Cleaning your Cat & fuel consumption

JHLOW

JHLOW

JHLOW

Associate
Joined
13 Dec 2009
Posts
145
Location
Plymouth
Hi All, I currently own a peugeot 306 2.0 xsi as a daily runner and i reakon im not getting good fuel consumption out of it i drive 15 miles each way to work and back and collect this missis from work in the evenings 10 mile round trip. so i have recently given it a service, oil & filter, plugs, full cambelt kit, checked for vac leaks & cleaned connectors etc.

But my fuel consumption is still average 25 - 28 mpg, I was curious is this good or bad and would i benefit from using some kind af catalytic converter cleaner? i have heard millers stuff is good but can't find any.

Also my idle seems strange it once started even from hot the car idle will run a tad high 1100rpm or there abouts until i comes to my first stop wait about 5-10 seconds and it will drop to say 850rpm then be okish, idle seems a little uneven too once warm, What would cause this any ideas?

Any help would be great this was a rush post will put more info when back from morrisons in a bit....thanks James:D
 
Air filter, fuel filter.
Clean the throttle body. (could explain rough idle)
Could run through some injector cleaner although I doubt that's the problem.

How you always had the same fuel economy?
 
[TW]Fox;15912183 said:
It's a 2 litre petrol engine, assuming this isnt on the Motorway that seems about right?
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Not motorway It's on an A road from Plymouth to Liskeard

( |-| |2 ][ $;15912191 said:
Air filter, fuel filter.
Clean the throttle body. (could explain rough idle)
Could run through some injector cleaner although I doubt that's the problem.

How you always had the same fuel economy?
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I have a new fuel filter to fit but i forgot and filled the tank on the way home from work yesterday so will have to wait till empty again as it's an underbody mounted jobbie.

I checked the air filter not long ago and it is fairly new but could order a new one from work tommorrow only a quick swop job done.

I cleaned the throttle bodie about 2 months ago could do it again at the weekend as a matter of courses.

I ran some injector cleaner through it about 6 weeks ago and didn't seem to make a difference.

I used to get about 20 -22mpg before i changed the plugs..now i get on average 25 - 28mpg.

Would i benefit form using some of the cat cleaner on the market? do you think i would see any better fuelage/mileage..

Also one other thing i noticed with the car is as it happend earlier again sometimes when coming to a set of lights or junction or just blip the throttle when standing still revs will fall and engine will stall, but will start straight away no problems, but this is only occassionaly.

I would just like to better mileage as iv'e been unemployed for 18 months and just started a new job on minimum wage during probation for 3 months (at 31 years old) and am finding with my income currently and the cost of fuel & cost of toll on the tamar bridge is taking almost a quarter of my wage every week.
 
28ish mpg sounds about right for that drive - the 2.0 XSi was never reknowned as a particularly economical car anyway.

If you are working for minimum wage isnt it best to do it in Plymouth anyway? Your effective takehome pay will be loads better without that travelling.
 
I don't think cat shampoo will help.

The only thing that could cause a drop in fuel economy related to the cat is if it collapses. So amount of cleaning will fix that though :p

The cold weather is probably causing the difference?
 
I'd have though that with a normal sized right foot on that size car a 2.0 L should get 30mpg.

Changing the lambda sensor made a substantial differance to my Volvo 850, as did changing the fuel filter. However the car was very marginal on emissions too, which was a sign the sensor was on it's way out.

Forte do a cleaner called Gas Treatment which is very good and i'd give that a whirl if i was you, but in reality no two litre engine is going to be especially economical and you maybe need to slow down or as suggested swallow your pride and get a DTurbo.
 
Cyanide said:
Doesn't look to be anything wrong to me. 2l engine + short trips = 25-30mpg
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this

especially in this weather as due to it being so cold it never really gets up to temperature on shorp trips. When its cold its operating outside of its optimum threshold, and wont be as efficient

hence the worse mpg.
 
Sounds about right to me. I do 7miles a day in my GTi6 and average 22 - 25mpg over a tank. 3.5miles each way at motorway speeds.
 
I measured my MPG over a tank the other week and it came out at 31 but I'd done a reasonably long trip in that, going really easy on the way up (65) and getting quite humpy and getting stuck in traffic on the way back. It was about a 230 mile round trip. Rest of the time is around town, and a 20ish mile each way commute which is just over half A roads. I was trying to be economical on the long trip too but it went out the window on the way back, had four wheels & tyres in the boot and got repeatedly stuck in traffic, so when it was free-flowing I was going faster because I was in a mood :D

Same car btw, 306 XSi
 
I live on a small Island and average 27MPG in my 2.5 Turbo.

25MPG seems shocking for a 2.0, my old (modified) 170BHP Calibra (2.0 16v) averaged 30 :/
 
s0ck said:
Swap it for a DT? Should see 40MPG ez.
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If i could afford it i would thats what i wanted in the first place but they were much more money for a good one.

[TW]Fox;15914293 said:
28ish mpg sounds about right for that drive - the 2.0 XSi was never reknowned as a particularly economical car anyway.

If you are working for minimum wage isnt it best to do it in Plymouth anyway? Your effective takehome pay will be loads better without that travelling.
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I used to run a nissan 300zx manual TT runnign @ 410bhp for a few years and downgraded to the pug when i got made unemployed as i just could'nt afford to keep it anymore.

As said above been unemployed for around 18months desperatly looking for work out every day on foot with a file full of cv's to no avail which is mentaly draining when i put so much effort in, Then I got offerd a job in trebrown, cornwall by word of mouth through a friend and i wasn't going to say no to being offerd a job, I was getting so depressed not working for so long it was affecting my relationship too, but now I am so happy to be in work my mood has changed for the better and life feels good now, but i just need to try and pull back on the travelling costs, Im already looking into getting a tamar tag to halve the cost of the bridge, i don't drive like a t**t as it's not going to get me there any quicker.

Simon said:
I don't think cat shampoo will help.

The only thing that could cause a drop in fuel economy related to the cat is if it collapses. So amount of cleaning will fix that though :p

The cold weather is probably causing the difference?
Click to expand...

Never though of the cold affecting it really...
 
The Edge said:
I'd have though that with a normal sized right foot on that size car a 2.0 L should get 30mpg.

Changing the lambda sensor made a substantial differance to my Volvo 850, as did changing the fuel filter. However the car was very marginal on emissions too, which was a sign the sensor was on it's way out.

Forte do a cleaner called Gas Treatment which is very good and i'd give that a whirl if i was you, but in reality no two litre engine is going to be especially economical and you maybe need to slow down or as suggested swallow your pride and get a DTurbo.
Click to expand...

I drive very conservatively in my pug as there is no point in thrashing it, it would just die on me if i did that lol... it would be nice to 30mpg+

Ill have a look out for the Forte treatment if it's a good price and not to expensive i might just give it a try, I am condering a Dturbo as it's what i initally wanted but could'nt stretch to one and now im in work id need to buy the new car first then sell mine otherwise i wouldn't be able to get to work...

The Edge said:
As a thought re the cutting out, air mass meter or MAP sensor could be the problem and may cause overfuelling.
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I will look into these thanks im sure it's Maf have a look at the weekend as i dont finish work till 7 pm and it's dark then so wouldn't be able to see what im doing. lol

MrLOL said:
this

especially in this weather as due to it being so cold it never really gets up to temperature on shorp trips. When its cold its operating outside of its optimum threshold, and wont be as efficient

hence the worse mpg.
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The car warm up prettly quickly to be honest around 4-5 miles into the trip it's at full temp....
 
JHLOW said:
The car warm up prettly quickly to be honest around 4-5 miles into the trip it's at full temp....
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Coolant temp and oil temperature are different things.

Your oil temperature takes much longer to get up to temperature. The gauge on your dash is for coolant temp :)
 
TripleT said:
Sounds about right to me. I do 7miles a day in my GTi6 and average 22 - 25mpg over a tank. 3.5miles each way at motorway speeds.
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PardonTheWait said:
I measured my MPG over a tank the other week and it came out at 31 but I'd done a reasonably long trip in that, going really easy on the way up (65) and getting quite humpy and getting stuck in traffic on the way back. It was about a 230 mile round trip. Rest of the time is around town, and a 20ish mile each way commute which is just over half A roads. I was trying to be economical on the long trip too but it went out the window on the way back, had four wheels & tyres in the boot and got repeatedly stuck in traffic, so when it was free-flowing I was going faster because I was in a mood :D

Same car btw, 306 XSi
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In comparison to you guys im getting relativly decent mpg then it seems, considering the short drive to work.
 
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