So i got my car tuned in 95 degree weather and now thats its a lil colder my a/f ratios under boost changed from a 12-1 to a 13.5-1....is this possible in a weather change from 95 to about 65-70ish? What are some other possible causes of this.


In order to sold this problem i tried turning my fuel pressure up from 45 to around 60, but the a/f ratio on the wideband did not change at all. What could be the cause of this?


uberdata tuned IAT mounted on charge piping, running my narrow band input off my plx instead of my stock o2 sensor.


PLEASE HELP!

Please read my most recent post cuz now my car is dead


Modified by ebp_dc2 at 7:17 PM 8/23/2005

 

yes, temperature change will affect a/f ratio

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by wantboost &raquo;</TD></TR><TR><TD CLASS="quote">yes, temperature change will affect a/f ratio</TD></TR></TABLE>


well yah i know that...but is it possible for it to change it that much, and also, how come when i raised my fuel pressure, it didnt' raise my af ratio?

 

The stock ECU usually compensates enough that the temp change allows about 0.1 or less change in your AFR. You could check that your IAT sensor is actually working. Other than that maybe your fuel pump is dying or the filter is clogged. Sonetimes you don't see this at idle - only while driving. An electronic fuel pressure gauge may be a good choice for insturments.

-Michael

 

uberdata wont compensate for iat changes

 

fuel pressure gauge is on the engine side of the filter...so filter can't be clogged right?...reads 60psi on engine side if im correct on this

 

up for more help

 

help me out someone...could it be the fuel rail...something?


vacuum is at -20 so i think thats ok

 

up i need help guys

 

What do you need help with? Temp changes can cause AFR fluctuations, and if your mesuring with a narrowband, who really knows whats going on? Its a good idea not to run that leaner under boost for this exact reason. Imagine if you hit boost on a nice cool night, say 60 degrees? Your going to be running quite lean.... Get a chip burner and burn yourself a chip and add some fuel while in boost....


good luck.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Blaze45 &raquo;</TD></TR><TR><TD CLASS="quote">What do you need help with? Temp changes can cause AFR fluctuations, and if your mesuring with a narrowband, who really knows whats going on? Its a good idea not to run that leaner under boost for this exact reason. Imagine if you hit boost on a nice cool night, say 60 degrees? Your going to be running quite lean.... Get a chip burner and burn yourself a chip and add some fuel while in boost....


good luck.</TD></TR></TABLE>

I agree this is normal and no reason to really be concerned. Temp do change AFRs. But it is wierd that it did get leaner on colder weather then get richer. But I wouldnt be concered try to get the car fully warmed up and then get some readings from a WB.

 

those readings i gave u ARE from a wideband...and to my knowledge turning up fuel pressure should compensate for lean conditions. Correct me if im wrong here, but turning my fuel pressure from 45 to 60 should compensate for the lean conditions and SHOULD definitely change my air fuel ratio....my concern was that turing up the fuel pressure did not change my A/F ratio.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Blaze45 &raquo;</TD></TR><TR><TD CLASS="quote">Get a chip burner and burn yourself a chip and add some fuel while in boost....


good luck.</TD></TR></TABLE>

 

You may have cranked up the fuel pressure, but that doesnt mean jack if your fuel pump cant support the injectors @ the pressure which you set...

hope you get things figured out,

Blaze

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EK-TSOHCV-TaKRider &raquo;</TD></TR><TR><TD CLASS="quote"> Temp do change AFRs. But it is wierd that it did get leaner on colder weather then get richer. But I wouldnt be concered try to get the car fully warmed up and then get some readings from a WB.</TD></TR></TABLE>

The AF is supposed to get leaner in colder weather because the O2 is more dense.

EBP , are you using a high flow intank pump? and what kind of FPR are you using?

 

walbro 255lph fuel pump and b&m fuel pressure regulator

 

have you checked that your o2 sensor is still calibrated correctly? maybe the sensor took a dump rather than your settings? weather will change AFRs but 1.5 points is quite a lot for a 30 degree swing IMO.

 

as far as i can tell my o2 sensor is fine...plx units are self calibrating

 

OK after driving my car for about an hour straight...it just stalled out. It will start back up, but idles kinda shitty and wiht a little rev it will go up, then stall out again. Someone needs to help me with this problem

 

up

 

come on guys someone help

 

My hondata idle a/f changes, I set it at 14.7 works for the day, next day its at 15.4-16.1???????Pisses me off hate hookin up the dam emulator and reburning.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ebp_dc2 &raquo;</TD></TR><TR><TD CLASS="quote">OK after driving my car for about an hour straight...it just stalled out. It will start back up, but idles kinda shitty and wiht a little rev it will go up, then stall out again. Someone needs to help me with this problem</TD></TR></TABLE>

What motor and car is it?

 

Here are a few things that come to mind:

1. Are you running in open or closed loop? Closed loop will drive 14.7 UNTIL you go into full throttle which will put you in open loop and these tables are preset by the tuner and do not change. One of the problems with Uberdata is that it does not compensate for IAT or Coolant Temp and currently there is no control for the open/closed loop change. With this being said, Big Wig has added a BETA Test program which gives you control of these features :

http://uberdata.pgmfi.org/foru...=3556

I have not tried it yet because I lost my chip burner, it was borrowed from a friend and he sold his car and tuning equipment. The replacement is on the way soon...

2. Check for an exhaust leak as that can cause your AFR's to go all over the place and if you are in closed loop the ecu will constantly try and make corrections which just worsens the problem...

Mase wrote an excellent article in this forum explaining AFR's in relation to temperature change etc. I would suggest reading it for further details.

Hope this helps.