David MY99

Anyone knows which figures stands for lean, stoichometric or rich ?
on a PSI3

I'm used reading figures between 0.01-1.0 Volts
Help would be usefull

Thanks in advance

David MY99

i'm a little bit in a hurry so if anyone can help me whith this one?

Bob Rawle

PSI 3 shows lambda, a lambda of 1.0 is stoich, smaller numbers indicate richer, larger numbers mean leaner. See below

Lambda AFR
0.70 10.30
0.75 11.00
0.76 11.19
0.77 11.33
0.78 11.48
0.79 11.63
0.80 11.80
0.81 11.92
0.82 12.06
0.83 12.21
0.84 12.36
0.85 12.50
0.86 12.65
0.87 12.80
0.88 12.94
0.89 13.09
0.90 13.20
0.91 13.38
0.92 13.53
0.93 13.67
0.94 13.82
0.95 14.00
1.00 14.70
1.05 15.40
1.10 16.16
1.20 17.62

5 Type R

Bob YHM

john banks

From Link ECU manual:

mV %CO AFR

<600 <1% >15:1
720 1% 14:1
760 2%
800 3%
840 5% 13:1
860 6% 12:1
880 >8% 11:1

David MY99

Not quite sure if i get it.

Readings at the PSI3 are at closedloop 1.00
driving it goes betweens 0.xx and 2.xx (rarely)
most of the time i read somthing like 1.66 on full throttle
The car is running full decat, GT-spec header inclusive uppipe, vf23 @ 0,9bar till 5000 rpm.
(the car has an knocklink fitted and no knocking at all)

need to know wich figures are good under full throttle.

David MY99

anyone?
@ full throttle the psi tells me 0.76, is this rich enough ?

Nathan L

0.76 is the richest the ECU will read AFAIK.

On over run my PSI 3 reads over 1.67

0.76 is rich

1.67 is lean.

Nathan..

Bob Rawle

PSI3 shows readings under all circumstances closed and open loop, John you quoted mv from a narrow band, PSI reads the pseudo wide band.

The readings are the same as Deltadash would show. As Nathan mentioned 0.76 lambda is as low (rich) as it will read, in practice the afr is richer than that although I have found that this is only a general guide and is not particularly accurate.

BTW the rst of my table is below ..

1.30 19.08
1.40 20.55
1.10 16.20
1.15 16.90
1.20 17.60
1.25 18.40
1.30 19.10
1.35 19.80
1.40 20.60
1.45 21.30
1.50 22.10
1.55 22.80
1.60 23.50

David MY99

tnx guys!

john banks

I am puzzled though, I thought from the username it was a MY99? Obviously not if the numbers are over 1

David MY99

it's a wrx01 from a friend of mine.
That's why i couldn't understand the way 'AFR' was shown at the PSI3. (And it still confuses me, but hey it's not my ride )