Lean on idle

sid

sid

Greenie N00B Member
Greenie Member
Year/Make/Model: 2007 Mazdaspeed6
Mileage: 180,000Km
Location: Canada
Concern: Lean condition on idle
DTC's: Lean on idle and missfire
Modifications:
Forged Manely rods
88mm 4032 supertech pistons (bored out the cylinders)
OEM bearings (rods and mains)
JBR Balance shaft delete
JBR oil pan baffle
BNRS3 Turbo
Bosch 3 Bar TMap Map Sensor
Grimmspeed EBCS (3 port mode)
Clean Bay Solutions Oil Return Line
Custom oil feed line with forced performance red inline filter
XS Power turbo manifold V1
CPE catless downpipe
Magnaflow 2.5" catback
CPE TMIC
Damond Motorsports PCV plate
Damond Motorsports EGR delete
Damond motorsports motor mounts (all 3)
JBR Tru-3.5 Wide Path Full Aluminum Intake
Corksport injector seals
ACT HD Clutch Kit 6 Puck Sprung w/ Streetlite Flywheel
Autotech hpfp internals
NGK Iridium IX Spark Plugs (LRT7IX-11)

ECU/Tuning Software: Cobb AP
Tuner: Freektune
Is the concern intermittent? Only on idle
Can you duplicate the concern? Idling
Recent Repairs: PRV valve replaced.
Correction: Vacuum leak fixed


Hi all, having this odd lean on idle issue. Did a smoke test, fixed a crack in the Bypass Valve Hose (replaced with a new one). Also got a new PRV and replaced it. Still running lean.

At this point I want to see if someone could take a look at these logs and let me know if there's any insight to be had from them before I keep digging.

The next steps for me to try to diagnose this issue are the following:
1. Do an other smoke test (cant be too careful at this point)
2. Clean the MAF sensor
3. Clean the HPFP internals
4. ??

Is there anything I am missing that might be easier to check off the list before I start taking apart my fuel pump?

Would there be a way for me to determine if this is a fuelling issue or an air leak issue based on the logs? I am assuming that the HPFP pressure logged would be at the rail, meaning if it were a fuel issue it would be the injectors given the logged pressure is normal.
 

Attachments

Why would you take apart the fuel pump?
What changed before this issue started?
Do you have a VTA catch can?
Are you currently in the process of being tuned?
Looks like you have a higher than stock idle, which could suggest another vacuum leak, unless the high idle is intended or the car is warming up (hard to tell without coolant temps logged)
 
I'm assuming I would need to take apart the HPFP to clean it. Nothing changed, I don't drive the car much (maybe 4-5 times a month). Started running lean on idle once in a while and now runs lean on idle at all times. No VTA catch can. Tuned it a few years back, been on the same tune since. The idle has always been that high, I assumed it was set that way on the tune.
 
Lean on idle only suggests a small vac leak.

Just in case, another quick test you can do is to rotate your air filter 90 or 180 degrees and see if you have the same issue; dirty filters can cause weird trims n such as well.

Also, when you do drive it, it gets nice and hot right? You aren't doing just 5 min trips and parking it right? Engines need to get hot to self-clean some parts of themselves.
 
Yeah i am definitely thinking a vac leak but my latest smoke test didn't show any leaks so I am a bit confused. Ill give it an other test and maybe a bit more time. Ill also rotate the filter and see if that helps.

And absolutely, when I do take it out its usually for more than an hour.
 
I had my P2187 (lean on idle) last fixed by replacing the purge valve (L3K918740B), it was stuck open. It would always siss heavily when I opened the gas cap to refuel.
 
You must log in or register to reply here.
Back
Top