Omega Owners Forum

Omega Help Area => Omega General Help => Topic started by: tigers_gonads on 04 June 2013, 17:38:40

Title: Just fitted 3ltr cats and ...............
Post by: tigers_gonads on 04 June 2013, 17:38:40
The spanner light is still on and the instant mpg is a little high.

Do I need to ask my dodgy Chinese friend to reset the fuel trims / turn light off ?

Must say, I've only been up the road and back but it is definitely running better

TIA
Title: Re: Just fitted 3ltr cats and ...............
Post by: aaronjb on 04 June 2013, 20:35:22
IIRC the pre-cat codes will 'disappear' (well, the light will go out and they'll be stored as a 'not present' code) after a while; a certain number of starts and up-to-temp cycles I think..

Or reset it all and wait for it to come back on (hopefully not, of course!) ;)
Title: Re: Just fitted 3ltr cats and ...............
Post by: Doctor Gollum on 04 June 2013, 20:37:57
Yes clear codes which will reset trims etc. ....preferable, but not vital though.
Title: Re: Just fitted 3ltr cats and ...............
Post by: tigers_gonads on 04 June 2013, 23:11:13
Okay, cheers for that.
Job for morning.
Went on a very steady run to stoke and back last week and all I could manage was 17.8 mpg on gas  :(

Hopefully, these cats should help out a bit
Title: Re: Just fitted 3ltr cats and ...............
Post by: Doctor Gollum on 04 June 2013, 23:26:53
Your aware Gas is less efficient?...?  :-\
Title: Re: Just fitted 3ltr cats and ...............
Post by: Entwood on 04 June 2013, 23:37:58
Your aware Gas is less efficient?...?  :-\

Incorrect .. gas is equally as "efficient" ... if not more so ...  :)

What is correct is that the number of miles obtained from a litre of gas is less than the same litre of petrol, but NOT for any reasons of "efficiency" (or lack thereof )  :)

ALL engines actually burn a MASS of fuel -not a volume of fuel - the MASS of fuel injected corresponds to the MASS of air detected by the MAF (think of why its called that !!)  to actually achieve the stoichiometric ratio.

LPG has a lower MASS than petrol - it weighs less - so you get fewer miles per gallon - but if you actually used MASS you would get identical miles per lb ( or kilo ), however we buy the fuel by volume not by weight .. :(

:)  HTH  :)
Title: Re: Just fitted 3ltr cats and ...............
Post by: Doctor Gollum on 04 June 2013, 23:45:19
See. Less efficient.  :P  ;D
Title: Re: Just fitted 3ltr cats and ...............
Post by: zirk on 05 June 2013, 00:10:32
In my experience of LPG (3 x V6 Migs, 1 1.4 Tigra, 1 x 2.0 Vectra and a 1.8 BMW) performance is down by about 10%, and MPG is down by about 10 - 15%, having said that I can get 25 MPG on Gas on a 3.2 Manual in and out of London.  ;)
Title: Re: Just fitted 3ltr cats and ...............
Post by: albitz on 05 June 2013, 00:27:32
In my experience of LPG (3 x V6 Migs, 1 1.4 Tigra, 1 x 2.0 Vectra and a 1.8 BMW) performance is down by about 10%, and MPG is down by about 10 - 15%, having said that I can get 25 MPG on Gas on a 3.2 Manual in and out of London.  ;)

The important fact in that sentence imo. ;)
Title: Re: Just fitted 3ltr cats and ...............
Post by: zirk on 05 June 2013, 00:33:51
In my experience of LPG (3 x V6 Migs, 1 1.4 Tigra, 1 x 2.0 Vectra and a 1.8 BMW) performance is down by about 10%, and MPG is down by about 10 - 15%, having said that I can get 25 MPG on Gas on a 3.2 Manual in and out of London.  ;)

The important fact in that sentence imo. ;)

yep, probably and the fact you wont do more than 15mph on average, which an Autobox will just eat the juice.  ;)
Title: Re: Just fitted 3ltr cats and ...............
Post by: albitz on 05 June 2013, 01:15:45
My MPG is horrific in town/city driving with the autobox. :y
Title: Re: Just fitted 3ltr cats and ...............
Post by: Doctor Gollum on 05 June 2013, 07:06:23
 can usually keep it at 18mpg in town by coasting the autos alot more ime.

It can be an interesting challenge to drive as much as possible with no feet on the pedals for as long as possible. Entry speed into roundabouts etc needs precise judgement from way back up the road. I mean there's bog all else to do stuck behind a blue rinse on a midweek lunchtime. ;D

Jedi powers are handy too.   ;D

Title: Re: Just fitted 3ltr cats and ...............
Post by: Doctor Gollum on 05 June 2013, 07:08:24
Apologies if teaching egg sucking though.  :-\
Title: Re: Just fitted 3ltr cats and ...............
Post by: Marks DTM Calib on 05 June 2013, 08:02:03
See. Less efficient.  :P  ;D

Effeciency the same pretty much.  :y

Title: Re: Just fitted 3ltr cats and ...............
Post by: tigers_gonads on 05 June 2013, 08:35:51
That 17.8 was sat was
50% ish @ 70 mph
30% ish @ 50 mph (average speed camera's)
The rest was 50 ish through the b roads.

Got a feeling the old pre cat's was totally shagged and I know that the lambda sensors was slow.

As said, the autobox will have a big affect when driving around town.
My old 3ltr manual with a 3.7 ratio diff would easily do 23 mpg around town with a boot full of cable, full gas tank and a fat barsteward driver  ;D
Daz thought these 4 lambda's were slow but his 2.6 was averaging 26 mpg on them so i'll reset the trims / codes later and see where it goes  :-\

Must admit, the gearbox fluid is ok but does need a flush. P1700 is present so i'll maybe get that done and see if it locks up any quicker  :-\

OR I may go back to Plan A and get rid of the slushbox and stick a R28 / R30 on it and try and remember what my left foot is for  :-X ;D ;D

I'll report back when I've plugged the laptop  :y

Thanks all  :-*
Title: Re: Just fitted 3ltr cats and ...............
Post by: tigers_gonads on 05 June 2013, 14:40:06
Everything reset.
Just been for a drive and the lights still on  :(

Anything I should be looking for here ?
Title: Re: Just fitted 3ltr cats and ...............
Post by: Doctor Gollum on 05 June 2013, 14:56:24
Codes?
Title: Re: Just fitted 3ltr cats and ...............
Post by: tigers_gonads on 05 June 2013, 15:10:41
Sorry, codes might help  ::) :-[

P0650
P0325 (I've got a sticking injector which sometimes stops the lpg engaging at the first time of asking if the revs are too low )

Clear the codes
P0650 comes back immediately
Title: Re: Just fitted 3ltr cats and ...............
Post by: henryd on 06 June 2013, 11:57:06
Sorry, codes might help  ::) :-[

P0650
P0325 (I've got a sticking injector which sometimes stops the lpg engaging at the first time of asking if the revs are too low )

Clear the codes
P0650 comes back immediately

p0650 is MIL light circuit malfunction.
Title: Re: Just fitted 3ltr cats and ...............
Post by: tigers_gonads on 06 June 2013, 12:10:42
Sorry, codes might help  ::) :-[

P0650
P0325 (I've got a sticking injector which sometimes stops the lpg engaging at the first time of asking if the revs are too low )

Clear the codes
P0650 comes back immediately

p0650 is MIL light circuit malfunction.


Cheers Henry, out on the pish yesterday afternoon so left it.
Sussed that one out this morning  :y

I did have problems with the lpg which would probably caused the knock sensor to throw a fanny fit  ;D
I've cleared the codes and reset the trims and the only one that comes back is the p0650 so i'll leave it for another day  :-\

What is bugging me now is the spanner light (emissions) refuses to do one  >:(
I'd have thought with replacing the cats with the modified 3ltr ones and resetting everything, that would have been enough  :-\

What else can keep this spanner light on ?
Title: Re: Just fitted 3ltr cats and ...............
Post by: Marks DTM Calib on 06 June 2013, 12:47:10
You conneted the correct lambdas up to the correct loom sections?
Title: Re: Just fitted 3ltr cats and ...............
Post by: tigers_gonads on 06 June 2013, 13:01:56
You conneted the correct lambdas up to the correct loom sections?


Done on the ramps of a local mechanic. ( I put my shoulder out while rounding off one of the manifold nuts so shelled out a few quid before I turned it into a 3.2 ltr bbq  :-[  ;D ;D)

Should add that the car is running smooth as a very smooth thing  ;D
Would a swapped sensor cause problems on a 3.2 ?
In a past life, I set fire to a pair of 3ltr cats by doing the same trick  :-[
Title: Re: Just fitted 3ltr cats and ...............
Post by: Marks DTM Calib on 06 June 2013, 13:37:13
If the post cat sensor is connected where the pre-cat one should connect then very much so yes.

Or the banks mixed up.
Title: Re: Just fitted 3ltr cats and ...............
Post by: tigers_gonads on 06 June 2013, 13:48:53
If the post cat sensor is connected where the pre-cat one should connect then very much so yes.

Or the banks mixed up.


Wouldn't it run like a sack off poo though ?
The car is running great on petrol and lpg

Just asking before I drive down there and say something
Title: Re: Just fitted 3ltr cats and ...............
Post by: Marks DTM Calib on 06 June 2013, 13:53:16
Not neccassarily.

What are the live values saying
Title: Re: Just fitted 3ltr cats and ...............
Post by: tigers_gonads on 06 June 2013, 14:05:35
Not neccassarily.

What are the live values saying


A mate has the car at the moment so i'll plug it in later and report back.
What should I be looking for ?
What readings should I be getting ?
Would a snapshot do or is it a case of recording it live then utube it ?

Cheers  :)
Title: Re: Just fitted 3ltr cats and ...............
Post by: Marks DTM Calib on 06 June 2013, 14:36:29
Learn values are always a good start.

Pre cat sensors should be switching, post cat should be static.
Title: Re: Just fitted 3ltr cats and ...............
Post by: tigers_gonads on 06 June 2013, 14:44:19
Learn values are always a good start.

Pre cat sensors should be switching, post cat should be static.


I'll plug it in and have a look later  :y

Thanks  :)
Title: Re: Just fitted 3ltr cats and ...............
Post by: AndyD_1961 on 06 June 2013, 15:47:39
Spanner light is not emmissons engine light is