Hi, could someone take a look at my evo 6 log, it's running lean with some knock. I suspect it's a fuel supply problem. afr's are 14 up to 5000rpm then richen to 13 at 7500 rpm.
boost is 1 bar to 6000rpm then tapers off to 0.7 bar

 

For some reason I couldn't open your log, but I imagine I'd still trouble shoot the same, seeing it or not. What fuel are you running? Injectors? Fuel pump set up? Stock fuel lines, rail, fpr? Any leaks? I'd start with the cheap and easy things first. Have your injectors flow benched and swap out a fuel pump or two with a friend. Pick up a $40 fuel pressure gauge that you look at in cabin.

 

Hi, just uploaded new log so should be open now.

Fuel pressure and flow is ok so I will get the injectors tested.

 

Are you certain that fuel pressure is rising above your static fuel pressure when boosting? That's a common issue especially if you get a tear or leak in the vacuum line going to the FPR. Might be the fuel pumps pressure relief valve is faulty and you are losing flow once pressure starts rising. Also check voltage at the fuel pump while at full boost.

 

Just checked pressure and flow and it's 50 psi at idle and about 65-70 psi under full boost and over 4ltr per minute flow, car is pretty much standard with uprated fuel pump.
Looks like injectors now, will get them tested.

 

50psi at idle? Did you test it with the vacuum line disconnected (and plugged) from the FPR? Stock static fuel pressure is 43psi I believe but I cant recall if hi flow pumps overrun static fuel pressure or not. Psi at 1 bar should be around 58psi I think, assuming static FP is 43psi of course.

 

Well i tested pressure with and without vacuum at idle and it didn't change, it only increases when under pressure which I thought was correct. my figures are higher than what you thought but my gauge maybe not 100% accurate, so certainly not going to cause a lean situation, the LTFT are at 5% so a restriction of fuel somewhere.

 

Lots of V and VI's do run very lean as standard, as a quick test disable lean spool and see if the AFR drop by about 1.3 points. If this has no effect, check the secondary voltage switching relay for the fuel pump, common failure on a V or VI.

 

The fuel pump has a seperate relay and supply so that should be ok.

I will dissable the lean spool and see what it does, I did another log showing the afr request and at 7000 rpm it was requesting 9 but it was actually 12, so the lean spool won't make this difference, or will it?

 

As the fuel pump has been hard wired this rules out OEM relay failure.
If the intake has been changed, it can have a big effect on the AFR map compared to actual AFR. On a single pull Lean spool (for want of a better description) does make a difference of about 1.3 points, so with it disabled you should be able to identify right away if it's a supply problem or MAP adjustments are required.

 

What is the easiest way to dissable lean spool, I thought there was a start stop rpm but can't see it?

 

Lean spool wouldn't affect your AFR at the top end of the RPM range so I doubt that's the issue. Could be a corrupt reflash. Maybe try copying over our settings into a fresh rom and see if the problem persists. More common than you'd think.

 

Is the rom ID 25570000?

It also depends on if the default LS start/stop have been adjusted. Can't open the csv file to see if the AFR starts to dip 7k, as you see when it's enabled.

 

Ok, I've tried a few different flashes and just the same, the LS start and stop was set at 2500 and 7500 so I changed the start to 7500 and it was just the same.
Just had a thought though, I've been testing afr's at the tail pipe so I'm going to weld a boss in the front pipe and measure from there and see what I get then.

 

Oh god yeah, any exhaust leak between the exhaust tip and the engine will skew the readings. Whenever I tune a car on the dyno the tailpipe sniffer reading are much leaner than actual AFR readings from the sensor welded onto the downpipe.

Try to install the wbo2 sensor as close as you can to the turbo but no closer than 18". Anything closer than 18" usually subjects the sensor to extreme exhaust gas temps and can pratirely degrade the condition of the sensor over time.

Also make sure the sensor is mounted on the top half of the pipe (9 O'clock-to-3 O'clock) so any condensation in the piping doesn't accumulate in or around the sensor and cause issues.