My 18is is consuming way to much fuel...

[mjimport]

What does toe and caster mean?

Is your wheel alignment in spec? This will definitely cost you mpg to some degree.
I also agree that tire pressure makes a huge difference as I've seen up to 2 mpg loss due to low pressure (not flat). It's also free to refill tire pressure at most gas stations so why not stay on it and save $ every fillup.

[MVincken]

Tyre pressure is indeed the first thing i should look at. Atm i´m driving with 2.3bar in wintertyres.
wheel bearings are the second, try to jack up the car and spin the wheels. backwheels can spin a little harder than frontwheels due to the diff, but frontwheels should rotate almost free.
if the wheels aren´t spinning freely, check your brakes, and if that´s not the problem then your wheelbearing is bad (but normally you hear a whining sound when you´re driving)
the rest of what it could be is your drivertrain, try finding another cheap differential and look for results.
other things to check are your AFM, filters, sparkplugs and compression.

[MTD]

Is your wheel alignment in spec? This will definitely cost you mpg to some degree.
I also agree that tire pressure makes a huge difference as I've seen up to 2 mpg loss due to low pressure (not flat). It's also free to refill tire pressure at most gas stations so why not stay on it and save $ every fillup.

Good tip, they should be fine but i will check them tomorrow nonetheless

Tyre pressure is indeed the first thing i should look at. Atm i´m driving with 2.3bar in wintertyres.
wheel bearings are the second, try to jack up the car and spin the wheels. backwheels can spin a little harder than frontwheels due to the diff, but frontwheels should rotate almost free.
if the wheels aren´t spinning freely, check your brakes, and if that´s not the problem then your wheelbearing is bad (but normally you hear a whining sound when you´re driving)
the rest of what it could be is your drivertrain, try finding another cheap differential and look for results.
other things to check are your AFM, filters, sparkplugs and compression.

thank you the tips, i'm also going to check the wheels and brakes

[MTD]

Guys, just one thing, in this thread we all are talking US MPG right?

[MVincken]

I assume yes, i just put km/l into google and it transferres it to mpg for me.

[MTD]

I assume yes, i just put km/l into google and it transferres it to mpg for me.

I have been using this site for reference http://www.calculateme.com/cGasMilea...rsPer100km.htm

[varg]

Something's wrong with mine too. If I'm lucky I get 19mpg. Completely baffled

[gespinal0301]

I'm averaging 27 actual mpg, that's 60% highway and 40% local. What does your coolant gauge read, could it be an open thermostat causing the engine to think it's cold?????

[MTD]

Something's wrong with mine too. If I'm lucky I get 19mpg. Completely baffled

What the hell, is this a chronic thing on 18is's? When i was resarching the best engine for me, everybody suggesting this one for mpg, now that i have this problem i find out lots of people have it as well... damn

I'm averaging 27 actual mpg, that's 60% highway and 40% local. What does your coolant gauge read, could it be an open thermostat causing the engine to think it's cold?????

Damn, i wish i had 27 mpg. It reads like it normally would i guess, when i start the car it's on the down low and it will slowly build up and stay at the half after driving. The temp sensor was also replaced some weeks ago

[gespinal0301]

When's the last time the car had a tune-up? Spark plugs, air filter, fuel filter, diff fluid change, tranny fluid? It wouldn't solve your problem, but it would help eliminate some things

[gespinal0301]

Something's wrong with mine too. If I'm lucky I get 19mpg. Completely baffled

How hard are you driving it?? I was wondering where'd you got it tuned by the way I'm just looking for decent shops in case I ever have to do a swap

[MVincken]

What the hell, is this a chronic thing on 18is's? When i was resarching the best engine for me, everybody suggesting this one for mpg, now that i have this problem i find out lots of people have it as well... damn

haha he trolled you, he has a turbo on it. than everybody would get 19mpg because fun :)

I filled it up yesterday and it was around 25-26mpg (11km/l) and I hit it hard on the mighty autobahn everyday. (not so smart with nankang 165/55 wintertyres )
I think if I would drive like a normal person i could easily hit 30+ (13 km/l or more)
buttt, i overhauled my complete engine before i put it in.

how is the power of the engine? maybe you have a piston with halve compression, forging the engine to work harder for same speed and so lose mpg

[MTD]

When's the last time the car had a tune-up? Spark plugs, air filter, fuel filter, diff fluid change, tranny fluid? It wouldn't solve your problem, but it would help eliminate some things

about 1/2 months ago...

haha he trolled you, he has a turbo on it. than everybody would get 19mpg because fun :)

I filled it up yesterday and it was around 25-26mpg (11km/l) and I hit it hard on the mighty autobahn everyday. (not so smart with nankang 165/55 wintertyres )
I think if I would drive like a normal person i could easily hit 30+ (13 km/l or more)
buttt, i overhauled my complete engine before i put it in.

how is the power of the engine? maybe you have a piston with halve compression, forging the engine to work harder for same speed and so lose mpg

oh ok, i fell into that one

the power of the engine is ok it seems, but i didn't check by any means. How do i go about checking that?

[varg]

What the hell, is this a chronic thing on 18is's?

It was a joke. See my sig.

My first check would be the coolant temperature sensor. There are two in the M42 cylinder head, and one should have two pins and a blue connector; this is the one the ECU reads. The one with one pin is for the gauge. Make sure that one of yours has two pins, and that it's hooked up to the ECU and not the gauge. Also check its resistance. See below. If that all checks out, check the continuity of the coolant temp sensor wire; from the sensor connector to pins 78 and 43 of the ECU connector also. Check the fuel pressure if none of that pans out, and the regulator itself (pull the vacuum line and check for presence of fuel). Finally I would check the injector spray pattern. Pull the fuel rail, unplug the ignition coils, and have someone crank the car while you watch the injectors spray. Do they all make a nice conical spray? Do any leak while the system is pressurized?


14+-4 F (-10+-1 C): 8200-10500 ohms
68+-2 F (20+-1 C): 2200-2700 ohms
176+-2 F (80+-1 C): 300-360ohms

How hard are you driving it?? I was wondering where'd you got it tuned by the way I'm just looking for decent shops in case I ever have to do a swap

Let's just say I'm in boost a lot. I tuned it myself, I do all my own work, and occasionally build a megasquirt or tune for someone. I don't want to hijack this thread, so PM me about your swap if you have any questions.

[gespinal0301]

It was a joke. See my sig.

My first check would be the coolant temperature sensor. There are two in the M42 cylinder head, and one should have two pins and a blue connector; this is the one the ECU reads. The one with one pin is for the gauge. Make sure that one of yours has two pins, and that it's hooked up to the ECU and not the gauge. Also check its resistance. See below. If that all checks out, check the continuity of the coolant temp sensor wire; from the sensor connector to pins 78 and 43 of the ECU connector also. Check the fuel pressure if none of that pans out, and the regulator itself (pull the vacuum line and check for presence of fuel). Finally I would check the injector spray pattern. Pull the fuel rail, unplug the ignition coils, and have someone crank the car while you watch the injectors spray. Do they all make a nice conical spray? Do any leak while the system is pressurized?


14+-4 F (-10+-1 C): 8200-10500 ohms
68+-2 F (20+-1 C): 2200-2700 ohms
176+-2 F (80+-1 C): 300-360ohms



Let's just say I'm in boost a lot. I tuned it myself, I do all my own work, and occasionally build a megasquirt or tune for someone. I don't want to hijack this thread, so PM me about your swap if you have any questions.

If I ever get serious about it I'll start bothering you lol. I've made up my mind that if the m42 lasts 3 more years than she has earned the right to a rebuild. Ive been watching wayyyyyyy too much petrolicous on YouTube which kind of reminded me that our car is a one year wonder so I want to keep it as original as possible.

O.P. any luck by testing the sensors?