Lean Question (update 2/14/13)

[nemovr4]

How lean is too lean?
From a cold start my car runs fine...relatively. Usually AFR #'s around 14.8 to 15.5. However once it has warmed up It runs around high 16's to 18.
I understand this is pretty vauge and could produce more info when needed..(to the best of my newbie knowledge) I have already done a boost leak test and came up with only a small leak on the BOV gasket. Held all the way up to 20psi...
As far as upgrades I use a lazy-Z pipe to carry the air to the turbo. The turbo is a standard 16g, Standard throttle body. Port-matching and cleanup of intake manifold runners, Ported head with HKS 264 Intake cam HKS 272 exhaust cam, Standard valves and pistons. Also has adjustable fuel-pressure regulator and fuel pressure gauge, and wide-band O2 sensor.
No form of engine management...

 

[5OF2k]

WAYYYY too lean.

At cold start, it's not abnormal to see an idle of around 13.0-14.0:1, once warm it will lean out a bit, but should NEVER see more that 14.5-14.7:1 at partial throttle/idle, and on the safe side 13.0 MAX. Any leaner and you have the potential of doing serious, serious damage to the engine.

Please, please refrain from beating on the car too much, pull your spark plugs, take a picture of them and post here in this thread so we can at least determine if it actually is running lean or it's sensor/guage error.

BTW, what are you using to monitor the AFR?

-Jake

 

[nemovr4]

AEM AFR gauges and boost gauge..
I will try and take pictures of the spark plugs today, but I dont have a socket to take them out so it might be tomorrow.
Haven't been pushing it at all, pushed a little to see how it would react but once I get home today I will park it.

 

[nemovr4]

Ha fail, turn out the plug socket I have is too small stopping by vatozone tomorrow, and will have the plug pictures up tomorrow.

 

[nemovr4]

Okay










New and Old for comparison...








May be a bit overboard but ask and you shall receive!
Thanks in advance.

-Chris

 

[5OF2k]

Not quite as white as i was expecting, but definitely looks lean-ish.

What are your fuel system specs, as in what injectors, pump, FPR, etc are you running?

Have you checked for boost/vacuum/exhaust leaks?

What boost is the car at and with which turbo?

Any check engine lights, abnormal bucking or studdering under boost/accelleration?

-Jake

 

[nemovr4]

I switched back to 450 stock injectors (was RC 550's) the pump is larger than stock but I'm not sure of the brand. Have a Walpro 255 FRP stock fuel lines (all since 2009). Have removed the Balancing shaft and EGR blockoff.
Did a boost leak test with Galantvr4559 up to 20psi and it held, only a small leak at the BOV. Standard 16G turbo running at stock boost (8psi I believe, doesn't go over 8 when I put the pedal down) and I'm sure I have an exaust leak at my flex pipe because its black.

The check engine light comes on when I start the car and goes off after about 5 min. Need to address tha, probably just run to vatozone and have them run the diagnostic to see what codes come up.

About all I can think of right now..

 

[5OF2k]

Why did you remove the 550s?

 

[nemovr4]

Previous owner, I have the 550's in a bag, they need some new o-rings but they are still good. I think it was to pass emissions though. Think I should put the 550's back in?
It was having the same problems with the 550's though.

-Chris

 

[5OF2k]

Does the car have any sort of aftermarket chip or ECU tuning? Have you by chance cracked it open and checked for leaky capacitors? It shouldnt be running that lean with that little boost, or at idle for that matter, even with 450s. What is the fuel pressure set at?

-Jake

 

[nemovr4]

Fuel prressure is at 37 +/- 1 (hard to tell because the needle bounces). I do need to check the ecu still, I don't believe it has ever been 'serviced'. Could the leaky CAPS be causing this kind of problem?

I will crawl under the dash and pull the ECU and take some pictures tonight..

-Chris

 

[5OF2k]

Needle bounces? It shouldnt, man. Should be a steady pressure. I also find they tend to be much happier around 38-41 psi with vac disconnected, FWIW. Might be something worth looking into.

-Jake

 

[nemovr4]

It moves from some vibration in the car, I think the needle/gauge is just old. I had the pressure up around 40 with the vacuum line off and I was told that it should be down at 37 because 40 was to high..

I will Check the ECU tonight. Also on that topic, are there any difference at all with the 1g DSM and the GVR4 ECU? I have seen a few 1g EPROM ECU's on Craigslist for reasonable prices, what should I look for if I need a new ecu?( I will buy a new one and have the old one fixed as a back up)

-Chris

 

[5OF2k]

Factory spec is 38-41psi, I run mine a tad higher because a little fat is better than a little lean. FatNhappy!

Have you done other maintenance to the car by means of fuel filter/etc? As I said, given everything done to the car there should be no reason to be running so lean.

 

[nemovr4]

Okay well I will kick the fuel Pressure back up and see what happens. I need to buy a new fuel filter. I did all the fluids, tranny, oil, trans case, clutch, and has a new timing belt, clutch fork and shimmed pivot ball. New ACT Clutch, new spark plugs (gap .28) NGK BP6ES I think..ha but I have not put those in yet.

Maybe I need to clean out my air filter while I'm at it...

Also thanks so far, I really appreciate it!

-Chris

 

[nemovr4]

Okay got new spark plug wires, new plugs installed and got the new ecu set up with socket and new caps...still same problems.
I also turned my fuel pressure up to 46 and it helped a little...

Any more suggestions??

 

[5OF2k]

Havent done the fuel filter and such yet? Youve either got something holding fuel back or a Fairly major vacuum leak, IMHO.

 

[James]

Pull the Injectors one at a time and see how they spray? Maybe you have clogged injectors

 

[nemovr4]

Well after getting new spark plugs, new spark plug wires and rebuilt ecu (caps and socket), also adjusted the fuel pressure back up to 46 it seems to be running a lot better.

AFR is 15+/- at idle and driving on the highway...still a little high but now I have to think seriously about getting ecmlink so I can get the kinks worked out.
Thanks for the input guys!

-Chris

 

[James]

I don't think the kink is in the electronics... You still have something mechanically wrong restricting fuel.