MY 99 / 00 beware, Dawes AFM and faulty MAF
 

Just a heads up really, not sure what to think. A mate borrowed my RB5 a couple of weeks / months ago, and managed to get 370 miles (on a good motorway run) out of a tankfull of fuel. I was shocked by this at the time, and posted on here about it. I've only ever managed 320 miles (also on a run) myself ;) more like 220 normally

Why is this a problem you might think? Surely that's really good. Well on WOT my Dawes AFM seemed to be displaying the mixture was a little lean (orange / red) but I thought at the time, it might be down to the earth on the ECU (where I've picked up the negative feed from) as I disturbed it around the same sort of time.

Someone on here suggested my MAF might be on the way out (as they are designed to last 3 years) which is something I hadn't even thought about, so I bought a new one last week and fitted it. Ever since then, my AFM is back in the blue, and fuel consumption is slightly poorer than before. Might be time to buy a new Lambda sensor as well.

I guess the morale of this story is trust what the instrumentation in your car is telling you......OMG £85 for a MAF is far better than £3000 for an engine rebuild :eek::rolleyes:

Whoever it was thanks for making me think.....Intended to replace MAF and Lambda, but kept putting it off!!

Phill

I only fitted an AFM to warn me about the Maf sensor issues, no problem yet!!

Thats what its for! ;)

It sounds like it was only just on its way out, a really ****ed MAF can give very odd readings on / off boost on an AFR.

A rare tale of good fortune though. Its the best thing you can possibly do when buying one, esp an STi. Many go for all the go faster mods first then the monitoring bits. Completely the wrong way round. KL / boost gauge / AFR / Oil press are essential before modding in my book.

MB

Sort of agree, I bought my AFM so I could up the boost with a Dawes and confirm the fueling was ok for the boost levels I'm running. As you say though this is a story that ended wheel fortunately for me :rolleyes:

So anyone running a MY 99 / 00 that hasn't got a recent receipt for a MAF sensor and hasn't got a KL / AFM should do themselves a favour and order a MAF before it too late.

Phill

I'm surprised changing the MAF would make much difference to fuel consumption on a run, as the fuelling would be closed loop for most of the time, using lambda voltage feedback...

How did the car feel to drive before you changed the MAF? Faster than normal? Or was it occasionally stuttery? Biggest concern there is the fact you'd increased the boost which, on top of an already lean MAF, could well have ended up at det-city... Plus, no knocklink :nono: tut tut...!


Anyway, all's well that ends well. You must be a very good mate, to lend your RB5 to anyone, mate or not! What collateral did you make him leave with you...? ;):D

Fuel consumption is worse in general, but I have done a fair bit of around town driving to be honest ;)

I reckon the car felt slower after I changed the MAF, so thought it must have been running lean. The tick over was fine with no stuttering, etc

I've got a K/L, AFM and Defis, and wouldn't up the boost without them. Also got a TEK 2 (John Banks) and use the dawes as the boost gets up there smoother.

My mate has an RB5 and a EVO 6 GSR, and I was living at his house, so it was reasonably safe ;) :rolleyes:

Phill

You didn't mention the Knocklink in your original post... was there any activity on that prior to changing the MAF?

:D