Crap Fuel Economey...

[justin911]

hey ppls

just wondering if u can all help me, ive got a r33 with the basic mods and a pfc..

I seem to only get like 250km a tank.. My pfc was tuned for max power, and ive played with the timing slightly to try and get better economy.. however it doesnt seem to affect the eco.. My car also has a bosch 040 pump.. Evan after i put in the pfc.. econemy still stayed at like 250km. I've changed the o2 sensor today, because my old one was completely dead.. it still didnt make any differance at all though ???

I cant smell petrol anywhere So i dont think its leaking ? and my car never has any black clouds of smoke or anything like that, it seems to run perfectly.. its basicaly always just using 250km regardless of what I do.. Oh yeah i've also tried that nylon fuel injector cleaning stuff, but that also didnt make any differance..

I realy dont drive around that fast.. so i should be getting abit better than 250km..

Im going to replace the fuel filter next weekend.. Im not sure if that will help though but is there anything else I should look at replacing before I take it to my mechanic.. ? cause its realy pissing me off now..

Oh yeah its possible my fuel gauge is screwed i suppose.... but i dont think so... ?

When i drive it goes up and down a little bit.. like one minute its 8/10 full... the next its 9/10 full... then its back down to like 8/10 where it might stay for a while..

It doesnt seem to sway up and down as if the petrol gauge sender thingy was floating in the fuel tank.. i dont think ???

Anyways have any ideas on what else I can test... ??

thanks heaps

[justin911]

its actualy quite funny cause my odometer thingy stopped working so now i cant evan measure my crap fuel economey

[PlasticStan]

Have you got a Z32 AFM fitted? When I fitted one, my PowerFC stopped going into closed loop fueling at contant throttle, it would just run rich all the time and it wasn't using the 02 sensor to trim the fuel. Problem was the ECU runs richer with a Z32 so you have to lean it out a bit to get it to go into closed loop mode.

Simon.

[race_snooze]

i am only running a remapped ecu with stock turbo fmic turbo back and pod 216rwkw, and i probably only get 250 round town and flogging it, but a trip i get about 400k, if i dont flogg it around town she sits about the 300 to 340 k mark, not good when it cost almost $90 bucks to fill up.

Thats why i bought an 720 with a l18 in it. $50 400ks its only 45L tank

[justin911]

well.. ppls... this is a bit embarrasing... but it would appear i didnt have the o2 sensor enabled in the pfc

shes works like a charm now, thanks for ya help specialy paul.

[RB30-POWER]

That just goes to prove how far out your base map figures actually are.

If the mapping was near correct (as it should be tuned) even when the closed loop is turned on the economy would only improve slightly.

Closed loop only allows adjustment either side of the base map figure by a few percent. So if the economy still doesn't improve, you will need to get all the light load map points tuned closer to stoich 14.7:1 so the closed loop feature can trim it to approx 14.7:1.

[Cubes]

Then once its out of closed loop due to heavier acceleration have it tuned to stoich afr's until it see's zero vacuum.

My view is no point having a high performance car if it sucks so much juice you can't afford to drive it every day.

One reason I sold the V8 and bought a small turbo 6.

Edited October 9, 2005 by Cubes

[RB30-POWER]

Have you changed your diff ratio yet cubes?

You really need 3.7 or 3.9:1 on these big torque monsters!

I say 3.7:1 is ideal.

Sorry about the thread hijack

[RB30-POWER]

double post!

Edited October 9, 2005 by RB30-POWER

[BL01]

Then once its out of closed loop due to heavier acceleration have it tuned to stoich afr's until it see's zero vacuum.

My view is no point having a high performance car if it sucks so much juice you can't afford to drive it every day.

One reason I sold the V8 and bought a small turbo 6.

<{POST_SNAPBACK}>

LOL, turbo 6s ain't small either

[Cubes]

A 2-2.5ltr is a small 6cyl.

[Tommyk]

considering the eunos 30x 1.8 v6 is the smallest production engine out there, the rb20 is damn tiny for a 6. Compare it to the SR20 which has two less cylinders and has the same total capacity

[ferni]

so what fuel economy do you get now justin911?

[Angry Fist]

Gee..up until now, I thought my fuel economy was bad...I usually put in about 51-52 litres at a time and it usually lasts about 410-415km. Thing is though I don't thrash it at all...maybe sometimes just a little bit. Funny thing is atm on this tank, i've managed 480km so far! I'm thinking of driving it until the low fuel warning comes on but don't have a clue when that will be and how many litres left in the tank it will mean. Any clues?

Cheers

[Tommyk]

ive improved my fuel economy greatly in the gtr

it has a lot to do with driving styles. Rather than trying to keep it in the highest gear, eg driving around in 5th at 50-60km/hr, i try to stay in 3rd or 4th and make sure that i operate in closed loop as regularly as possible. This has improved economy greatly

[Josh]

Does the R32 have a fuel light? Ive never seen one come one and it has been pretty farkin empty some times

So you reckon sitting in a slightly lower gear will help with economy eh? May have to give it a burl

[Cubes]

The R32 does have a fuel light. It apparently turns on when there is approx ~10litres in the tank.

If your having to slip it in to a lower gear for the o2 sensor to work properly I would look at the injectors, chances are they are clagged, at low rpm they will have really poor atomisation.

'When' my rb20det injectors were fine I used to get around 470km's to 50litres of fuel for local driving, not so much peak hour driving but short 10-20km trips to uni and back. I also often gave it a bit, it was always reving to 4k on 15psi, I never drove it easy. But what I did do was always drop it in 5th. Even at 40km/h. Should I need to accelerate I would drop it back.

Edited October 11, 2005 by Cubes

[benl1981]

Ive been looking at the handcontroller to ascertain what is the best rpm to cruise at. It seems it is better for economy to get into the higher gears early (assuming not up a big hill), the injector duty cyle is for example at 75km/h in 4th gear 6% but then put it in 5th and it's about 4.5%. As soon as you take your foot of the accelerator while in gear 0 fuel is used!

I'm wondering why my economy isn't good. About 11L/100km on the highway and about 12L/100 doing 10-20km journeys. R33gtst.

The engine stays in closed loop for quite a while!

[Tommyk]

Cubes

I have brand new SARD 700 cc injectors. closed loop seems to start operating at around 1500 rpm +. This was the case both with stock and aftermarket injectors

[Tommyk]

oh and fyi - i get about 400km to 55L in my gtr