Car is running lean. need advice what to test

[Dr0]

Basically I'm at a loss...

The car is running really lean and not producing power at all.

What I've done-

Silicone hoses all throughout (including cs ic hoses)
New plugs
Cleaned injectors
Checked every bit of exhaust to find no cracks/leaks
Wg is operating as it should (I know bc I pulled my turbo to see)
Cleaned MAF
Boost leak tested (it would always leak air through the crankcase so idk if that's bad or I'm just doing it wrong... But I'm pretty positive its not a hose bc their all new!)


I'm at a loss... The only live data that struck me as odd was the short term FT on the scan tool was pretty much at a constant -5.50. Which means the computer is taking fuel... But why?

My symptoms are pretty obvious
No POWA
Slightly muffed up mpg at about 25-28 (usually 29-30 since I drive highway 80% of the time)
Runs worse in boost
Plugs are fairly white
All I get is a loud whooshing noise from the turbo when it spools up at 2600-3000 rpm followed by the car hitting a wall
Annndd last but not least I did get a p0171 a while ago when I first got the car but it was running ok, now its running like poop and I haven't gotten that code since

I am def no diagnostic guru, especially when it comes to forced induction ha

And advice on what I should check would be kick ass!

Last tip. I forgot to plug the map sensor In when I did the vacuum lines (making it pig rich) and I went for a drive, and the car pulled like a bat out of hell! Plug the map sensor in and it was back to the exact same thing as stated above

 

[Dr0]

i will probably be picking up an 02 sensor tommorow to see what that does for me. i just want this damn thing running right before i hook up all my goodies (SSAFC v2, pope dp, 3in catback) im pretty sure the SSAFC would prob fix it but me being a mechanic im really OCD about making sure everything is running 100% before i do anything modification wise...

 

[Dr0]

No input?

 

[evilmonkeyMSP]

you changed the coils?

 

[Dr0]

No, do my symptoms seem coil related?

 

[evilmonkeyMSP]

Possible, would have been something easy to change along with the plugs. I had power loss in boost with the car jolting any time it was in boost...coils and plugs fixed it.

 

[protege3690]

do you have a boost gauge? is the vacuum at -20 to -23ish? if you have a stock bpv could have gone bad. same happened to me sort of because the diaphram in the bpv was shot

 

[Dr0]

Hmm, did you have similar symptoms as I stated? Bc when I hit boost it sounds like pressure is leaking followed by the car hitting a wall and pretty much loosing speed

 

[JDMazdaFamilia]

If your car really is running lean and your fuel trim is -5 then you have a lying upstream o2 sensor. But I would comfirm that its running lean before buying an expensive part just hoping it fixes it. A wideband would help in this situation. Anywhere in between + or - 10 is pretty damn good for fuel trims. As far as the leaking crankcase I don't think I've ever gotten a leak from there when doing a vac test. Did you do it with a smoke machine? I'd say the only place you should leak from is slightly from your EGR but I'm not 100% sure on that but I've never seen my crankcase leak. My car said It was running lean when I didn't have the map sensor hooked up, make sure that's plugged in

 

[Dr0]

Can I test the bpv? And by leaking through the crankcase I mean when I apply pressure to do a boost leak test I can hear it his through the oil cap hole on the valve cover

 

[protege3690]

you can pinch off the vacuum line that goes into the bpv and see if you hear the engine idle differently. or if you have a boost gauge youll see your vacuum drop down into -20ish area where its supposed to be.

 

[Dr0]

I'm sorry I forgot to say my vacuum is fine, my cars idle does dip sometimes but typicaly I'm right at 21-22 inhg. I feel like the problem is just simply worse when Im in boost because that's when the problem is most noticable

 

[jscott]

have you checked MAF sensor? the connection on mine was loose causing power lose in boost...just a thought and haven't seen any one bring that up

 

[Mazdaspeed_2003]

I had the same problem, my mechanic replaced the airflow meter and egr valve, i mean I had just hit 100k so it was about time for maintenance, but you should get a full diagnostic. It's really hard to pintpoint what's wrong when your car is running too lean. Another thing is, the pcv valve might be the problem but it hardly is, just some advice.

 

[Dr0]

Yeah I guess the whole fact that I can hear the whoosh of air when the turbo spools is throwing me off... I want to hook up an ssafc but I worry that things will just get worse until I uncover the actual problem

 

[protege3690]

check to make sure the your air intake tube is on properly, clamps on the coupler could be loose.

 

[Mazdaspeed_2003]

Try to get a diagnostic on it. Would definitely be worth it

 

[Dr0]

Update.

checked a couple things over

replaced the pcv bc it was gummed up and it helped a little
ran a compression test and im sitting at 200 195 190 195 which is solid
one plugged looked a "little" lean but nothing major
installed a boost gague tonight (finally!) and it turns out that A) my car idles at 21-23 in hg and B) the car holds boost fine and i can get it to 8 psi in every gear pretty much

Ive noticed that the car "overall" has less power and the problem is furthur worsened soon as i go into boost. And ive never had any missfire codes, just a p0171 many moons ago when the car was running fine...

also my fuel pressure was sitting at about 44 psi last time i checked, and it jumped to about 48-50 under WOT

Im dying to see what my afr is hitting in boost

so yea if any one has a good guess ill run with it or else ill just wait till i get my wideband in tommorow or this weekend