940 Replaced Air Flow Meter - now High Fuel Consumption

lendyer · Nov 6th, 2010, 10:56

Hi
Can anyone help? I replaced the Air Flow Meter last week on my 940 2.3 Turbo auto Estate. The new airflow meter is a genuine new Bosch one. The problem with stalling after starting, and when engaging gears is now sorted, and car running smoothly, but the fuel guage now literally drops before your eyes! It has been tested at the garage this morning, and no computer errors found. Is there anything else I should have changed at the same time? I can see there is a temperature sensor which runs in conjunction with the air flow meter, could this be the cause?

barkster1971 · Nov 6th, 2010, 21:02

What mpg are you getting? 20-25 ? If it's less than 20 then I would be slightly concerned. Less than 15 then something's definitely wrong.

lendyer · Nov 7th, 2010, 14:15

To be honest, I have not checked it, it was very obvious on the last drive out, which was only really to test the car after fitting the new airflow meter. The petrol guage needle moved considerably on only a couple of miles journey! I know there is a temperature sensor that works in conjunction with the meter, and wondered if it was still thinking that the car was cold?

CTCNetwork · Nov 7th, 2010, 17:43

Hi,

Might be worth unplugging your battery for a few hours (over night would be good) to reset your ECU and then seeing how things go from there.
Make sure you have your radio code!

Des. . .

arcturus · Nov 7th, 2010, 21:20

Also check that the IAC isn't sticking,it would be like running with the choke partly on.Check your tail pipe to see whether or not it's running rich.

lendyer · Nov 8th, 2010, 09:17

Thanks for the suggestions, not sure about the IAC sticking, as everything was fine before I replaced the Air Flow Meter!

After fitting the meter, I did take it to the local garage, and had it tested with their computer, and there were no fault codes.

karlos_uk · Nov 11th, 2010, 09:07

it could also be the lambda

lendyer · Nov 11th, 2010, 09:21

wouldn't I see a warning light on the dashboard? Also, the computer test shows Lambda is OK.

'88740GL · Nov 11th, 2010, 09:56

Does your engine have a small toggle switch near your throttle body? i mean if you see where the throttle cable is, the drum that the cable rotates, is there an electronic switch around there? it clicks open when you crack open te throttle, then clicks again when closed..this is the overrun switch, it opens an air valve which relieves vacuum inside the air box and trunking, just so the engine doesnt bog out and flood,

i found my 740 drinking the petrol like i couldnt beleive, and juddering when on light cruise throttle, i found this switch was not closing when i took my foot off, and hence it was piling in the fuel even at idle speeds...i adjusted the throttle stop and the car is getting brilliant mileage from its fuel now!

RealEstate · Nov 11th, 2010, 23:21

Injectors mismatched - need cleaning perhaps? Have a word with jimathan on here
All the best,

Nov 6th, 2010, 10:56	#1
lendyer New Member Last Online: Dec 21st, 2012 12:09 Join Date: Nov 2010 Location: Burnham	940 Replaced Air Flow Meter - now High Fuel Consumption Hi Can anyone help? I replaced the Air Flow Meter last week on my 940 2.3 Turbo auto Estate. The new airflow meter is a genuine new Bosch one. The problem with stalling after starting, and when engaging gears is now sorted, and car running smoothly, but the fuel guage now literally drops before your eyes! It has been tested at the garage this morning, and no computer errors found. Is there anything else I should have changed at the same time? I can see there is a temperature sensor which runs in conjunction with the air flow meter, could this be the cause?

Nov 6th, 2010, 21:02	#2
barkster1971 VOC Member Last Online: Today 13:22 Join Date: Jun 2009 Location: Swineshead/Salford	mpg What mpg are you getting? 20-25 ? If it's less than 20 then I would be slightly concerned. Less than 15 then something's definitely wrong.

Nov 7th, 2010, 14:15	#3
lendyer New Member Last Online: Dec 21st, 2012 12:09 Join Date: Nov 2010 Location: Burnham	Air flow Meter - 940 , high petrol consumption To be honest, I have not checked it, it was very obvious on the last drive out, which was only really to test the car after fitting the new airflow meter. The petrol guage needle moved considerably on only a couple of miles journey! I know there is a temperature sensor that works in conjunction with the meter, and wondered if it was still thinking that the car was cold?

Nov 7th, 2010, 17:43	#4
CTCNetwork Forum Support Team Join Date: Dec 2004 Location: Liège, Belgium View Photos By: CTCNetwork	Hi, Might be worth unplugging your battery for a few hours (over night would be good) to reset your ECU and then seeing how things go from there. Make sure you have your radio code! Des. . . __________________ Density:- Not just a measurement ~ It's a whole way of Life.! ! ! I drive a Volvo, Please Don't Get In My Way! OldVolvos4Ever He shows up. People die. He vanishes. People should not be afraid of their governments. "He'll deliver more justice in a weekend than 10 years of your Governments should be afraid of their people... "V" courts & tribunals. Just stay out of his way." "I plan to."

Nov 7th, 2010, 21:20	#5
arcturus arcturus Last Online: Today 08:14 Join Date: Mar 2006 Location: Sagres Portugal	Also check that the IAC isn't sticking,it would be like running with the choke partly on.Check your tail pipe to see whether or not it's running rich. __________________ life's too short to drink bad wine

Nov 8th, 2010, 09:17	#6
lendyer New Member Last Online: Dec 21st, 2012 12:09 Join Date: Nov 2010 Location: Burnham	Thanks for the suggestions, not sure about the IAC sticking, as everything was fine before I replaced the Air Flow Meter! After fitting the meter, I did take it to the local garage, and had it tested with their computer, and there were no fault codes.

Nov 11th, 2010, 09:07	#7
karlos_uk Master Member Last Online: Jul 13th, 2019 10:01 Join Date: Mar 2009 Location: Derby	it could also be the lambda

Nov 11th, 2010, 09:21	#8
lendyer New Member Last Online: Dec 21st, 2012 12:09 Join Date: Nov 2010 Location: Burnham	wouldn't I see a warning light on the dashboard? Also, the computer test shows Lambda is OK.

Nov 11th, 2010, 09:56	#9
'88740GL Senior Member Last Online: Jun 2nd, 2013 22:00 Join Date: Jun 2010 Location: salford	Does your engine have a small toggle switch near your throttle body? i mean if you see where the throttle cable is, the drum that the cable rotates, is there an electronic switch around there? it clicks open when you crack open te throttle, then clicks again when closed..this is the overrun switch, it opens an air valve which relieves vacuum inside the air box and trunking, just so the engine doesnt bog out and flood, i found my 740 drinking the petrol like i couldnt beleive, and juddering when on light cruise throttle, i found this switch was not closing when i took my foot off, and hence it was piling in the fuel even at idle speeds...i adjusted the throttle stop and the car is getting brilliant mileage from its fuel now!

Nov 11th, 2010, 23:21	#10
RealEstate Master Member Last Online: Nov 4th, 2018 16:06 Join Date: Dec 2003 Location: Berkshire & N Wales View Photos By: RealEstate	Injectors mismatched - need cleaning perhaps? Have a word with jimathan on here All the best,

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