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

[6o4turbo]

Here is my fuel setup.

- Walbro fuel pump
- Aeromotive fuel pressure regulator
- 550cc Bosch fuel injectors, Part # 0280150403
- SAFC II
- Lex AFM

Base fuel pressure (W/o Vac) = 40 PSI
Vaccum draw at idle = 21 inHg
AFR at idle = 18 +... Higher than my AEM Uego reads
Minor misfire at idle.
Timing set bang on to 10 degrees advanced.
No hesitation with throttle response, brand new TPS.

The motor is struggling to idle, wants to die out. Currently idling in the 580 - 620 RPM range.

Even when I add 12% Fuel at the 800 RPM mark, the car idles at 17 AFR.

AFR richens up nicely when on the throttle. Fuel pressure, oil pressure, vac. all respond accordingly as well.

Not throwing any codes.

I have recently changed a whole bunch of stuff around, (IE put my idle screw all the way in, as it was out quite a ways before) is it risky to zero out my SAFC and drive around to see in the ECU will 'learn' to ruchen up at idle?

Would spraying some brake cleaner at the intake mani and surrounding hoses to check for leaks be a good idea?

I've tried adjusting my base fuel pressure, bring it up didn't seem to help any.

Thanks in advance for the help.

- Kev

 

[soup]

does the safc have an injector size option? ie you tell it you're running 550's instead of 440's?

 

[6o4turbo]

does the safc have an injector size option? ie you tell it you're running 550's instead of 440's?

No...

 

[GrimJack]

Might be a pretty serious boost leak. How much of your intercooler piping is still stock?

 

[6o4turbo]

So I just went out to check my O2 sensor.

I was following the TRSM, first step was get the motor up to normal operating temp.

So I fire the car up, running incredibly lean now, too see just how lean, I used the SAFC to see how much fuel I needed to add to even get on my EAM Uego's range. I had to 26% Percent fuel to get the car to idle at 17!

I'm thinking I might have a clogged or stuck fuel injector.

What's going here?

 

[6o4turbo]

Might be a pretty serious boost leak. How much of your intercooler piping is still stock?

I've gone over my charge pipes many a times before, including a couple days ago. I'm confident that's not the problem.

I have no stock pipes left, all 2.5" aluminum with 3 ply silicone couplers and T clamps.

 

[6o4turbo]

If my car is running this lean already at idle, would zero'ing out my SAFC be a bad idea?

Running lean (Or VERY lean in my case) at idle is not dangerous as long as you richen up when under load, correct?

 

[Mr.PFloyd]

it wouldn't be a problem... considering if your car doesn't stall by then, then it is a fucking trooper!

 

[6o4turbo]

it wouldn't be a problem... considering if your car doesn't stall by then, then it is a fucking trooper!

At least I will have the most fuel-efficient Supra in town... :icon_conf

 

[robbo185]

didi you mess with the screw on the lexus afm at all?

 

[6o4turbo]

I don't believe I did, but I'm not sure what the screw was set to when I bought the AFM...

Is stock position for it all the way in?

 

[GrimJack]

Stock position varies, but the adjustment on that won't make your AFR change to the extremes you are getting.

 

[GrimJack]

Have you plugged a voltmeter into the Vf1 & E1 terminals in the diag block and checked what the TCCS is doing at idle?

 

[6o4turbo]

Just took the car out for a drive, it was struggling to idle. It definitely liked having the throttle adjustment screw open. When it got warm, idle dropped to 500, wanted to die out on me. Still lean off the charts at idle, but richening up under load.

Have you plugged a voltmeter into the Vf1 & E1 terminals in the diag block and checked what the TCCS is doing at idle?

I did think to check this, but for some reason I haven't been able to get an accurate reading from those two terminals. I'll go try again.

 

[tissimo]

do you have an aftermarket intake pipe? is your isc routed post AFM?

 

[6o4turbo]

do you have an aftermarket intake pipe? is your isc routed post AFM?

Yeah it is, and it's routed after the AFM, only thing prior to that is the air filter.

 

[6o4turbo]

Have you plugged a voltmeter into the Vf1 & E1 terminals in the diag block and checked what the TCCS is doing at idle?

I just did this again, for the second time today, thought I might have hooked up the wrong terminals earlier, but I got the exact same results this time as well.

I get a steady .029 V at idle. Didn't drive around and monitor, as the car isn't driveable in it's present state. But I did rev the motor up to 2500 RPM from underneath the hood while watching the voltmeter, it stayed stead at .029 while I did that as well...

I also tryed completley Zero'ing out my SAFC, just to see what would happen, the car fires up good, and stalls out within 3 seconds unless I give it some throttle...

Any insight?

 

[MK3Brent]

Check the accordion intake hose for cracks, or power steering idle up hose disconnected?

A post AFM / pre-turbo vacuum leak will cause some lean readings which won't register on a vacuum gauge.

 

[jetjock]

I get a steady .029 V at idle. Didn't drive around and monitor, as the car isn't driveable in it's present state. But I did rev the motor up to 2500 RPM from underneath the hood while watching the voltmeter, it stayed stead at .029 while I did that as well.

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.

 

[6o4turbo]

Check the accordion intake hose for cracks, or power steering idle up hose disconnected?

A post AFM / pre-turbo vacuum leak will cause some lean readings which won't register on a vacuum gauge.

It's an aluminum pipe, definitely not cracked, couplers all appear to be tight. And I don't have power steering anymore, or AC.

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 agree, something isn't right there. Just checked for VF again, even with the IDL cracked, still got the reading of .029

For monitoring the OX terminal, just jump that instead of VF1 along with E1?

The car starts up fine, AFR's in the 15 range, then leans out as the idle drops down, eventually getting to the point where it's struggling to idle at 500 RPM and the AFR's are off the charts lean.

I'm also getting some blue-ish smoke on start up when the car was cold this morning.