Maf and lambda change

[Scooby Wez]

When i got my classic it had all the symptoms of the maf being on it's way out so changed it the problem with the hesitation stayed.After the 2 long run's i have done this got worse to the point this morning that on warm up it just did not want to go pulled over and let it get to temp and all seamed fine then the hesitation came back from approx 2.5k-3.2k making the car fell like someone was dabbing the brake on and off.So bit the bullet and got a new lambda and wow what a difference feels like a new car from the one i brought.All the hesitation has gone and now pulls like and train.Also the exhaust tone has changed i was not the only one to notice this which seams funny from just changing the lambda.The Subaru one was different on the probe end to the one that came out but both made by Bosch.Here's the one that came out
[img]http://img110.imageshack.us/img110/6404/lambdast22oy5.jpg[/img]
The Subaru one has a solid looking probe with a shield round it with holes in (Sorry forgot to take a pic)
Can the lambda failing make that much of a difference as i am even more shocked by how it goes now

[Scott.T]

Didn't I sat 'Lambda' when you mentioned it. Although I think you had already changed the MAF at the time.
The car will nearly always surge when cold until the lambda is up to temperature. The OE ECU is worse at this then the Apexi.

When they fail they tend to send a lean signal to the ECU hence the ECU will be thow fuel in and run rich at idle/cruise. This is why so many lambda faults are picked up at MOT as it will be running too rich to pass

The ECU can also use the offset it needed to apply to fuelling based on the lambda to adjust on boost fuelling, and hence on boost you may also of been running rich.

The later cars do this alot more then the early ones as the ECU is alot more inteligent. It can add a +/-14% difference. And can throw a CEL if it get this bad (a badly mapped car will also do the same).

The early cars tend not to throw a CEL and infact you can drve with the lambda disconnected. It runs smoother when cold like this due to the ECU not recieveing confusing signal from a Lamda going through the warming up process.

[Scooby Wez]

Yep mate you sure did The maf to be far did calm it down for a bit but with 1200 miles in ten days and a lot being at cruise motorway speeds think it killed it off.I want for a Subaru one as had seen a few reports of the pattern ones failing quickly so a bit more money but it's worked.

[majorscooby]

Originally Posted by Scooby Wez

Yep mate you sure did The maf to be far did calm it down for a bit but with 1200 miles in ten days and a lot being at cruise motorway speeds think it killed it off.I want for a Subaru one as had seen a few reports of the pattern ones failing quickly so a bit more money but it's worked.

Just reading this thread and finding it an interesting read but just out of interest how much was that sensor from subaru? just curious.

[Scooby Wez]

Now you need to be sitting down for this £163.89 and mine was one of the cheap ones they said When you think my new wheels with vg tyres cost £17 more it's a lot for a little sensor,but what a difference

[Scott.T]

The Subaru item is a Bosch sensor, but Subaru/IM have not released or allowed the OE item to be sold through the trade.

However, there is a Bosch equivelant for about £68. The only diffierence is I think you have to fit the OE connector to it.

I've run £30 universals without issue. I think these only fail on the models where the lambda is in the header due to the extra heat absorbed.

I currently run an OE WRX unit in the header and a wideband in the downpipe.
The OE in the header is even more expensive due to having a longer loom.
IIRC they are about £330...but got mine off Ebay (new-unused-unwanted) for about £20, and still in the Subaru/Graham Goode Racing box

http://www.grahamgoode.com/subaru/parts ... tem=GGS822

[doobydave]

I've been meaning to get mine replaced to see if it removes the small but noticeable hesitation on my MY99 between 2-3 K rpm.

Are you saying (Scott) that I can just disconnect it and notice an immediate improvement if it is defective? (or get tone to )

[Scott.T]

Yep, just unplug the 3-pin connector
But only to do this to verify the fault (although they do all surge a little at light throttle 2-3K), expecially when cold/during the warm up period.