I fitted a Dawes AFR Meter and it seems to be fine, if i boot it through the gears, as soon as it comes on boost i get a blue light

However if i drive fairly hard for a wee while then it seems to get lower and lower until sometimes i only get the red light or maybe orange

If i back off again and take it easy for a minute or two it goes back to normal.. The only thing i could think of is if my fuel pump is on it's way out and couldn't supply sufficient fuel for prolonged periods.... This is my completely uneducated guess so am prepared to be shot down... Only other mods are exhaust, filter and VTA BOV.

Any thoughts/opinions would be apreciated as i don't want to blow it up

 

Check MAF and lambda sensors pretty damn quick.

 

How would i do that john?

 

When driving hard for long periods - high EGTs may be causing the AFR (Lambda Sensor) to under-read - this is quite common & may not necessarily be a problem?

You still need to check everything though - just to make sure.

Chris

EGT gauge &/or Det. Display gauge would help here.


[Edited by Chris.Palmer - 1/18/2003 9:27:50 PM]

 

As Chris says may not be a problem, lambda sensor sounds tired though. Need to check the MAF to make sure it really isn't lean. You need it on a Select Monitor or similar. Reason I say that is that many cars with a healthy lambda sensor thrashed around a track would still stay on green or blue. Tiring lambda sensors seem to drop off quicker as the EGTs go up.

[Edited by john banks - 1/18/2003 9:21:01 PM]

 

If a post 98 model Delta Dash would help diagnose the problem - or maybe John is too polite to advertise his services.

 

Thanks for your help guys.. It is a MY97 with 80k on the clock It is serviced at the regular intervals (every 7.5k) at a Subaru dealer so would they not do this check at the service?

I'll pop round anyway and get them to plug in the select monitor to see if it comes up with anything.

 

Had this very same problem a few weeks ago posted a few threads on here if you do a search for lambda sensor or AFR heading.

The fault never showed up on computer when I took car to Main dealers.

Went ahead and bought a new Lambda sensor, fitted it took about 5 mins, Bobs yer uncle, works fine now Blue light constantly at WOT.

 

How much did a new Lamda sensor cost Steve?? Which part of the exhaust does it go in? I think I've seen it if it is on the DP

 

Yes it's on the down pipe.

Wanted £95.95 +VAT main dealers, fortunately for me there is a scooby specialist and scrappers near me so it only cost me £20

 

Just got a quote from the main dealers for £119 inc VAT... Seems to be about the going rate though

 

Try calling Jim Childs at Cheam Motors: 020 8394 2263

You should get an SIDC 10% discount, and tell him I told you to call him!

 

Just been thinking (scary isn't it) I'm sure i read somewhere that that when you're on WOT the MAF takes over for the fuelling as opposed to the Lambda sensor The Lambda is only used when it's not on WOT... In which case it couldn't be a faulty Lambda causing my probs

Or have i got it the wrong way round

 

Seems to be a pretty common fault this one

I too have a 94WRX which is showing exactly the same symptoms, but i have an Autometer AFR. I was actually beleiving that the gauge was shot.....

New lambda sensor on order as we speak