WAY lean at idle. 18+ AFR's...

[6o4turbo]

Something is wrong there. If you're lean Vf should be showing 5 volts. Makes me wonder if you're even in closed loop at idle. You can't use Vf to check at idle though. You'll need to measure the OX terminal instead. Or use Vf and crack the throttle just enough to open the IDL contact.

I hooked up to the OX terminal and grounded terminal. I'm guessing that is the proper way to test OX?

To my understanding,

0.00 MV is lean

450 MV would be Stoich

800 MV would be rich

It's measuring 420 MV at idle, fluctuates from 400 - 440, but stays at 420 MV more, less.

 

[Doward]

What wideband setup are you using?

 

[6o4turbo]

What wideband setup are you using?

AEM Uego...

 

[Doward]

Have you checked for any exhaust leaks upstream of the sensor?

 

[jetjock]

That should make it run richer, not leaner, assuming the NB and WB are near one another..

6o4: 800 mv is rich. If the average at OX is 420 mv your WB is lying to you. I suspect that's what Doward is getting at.
Btw there's no way you could have cross counting at 420 mv and Vf be 0 like you measured earlier.

 

[Doward]

JetJock, that's exactly what I'm getting at.

6o4, do this - ensure that you have a good stock O2 sensor hooked up behind the turbocharger, make sure you have no exhaust leaks, and disconnect your AEM for the moment (I'm assuming you are using no narrowband simulation?)

Test your oxygen sensor as per the TSRM:
http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?Section=FI&Page=119

BTW, I *highly* recommend purchasing a copy of the TSRM for your year Supra.

 

[jtran8]

have you done initial set up before you start your car up ? i have the same set up as yours ,i installed zeitronix and safcII two days ago . Started the car up and it idled like crap some time too rich and some time too lean ,i stepped on the gas and the car die : turned out i forgot initial set up . After i've done initial set up , my car idle stable at 680 rpm and 14.7:1-15.2:1 and my car running strong now , just need some fine tune.

 

[6o4turbo]

That should make it run richer, not leaner, assuming the NB and WB are near one another..

6o4: 800 mv is rich. If the average at OX is 420 mv your WB is lying to you. I suspect that's what Doward is getting at.
Btw there's no way you could have cross counting at 420 mv and Vf be 0 like you measured earlier.

Your thinking my wideband might just be out of sync? What could cause that? It's always seemed to be fairly accurate.

JetJock, that's exactly what I'm getting at.

6o4, do this - ensure that you have a good stock O2 sensor hooked up behind the turbocharger, make sure you have no exhaust leaks, and disconnect your AEM for the moment (I'm assuming you are using no narrowband simulation?)

Test your oxygen sensor as per the TSRM:
http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?Section=FI&Page=119

BTW, I *highly* recommend purchasing a copy of the TSRM for your year Supra.

My WB sensor and the stock O2 sensor are right beside each other on the DP. Not sure what you mean by narrowband simulation. I don't believe I have any exaust leaks...

When the TRSM says "Count the number of times the voltmeter deflects in 10 seconds" what range should I expect that fluctuation to be?

have you done initial set up before you start your car up ? i have the same set up as yours ,i installed zeitronix and safcII two days ago . Started the car up and it idled like crap some time too rich and some time too lean ,i stepped on the gas and the car die : turned out i forgot initial set up . After i've done initial set up , my car idle stable at 680 rpm and 14.7:1-15.2:1 and my car running strong now , just need some fine tune.

I've had the SAFC II and Wideband in the car for 2 years. I'm long past the initial setup.

 

[Doward]

The range isn't really important, as long as you see the fluctuation.

Wait wait wait - you've been running this combo for 2 years, and it's just now acting up?

If that's the case, ohm test your injectors real quick, and see if one is dead.

 

[6o4turbo]

The range isn't really important, as long as you see the fluctuation.

Wait wait wait - you've been running this combo for 2 years, and it's just now acting up?

If that's the case, ohm test your injectors real quick, and see if one is dead.

I've had the wideband and SAFC in the car for 2 years, but of that 2 years, I've actually driven the car about 6 months or 4,000 Kms. Until last Friday, car hadn't ran since November.

All though I was also suspecting a stuck injector. Shouldn't I be able to hear it with a stethoscope if one isn't firing?

 

[Doward]

Possible, yes. I'd verify activation with a set of noid lights, and ohm test them anyway.

You do not want to be running on 1 really lean cylinder.

If one was stuck, and no fueling changes present, I would expect a former ~13:1 afr to be sitting around 18:1 with an injector not firing.

 

[jetjock]

If that were the case it'd be reflected in the NB signal. It's not. Then there's the Vf issue. The data (assuming it was taken correctly) doesn't jive yet it's being ignored. Tangents are sure to follow

 

[TurboStreetCar]

seems like it could be a dead 02, if its not sweeping. still doesnt explain the lean condition, unless it was at the high end causing the computer to reduce fuel untill it cant any further to try to correct the problem based off the erroneous 02 signal.

 

[lintlars]

are you running a ffim?

 

[Doward]

If that were the case it'd be reflected in the NB signal. It's not. Then there's the Vf issue. The data (assuming it was taken correctly) doesn't jive yet it's being ignored. Tangents are sure to follow

You're absolutely right. What the TCCS and the AEM UEGO are saying, is two different things.

Now, since the car is stumbling and dieing, I'd lean toward the TCCS data being wrong. But thinking along the lines of garbage in, garbage out, I'd verify the TCCS is getting proper data, first.

Has that been done?

You said you're getting .029v on Vf - that tells me the TCCS thinks you are running rich, and is pulling fuel accordingly - this shows up as 'lean' on your WB02.

If you see that your oxygen sensor IS working correctly, my next step would be to verify proper fuel delivery. If that checks out good, I'd verify proper lighting of the mixture (a very long shot, but if it's not the O2 sensor itself or the fuel - it's got to be something

 

[vinylspinr]

Well I know this post is pretty old, but I believe 100% that putting the Lexus MAF sensor causes these cars to run way lean, even with 550 injectors. I blew a piston probably because of this and now that I have a new engine and a wideband, I was seeing the same very lean issues. I put on the original MAF sensor along with its metal housing and mixture richened up to normal immediately. I'm very skeptical now of the Lexus MAF upgrade.

 

[xzeror]

Well I know this post is pretty old, but I believe 100% that putting the Lexus MAF sensor causes these cars to run way lean, even with 550 injectors. I blew a piston probably because of this and now that I have a new engine and a wideband, I was seeing the same very lean issues. I put on the original MAF sensor along with its metal housing and mixture richened up to normal immediately. I'm very skeptical now of the Lexus MAF upgrade.

did you tune it?