Coming from a fellow 1.6er the mpg your reporting is a little worrying, currently in stop/start commuting im probably returning 32ish, but regular commuting I get around 36!
Technical MPG Drop – What can it be?
- Thread starter MF-Racing
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Technical MPG Drop – What can it be?
just to add...took mine for a good old italian style tune up last night (gave it a bit of stick... to hopefully clear it out...
yesterday morning returned 34.5 mpg for 50 miles at a steady 70...
today returned 41.0mpg... at a steady 70
had the map sensor replaced on mine june time.... easy to get to.. take off the plastic engine cover and on the top left hand side of the inlet manifold/air intake... right next to the cooland header tank is the map sensor... screwed in with 2 self tappers.. and a connector on it...
another thing that helped mine to was clearing up the residue you get inside the ventura of the throttle body.. at the top and the bottom of the butterfly is a stickey thick gunk which causes floaty idle and make your revs bounce... might help....
im sure a guide was done about it...
yesterday morning returned 34.5 mpg for 50 miles at a steady 70...
today returned 41.0mpg... at a steady 70
had the map sensor replaced on mine june time.... easy to get to.. take off the plastic engine cover and on the top left hand side of the inlet manifold/air intake... right next to the cooland header tank is the map sensor... screwed in with 2 self tappers.. and a connector on it...
another thing that helped mine to was clearing up the residue you get inside the ventura of the throttle body.. at the top and the bottom of the butterfly is a stickey thick gunk which causes floaty idle and make your revs bounce... might help....
im sure a guide was done about it...
Yes, if there's no change to your driving style, air filter's clean and no other outside factors then it's obviously overfuelling and MAP sensor and Lambda sensor would be 1 and 2 on my check list.
Time for the multimeter and accupuncture needles?
OP
OP
Thanks guys.
So, would it be wise to disconnect the MAP sensor and try running it without to see if the MPG goes back to normall?
I've also got a OBD PC interface on its way, will this help me locate the problem?
So, would it be wise to disconnect the MAP sensor and try running it without to see if the MPG goes back to normall?
I've also got a OBD PC interface on its way, will this help me locate the problem?
hope you can get it sorted , at the price petrol is it needs to be
just to rub it in.
ive got the JTD 115, coming back from york tonight. estimated range 603 miles, and i had travelled about 70 miles on that tank already
, at the price petrol is it needs to be just to rub it in.
ive got the JTD 115, coming back from york tonight. estimated range 603 miles
, and i had travelled about 70 miles on that tank already
I've also got a OBD PC interface on its way, will this help me locate the problem?
Ooo Ya!
Ok try this. Sometimes it just needs a good slapping. You're just going to kid your motor that the MAP has died and you've fitted a new one
So disconnect the map sensor- here it is
Start the car- it'll bitch a bit that there's an engine fault ya da ya da
but it will run real fine so take it for a short trip
If you want you could reset trip A and see what av cons it kicks out now
Ok engine off and now reconnect the MAP and MOST IMPORTANTLY clear the fault codes- remember you need the ignition on but engine not started to read and clear codes (See if there's any other fault codes there by the way and make a note if there are)
Anyway, imaginary new MAP installed now(ahem)
Start engine and it should be happy with new MAP sensor. Oh Joy
Off you go and let it relearn what a good MAP should be. Reset your trip B and see what av cons figure you're getting now compared to trip A
What software are you going to use? Gendan is pretty good if you're not sure, you can download it, pay for it (about £25 I think) and it's up and running within the hour. Then you can do live graphs as you drive around to see what's happening from a load of engine sensors as well as read and clear fault codes
(Click to enlarge)
Top graph shows rpm and 02 sensor output. O2 is swinging nicely between 0.15v and 0.85v like a good little O2 sensor
Bottom graph shows car speed and MAP sensor output. This is a good MAP and you can see the MAP output closely follows the rpm but is slightly ahead
just like it should be- air first then revs
Ooo Ya!
Ok try this. Sometimes it just needs a good slapping. You're just going to kid your motor that the MAP has died and you've fitted a new one
So disconnect the map sensor- here it is
Start the car- it'll bitch a bit that there's an engine fault ya da ya da
but it will run real fine so take it for a short trip
If you want you could reset trip A and see what av cons it kicks out now
Ok engine off and now reconnect the MAP and MOST IMPORTANTLY clear the fault codes- remember you need the ignition on but engine not started to read and clear codes (See if there's any other fault codes there by the way and make a note if there are)
Anyway, imaginary new MAP installed now(ahem)
Start engine and it should be happy with new MAP sensor. Oh Joy
Off you go and let it relearn what a good MAP should be. Reset your trip B and see what av cons figure you're getting now compared to trip A
What software are you going to use? Gendan is pretty good if you're not sure, you can download it, pay for it (about £25 I think) and it's up and running within the hour. Then you can do live graphs as you drive around to see what's happening from a load of engine sensors as well as read and clear fault codes
(Click to enlarge)Top graph shows rpm and 02 sensor output. O2 is swinging nicely between 0.15v and 0.85v like a good little O2 sensor
Bottom graph shows car speed and MAP sensor output. This is a good MAP and you can see the MAP output closely follows the rpm but is slightly ahead
just like it should be- air first then revs
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OP
OP
Thanks very much Decks! :worship:
Hopefully the interface will be turning up tomorrow, so I’ll do this ASAP.
I was going to use the free software that comes with the unit (scantools.net) but I’ll look into the one you posted up.
I’ll report back my findings as soon as I have done it! :idea:
Fingers crossed this will fix it; I’m skint at the moment due to the amount of fuel the car is using!!
Cheers
Matt
Hopefully the interface will be turning up tomorrow, so I’ll do this ASAP.
I was going to use the free software that comes with the unit (scantools.net) but I’ll look into the one you posted up.
I’ll report back my findings as soon as I have done it! :idea:
Fingers crossed this will fix it; I’m skint at the moment due to the amount of fuel the car is using!!
Cheers
Matt
PMSLFingers crossed this will fix it; I’m skint at the moment due to the amount of fuel the car is using!!
"Fingers crossed this will fix it"
Hope so but the next man on the hit list and just as much a suspect is the lambda sensor. More of that later, see how you get on with the MAP first. Bad lambda can easy knock 25% off your mpg and doesn't always trigger a warning
Look for any fault codes already stored first though once you get your interface
"Time for the multimeter and accupuncture needles?"
Ha! Could be as you can test most items with quite inexpensive test gear but with an interface and reasonable laptop software you can see much more of how things react on the same timescale.
Scantool software might well be fine and do all you need, haven't looked at the most recent edition
Hope so but the next man on the hit list and just as much a suspect is the lambda sensor. More of that later, see how you get on with the MAP first. Bad lambda can easy knock 25% off your mpg and doesn't always trigger a warning
Look for any fault codes already stored first though once you get your interface
"Time for the multimeter and accupuncture needles?"
Ha! Could be as you can test most items with quite inexpensive test gear but with an interface and reasonable laptop software you can see much more of how things react on the same timescale.
Scantool software might well be fine and do all you need, haven't looked at the most recent edition
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Roughly
35mpg town and open road
40mpg motorway seems more normal for the 1.6
Mine's on 36.1mpg av consumption at present
35mpg town and open road
40mpg motorway seems more normal for the 1.6
Mine's on 36.1mpg av consumption at present
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Re: MPG Drop – What can it be?
I notice a massive change in my MPG once it gets properly cold as I do a lot of short runs & don't have the mixer on my airfilter to help cold starts (although I do drive a Sei).
I notice a massive change in my MPG once it gets properly cold as I do a lot of short runs & don't have the mixer on my airfilter to help cold starts (although I do drive a Sei).
OP
OP
You sir are a genius!
Just done this today, and been for a 50 miles run and my MPG is back up to 35.7!
Thank you very much! :worship:
Its strange as no fault codes where listed when I first plugged the interface in, so I don’t really know what was going on.
Now I’ve got my interface, I’m gonna start looking at intake temps through the GSR kit. Watch this space…:idea:
Cheers mate
Matt
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Good stuff!
Saved an unnecessary £90 for a MAP sensor there then
If a 1.6 is a real struggle to get higher than 25-30mpg around town then it's very likely running on base settings and missing out on the economy the MAP and Lambda sensors can give
As you found, it runs very well indeed on base settings and so there's no clues apart from the mpg figures and number of visits to the petrol station!
More dosh for Christmas now!
Saved an unnecessary £90 for a MAP sensor there then
If a 1.6 is a real struggle to get higher than 25-30mpg around town then it's very likely running on base settings and missing out on the economy the MAP and Lambda sensors can give
As you found, it runs very well indeed on base settings and so there's no clues apart from the mpg figures and number of visits to the petrol station!
More dosh for Christmas now!
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Decks, that a very impressive tip you've given there
Do you think the same trick could be used on a MAF sensor (JTD)?
I presume this is different to just an ECU reset :chin:
Do you think the same trick could be used on a MAF sensor (JTD)?
I presume this is different to just an ECU reset :chin:
