My mpg gone done?
- Thread starter jeegnesh
- Start date
Assuming you're not getting an engine warning light, it could be a partially-malfuntioning MAF or oxygen sensor - or any other sensor interfacing with the DME for that matter! If performance is down a bit too, it could be a blocked injector or a leak in the inlet or exhaust system.
If you're really concerned it would be advisable to get someone to run a full diagnostic check (PIWIS or Durametric).
Jeff
jeegnesh
New member
Just come out of the garage. New AOS did have an air leak, new bank sensors and coil packs very recently (due to engine light, misfiring), been serviced. Actually driving nicely just the mpg has gone down which was true prior to the service too. Has been on some computer will have to check what that was actually.
Who knows Jeegnesh...?
There are so many sensors in the fuelling control loop: MAF, air and coolant temp, oxygen, etc., any one (or more) of which could be borderline and not showing up during the check.
If it's driving well, perhaps the engine's over-fuelling slightly, leading to the drop in fuel consumption you're experiencing. Are your exhaust tailpipes blackened more than usual? That would be a sign.
Jeff
ORIGINAL: smbaker
If you cruise on a light throttle should be able to get tips to go grey. []
Just a suggestion but now that the weather's good, get the hood down, give it some welly in second gear and see if you're trailing an excessive amount of black smoke. If you remove the wind deflector, you might possibly get to smell something too due to air recirculation?
Of course, it could just be your driving style Jeegnesh! Maybe you should try driving economically to see what you can achieve and then you can decide how you want to drive.
Jeff
jeegnesh
New member
[ORIGINAL: Motorhead
ORIGINAL: smbaker
If you cruise on a light throttle should be able to get tips to go grey. [
Just a suggestion but now that the weather's good, get the hood down, give it some welly in second gear and see if you're trailing an excessive amount of black smoke. If you remove the wind deflector, you might possibly get to smell something too due to air recirculation?
Of course, it could just be your driving style Jeegnesh! Maybe you should try driving economically to see what you can achieve and then you can decide how you want to drive.
Jeff
] he he, I got my family 4x4 for that, think I'll forget about it because to be honest it's never driven so well since my ownership as it is right now. I also find the more you drive it including going through the rev range the less problems the car gives, the more idle the car is left seems to invite trouble, so my new goal is to use it as much as I can
A very sensible plan Jeegnesh!
But if the problem does get worse and you're getting concerned about it, I think that you're going to have to check out it out more thoroughly. As I said in an earlier post, despite the fact that you've had it checked out (on a PIWIS or Durametric system?), there might be a slight problem with one or more sensor,injector,etc., or there might be an inlet or exhaust sytem leak.
Unfortunately, I don't have any first-hand experience using either system so can't comment on their ability to pinpoint a fault on a specific item but as a starting point, I'd check that the MAF sensor and the Lambda (O2) sensors aren't contaminated and appear to be functioning correctly; access to these items is relatively straightforward too. Opinions seem to be divided as to whether or not the MAF sensor can be cleaned satisfactorily but whatever you do, it's possible that you're going to be into component swapping, which is likely to prove expensive. Maybe best just to take the hit in fuel bills..!
Enjoy your summer drives and keep us posted if you do manage to effect a cure.
Jeff
jeegnesh
New member
Thanks Jeff, considering I had a very expensive last year changing a lot of components, I think as long as I stay above 20mpg I will leave alone, currently running at 23mpg (driven overenthusiastic) and wait till a point I feel like ofloading more cash (unlikely )
I do think MAF sensor is my first port of call I think mine is 5+ years old looking at receipts so I strongly believe that may well be the cause.
Besides I have this overwhelming urge to get the swirl marks removed, I have tried myself but don't think I am patient enough for the job, but also hurts spending so much just to remove them, it looks amazing from a distance
)I do think MAF sensor is my first port of call I think mine is 5+ years old looking at receipts so I strongly believe that may well be the cause.
Besides I have this overwhelming urge to get the swirl marks removed, I have tried myself but don't think I am patient enough for the job, but also hurts spending so much just to remove them, it looks amazing from a distance
ORIGINAL: jeegnesh
Besides I have this overwhelming urge to get the swirl marks removed, I have tried myself but don't think I am patient enough for the job, but also hurts spending so much just to remove them, it looks amazing from a distance
One of the downsides of black(?) cars Jeegnesh. My Cayman's arctic silver, so swirl marks aren't really a problem unless the body's viewed under arc lamps.!
I read somewhere that Autoglym's Super Resin Polish is good for filling the swirl marks, followed up by the application of a good carnauba wax to seal the surface. I know that it's only a temporary fix but it'd much cheaper than handing the car over to the "Detailing Posse" and you'd have the satifaction of having done it all yourself..!!
Jeff
You can check the maf quite easilly.
Engage gear and from tickover give it the beans - if the maf is playing up you will find the acceleration hesitates at some point between tickover speed and max revs - you will feel this "hesitation" it is noticable because the power seems to diminish then comes alive a little higher up the revs.
A very cheap fix, to be honest if you suspect it just fit a new one - if that doesnt solve your problem you will know you have a good working maf as a spare.
The maf is a regular issue so by getting a new one and having a spare will save you money down the road as you will save when the price rises because you already have the spare (does that make sense?)
Engage gear and from tickover give it the beans - if the maf is playing up you will find the acceleration hesitates at some point between tickover speed and max revs - you will feel this "hesitation" it is noticable because the power seems to diminish then comes alive a little higher up the revs.
A very cheap fix, to be honest if you suspect it just fit a new one - if that doesnt solve your problem you will know you have a good working maf as a spare.
The maf is a regular issue so by getting a new one and having a spare will save you money down the road as you will save when the price rises because you already have the spare (does that make sense?)
GOOFY
New member
Hi Jeegnesh,
Let me know if your problem is cured by changing the MAF. I do not keep tabs on my MPG but I do have a flat spot between 3k-4k rpm . just the point where the cams/ manifold change over and always though it was "normal " condition. But I think this could be a MAF by the posts above.
Let me know if your problem is cured by changing the MAF. I do not keep tabs on my MPG but I do have a flat spot between 3k-4k rpm . just the point where the cams/ manifold change over and always though it was "normal " condition. But I think this could be a MAF by the posts above.
pjwakefield
New member
My emissions warning light came on, and has gone back off since, but its my bank 2 sensor 1, o2 sensor fault and im only getting around 16 / 17 mpg!
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