Lean Problem

[Guero]

So my car Wide band goes very lean!! Under 2k rpms it will sometimes go all over the place from lean to rich which is normal but once I pass 2k rpms no matter what I do it goes lean enough to were the wideband cant read which is 17:1. I cant go full throttle and about 15 mph in forth gear and go wot and under 2k rpm its lower than 10:1 but once it goes about 2k or over it goes over 17:1 were the wideband cant read no more. Were do I start????

 

[PAzYearazzUP]

That 17:1 is normal cruise. You hit the pedal, that sends the TPS to rich, so you see that richer set go flying to 11:1/9:1 on the WOT or accelerator pedal heading lower the deeper you plant your foot is the lower the voltage value.

So, you want to fatten the 17:1 to about 14:1/13:1 at under 2K or at the 2K and over is layer some rich at 2,000rmp and then add rich to the next 500rpm is lay some milliseconds on the injector there at 2,500rpm.

 

[Killercanary]

Did the wideband require any sort of calibration when you set it up? A lot do and this may be your problem.

Is it still going to 17:1 under WOT above 2000rpms?

I wouldn't say that 17:1 is a normal cruise ratio as that is a bit lean. 14.5-15.5 is where most OEM cars run at under little to no load while cruising. I've leaned mine out to the mid 15:1 range in my car to improve mileage.

 

[Guero]

Yes killer. At aroung 2k I go wot and the in leans to were the wideband cant read no more. And no you dont calibrate it. Its the AEM Wideband. Thanks

 

[Guero]

Pulled code 22.......

 

[Guero]

Fixed code 22....


Could It be my Computer is out of wack cuz of the cam and the gt40 heads?? My fuel pressure is at around 38-42, it idles pretty good, dont know why it would go lean... What should I look at??? Im lost

 

[PAzYearazzUP]

Usually rail pressure is about 44psi. So a lean out could happen with a low fuel pressure. Because of the advanced tech with the aluminum engines removing heat sooner than cast iron engines, you can step the lean down and the Japanese have your 17:1 as a small peak performance and mileage being within that cruise at top gear is say you average about 65mph, you are running around 17:1. Hot Rodding is 13:1 to 14:1 if you are chasing for power on a richer scale.
Gotta remember that airplanes run high altitude with little air and they match the A/F by leaning out the engine is watch the temp rise, then trim about 25°F/50°F lower is safe lean.
So, either low fuel pressure, and for sure, you can tweak the injector milliseconds is the way you set the jetting for injectors if fuel rail pressure (say go to about 100psi) is rich is another way getting there if the electrical trim is keeping you out, code wise. Meaning, the computer will keep sending the spark box the retard/lean values if it goes out of spec at 17:1 is it could be programmed to do that, but I doubt it.

 

[hotcobra03]

just following

Usually rail pressure is about 44psi. So a lean out could happen with a low fuel pressure. Because of the advanced tech with the aluminum engines removing heat sooner than cast iron engines, you can step the lean down and the Japanese have your 17:1 as a small peak performance and mileage being within that cruise at top gear is say you average about 65mph, you are running around 17:1. Hot Rodding is 13:1 to 14:1 if you are chasing for power on a richer scale.
Gotta remember that airplanes run high altitude with little air and they match the A/F by leaning out the engine is watch the temp rise, then trim about 25°F/50°F lower is safe lean.
So, either low fuel pressure, and for sure, you can tweak the injector milliseconds is the way you set the jetting for injectors if fuel rail pressure (say go to about 100psi) is rich is another way getting there if the electrical trim is keeping you out, code wise. Meaning, the computer will keep sending the spark box the retard/lean values if it goes out of spec at 17:1 is it could be programmed to do that, but I doubt it.

QUESTION ON WIDE-BAND........sensativity.... Does this react to vacuum leaks as to un-metered air entering engine .
and restricted fuel flow to send lean readings??

 

[toyman]

Fixed code 22....


Could It be my Computer is out of wack cuz of the cam and the gt40 heads?? My fuel pressure is at around 38-42, it idles pretty good, dont know why it would go lean... What should I look at??? Im lost

I'm missing something here. Are you running the stock EMS? (The computer out of wack comment seems to indicate that.) If not what is managing the system? Tweecer? Chip? AEM-EMS? Are the stock NB O2 sensors still in play? Where did you place the WB O2 sensors? Just need a clearer picture here.

 

[Guero]

Stock computer, wideband is right after the x pipe.


And more info I just noticed. When I 1st start the car the a/f ratio is good and then about 30 seconds or 15 seconds later is when it starts to crap out.

 

[Guero]

Well I finally got the right fittings at work and installed the Fuel pressure gauge. Im at like 49 with the vacuum line disconnected and still running lean!!! WTF!!!! I wanna drive the car already!!! Im not gpnna drive it like this and blow it.....


I have a 255 pump 28lb LS1 injectors and a stock pressure regulater...

 

[toyman]

Stock computer, wideband is right after the x pipe.


And more info I just noticed. When I 1st start the car the a/f ratio is good and then about 30 seconds or 15 seconds later is when it starts to crap out.

So the computer is not using the WB signal. I assume that you installed a WB and have a guage that is reading the A/F ratio. The WB sensor is installed after the X pipe. Is this an OR x-pipe without cats or is the WB sensor located after the cats? Is this correct? Now, you do know that the WB sensor takes about 30 seconds to heat up before a signal is sent. It sounds like from your description that the A/F reads a default value at start up then 30 seconds later sends a signal (or no signal) that appears to read lean (A/F > 17). I'm leaning towards a bad ground, a faulty harness or bad sensor.

 

[PAzYearazzUP]

Does this react to vacuum leaks as to un-metered air entering engine .
and restricted fuel flow to send lean readings??

Good question. I would think the lean at the rear 02 would richen the metering up if there was a lean condition. Usually a lean at a vacuum leak would stall the engine. That means; each cylinder would receive that same lean suck being the lean or vacuum leak would affect each cycle trying to fire off. So, stall she goes is no metering is gonna help that fuel cut, (ultra lean is the air went in faster and took up that space is the gas is there is not a lot is wow is that ratio off like a bunch of air took that space right quick.

Remember if the sensor goes out, she goes to backup. Said another way, if she signs off as closed loop, she goes open loop. Said another way is if the analog says adios, then the digital sends the signal in. Said another way... If the electrical voltage is not within spec, the sensor is no longer acts the rheostat is the ECM acts the 1Atmo in now a, fail-safe mode.

So, no matter your trump to the wire harness, your new signal is the 1Atmo if you see 17:1. That means the computer is functioning that 30 second window correctly (in safe-mode 1Atmo function is single digital signal not all analog'd) and shuts off is more like, safe rich, (is the safe-mode/backup function). That is why it is safe to run watching the 'check engine light' blinking at you.

It is so complex, and then easy at the same time is you have to know some key functions is like it follows itself in the absolute is there I go with that word again. And if you wanna tune a computer car is you have a few fundamentals and you are on your way to beating the Chev is Shove that stove bolt up dare assis.

 

[Guero]

No it does not react to vaccum leaks I purposely got aq leak and it did nothing to my a/f ratio.

 

[Guero]

So I dont know wtf to do now. Change MAF(free), new fuel filter, good fuel pressure, no leaking fpr. Tired of this car already. I just wanna drive it but cant

 

[final5-0]

I don't see enough info to make much of a helpful response

Don't know about the meter

Never the less ... I'd bet mony it ain't caled to Chevy 28# inj's

If I understand correctly

You don't have your Tweecer yet

I mean ... How are you gonna be able to compensate for those
parts that don't match

See where I'm goin here ..............

You can't even run the meter and inj's in Cheat Mode

Grady

 

[Guero]

It ran fine with the injectors final5.0 before it was stolen I have put them on since I did the intake and last head gasket swap right before it was stolen.

 

[Guero]

Meter?


Its a stock MAF btw...