MPG after 304 ?????????

[cameron]

Before i had my Hamish 304 done around town i was getting about 20 - 22 MPG.

Since having the 304 done i'm lucky if i get 15 MPG :(

I understand that more power means more petrol but should it be this low? its an auto by the way.

And im not driving like a loon either, your lucky if i pass 2.5K RPM so very light footed :B_thumb:

On a run im still getting 34 - 35 MPG so thats not so bad.

Cheers

Lee

[MIKESC70T5]

My old 850 had the official rica304 (not sure if it's the same)as the Hamish one, but fitted by the same guy. My car was a manual, but before the remap around town was 24-25, after it was 27-29mpg.
Yours seems it's very low around town, but very good on a run. I would of thought it would of affected both t.b.h.

[cameron]

No matter how light footed i drive it its the same.

I done a wee test last night and until i hit traffic lights i was doing 18.5 MPG but after sitting for about a minute i checked again and it had plummeted to 14.9 MPG.

Does it sound as though its running lean?, and apart from another ECU is there anyway of altering the mixture?

Cheers

Lee

[Jod T5]

Before i had my Hamish 304 done around town i was getting about 20 - 22 MPG.

Since having the 304 done i'm lucky if i get 15 MPG :(

I understand that more power means more petrol but should it be this low? its an auto by the way.

And im not driving like a loon either, your lucky if i pass 2.5K RPM so very light footed :B_thumb:

On a run im still getting 34 - 35 MPG so thats not so bad.

Cheers

Lee


If you are running Super, you should be getting a better consumption than stock on premium...
That said , people tend to find there consumption goes down after a remap because they have the loud pedal down all the time ;)...That said 15 is poor, i take it you have seen no dash lights.....I would expect if, as you say , you are not driving like you stole the car, you have a fuel trim issue....
Cheers
Jod

[cameron]

No lights on the dash whatsoever mate.

Fuel trim :confused: Youve lost me there :rotfl:

That dude that drove miss daisy would probably pass me up manchester road, the turbo guage is never passed midway :jaw:

Im filling with either Shell V power or Tesco Super 99 ron

Cheers

Lee

[Jod T5]

Does it sound as though its running lean?,


Rich.... Lee.....
Maybe check the PCV heater nipple (small pipe) to see if its blocked.....
Cheers
Jod

[cameron]

Where would this pipe be located Jod ?

Cheers bud

Lee


Rich.... Lee.....
Maybe check the PCV heater nipple (small pipe) to see if its blocked.....
Cheers
Jod

[Jod T5]

No lights on the dash whatsoever mate.

Fuel trim :confused: Youve lost me there :rotfl:

Im filling with either Shell V power or Tesco Super 99 ron

Cheers

Lee

Fuel trim is difficult to explain, however your car should be able to tell you if you are running rich or lean but not which (without specialist equipment) and whether it is at idle or at throttle....
Cheers
Jod

[cameron]

Ive gotta mate that owns a garage, if its running rich will the AFR's be sky high ?

He says he'll do an emissions test for a fiver which sounds like a bargain to me.

Cheers

Lee

[Jod T5]

Where would this pipe be located Jod ?

Cheers bud

Lee

The PCV valve is situated at the end on the induction flexipipe just before the turbo..
There should be two pipes attached to a two pronged tree with a electrical connector as well..The fat pipe is from the oil seperator and the thin from the inlet manifold....The thin pipe can be removed from the tree and the tree extension cleaned with a pin or the like...Alternatively the whole valve can be removed from the inlet trunking....
The thin pipe can break behind the inlet manifold but this is most likely to give a lean mixture as boost pressure is lost and unmetered air sucked in under manifold vacuum.....Only blocking will run lean....
Cheers
Jod

[Jod T5]

http://i35.photobucket.com/albums/d157/jod1jod/Inlet%20to%20pcv%20re-route/Picture034.jpg
There it is...
Cheers
Jod

[cameron]

Ah Ha so one of my PCV pipes isnt exactly a pipe.

It should have the brittle hard pipe inside the rubber outer where as i only have the rubber outer, the guy i bought it off swears its had the PCV done but from the look of the pipes id say it hasnt. :(

So maybe i have a leak somewhere?

Cheers

Lee

[Jod T5]

Ive gotta mate that owns a garage, if its running rich will the AFR's be sky high ?

He says he'll do an emissions test for a fiver which sounds like a bargain to me.

Cheers

Lee
Personally i doubt the Map will be the issue.., most likely there is a reason other than this why you are losing Idle pressure
Cheers
Jod

[Jod T5]

Ah Ha so one of my PCV pipes isnt exactly a pipe.

It should have the brittle hard pipe inside the rubber outer where as i only have the rubber outer, the guy i bought it off swears its had the PCV done but from the look of the pipes id say it hasnt. :(

So maybe i have a leak somewhere?

Cheers

Lee

As i say i doubt you have a leak, otherwise you will get juddering at WOT,.....
It may be wise to remove the small pipe and finger test for vacuum at idle..
Cheers
Jod

[cameron]

Finger test ? also what is WOT ? :D

I am once again LOST LOL

Anything else other than the engine and im excellent but start proding about under the bonnet and im stuffed big time :D

I can change oil and filters and the like but boost hoses and all that stuff, im completely goosed.

Cheers

Lee

[Jod T5]

Finger test ? also what is WOT ? :D

I am once again LOST LOL

Anything else other than the engine and im excellent but start proding about under the bonnet and im stuffed big time :D

I can change oil and filters and the like but boost hoses and all that stuff, im completely goosed.

Cheers

Lee

LMAO.., Finger test, pull the elbow off and stick your finger over the elbow hole and feel/listen for suction...
Another test is the ECT, (coolant temp sender) at hot running it should read 170 odd Ohm's..any thinig over 300 and you are overfueling, how does your on board temp gauge behave?....When was the thermostat last changed?...
Im up at five so i will catch you later Lee...
Cheers
Jod

[cameron]

The onboard temp is as like my last manual un304'd T5

It hovers just south of midway on the guage.

As for the thermostat being changed, eh PASS ! lol

The old fella that had the car spent £1750 on it a month before i bought it. went to kwiksh*t the other day and he pointed out its had brand new suspension all round and new wishbones. Plus all new brakes. :)

So if the guy says the PCV has been done id tend to agree with him althought the dodgy pipe has me flumoxed ?

Is it the pipe with the Yellow tape round the end or summit else ?

Cheers Jod appreciate all the help mate

Lee

[850twr]

no thats your actuator pipe, its the one just below that.

[Jod T5]

It hovers just south of midway on the guage.



I would start here....
The gauge should in my experience be halfway....This is commonly recognised as correct.....Sounds to me like the thermostat may be slightly stuck open, which will keep the water cooler and fueling higher...
Cheers
Jod

[nathT5]

if its anything other than the new map, would,nt it have done this before???

btw, mines doing 30mpg on a steady run but only 15 around town and its only averaging 19mpg,
and thats with a new thermostat, no leaks but probably a 25% lead foot...

[850twr]

i average 17 around town and can get 30+ on a run, stock ecu, but running 13psi

[Big Pete]

I get around 18-19mpg around town in my auto with 25% lead foot, and around 33mpg on the motorway leaving the cruise control at 75mph.

My temperature dial in the dash at present on the motorway and light town driving seems to stay around 1/4 of the way and then once I hit heavy town traffic it goes to half way. Does that seem about right? Only had the car since 1st November so the outside temperature has always been cold.

[cameron]

Before the map i was getting 20+ around town but now struggle to get 15mpg.

If im really careful i'll be sat about 19mpg but then i stop at the lights and it plummets below 15 :confused:

Not really worried about it, the car runs mint, i just thought it was quite a big rise in fuel consumption.

Ive checked all the pipes and none are blocked or split :B_thumb:

Cheers

Lee

[850twr]

yea the 850 computer drops ur overall average very quckly once you've stoped, especialy if you'v only recently reset it, other cars av.mpg computers pause the calculations when your stationary.

[850twr]

and yeh big pete your temp gauge behaves the same as mine.

[nathT5]

more power always means less mpg, i dont care what the salesman says,
more air + more fuel = more power,
if you do get more mpg, your just not driving it hard enough to make the extra power and thats a waste,
you dont buy a 280+bhp car for economy...

[850twr]

hmmm, but part of a remap is to make the engine more efficiant as well as more powerfull, so e.g. cruising at the same speed but with a remap you would use less throttle to maintain that speed and so use less fuel? was always my theory onit anyway.

also all remapping services advertise improved mpg

[nathT5]

re-maps more efficiant? yes,
use less throttle at a constant speed? yes,
less fuel? for a car to travel the same distance it will surely use the same amount of fuel,

but if you actually want to make use of the extra power it WILL drink more, fact.

[Jod T5]

re-maps more efficiant? yes,
use less throttle at a constant speed? yes,
less fuel? for a car to travel the same distance it will surely use the same amount of fuel,

but if you actually want to make use of the extra power it WILL drink more, fact.

Hi,
There is no doubt in my mind that you will get better consuption from a car (built by map to) run on super unleaded fuel...

Yes the power of a remap is likely to make you hit the loud pedal more often and for longer, However....

You use less fuel because you can run more ignition advance (higher cyl pressure thus more efficiency) and thus get more torque from the same amount of fuel and air, which means the ecu can inject less fuel for the same torque as before.

The reason lower rons fuels make less power is that you can run to much timing advance as the cylinder pressure become so high the fuel\burn becomes unstable. with higher ron you can run more timing and thus higher cyl pressure and thus more torque and therefore more power.

What this means is that the spark will occur closer the top of the piston travel, thus giving more travel during the combustion cycle and therefore better economy for the same volume of fuel used...

Cheers
Jod

[colnotts]

:hilariousgo to bed jod rest your brain you know to much. lol lol lol

[Justin]

:hilariousgo to bed jod rest your brain you know to much. lol lol lol

Lol :smileypul

[lance]

I would say colder weather will reduce your economy longer warm up cycles heating and AC for demisting will use more also! Plus people drive slower.
Maybe if you use more revs than just 2500 rpm every now and then clean the carbon out and may improve economy!

[Jon K]

A quick comment on the 1/4 way up temp guage.

Mine did that when I bought it (climbed in traffic etc.), so the first job was to change the thermostat and now it sits at half way all the time. the spring on the old stat was very weak.

So you should get those changed really to be on the safe side.

[BruceT]

My temp gauge rears just above 3 o-clock posistion so for a few quid its worth changing, even if its okay.

[Big Pete]

and yeh big pete your temp gauge behaves the same as mine.

Cool so no need to worry then, all is good?

[flyingbrick]

I've had lots of work on mine over the last view years and I still only get 19mpg:grumpy: With a lead foot and when I drive like me mam:cry:

[timbo_1975]

As others have said, start with the basics, thermostat, and intake hoses for leaks.


An mot emissions test will immediately show if it is overfuelling, or otherwise not running 100%. This is your first step.

Does sound like she is running too cool anyhow- temp gauge should be bang on 3 o'clock, although it could be the coolant temp sensor gone astray.

As the gauge is fed by the ecu, if she isnt upto temperture it will be fuelling too rich, as well as not entering closed loop running.

The only way to check running temp is either via live data from the ecu , or the old fashioned way- a thermometer in the header tank immediately after a drive with the rad cold.

Can you tell us what the idle quality is like and how it generally runs / pulls too- this will show up if you have intake leaks...perhaps now is a great time for a stage 0 tune up.

Tim.

[dangerstevie]

What this means is that the spark will occur closer the top of the piston travel, thus giving more travel during the combustion cycle and therefore better economy for the same volume of fuel used

Not entirely correct.... The more advance you run the sooner the spark occurs in the cycle, so it sparks closer to BDC than TDC, which is why high revving engines usually run more advance than a low revving lump so the flame front has chance to consume all fuel and air mix before the piston reaches TDC and the pressure begins to drop in the cylinder as the piston travels back down on the power stroke. But it does increase the efficiency and therefore the fuel economy.

As for the temp guage, when driving steady mine sits at about half way, when cruising it drops to between 1/2 and 1/4 and when i boot it it rises to just over half.

My MPG round town is about 17-19mpg driving steady, 5-6mpg when i floor it, 30-32mpg cruising at 75 and less above that. over the last 330 miles i have managed to average 28.8 MPG. and thats with lots of motorway driving and a bit of round town.

[Jod T5]

Hi,
To those who are still keeping up the following chart is a description of temp V/s resistance...
The higher the resistance the higher the fueling, which may well explain why a hotter runing engine will overfuel...
http://i35.photobucket.com/albums/d157/jod1jod/various/image001-1.gif
This may also explain why a large resistance incriment may only make a small difference to the in car gauge....And the importance of the thermostat in the fueling cycle...
Cheers
Jod

[Jod T5]

Not entirely correct.... The more advance you run the sooner the spark occurs in the cycle, so it sparks closer to BDC than TDC, which is why high revving engines usually run more advance than a low revving lump so the flame front has chance to consume all fuel and air mix before the piston reaches TDC and the pressure begins to drop in the cylinder as the piston travels back down on the power stroke

A very fair summary, i would say.....




As for the temp guage, when driving steady mine sits at about half way, when cruising it drops to between 1/2 and 1/4 and when i boot it it rises to just over half.

Im sorry this is not right, the thermostat should thru the ECT regulate the gauge to a solid state at "3 o'clock"...If your gauge is up and down you have a problem, i would expect meaning you are running cold engine (Rich) at idle and cruising and the correct temperature at WOT..., this is obviously preferable than lean but none the less not normal...



My MPG round town is about 17-19mpg driving steady, 5-6mpg when i floor it, 30-32mpg cruising at 75 and less above that. over the last 330 miles i have managed to average 28.8 MPG. and thats with lots of motorway driving and a bit of round town.
I get 22mph odd over 1000 miles of hard and cruising....My AFR is good with a fair boost as seen below...
http://i35.photobucket.com/albums/d157/jod1jod/various/05122008.jpg
Obviously this result is not done by map alone, the AFR is manipulated by ECT temperature signals which does have cold start issues but i think you will get the drift...
Cheers
Jod

[Jod T5]

:hilariousgo to bed jod rest your brain you know to much. lol lol lol

LOL, no time to sleep im afraid, only 5 hours a night..., perhaps that explains a lot...lol
Cheers
Jod

[850twr]

to be fair its just basic internal combustion principals.

[PNuT]

does the engine have the correct injectors for the map?

[Alan M]

I'm running white injectors on a 304 designed for orange injectors and mine seems to be fine. I average around 350miles to a tank in the cold weather and considerably more in the warmer weather.

[dangerstevie]

Ill have to check my thermostat too if the temp gauge is not supposed to move. I have a wideband lambda kit ready to go on a car sat in my garage but no gauge, however i was saving this for my mini turbo. However if these ECU's are so sensitive to temperature changes it might be a good idea for me to use it on this car and get another one for my mini.

[PNuT]

Ill have to check my thermostat too if the temp gauge is not supposed to move. I have a wideband lambda kit ready to go on a car sat in my garage but no gauge, however i was saving this for my mini turbo. However if these ECU's are so sensitive to temperature changes it might be a good idea for me to use it on this car and get another one for my mini.

they are not sensitive, they just have a good cooling system & rely heavily on the thermostat to do its job

[PNuT]

I'm running white injectors on a 304 designed for orange injectors and mine seems to be fine. I average around 350miles to a tank in the cold weather and considerably more in the warmer weather.

when i tried my greens my trip computer went mental...... i havent worked out yet if the OP is actually only doing 15mpg or the trip computer is only showing 15mpg? two different things really ;)