[Spoolin Turbo]

Hey guys, I have a VPC/SAFC2 and an FJO wideband. VPC at 12 across, SAFC2 set on hotwire 12 12 1 1.
When my car is cold and im ready to drive off my a/f's will ride up to 19.2 then come back down to 14.7 1st 2nd and 3rd. When the car is warm it is normal 14.7-15.2.
Any ideas why the a/f will ride up when the car is cold?
This is just when its cold and im leaving to go wheverever. Its not WOT.
Thanks Ryan

 

[carendt242]

one reason - when car is cold, gas doesn't combust... so there's a lot more oxygen in the air and thus your high A/F.

normally cars prevent this by dumping more fuel in when the o2 sensor is still cold.

you may want to check our o2 sensor.

 

[Ckanderson]

because the o2 sensor hasnt heated up... it takes about 45 seconds to fully heat up

 

[Spoolin Turbo]

Well when I say cold, i mean the car has been warmed for about 5 mins or so. So its not like im starting it and driving right away, I let me car warm up a bit before taking off. Any ideas?

 

[michaelvanle]

because the o2 sensor hasnt heated up... it takes about 45 seconds to fully heat up

Yes, something like that. I'm about to install the Innovate wideband kit. On the instructions it says that the sensor has to fully warm up before it reads accurately. It doesn't say how long though. But on the screen it'll be like "warming up: 55% complete".

 

[Spoolin Turbo]

could my wideband be bad?
Or do you think my VPC temp sensor is bad?
I mean i'll drive and the car will be warm and this happens.

 

[michaelvanle]

sensors are known to go bad after a while. I mean if you say the a/f will go back down after car is warmed up, then I guess that is when the sensor has fully warmed up too.

Also what does the vpc temp sensor have to do with the wideband? I'm asking because I just installed a vpc/safc2 combo yesterday, and I'm gonna install my Innovate wideband tomorrow (hopefully).

 

[Spoolin Turbo]

well im wondering if its the VPC sensor sending a signal and causing the wideband to read the way it is.
But even when its fully warm it does the same thing. Any idea?

 

[michaelvanle]

well im wondering if its the VPC sensor sending a signal and causing the wideband to read the way it is.
But even when its fully warm it does the same thing. Any idea?

Huh? I thought a wideband is fully independent. It runs on it's own o2 sensor...

 

[Spoolin Turbo]

very true very true.
Also I dont have info on the resistor you asked about. It is in the harness I have. Its the genuine HKS harness which has the resistor.

 

[Ckanderson]

I really wouldent worry about it..

 

[Spoolin Turbo]

problem still persists. I reset the ECU and its still doing the same thing. It seems occur mostly in 1st gear and the car gets to 20.0 and will stutter for a bit.
Anyone have any ideas?
Thanks Ryan

 

[michaelvanle]

Beats me bro. Worse way is to just buy a new sensor. I mean sooner or later you will need a new sensor anyways, so just shove out th e100 bucks now and store the sensor for later use.

Aren't you supposed to be more worried about your a/f in 3/4th gear anyways?

 

[Spoolin Turbo]

3rd and 4th if you are WOT as long as the af is reasonable. But cruising is another thing. Im going to post up looking for a VPC temp sensor and see what happens from there.

 

[Spoolin Turbo]

checked vpc pressure sensor like the instructions say and its fine.

 

[michaelvanle]

Maybe you just need to retune the SAFC, low throttle and high throttle.

 

[Spoolin Turbo]

set it at 69/70
its all 0% across. They say dont tune below 4K so i havent.

 

[carendt242]

as i said in the 2nd post, try checking your primary o2 sensor.

when o2 is cold, there's no reading for ECU. ECU doesn't know much gas to put in; if o2 sensor was giving the wrong reading when it was cold, it could lead to any number of fuel problems, including what you may be experiencing.


you may also want to check the engine temp sensor. when your car is cold, it needs more fuel for combustion. it sounds like you're not getting enough. if the engine temp sensor is giving a wrong voltage reading while cold, the ECU will not give you the proper amount of fuel.

i'm unsure if the ECU uses the 02 sensor + engine temp sensor, or some combination of the two, but both of these sensors could result in the troubles you're having.

 

[chevyeater-on-sf]

The engine wouldn't run at 20:1 A:F. Does this only occur on decel (closed throttle), perhaps?

 

[Spoolin Turbo]

well if the primary O2 was bad wouldnt the car throw a code?
There are no codes when I checked today.
Ive now been monitoring the prob. Cold start its fine, its when it warms up is when im getting the prob. It seems to occur mostly in 1st gear just pulling off.
It occurs when on the throttle, not off. I know it goes to 20.0 when off but thats normal.
What are the signs of a bad intake air sensor?