Fuel economy

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paz

Active Member
Fuel Consumption Far Too High - Fault Codes 21 and 34

Morning all :)

Now, firstly before anyone says it, I know that these cars drink fuel for fun already. I'm asking a question about it as something appears to be wrong.

On gentle driving, pretty much never going on boost at all, and never putting my foot down I'm getting about 80-100 miles to a tank. I'd expect maybe double that.

Is there anything on these cars that could give way and cause that (despite there being no other noticeable issues) or is it just a case of getting it mapped again?

Car is running 1 bar, usual kind of mods, safc.

Cheers

Paz
 
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PobodY

PobodY

Moderators
Staff member
Leaky fuel tank/lines/rail/filter?
Lambda sensor knackered (so it keeps telling the ECU the mixture is lean)?
 
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geoff pine

Well-Known Member
Have you had the dipstick out and had a sniff :lol:??. How's your maf does it need regrounding or leave the car ticking over and have alook under the tank for a leak. Mine did not show with the engine turned off but pissed out on idle.
 
warringtonjack

warringtonjack

Active Member
Hey Paz

Just for comparison, my R used to get 240miles out of a tank on a motorway run at 1Bar.

Even if most of your driving is round town, I'd still expect more than you're getting. :s
 
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paz

Active Member
Thanks everyone, the other thing I need to look at is oil temp - its pretty low normally from what I remember, probably 70-80 degrees rather than 80-90 which can apparently keep the car running on its warm up map.

Managed to eek out about 120 miles on the current tank, with just under quarter of a tank left but I've literally not put my foot down once. I don't mind shit economy, but somethings not right at the moment.
 
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paz

Active Member
Ok, oil cooler is now blocked off with cardboard both sides. Didn't notice any real improvement with foil, so I'm going to assume its not that.

No fuel leak that I can see with either engine on or off, and no real fuel smell. No obviously disconnected pipes to the intercooler or elsewhere.

So I'm left with Lambda/MAF/ECU temp sender/thermostat suggestions. Which is the best thing to target next, and what do I actually need to do?

The only other thing in the back of my mind is that the car was stood for a while, so there is a chance it could have lost its SAFC settings? Could be worth taking back to the racing line?

Thanks all

Paz
 
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vss irvine

vss irvine

Well-Known Member
i would get the fuelling checked as it could be chucking it in,

do the fault code check first so you dont waste any money letting a garage do the basics
 
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paz

Active Member
Forgot all about that thanks, I get codes 21 and 34 which I'm guessing isn't great.

What do I need to do to resolve them?
 
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paz

Active Member
Sorry, realised I should have searched! :doh:

Still searching and reading. I see 34 is det sensor but I've not got upto how to fix yet.
 
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paz

Active Member
So done even more reading and it seems like the majority of knock sensor issues are fixed by replacing the sensor. Anyone know where I can pick one up cheaper than Nissan?

Now onto code 21!
 
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paz

Active Member
:lol: I think it's a job for the local garage to be honest ;) I'll do even more reading and see if I fancy it, got a bit more adventurous in my old age :lol:
 
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paz

Active Member
For the benefits of people searching in the future, my economy has improved a lot with the new DET sensor.

I think its safe to say that a dodgy det sensor (aka fault code 34) causes shit fuel economy.

Paz
 
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paz

Active Member
Not fixed that yet :lol:

Not having any running problems which is confusing me a little, no lumpy idle or misfire even at high revs/boost.

I was wondering whether having an ignition amplifier might be contributing to/causing the problem, but I guess I'm going to just changing out all the ignition related components such as plugs/leads etc
 
wrc

wrc

Member
21 issue will be your ignition amp breaking down. Get some thermal paste and a heatsink on it.
 
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