MY 99 / 00 beware, Dawes AFM and faulty MAF
#1
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
Whoever it was thanks for making me think.....Intended to replace MAF and Lambda, but kept putting it off!!
Phill
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
Whoever it was thanks for making me think.....Intended to replace MAF and Lambda, but kept putting it off!!
Phill
#3
Scooby Regular
Join Date: Apr 2002
Location: Bournemouth - 5x Ex Impreza owner. 997 GT3 CS.
Posts: 7,333
Likes: 0
Received 0 Likes
on
0 Posts
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
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
#4
Originally Posted by Dark Blue Mark
Thats what its for!
MB
MB
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
#5
Scooby Regular
Join Date: Jul 2003
Location: Out of darkness cometh light
Posts: 1,457
Likes: 0
Received 0 Likes
on
0 Posts
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 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...?
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 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...?
#6
Originally Posted by The_Judge
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 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...?
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 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...?
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
Phill
#7
Scooby Regular
Join Date: Jul 2003
Location: Out of darkness cometh light
Posts: 1,457
Likes: 0
Received 0 Likes
on
0 Posts
You didn't mention the Knocklink in your original post... was there any activity on that prior to changing the MAF?
My mate has an RB5 and a EVO 6 GSR, and I was living at his house, so it was reasonably safe
Thread
Thread Starter
Forum
Replies
Last Post
Mattybr5@MB Developments
Full Cars Breaking For Spares
28
28 December 2015 11:07 PM
Mattybr5@MB Developments
Full Cars Breaking For Spares
12
18 November 2015 07:03 AM