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vrg3 check on ebay, I have heard of the speaker bov It is on the shelf next to CAI that looks like a front mount IC. The BOV vents most of the air back in and a little goes out and woosh.
Sir Yach-o I don't think it would change your mpg, and a little rich during shifting is actualy a safe thing.

Sir Yach-o:
Can do, I will keep logs of the gas used for the next two tanks or so. I use this car for deliveries so I go through a lot of gas. I'm not sure what the mileage was to start with but, I will be sure to keep track of the mileage and get back to you.

Oh, heh... We thought we had just invented it. The only hard part is finding a loudspeaker loud enough; the rest is cheap and easy. We're going to be turbocharging the 6MGE that's been transplanted into his Mark II Supra, and doing it as cheaply as possible, since the car only cost a couple hundred bucks. We'll probably end up building one of these electronic BOVs for it on the way as we build a new EFI system based on MegaSquirt.

BTW: How many gallons is our gas tank?

15.9 gal

i unhooked my bypass for a couple days, but had to plug it back in cuz i was running rich, even tho it is plugged back in, im still running rich, it keeps bogging down until it just stalls. could the injectors be messed up, or the spark plugs? i dont know why it is still running rich with the bypass being hooked back up, whats wrong with my car?

You should reset your ECU to clear the fuel trims. Disconnect the negative battery terminal, press the brake pedal for 30 second, and hook it back up.

It could be your O2 sensor making you run rich.

Does your car idle rough too? If so the IAC valve could also be causing the stalling.

My car was running extremely rich for awhile and I couldn't figure it out because I had no CEL or stored codes. It ended up being the O2 sensor was shot and wasn't throwing a CEL. I put a new one in and the problem cleared right up.

I need a new one again though and actually I'm going to be moving it to my passanger side exhaust manifold and upgrade to a 4 wire sensor.

Definitely try reseting the ECU first like vrg3 suggested (while I was typing)though. If that doesn't help then check your O2 sensor.

i reseted the ecu, but nothing changed, so i think ill have it looked at to see if it is the o2 sensor, my car cant even move until its completely warmed up, and black smoke is coming out of the exhaust. would the black smoke be from a bad o2 sensor?

It could, if the sensor is reading lean and causing the ECU to trim fuel way up.

It could be a water temperature sensor too.

I thought the o2 only worked when hot? So the cold running problem would be a different issue. Water temp reading too cold or maybe MAF reading too little fuel?

Steve

The ECU learns fuel trims from the sensor and uses them all the time though.

My point is more that the O2 doesn't work when cold, so it couldn't be causing the overfueling when cold right? If the problem goes away when warm, maybe the o2 is telling the ECU to correct for some other sensor that's faulty?

Just trying to understand this myself.

Steve

The oxygen sensor itself works pretty much all the time. It has a heater so it doesn't rely on exhaust heat. But, since the engine needs to run rich when cold, and the sensor can only read accurately around stoichiometric, the signal is pretty much useless when the engine's cold.

However, whenever the ECU is in closed loop (warm and under light load) it does use the sensor to maintain stoichiometric ratios. As it does this, it takes note of how much it had to change fueling relative to its internal mapping. It remembers these fuel trims and uses them to adjust static fueling. The greatest effect is at portions of the map near the active one but it does affect things across the board.

I know this is an old topic, but this just came to mind...

Why couldn't you retain the stock BOV, and add another fully-atmospheric BOV, both attached in the same fashion, and then use a check valve on the control hose to prevent the stock BOV from seeing manifold pressure? That way, the stock BOV would open at idle and draw air from the other side of the turbo, and when shifting the check valve would close, so that only the aftermarket BOV would operate, blowing air out. Sure, it would still run rich for a second during a shift, but it would cure the crappy idle problems and make your car sound like a universal studios ride at the same time!

Putting a check valve on the bov return line lets it idle normally and vent to atmosphere on shifts. At idle, air coming through the bov isn't necessary.

MK

mTk wrote:Putting a check valve on the bov return line lets it idle normally and vent to atmosphere on shifts. At idle, air coming through the bov isn't necessary.

MK

So would that work then?

Yes, it works for idle, but the richness after shifts can make for a bit of trouble when driving around normally when you get into small amounts of boost. The richness can make you bog a bit.

MK

Alrighty then, another project this weekend it to get creative

There's a thread about ti somewhere. Most hardware stores will have the checkvalve that you need. I used a brass one and cut the spring so it would stay closed normally, but open under any pressure.

MK

I was just going to see about making something that would amplify the stock woosh sound so you could hear it. But I might actually do the check valve thing too.

Moving it as close to after the maf sensor will help, if you are using a check valve, then routing it as close to outside the hood as possible will make it loudest outside.

MK

How about a valve that will only open above 6-7 psi (or wherever the ecu switches to the super rich boost maps)? under that it is routed back into the intake (should help low boost stumbling). they make blow-off valves like that, but of course they cost about $200.