just fitted my dawes afr as instructed by the on line instructions running live and earth to the battery and the white wire to the signal wire on my oxygen sensor.

when running the car it lit up as predicted but once i gave it full throttle the lights went out and never came back on.

after stopping the car and restarting it the lights started working again as normal until i gave it full throttle again and they went right up the scale (red,yellow,green,blue and then out)

after this happened again i went to see a friend that has all the equipment for measuring the signal from the oxygen sensor.

we fitted it to the car and went for a run!

the afr was omitting the same readings as the £2000 meter but as soon as i went to full throttle the signal from the oxygen sensor went off!!!

we went back home, switched the car off and started the experiment again.

same results!!!

i have ordered a new sensor at the price of £64 (trade)

will be fitting it on sunday and will post the results then.

when the sensor went off the car started running very lean!!!

not sure how long this problem has been happening but it looks like the afr has saved my engine already.

any ideas why this is happening would be greatly appreciated

thanks

oh its a 95 WRX



[Edited by jonny gav - 6/25/2002 9:09:51 PM]

 

For some reason, my AFR shows that I'm running really rich.

 

which wire did you take your feed from???(3 wire sensor)

 

Johnny,

Im no expert but i believe its your maf that is used to control fueling in WOT (Closed vs open loop), although the oxygen sensor is still capable of monitoring the afr passing it. Just a thought, could it be that affecting the signal at wot? Can you not swap out a o2 with someone else first?

Cheers


Paul.

[Edited by paulwadams_my99 - 6/25/2002 9:48:07 PM]

 

Katana,

Thats probably cos you are

I read at least 0.94v at WOT

Cheers

Paul.

 

The signal from the AFR should pulse at tickover approx once every two seconds. The pulse should max at approx 600mV - 700mV although this voltage reading is not critical as long as it pulses.
If it is a steady reading at tickover then the Lambda may be dead.

The Lamda will take a while to get warm, so don't expect reliable results for the 1st five mins or so, if the car is stone cold.

When you go WOT or in most cases above 0psi, the Lambda signal will change from a pulse to a constant signal. Typically at WOT this needs to be about 880mV or more.

I can't remember the exact figures that John Banks got in the early days of his tinkering, but they were around or above that.
Mine is about 880mV - 900mV using the DIY AFR.
Maybe your Dawes AFR needs tweaking as you maybe going of the scale at WOT.

 

the oxygen sensor just goes dead,no signal at all from it.

if it was the maf it would affect the idling aswell but everything else is working ok.

i will fit the sensor on sunday and see what happens.

the sensors have a life of around 50k miles,mine has done 53k

its due one anyway so what the hell,one less thing to worry about

 

I took my readings from the ECU Jonny. And yes, I think I am running a tad bit too rich..

 

Yeah fair point, was waiting to see if you had any idling probs.

Probably is your o2 sensor then, checked for any error codes?

Last time the afrs were calibrated to
1st light (red) .81v - .83v
2nd light (yellow) .83v - .85v
3rd light (green) .85v - .87v
4th light (blue) .87v to limit of O2 sensor






[Edited by paulwadams_my99 - 6/25/2002 10:09:23 PM]

 

paul-i haven't got the gear for reading the codes mate.

it was pulsing twice in a second at idle but after a run there was nothing at all!!

i am hoping its the sensor!