Okay so I have an 06 Ralliart at 106,000 miles and the engine runs fine while cold. Once it warms up and I come to stop the idle tends to fluctuate from 600-1000 rpm. At approximate 750-1000 the car sounds fine. When it drops below 750 it sounds like my car is making a knocking noise and it feels rougher than it should with polyurethane motor mounts. When I feather the gas and raise the rpm to 1000-1200 the car feels perfect at idle. Any idea as to what the cause of the this noise is and why its dropping below 750rpm? My mods at the moment are as follows:

Custom downpipe and catback exhause
SRI
Lightweight Flywheel
UDP
RRM ecu upgrade

Any suggestions?

 

Not sure of the issue but I raised my idle with the reflash to 1k for this reason, in 2010.

 

by any chance have you ever filled the tank to the rim and had trouble starting the engine?

 

@Cranswich

I don't believe I have ever overfilled the tank and its never given me any problems starting either. Can the idle be adjusted through the RRM Piggyback I have installed?

 

there's your problem right there....

are you running a wideband?

 

no I'm not running a wideband. The piggyback has been in my car for a year and half now but just started idling weird about 3 months ago and it is on and off.

 

maybe you have a leak in your system somewhere?
or some of the wires that connect to the piggyback are loose?
first, i think you should try to double-check all your connections and if the flow is good.
after that, if it still persists, you gotta dig deeper (eg. piping measurements, air flow, etc.)
hope that helps...

 

I don't think there is a leak. My buddy tested for a leak when it started happening originally and its hasn't thrown a CEL for a leak. I double checked all the wires a week or 2 ago and didn't see any problems:/

 

I still haven't been able to pin point the issue:/ I thought maybe it was my heatshield coming loose again since it sounds like its right under my shifter but that wasnt the case. I will try and post a video later so you can hear it.

 

reset the piggyback and ECU...

 

I will try resetting it over the weekend once I get my laptop back. Does anybody know if you can change the idle rpm through the piggyback?

 

idle RPM is targeted in the ECU ROM, and various signals contribute to the calculation...if it's idling outside of spec, something is wrong...I would blame the piggy back first...then I would start looking at the evap system if you're sure there's no intake or vacuum leaks...

 

So a wideband is highly recommended if looking to purchase a piggyback for the ecu? the spending never ends

 

any time you do any tuning you need a wideband...every change you make to timing, you need to correct the AFR...you won't know what your AFR is without a wideband...