[Mk2] [NA] Below average MPG

[TheBaker]

I believe my 2 is suffering from Poor MPG(Ever since I got it) or it is atleast not upto the miles I've read of people getting on here.

I mainly do town driving and get about 40 miles to a tenner(9.40 litres roughly) which equates to roughly 160 miles a tank, right? Mainly Motorway will get me 60-70 max and that is still 280 at max..

How much I use my right foot doesn't seem to affect it that much, it seems to stay roughly the same.

I've read of people with NA's getting high 300's(even 400+ motorway) and even turbos getting in the 300s with 'spirited' driving.. in a way I feel like I could be paying for a turbo with the amount of petrol it's using..

I better address this before someone says: I know it's a 2 litre sports car but It doesn't mean I will accept crappy MPG due to mechanical issues.

So anyway to the point. What should I be looking at?

The exhaust had major holes in it when I got it but I got a new straight pipe(it's de-cated) in that and it didn't really affect the MPG like I thought it would. I changed the spark plugs.

The Rocker Cover gasket is leaking and there is oil in plug holes 2 and 3, I had them changed anyway since I bought the new plugs and the car runs fast and nicely.

The other thing I'm aware of is the Lambda sensor, Could this be fault? I went under the car and most of the back area of it is covered in Oil, I've read that Oil in the lambda sensor can affect it working properly? Could giving it a clean help?

What else? Could it be the HT Leads or Distributor Cap? I've thought about cleaning the dizzy cap.

Any help appreciated because I can't afford to p1$$ petrol away.

Cheers.

[toxo]

Lambda sensor is the usual culprit. There are a myriad of causes though and lambda's are expensive so changing it is possibly not the best route to go down straight away, unless you can borrow one off someone else.

Can you smell the car overfueling? If you start up the car and then stand behind it does it reek of fuel? If you then go for a drive, get it up to temp etc, and do the same test when you pull up does it reek of fuel then?

Really you should look at getting your engine healthy first and sorting out the oil leaks etc.

[SFLee]

that sound like very little for NA
what rev is the car ? can be AFM sensor yet also £££

but in long turn fix it will save $$$
have you also did a service ?

and does the car feel right ?

[TheBaker]

Lambda sensor is the usual culprit. There are a myriad of causes though and lambda's are expensive so changing it is possibly not the best route to go down straight away, unless you can borrow one off someone else.

Can you smell the car overfueling? If you start up the car and then stand behind it does it reek of fuel? If you then go for a drive, get it up to temp etc, and do the same test when you pull up does it reek of fuel then?

Really you should look at getting your engine healthy first and sorting out the oil leaks etc.

I went out and tested for the fuel smell earlier. It smells when the car is first turned on but not really after it's been on for a while. It does have an odd smell though, think it's Oil though(?).

Yeah I agree about getting the Oil issue fixed but just checking to see if there is anything I can do in the mean time as I can't see that getting fixed until I get the money.(Got a quote of 200 for the RC gasket and Clutch getting done, just labour as the guy at the garage said the clutch is starting to slip, this could affect the MPG too right?)

SFLee, it's a Rev2.(Also says at the side below my name )

The car feels good, very fast.

Thanks.

I went under the car yesterday looking for the Lambda sensor, I thought I found it but then I looked it up again today on the net and it wasn't it. From what I saw, the Lambda sensor is plugged into the downpipe?

[toxo]

Lambda is in different places on turbos and n/a's. On the turbo it's in the downpipe, nice and accessible from the top of the engine bay. In the n/a it's much further down the exhaust pipe.

This is because the lambda has to measure all 4 branches of the exhaust manifold - on a turbo engine these come together very early in the exhaust pipe as the output from all 4 exhaust pipes drives the turbo. However on an n/a exhaust manifolds are tuned to control emissions pulses and backpressure so as they don't impact on low down torque so they don't all join together until much further down the exhaust.

[JJ]

To add to the lambda sensor....

Dont forget the simple thigns too....you can improve Mpg remember by checking your tyre pressures, alignement.. and important is the quality of the engine oil too.

Also the engine is more inclined to do a lot more cold starts where the enrichment is higher than summer time running.

Again.. also often an oversight, old Sludgy / low viscosity oil will create some drag on the engine prior to warming up this time of year....

New set of ignition components too will help.... All small things that tot up !

[BoJohannsen]

Quick question RE the Lambda sensor. Will this still make a difference if the car is de-catted? The economy on my NA is not the greatest either and I did see by reading the forums that the lambda could be at fault but wasn't sure if it was relevant on a decatted car?

Thanks.

[JJ]

lambda / 02 sensor stablises the fuelling when cruising / idling.. if its screwed, generally the engines use more juice...

Decat is irrelavent, its a catalyst to clean the gases up from the engine...

[TheBaker]

To add to the lambda sensor....

Dont forget the simple thigns too....you can improve Mpg remember by checking your tyre pressures, alignement.. and important is the quality of the engine oil too.

Also the engine is more inclined to do a lot more cold starts where the enrichment is higher than summer time running.

Again.. also often an oversight, old Sludgy / low viscosity oil will create some drag on the engine prior to warming up this time of year....

New set of ignition components too will help.... All small things that tot up !

True, I did change the Oil not long after getting it with 10/40w stuff but I will be changing it again since it's got the leak.

I think it's 5/40w people are reccomending on here for 2's, would that be better for this weather?

It's all money right now, I will get new ignition components when I can afford them.

Is it worth taking off the dizzy cap and giving it a clean if it's dirty?

My 2 is decatted also, so where is the Lambda sensor located?

Cheers.

[TheBaker]

So I've changed put on new Leads/Dizzy cap/Rotor arm and the plugs were changed a few months ago(although, have that black stuff on them), changed the RC Gasket which so far has stopped leaking into the 2&3 chambers which I thought may have affected the MPG.

It's gone up a little bit maybe, to say 10 miles more per tenner, 200 miles per tank. Still low though compared to some on here.

I have a slipping clutch that needs done, could that be contributing largely to it?

What about other components like fuel filter etc, is it a potential culprit?

I was in Halfords today and noticed the fuel system cleaners/boosters etc, are they worth it?

Thanks.

[DeusMR2]

So I've changed put on new Leads/Dizzy cap/Rotor arm and the plugs were changed a few months ago(although, have that black stuff on them), changed the RC Gasket which so far has stopped leaking into the 2&3 chambers which I thought may have affected the MPG.

It's gone up a little bit maybe, to say 10 miles more per tenner, 200 miles per tank. Still low though compared to some on here.

I have a slipping clutch that needs done, could that be contributing largely to it?

What about other components like fuel filter etc, is it a potential culprit?

I was in Halfords today and noticed the fuel system cleaners/boosters etc, are they worth it?

Thanks.

A slipping clutch will significantly ruin your fuel economy (and your flywheel if you leave it too long!).

[TheBaker]

So I've changed put on new Leads/Dizzy cap/Rotor arm and the plugs were changed a few months ago(although, have that black stuff on them), changed the RC Gasket which so far has stopped leaking into the 2&3 chambers which I thought may have affected the MPG.

It's gone up a little bit maybe, to say 10 miles more per tenner, 200 miles per tank. Still low though compared to some on here.

I have a slipping clutch that needs done, could that be contributing largely to it?

What about other components like fuel filter etc, is it a potential culprit?

I was in Halfords today and noticed the fuel system cleaners/boosters etc, are they worth it?

Thanks.

A slipping clutch will significantly ruin your fuel economy (and your flywheel if you leave it too long!).

I see, probs the culprit then.

Are there any clutch 'techniques' to lessen it's effects on the MPG?? I may have some bad habits contributing to it.

Cheers.

[DeusMR2]

Generally the less slip the better, but try not to shock load the gearbox (e.g. dumping it).

If it is slipping too easily and the bite point is high on the pedal, then there is not much you can do really apart from getting it replaced.

FWIW Mr. Clutch charged me £500 to replace mine + regrind flywheel - they did a good job but they are probably more expensive than others, except Mr. T. of course

[HighwayStar]

I think my Unipart clutch and fitting came to just over £300 at Pacific Works 3/4 months ago. No issues to report.

R.

[TheBaker]

Don't think it's slipping too bad atm, just a small delay when accelerating, mechanic said it had a few months left, 2 months ago or so but I will get it done ASAP when I can afford to.

Had a friends friend(young mechanic) said he'd change it for 40 quid, don't trust him though lol, the mechanic I mentioned first said he'd change the RC Gasket and Clutch for 200, done the RC Gasket myself so should get the clutch for about 100-150, pretty good rate I guess.

How much do flywheels cost? Google shopping brought up numbers in the 300's but I think those are performance flywheels? Hoping I don't need one too but may aswell figure the potential cost.

Thanks.

[toxo]

TBH the prices you see for lightweight flywheels are cheaper than you'd get a new one from Toyota. Any 2nd hand might require skimming unless it's very low mileage.

[eurosmith]

Have you checked your brakes aren't binding? Had a chap in the garage today with both front wheels practically locked up when the car was raised off the floor.

It would definitely be my first port of call and cheaper than paying for a clutch that (from what you've described) sounds healthy enough to eliminate.

Just a thought,

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