps, oil starvation, etc... anyways GOOD LUCK!

Lalasissyboy

What's the process for measuring that? I may do this when i swap out my pan.

taromilk

after a lot of inspection and getting a second opinion, it doesn't appear to be a crank walk / engine issue.
Only when the car is warm does the rpm drop enough for the engine to stall.

I found out my primary O2 sensor is dead and possibly that may be the cause of the stall? bad AF ratio and maybe running to rich on idle and the car stalls.

I've used flashpro to do a closed loop on both primary and secondary O2 sensors. initial tests, drove for 15 minutes and no stall yet. but still time to time the car will drop to ~600 rpm and the car will shake.

Will try to find a working primary O2 and test it out to see if it resolves it.

its weird why an 02 sensor would make such a big difference. However i have one theory, prior to seeing this issue my ECU was configured with the stock header and never relearned. Once I had my clutch put in (the battery was disconnected for a long period of time) , the issue was seen. This time around my ECU has a PLM header in AND a bad O2 sensor... possibly its not able to learn the idle properly now ?

I did get the P0506 - Idle Control System RPM Lower Than Expected code.
I will also try to clean the IACV and do a map whack . also disconnect my battery again for a few hours, reconnect it , fire it up and hold it at 3k rpm until radiator fans turn on. maybe that will help it learn to idle higher.

let you all know how it goes!

taromilk

Looks like the idling issue has been fixed. I unhooked the battery for a couple hours to reset the ECU then did a reflash and set a "open" loop on both O2 sensors. (i made a typo above)

Now the car idles properly. I'm surprised the ECU can be in a messed up state like this and doesn't know how to adjust itself.


I went and cleaned the throttle and MAP sensor as well.... however, i sprayed the MAP sensor with some electrical cleaner and now my VTEC won't engage and car is sluggish. It also jerks on low rpm while in gear and moving. Symptoms point to a bad MAP sensor.

Lucky me eh... =)

Anyways, hope this helps some others. Looks like if you unhook the battery and the ECU resets, if you don't let it learn the idle properly and with a combination of bad O2 sensors, the car may not idle properly.

Solution : Reset the ECU again then do the idle relearning steps (hold at 3k rpm until radiator fans turn on) and also have working O2 sensors .