changed oxygen sensors, now seems to be wasting same amount of fuel if not more!

[admir87]

hello everyone,

well my vs calais v6 been chewing abit of fuel lately, so serviced it and changed the o2 sensors..

i reset the ecu aswell

but now the car seems to be wasting same amount if not a bit extra according to the trip meter

anyone got any ideas/info?

does the computer now need to adjust again or does it not need to adjust from a ecu reset?

cheers in advance

[immortality]

most likely the engine isn't getting upto temp or the ecu thinks the engine isn't getting upto temp. does the dash temp gauge come up to operating temp at all?

possibly may need to change the temp sender for the ecu.

what is the consumption average on the trip comp?

the ecu will adjust itself after a reset but you should notice a change from the old O2 sensors immediatly.

if your going to change the temps senders you may as well change the thermostat whilst your at it, save you dropping the coolant twice

[Brett_jjj]

Id first check for any error codes.Checking error codes VR/VS (Revised)

[admir87]

ive checked the temp sensor and resistances are correct to appropriate temperatures..

also the car does come to operating temperature

[admir87]

checked error codes and there are none only 12,

getting an average of 16.5 around city driving it pretty easy

[Reaper]

If you drive with a heavy right food it's still a little heavy but wouldn't surprise me.

Reaper

[The1]

16.5 is still in the normal range for town driving, i average around 12 - 13 not driving hard or easy. with a mix of town and highway is goes down to 9.

Have you tested the new o2 sensors? they can still be faulty out of the box, ive had a few before. Hows the car otherwise in general? fully serviced? Fuel and air filter in good nick? MAF sensor might do with a clean, there's plenty of threads here how to do this as well.

[88GreenVN]

Probably run some injector cleaner though it as well if you haven't done it for a while.

[ephect]

what year is ur car?

[admir87]

what year is ur car?

october 96...

ive cleaned maf

ran injector cleaner,

done a full service

how do you test o2 sensors?

[88GreenVN]

october 96...

ive cleaned maf

ran injector cleaner,

done a full service

how do you test o2 sensors?

Re-do the error code test....

[admir87]

Re-do the error code test....

will do it tommorow morning again but ive had nothing and i checked a week ago...

i havent had the engine light pop up ever

[The1]

Theres two wires on the ecu D15 LH Sensor D13 RH Sensor you can hook a multimeter up, when the engines fully warmed up tap the throttle and it should go up and down from 0.1v to 0.9volt, 0.1v lean 0.9v rich. If it's sitting in one spot the sensors stuffed or not warmed up.

To see it properly in realtime you need a scantool, but the multimeter lets you know it's not totaly dead.

Sometimes the sensors might not log an error code but are slow or not working right.

[BT1-355]

checked error codes and there are none only 12,

getting an average of 16.5 around city driving it pretty easy

That sounds about right for city driving

[Kurtp]

16.5? how does that sound about right, i drive pretty hard and i have a buick and use about 12. And i thought that was shit!

[ephect]

june 96 was the first of the series 2, i was thinking possibly an O2 earthing issue which may also contribute to ur consumption, but that was a major issue with the series 1, might be something to consider though

[88GreenVN]

You could try a different ECU just in case it's that. If all the sensors are new and working then the ECU may be sus and not processing the sensor data properly.

[admir87]

june 96 was the first of the series 2, i was thinking possibly an O2 earthing issue which may also contribute to ur consumption, but that was a major issue with the series 1, might be something to consider though

hi mate, ive read your thread on the earthing issues..

so this mostly applies to pre june 96 vs models?

i do have the 4 wire sensors but yes it is a series 2 oct 96

[ephect]

it was a known issue with the series 1, but im not 100% sure if it was fixed in series 2 models.

the way i look at it is; it doesnt cost anything to do and at least you can rule out that whilst trying to diagnose/eliminate possible causes.

[ipsy]

yer i had the same problem i changed the oxygen sensor and my fuel went form 13.8 per 100km to 17.8 per 100km's i fixed this problem by cleaning the throttle body changed the fuel pump and filter and get the car electronically tuned and now the car runs 12.8 in city driving and 10.2 on hwy .

[Trikky]

What temp should the dash gauge show for normal driving as mine barly gets off the first marker showing cold, as I have only owned the car a short time not sure if this is normal or some clown has removed the thermostat on it as it will get to half on the gauge if left idling for extended period or under continued load

[Wombles]

it was a known issue with the series 1, but im not 100% sure if it was fixed in series 2 models.

the way i look at it is; it doesnt cost anything to do and at least you can rule out that whilst trying to diagnose/eliminate possible causes.

Hmm. I should test this on mine as it's a pre 96 model. :S

For the thread creator, just make sure the air filter is clean, the fuel filter has under 50,000 k's on it and clean the throttle body out.

[calais_cruzin]

What temp should the dash gauge show for normal driving as mine barly gets off the first marker showing cold, as I have only owned the car a short time not sure if this is normal or some clown has removed the thermostat on it as it will get to half on the gauge if left idling for extended period or under continued load

Last owner could have removed the Thermostat, or it could be seized open.

Not hard to change, 30bucks around for new part.

Ur temp should sit at the 1/4 mark at running temp.

[Not_An_Abba_Fan]

Half on the gauge is pretty normal for a VS.

How is your air filter?

[admir87]

Hmm. I should test this on mine as it's a pre 96 model. :S

For the thread creator, just make sure the air filter is clean, the fuel filter has under 50,000 k's on it and clean the throttle body out.

ive done a service on it a few kms ago, changed fuel filter and air filter and cleaned maf cleaned inlet manifold and throttle body

ive done pretty much all you can when it comes to servicing besides changing injectors