Omega Owners Forum

Omega Help Area => Omega General Help => Topic started by: Omegab25v6 on 03 January 2010, 12:50:42

Title: Getting very poor mileage with 2.5 automatic
Post by: Omegab25v6 on 03 January 2010, 12:50:42
Car is 1995 Omega B 2.5 automatic.
Sedan.

Yesterday i tested,about 9 at evening in city. So only few cars,not hevy traffic. I got about 15mpg, its about 16 L per 100km. Mostly easy ride,some harder moves with gas pedal.

I think its a lot.  Or not?

Whats the most typical problem? Is engine worn out or just screaming for big service(filters and those things).

Car odometer shows 230 000,but it is suspicious,because steering wheel is pretty worn.


Any information?

Edit:My English isnt very good  :)
Title: Re: Getting very poor mileage with 2.5 automatic
Post by: Darth Loo-knee on 03 January 2010, 13:11:54
Your English is fine mate :y

Is the car missing? smelling of oil?
How often do you change the oil? Have the breathers been cleaned out? you would be suprised on how much difference that makes :y
Daz
Title: Re: Getting very poor mileage with 2.5 automatic
Post by: tunnie on 03 January 2010, 13:15:39
your english is excellent, much better that some of the native speakers  ;D

15mpg is quite bad, as above check the breather system, but for it to be that bad something else has to be up.

Worth doing the 'paperclip' test to get some fault codes, instructions on this are in the maintenance guide second  :y
Title: Re: Getting very poor mileage with 2.5 automatic
Post by: Andy H on 03 January 2010, 13:28:23
I found that a faulty thermostat wasn't allowing my engine to warm up properly which made fuel consumption worse.

What country are you in? Is your MID (computer) displaying miles per Imperial (English) Gallon?

US gallons are smaller. I don't know whether regionalisation would allow the MID to display US mpg or L/100kM. :-/
Title: Re: Getting very poor mileage with 2.5 automatic
Post by: Andy B on 03 January 2010, 13:39:36
Quote
I found that a faulty thermostat wasn't allowing my engine to warm up properly which made fuel consumption worse.

What country are you in? Is your MID (computer) displaying miles per Imperial (English) Gallon?

US gallons are smaller. I don't know whether regionalisation would allow the MID to display US mpg or L/100kM. :-/

My guess is Europe hence the litres/100km. Americans doen't usually do metric  ;) ;) ;)
Title: Re: Getting very poor mileage with 2.5 automatic
Post by: Omegab25v6 on 03 January 2010, 13:47:59
Dont smell oil,but i think is missing(Must check later) I have owned it about week or two. So dont know excactly yet. I havent changed oil ,but oil seems good brown,not black. Its also in to do list.
 
I havent cleaned breathers,but want to do this soon. Need to find garage first.

I did paperclip test. Only 12 (start of diagnosis) and 31 with engine not running. So its normal. And if running,only 12.

Engine is working 90-95 celsius. So its also normal i think. Coolant is clean and green. Oil cap has a little cream. But as i have heard its normal on a v6, if driven short distances.

Location is Estonia. We have -10 C at moment here :) And about 60cm of snow. It should be a record of long times.

Computer shows only date,time and outside temperature.

Yes,i know that US and Englist gallons are different, i calculated L/100km to English gallons :)


Also if car is stayed out all night,then it starts about 3-4 times. With every start it runs longer and dies. Finally starts beautifuly.

Ok,then its fine, i rembember english.  Mostly only reading,not writing,so words get forgotten
Title: Re: Getting very poor mileage with 2.5 automatic
Post by: Andy H on 03 January 2010, 13:48:07
Quote
Quote
I found that a faulty thermostat wasn't allowing my engine to warm up properly which made fuel consumption worse.

What country are you in? Is your MID (computer) displaying miles per Imperial (English) Gallon?

US gallons are smaller. I don't know whether regionalisation would allow the MID to display US mpg or L/100kM. :-/

My guess is Europe hence the litres/100km. Americans doen't usually do metric  ;) ;) ;)
Oops. L/100km plain as day in OP but I missed it  ::)

I was thinking there might be some confusion over units but 16 L/100km is very close to 16 Imperial mpg so that isn't the problem....
Title: Re: Getting very poor mileage with 2.5 automatic
Post by: alunonhisown on 03 January 2010, 13:57:07
Daz does MOBILE Tuning, sounds like a job for him, IMO.
Off you go Daz
Just the start you need to freshen you up
Title: Re: Getting very poor mileage with 2.5 automatic
Post by: Andy B on 03 January 2010, 13:59:03
Quote
.....
Ok,then its fine, i rembember english.  Mostly only reading,not writing,so words get forgotten

Not only will you learn more about how to mend/fix your car, you will also improve your English. Cem, in Turkey, has learned lots of swear words too!  :-[  :-[  ;D  ;D ;)
Title: Re: Getting very poor mileage with 2.5 automatic
Post by: Andy H on 03 January 2010, 14:01:20
Quote
Engine is working 90-95 celsius
I think that is correct for the 2.5  :y

Quote
Also if car is stayed out all night,then it starts about 3-4 times. With every start it runs longer and dies. Finally starts beautifuly.

That doesn't sound right. We occasionally get -8 Celsius on one or two nights a year (not for weeks at a time as central Europe does) but I would still expect the Omega to start first time.

Perhaps one of the temperature sensors (air intake or engine coolant) is giving a wrong reading to the ECU to cause starting difficulty and poor mpg?
Title: Re: Getting very poor mileage with 2.5 automatic
Post by: Darth Loo-knee on 03 January 2010, 14:07:43
Quote
Daz does MOBILE Tuning, sounds like a job for him, IMO.
Off you go Daz
Just the start you need to freshen you up

Its a long bloody walk  ;D ;D
Title: Re: Getting very poor mileage with 2.5 automatic
Post by: Omegab25v6 on 03 January 2010, 14:09:53
Air intake sensor is thinkable. Coolant sensor then should also give false readings to dash also? But its ok.
Title: Re: Getting very poor mileage with 2.5 automatic
Post by: alunonhisown on 03 January 2010, 14:10:56
PMSL
Freshen you up for the Rest Of Your Life, and you get to go in the Guinness Book for Most Dedicated Omega Mechanic
What, I just created a new New Years Honour
How Cool Is That?
Title: Re: Getting very poor mileage with 2.5 automatic
Post by: tunnie on 03 January 2010, 14:11:15
Quote
Daz does MOBILE Tuning, sounds like a job for him, IMO.
Off you go Daz
Just the start you need to freshen you up

Think even Estonia is out of reach for the dark one
Title: Re: Getting very poor mileage with 2.5 automatic
Post by: Andy H on 03 January 2010, 14:13:07
Quote
Air intake sensor is thinkable. Coolant sensor then should also give false readings to dash also? But its ok.
There are two coolant temperature sensors, one for the display and one for the ECU.

I know that Volkswagen coolant temperature sensors are very unreliable but I have never heard of one failing on an Omega.
Title: Re: Getting very poor mileage with 2.5 automatic
Post by: Omegab25v6 on 03 January 2010, 14:17:31
Quote
Quote
Daz does MOBILE Tuning, sounds like a job for him, IMO.
Off you go Daz
Just the start you need to freshen you up

Think even Estonia is out of reach for the dark one



Only 3 hour flight from Tallinn to London ;) Went there last year.





Is there a way to test senors? Their resistance or something? ECU dont give any false codes.
Title: Re: Getting very poor mileage with 2.5 automatic
Post by: Darth Loo-knee on 03 January 2010, 14:26:11
Quote
PMSL
Freshen you up for the Rest Of Your Life, and you get to go in the Guinness Book for Most Dedicated Omega Mechanic
What, I just created a new New Years Resolution, Your Honour
How Cool Is That?


Very Cool indeed to call me Your Honour D ;D

But if you keep trying to find me work so far away (as I didn't get this Physique through Exercise) I will put you over my knee  :D ;D ::) :P
Title: Re: Getting very poor mileage with 2.5 automatic
Post by: Omegab25v6 on 05 January 2010, 19:25:59
I have also question about oil. V6 oil cap is  covered with this looking like a mayonnaise. yes i know,its oil with water.  Cap is covered with this,and also oil tube walls inside are covered with this. I know that little this on cap is normal,if short distances. But is this amount normal? I checked, and coolant is clean and all is there,nothing missing.