Vf signal is 0.30V , Why?

[CarlosPTR210]

Hi guys,

I'm desperate, my A/F at idle is around 15.5 to 16.5, so I check the VF signal with my voltmeter and read 0.30V!:aigo:

Fuel pressure set to 30psi with vaccum
Walboro fuel pump with 12VMod
Lex AFM
550cc injectors

Why!, :cry: What can I do?:1zhelp:

 

[Doward]

Sounds like it's on the first step of the 5 step Vf signal. In other words, the stock ECU is pulling some fuel, to maintain what it thinks is the 'correct' AFR. Lean it out some (drop the fuel pressure a couple psi)

 

[CarlosPTR210]

Sounds like it's on the first step of the 5 step Vf signal. In other words, the stock ECU is pulling some fuel, to maintain what it thinks is the 'correct' AFR. Lean it out some (drop the fuel pressure a couple psi)

So is not big deal?????:aigo:

 

[mkIIIman089]

Well, its pulling out as much fuel as it can, but obviously its too much for some reason.

Check your codes

 

[CarlosPTR210]

Well, its pulling out as much fuel as it can, but obviously its too much for some reason.

Check your codes

Two months ago , I send the injector to clean and flow test.

The injector flow was around 530 ~ 543 more or less.

I will check the codes tomorrow.:cry:

 

[jetjock]

Now why would it be pulling at least 20% fuel when the mixture is already lean? There's a message in that.

 

[bigaaron]

The "12v mod" would be one likely cause of this.

 

[mkIIIman089]

If it were .30 and rich... its .30 and lean.

 

[Supracentral]

Answer JetJock's question and you have your answer.

 

[antman]

Incorrect sensor reading?...

 

[steve_mk3]

bad O2 sensor?
I dont know, I am asking

 

[Supracentral]

bad O2 sensor?
I dont know, I am asking

Ding!

Good place to start.

 

[SLO-MK3]

I've had this same problem now for awhile now and have tried changing the o2sensor and am about to try another o2 sensor. I'll keep an eye on this thread to see if anyone else has any other iedas.

 

[pimptrizkit]

re-calibrate your w/b...

 

[SLO-MK3]

re-calibrate your w/b...

Who are you talking to? I have aem and it says no calibration required.
I thought it might be the w/b sensor giving a bad reading so I hooked up my autometer a/f gauge, and it says the same thing. Lean.

 

[pimptrizkit]

more so the guy who started the thread, but that woul be the first thing i checked, then i would unhook the o2 sensor and force open loop and see what the afr is using my w/b and see what the ecu is doing in the learned vaule charts. like a fail safe.

along with pulling the vac line off the fpr and forcing higher fuel pressure at idle, which will richen her up, if the stock o2 doesn't rear a change, or vf doesn' show it, inspect stock o2 sensor for problems..

 

[Doward]

I'd lean it out just little, to see if the AFR continues to climb, or if the TCCS pulls it back down. I've watched my own AFR 'sweep' from 14.2-17.2, then the Vf comes up a notch, as the AFR settles down to a normal 14.5-16.5 sweep @ 2.0v (where my 2.5v actually is)

JJ, I didn't even think of a bad O2 sensor... good catch on that

 

[CarlosPTR210]

I check the codes today!

31 AMF AAAAAHHHHHHHHHH!!!!!!!!!!!!!!!!!!!! :cry:

:1zhelp: :1zhelp: :1zhelp: :1zhelp: :1zhelp: :1zhelp: :1zhelp:

 

[mkIIIman089]

Swap out the electronics on the AFM to the one your car came with. I'll go out on a limb here too... it is plugged in right?

My guess at 1st was bad 02 sensor as well, figured I'd try and cover all the bases 1st.