Turbo O2 sensor?

[ausubaru92]

Thanks for the schematic, do you have any pictures of the finished product?

 

Just looking at the circuit, i notice that it shows D1 and D2 are joined on the bottom, is that correct?

 

Also, is pin 4 (12V+) connected directly to pin 8?

 

 

boost solinoid is constantly opening and closing right? don't you think this will fail shortly if you keep running it like this?

Ive noticed that in my car, the boost soleniod is nearly always pulsing, but as boost reaches 5-7 psi, it gets louder. It makes sense as presslab said

The original signal from the ECU is a 20 us pulse at 15 Hz, with this short pulse it can detect if the solenoid is plugged in and throw a code if not

[presslab]

Thanks for the schematic, do you have any pictures of the finished product?

 

Just looking at the circuit, i notice that it shows D1 and D2 are joined on the bottom, is that correct?

 

Also, is pin 4 (12V+) connected directly to pin 8?

 

It's that pic I posted earlier:

 

Yes, you are correct about the circuit connections.

 

 

The circuit is fairly common, and I've seen this kit board which should work with a few component changes:

http://www.quickar.com/tkit.php

The PN is ML-804.

 

I've never tried it though, and I'm just guessing based on the photo.

[presslab]

Yesterday I replaced the cap, rotor, and wires. It's perhaps better but still not as it should be. It still loses power at high RPM when boosting more than around 10 PSI.

 

I advanced the timing to 25 BTDC and it made a little more power all over but the high RPM problem was still there. I put it back to 20 BTDC.

 

I think the next step is to get my WBO2 sensor working. It is not going lean based on my narrow band O2 but I don't know how rich it is. Maybe it is too rich?

[ausubaru92]

Thanks, i will see how i go.

 

I also found this, http://autospeed.com/cms/A_2546/article.html

 

Looks like it will do the trick

[presslab]

Thanks, i will see how i go.

 

I also found this, http://autospeed.com/cms/A_2546/article.html

 

Looks like it will do the trick

 

That looks pretty handy! There are some other kits from them I'd like to get my hands on but the shipping from your far away land is a little too much for me. :-\

 

If you run into any troubles feel free to send me a PM.

[presslab]

Alrighty, a little progress has been made. The relay on the O2 sensor works good, as soon as it clicks on the car goes open loop, and when it goes off the car goes closed loop quickly. No codes either. This should solve the surging once and for all. :cool:

 

I adjusted the stock boost switch to come on at 2 PSI. There's a little plastic cap over the adjuster, just drill it out and back the adjuster all the way out. This is what triggers the relay.

 

The high RPM / boost hesitation is being caused by the timing being pulled but I haven't found the definite root cause yet. I desensitised the stock knock sensor by adding a 470k resistor in series with it; my engine has 150k miles and is a bit noisier than new. I don't hear any detonation with it like this and I'll check the plugs for oil specks after a bit of driving. I also put in some BPR8ES plugs, let's hope they don't foul out quickly. According to some web site, based on how my BPR6ES plugs were looking they were running too hot. Something about the location of the brown band on the ground electrode.

 

http://www.dragstuff.com/techarticles/how-to-read-plugs.html

 

 

I'm not sure of my boost gauge now as when I turn the boost circuit off it is showing about 5 PSI yet before the intercooler install it was showing 7 PSI. I even hooked up the gauge to the wastegate and it still showed 5 PSI. So quite possibly I am boosting more than 10 PSI. For now I have turned the boost down to 8 PSI and it is running good.

[presslab]

New boost gauge now; the old boost gauge was bad! OOOPS! I was pushing more boost than I thought. Poor wittle engine.

 

I'm now running 11 PSI boost on 91 octane R+M/2 gas. The narrow band O2 never goes lean under WOT, no surging (not even a hint) after the addition of the O2 relay. No CEL codes. Starts great, runs great, feels great, I'm gonna leave the engine alone now!

 

 

Next up, paddle shifters.

 

 

PS: A note about the MAF sensor. The ECU uses the MAF to do fuel cut, as a lot of you know. However the ECU has a long-term-fuel-trim to adjust for MAF errors. It is quite possible to "lean out" the MAF and allow the ECU to adjust it's long-term-fuel-trim to compensate. This will still give the correct mixture, but the fuel cut will be at a higher air flow. The ECU only has a certain range of adjustment though, but this explains why fuel cut is achieved at different boost levels on different cars.

[ausubaru92]

The narrow band O2 never goes lean under WOT

 

Are you sure you arent gonna do harm with it lean at WOT?

 

I had a hesitation issue so i hooked up a A/F gauge and i was lean under boost, so i replaced the fuel pressure gauge and set it to 30psi (according to my old gauge) and it now shows rich under boost, no more hesitation

[presslab]

Are you sure you arent gonna do harm with it lean at WOT?

 

I had a hesitation issue so i hooked up a A/F gauge and i was lean under boost, so i replaced the fuel pressure gauge and set it to 30psi (according to my old gauge) and it now shows rich under boost, no more hesitation

 

No, I'm saying that it NEVER goes lean, meaning always rich, when the ECU is in open loop, i.e. WOT.

 

The surging problem I was having was the computer trying to run closed loop under boost. The computer just guesses at when there is boost as it doesn't have any connection to manifold pressure. Changing anything in the fuel system will confuse the computer so it can try to close the mixture loop while under boost which is what was causing my surging.

[ausubaru92]

Sorry, i musta missed the 'never' part.

[presslab]

I noticed a couple weeks ago a bit more odor when the interior vents were open. More than my little oil leaks. I checked it out and sure enough my header has cracked. (Again.)

 

So I made a new one. It turned out pretty well. A bit more power now, not earth shattering but I think whenever I do the exhaust turbo-back it will have much more power. Boost comes on a little sooner. The top end pulls nicely. I also elongated the rear hole for a TD04 in future.

 

BTW it has been running great too!

[beataru]

Mine doesn't do that. I have an O2 sensor "gauge" thing and it still uses the O2 sensor at ~7 PSI boost. (Meaning the "gauge" flickers back and forth.) At full throttle it does not use the O2 sensor.

 

SO you have a fuel Mixture guage, aka rich lean?

[beataru]

make me a header PLEASE... This thread is great, extreemely informative, I had my car pushing around 11 psi, but the tdo4 likes to creep, so I hit fuel cut often.

Once I get a job Ill get her running again.

[presslab]

SO you have a fuel Mixture guage, aka rich lean?

 

It just hooks to the stock O2 sensor. It tells me if the mixture is richer or leaner than stoichiometric (perfect mixture) but not by how much. It tells me a couple things, like if the computer is open or closed loop, and if the mixture ever goes real lean while at full throttle/high RPM.

[presslab]

make me a header PLEASE... This thread is great, extreemely informative, I had my car pushing around 11 psi, but the tdo4 likes to creep, so I hit fuel cut often.

Once I get a job Ill get her running again.

 

Can't make you a header... I just had knee surgery; they drilled holes in my bones, stripped two tendons off my hamstring and made me a new ACL ligament. It's gonna be a while...

 

I bought 6 of these pipes:

http://store.racing-solutions.org/1mist180de2r.html

 

I cut 'em up with an angle grinder, welded it up with a cheap MIG, and bamo there it is.

 

 

Your TD04 might be creeping because of your boost controller... To fix your fuel cut you need bigger injectors (and/or adjustable FPR) and a modded MAF.

[beataru]

Can't make you a header... I just had knee surgery; they drilled holes in my bones, stripped two tendons off my hamstring and made me a new ACL ligament. It's gonna be a while...

 

I bought 6 of these pipes:

http://store.racing-solutions.org/1mist180de2r.html

 

I cut 'em up with an angle grinder, welded it up with a cheap MIG, and bamo there it is.

 

 

Your TD04 might be creeping because of your boost controller... To fix your fuel cut you need bigger injectors (and/or adjustable FPR) and a modded MAF.

 

or it may be creeping because of the poopy design of the internal wastegate, thanks for the link!

[presslab]

Still running good, not blown up yet!

 

Needed to do CA smog the other day. Pulled off the intercooler. (It's supposed to be smog legal but didn't want to deal with it.) There aren't many visible mods, the only one being the custom header. It passed just fine!

[4WDFrenzy]

Holy Crap presslab!!! You have been making leaps and bounds since the last time I looked at this thread. Dang, I feel like I have been in a cave or something(no Osama bin Laden jokes either, please). Anyway, I'm sorry to hear about you having to have reconstructive knee surgery. I know that it can't be fun. But I hope that you get better soon.

 

If you don't mind, I might be hitting you up for some info in the next month or so on how to construct those mods, as I am itching for more power on my GL-10. Good Work and Get Better Soon. I can't wait for what is in store for the next installment!

 

Patrick

[presslab]

Thanks Patrick! The knee is doing great actually, it's been three months since the surgery. I am riding my mountain bike a lot and I'm going to take my motorcycle today for a little ride.

 

 

Don't hesistate to ask, I'd be happy to help.

 

I knew I said that I wouldn't want more power. But you know, I had this TD04 sitting there and when I made my headers I modified the flange to work with both turbos...

 

Yesterday I started the TD04 install. This is going to be a "smog invisible" mod too. I clocked the compressor housing to point straight up, this will allow the stock intake pipe to be installed for smogging. I have a WRX stock downpipe on the way, with cats and all, so that will look stock too.

 

The turbo oil drain hose fits perfect. The oil feed pipe works fine, and the support bracket can be flattened and it will bolt to the compressor housing. The coolant pipes from the VF7 worked with a few small bends, and I removed the metal that connected the two pipes together. The coolant hoses are fine. I cut the wastegate actuator bracket off and I'm going to weld on a new one.

 

I'll post some pics later.

[Frank B]

I had a similar surging with an 89 gl-10, I replaced the nearly new Bosch O2 with a BWD, (Borg Warner) and it went away. it was a universal one wire off of Ebay for like $12.

[presslab]

I had a similar surging with an 89 gl-10, I replaced the nearly new Bosch O2 with a BWD, (Borg Warner) and it went away. it was a universal one wire off of Ebay for like $12.

 

Interesting. The BWD probably has a faster response time than the Bosch. I've not been impressed with Bosch stuff lately.

 

Did your car originally have a heated sensor?

[Frank B]

Interesting. The BWD probably has a faster response time than the Bosch. I've not been impressed with Bosch stuff lately.

 

Did your car originally have a heated sensor?

 

I can't remember what brand was in it. But I did put the Bosch O2 in it shortly after I bought it as part of the initial tune up. I never suspected it untill there was nothing else to replace or adjust! Just make sure you have no exhaust leaks before the O2, it will suck outside air into the exhaust under load and create a false signal form the O2.

[presslab]

Here are some pics of the modded TD04:

 

 

 

 

There is about 1/8" clearance from the silicone elbow to the coolant manifold. I have the standard upright intake manifold, not the spider. The silicone elbow is a 2" to 2.25" reducer elbow, the 2" side was shoved onto the turbo inlet. The reducer elbow gained me a bit more clearance to the coolant manifold.

[zukiru]

 

EXCELLENT THREAD! I am watching this one!

 

I think I need to scoop up an Ea82t :cool:

[joostvdw]

I have a spare MAF laying around so I decided to open it up and see where exactly those traces where and solder in a variable resistor. But guess what?

My MAF is totally different

I will try to take a picture later on, but my cell phone is acting up (windows mobile ) and my normal camera is empty...