o2 readings

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dvernst

Well-Known Member
Joined
Jan 9, 2006
Messages
1,880
I'm just looking for some opinions on my readings. I just put in my new TT chip, and at idle my o2's are between 500 and 600. If I crank the fuel pressure they won't go any higher, but if I lower it they drop as I go. The chip is set up for 25 psi, and I had the boost at about 13 psi the readings at full throttle were around 780. It should be running totally rich. The cross counts are cycling from 0 up about every 5 seconds. The chip has the fast sm update. I had similar readings with my Denso and my Delco o2, but they are both from last season. Any ideas? Thanks
 
Go off BLM for idle. I would not worry about the o2's at idle...

On the WOT issue..I had the same worry but with my car the o2's are 780-790 wether I run 10 PSI or 22 PSI WOT. I guess the chip compensates? I wouldnt worry about it unless it is lean at the boost you want to run.

My $0.02 Jason
 
That is lean. What is your FP line off set at? I am now to the point with these cars if it runs good and has no ill effects leave it alone. I learned that with the IAC...

Jason
 
Your O2's are suppost to swing around a certian point when out of PE mode. I forgot exactly what the value was, but it corresponds to stoich (14.7 AFR). A BLM of 140 means your ECM is adding fuel to get it to stay swinging around that value at idle to achieve a 14.7 AFR.
 
You should ask Eric for sure, but I think his chips idle in a kind of open loop. He has orchestrated several data points in the chip for best idle as well as WOT. At idle I believe he has kept some things functioning, like the BLM data.

Send him an E-mail. He will clear it up for you. Check your fuel pressure about 45 PSI with the vacuum line off.

:)
 
Thanks Guys. Eric said if it is running o.k. it should probably be o.k. I just have to keep a close eye on it when I start turning up the boost, which I would be doing anyway. I'm going to try a new o2 sensor. if it doesn't change i'm not that worried about it.
 
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