jr m45 w/bov and having air/fuel ratio questions

[imperfekt]

Sorry if this is long, but I'm hoping with enough detail, someone can help me out.

I'm running an m45 with a bov. Yes, unconventional and unnecessary, but it puts a big smile on my face

Aside from that, however, I'm having fuel management problems that I'm lost in the dark about. I've been playing with it a lot, and can't find a way to make it acceptable. Throughout my tinkering I've had the physical setup remain constant: air filter, MAFS, IAC hose, blower w/bypass valve, bov, throttlebody, intake manifold.

At first, I didn't run a vacuum from the bypass to the intake manifold. The charger was pretty loud (whining) and the BOV on the charged/crossover pipe was constantly venting air to atmosphere in large quantities. With the PowerCard installed, there was much much thick black smoke. When I unplugged the PowerCard, still smoke, not as much but black and usually upon startup and during idle/throttle spikes. The check engine light never comes on with or without the PC. The car sucks noticeably more gas with or without the PC hooked up.

I decided to listen to Dallas and Cjsafski (as they both have run a sc/bov setup) and hook a vacuum hose to the bypass valve which quieted the charger a lot (especially during cruising) but almost eliminated the BOV except under heavy acceleration. The car sucks down noticeably less fuel. With the PowerCard hooked up, the black smoke is there. Without the PowerCard hooked up, the smoke is less, but still slightly black (not as thick or dark) and overall the car runs pretty smooth. While cruising for a little while, the check engine light comes on (code 17, o2 sensor inverted) and instantly turns off when I depress the gas pedal, only to return after a few more minutes of just cruising. At first, I had thought that the check engine light was coming on because the car was running lean (as the car would sputter a bit and seem to droop in power a hair the instant the light came on), but now I'm not so sure of that theory. With the PowerCard hooked up, the check engine light never comes on, but she smokes badly...

Right now vacuum is running to the bypass, PowerCard is unhooked, she sucks less fuel, smokes noticeably, shines a check engine light while at cruising, and I just settle for spiking the throttle to get it to go away...

someone suggested I might need a megasquirt...

[iamdallas]

You need that bypass hooked up because it allows the SC to be bypassed so that it isn't compressing air constantly. You only need the bov to release air when you let off the gas and the throttle plate closes

Second, do you have a mass air flow sensor? What year is your car?

If you have a MAF, then the combination of having a bov venting to atmosphere and having no fuel management would result in VERY lean fuel mixture. Thus the code.

When you use the power card with a maf, it would result in a too rich mixture. Because your bov introduces atmosphere and confuses your maf into reading lean. Then the power card over compensates. Black smoke.

If you have a bov and a maf, you need to recirculate or get rid of the Maf. This is all assuming you have a Maf. If you don't.

Then I have no clue. Haha. If you have an NA like your Avatar leads me to believe, this is your problem. I think.

[imperfekt]

yup, NA 1.8, 1994... so I should disconnect my MAF and re-connect my PowerCard? :\

thanks much for your advise

[iamdallas]

yup, NA 1.8, 1994... so I should disconnect my MAF and re-connect my PowerCard? :\

thanks much for your advise

I'd recommend recirculating the bov. It will cost lots of $$$ to remove a Maf. To me a super with a bov is only practical if you have after market engine management.

[iamdallas]

Im no expert. Btw. ;)

[imperfekt]

so I unplugged this thing (what i think to be the MAF) and left the PC hooked up... and it ran (if you would even call it 'running') fine until I tried to drive it lol, it then proceeded to choke and die...

maf.jpg

[imperfekt]

so, right now I have the PC hooked up with the airflow meter/maf plugged in and vacuum running to the bypass canister... the smoke isn't as thick black as it was before, but it's plentiful and gray. I have straight pipe from engine back to the OEM muffler (which may be getting its insides burnt out...) no cat, no test pipe...

I'm afraid she's burning oil.

[iamdallas]

I think you're probably just running rich.

You can't run without a MAF on the stock ECU. Recirculate your BOV and see what happens.

[imperfekt]

i'm not sure what you mean by recirculate, take the trumpet off the bov and run a hose to a spot ahead of the blower? :\

thanks again

[— Agent☣Orange —]

I think you should return the car to normal with the M45 and get it running right first. You're going around in senseless circles. Ditch the BOV for a regular crossover tube, plug your MAF in and leave it alone and connect you SC bypass hose to vacuum. Then get it running right.

Do you even have a wideband O2 gauge? Because you have to know what your air fuel mixture is in order to tune. Are you getting any CELs? Is your PowerCard programmable?

Once you get things set up right from the start, you can add your BOV if you want. I wouldn't do it but not my choice. It's just that right now, you're playing automotive Whack-a-mole by unplugging this and that and wondering why it's not running right.

[iamdallas]

I think you should return the car to normal with the M45 and get it running right first. You're going around in senseless circles. Ditch the BOV for a regular crossover tube, plug your MAF in and leave it alone and connect you SC bypass hose to vacuum. Then get it running right.

Do you even have a wideband O2 gauge? Because you have to know what your air fuel mixture is in order to tune. Are you getting any CELs? Is your PowerCard programmable?

Once you get things set up right from the start, you can add your BOV if you want. I wouldn't do it but not my choice. It's just that right now, you're playing automotive Whack-a-mole by unplugging this and that and wondering why it's not running right.

Yeah. Kinda agree. Unless you have a header that will not allow you to use your tb in the location that Jackson intended.

An lc-1 wideband can be had for $200. Very useful.

[imperfekt]

I had to shave an inch off the dummy throttle body to get the sc to fit with the header I'm running... It's all a cramped fit... I don't mind how it runs, I just wish it wouldn't smoke so much. I got a buddy with ms2 for 400ish but I can't afford it at the moment. And an o2 sensor is also something on my wishlist...

[— Agent☣Orange —]

Huh? What do you mean you had to shave an inch off your dumny TB? Why isn't that on your intake mani?

[imperfekt]

because then the bov wouldn't work. tb is in oem location... :\

http://mazdaroadster.net/showthread....c-setup-please

has the discussion/video which inspired my particular build

[— Agent☣Orange —]

Ah, I understand now.