reb78 Posted April 17, 2012 Share Posted April 17, 2012 I think i have a fault with my MAF sensor. I get a hesitation at high revs (first noticed when i booted it out of a junction in 1st and it was like the clutch was dipped at 4250 revs). It will rev higher, so its not the rev limiter. I've noticed it recently at motoray speeds in 4th (its more subtle then though). Also had slight starting problems where it judders initially as it seems to struggle to reach idle revs. It doesnt do any of this and also runs a lot better with the MAF disconnected. Until i get a replacement MAF, should i run with it disconnected? What does it do when running with the MAF disconnected? Will this cause any damage/increase fuel consumption? Quote Link to comment Share on other sites More sharing options...
sierrafery Posted April 17, 2012 Share Posted April 17, 2012 no probs, the management will use a default value stored in memory untill u put a good MAF....and go for genuine ...the MPG in this case is very "leg sensitive" if u know what i mean Quote Link to comment Share on other sites More sharing options...
reb78 Posted April 17, 2012 Author Share Posted April 17, 2012 Thanks for that. I'll have to wear my lighter shoes tomorrow then! Got about 500miles to do, so will unplug it and see how it goes. Got a genuine replacement on order, but cant pick it up until Thursday. Quote Link to comment Share on other sites More sharing options...
sierrafery Posted April 17, 2012 Share Posted April 17, 2012 u can go with MAF unplugged without probs just dont be be violent with the throttle... if u have the EGR blanked it's even better cos the EGR management is based on MAF inputs too... If EGR still on u can try to disconnect and clog well(with a rivet or something) the vacuum hoses from the EGR and ILT valves(seeing that yours is a 2004 modell)...the car will be more responsive.(it's a kind of non-invasive EGR blanking) Quote Link to comment Share on other sites More sharing options...
reb78 Posted April 19, 2012 Author Share Posted April 19, 2012 Right. 500 miles today with the MAF unplugged. It ran much nicer. When i fit the new MAF, will it run even better? Today I averaged 26mpg. I got 29mpg on a previous run with the MAF connected and a much lighter boot, so not a huge difference. EGR is not there (all properly blanked off), so i presume the PO removed it. Quote Link to comment Share on other sites More sharing options...
sierrafery Posted April 19, 2012 Share Posted April 19, 2012 If the EGR is blanked IMO there will be no noticeable difference. The MAF sensor is not a vital part of engine management, it's part of emmision controll system... Quote Link to comment Share on other sites More sharing options...
reb78 Posted April 19, 2012 Author Share Posted April 19, 2012 If the MAF operates mainly on the EGR, would a faulty MAF still explain my original symptoms? I presume it still allows the management system to make alterations to fuelling and such like (i.e. for absolute optimum running its worth having one fitted rather than removed completely)? Quote Link to comment Share on other sites More sharing options...
sierrafery Posted April 19, 2012 Share Posted April 19, 2012 off course it has a management implication too especially if it's in short circuit to earth or to vehicle supply cos it disturbes the ECM's internal voltages... but if it was open circuit u might have not even noticed it.... try with a new one, see the difference and come back with the impressions Quote Link to comment Share on other sites More sharing options...
reb78 Posted April 23, 2012 Author Share Posted April 23, 2012 Just to update. I fitted the new MAF. Not a lot of difference between now and having it disconnected, but, i think the engine is ever so slightly smoother (compared to disconnected). There is no hesitation at any revs (tiny lag around 1000-1500rpm but thats been there all along and i think to be expected as the turbo spools up), so i guess a MAF fault was causing the original problem. Need to drive it for a bit longer before i can report back on economy (but thats never very accurate really). Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.