Very bad fuel economy VN V8

[Noy]

Ey guys just put $40 of 98 octane premium fuel in, which was 31 litres or something like that. So far ive only done 80k's since filling up and im already on red line. I also just serviced the car oil change/filters/leads and sparkplugs, I did the leads and sparkplugs due to it was jerking/missing while driving that problem went away but now seems to be haunting me again.

Any ideas on what this could be? I was thinking maybe a leaking injector.. car is virtually stock as a rock CAI and exhaust system.

Cheers

[dufus]

I have an idea............

Search

[8rody]

The gauge is accurate yes? :P

If you can, get the car up on ramps and run it for a bit. Check all the steel fuel lines from the fuel tank to the engine bay for pinhole leaks. Check all rubbers.

Check the fuel rail for leaks.

If all is a-ok, its it's likely leaking injector, or a dodgy sensor (oxygen sensor for example) that is causing it to run really rich.

[delcowizzid]

oxygen sensor and coolant sensors are a good start and a new thermostat of the correct temp and check the base timing

[Noy]

Hmm Im more pointing towards the coolant sensors, as going by the gauge its over cooling which results in more fuel consumption yeh?

[delcowizzid]

if its not warming up or not warming up fast enough will cost a lot of fuel.thermostat and ecu temp sensor will be a good start

[88GreenVN]

Ey guys just put $40 of 98 octane premium fuel in, which was 31 litres or something like that. So far ive only done 80k's since filling up and im already on red line. I also just serviced the car oil change/filters/leads and sparkplugs, I did the leads and sparkplugs due to it was jerking/missing while driving that problem went away but now seems to be haunting me again.

Any ideas on what this could be? I was thinking maybe a leaking injector.. car is virtually stock as a rock CAI and exhaust system.

Cheers

31 Lts will get you 200k's or so. The missfire could be dizzy cap/rotor button - as you have changed leads and plugs. A leaky injector probably wont give a missfire. A blocked injector may do so - but would probably have a miss at idle.

Id start with replacing the O2 sensor and temp sensor as Delcowiz said ^^^ first and check the contacts on the rotor button/dizzy cap.

[Noy]

Cheers guys, yeah going to go to holden tommorow and buy an O2 sensor and temp sensor.. holden stock them still yeah?

[greenfoam]

Is it an auto and if so is the torque converter locking up

[immortality]

if the coil is original it may be time for repalcement as well. also check the static timing on the dizzy. may not be your problem but can't hurt to check anyways

[ScoHar]

Just on a side note, will replacing the coil actually make much of a difference if im not having misfiring problems, i.e original coil but runs fine.

[Reaper]

Ey guys just put $40 of 98 octane premium fuel in, which was 31 litres or something like that. So far ive only done 80k's since filling up and im already on red line. I also just serviced the car oil change/filters/leads and sparkplugs, I did the leads and sparkplugs due to it was jerking/missing while driving that problem went away but now seems to be haunting me again.

Any ideas on what this could be? I was thinking maybe a leaking injector.. car is virtually stock as a rock CAI and exhaust system.

Cheers

Hmmm..... I'd be happy if I got that far in the VP.

Reaper

[greenfoam]

I rekcon I win the diagnosis on this one

[HSV472]

greenfoam how do you tell if the torque converter locking up ?

[delcowizzid]

you will feel it lock up at 80+ kmh in 4th feels like the box has 5th gear

[HSV472]

what happens if it does not lock?

[greenfoam]

Then somethings buggered

[Noy]

I rekcon I win the diagnosis on this one

Looks like you did, thanks for your help all

Bloody VN's.. its times like these I wish I still had my army tank aka vt

[Reaper]

I'm still in awe that somebody actually gets 80 km from a tank on a Holden 5 Litre.

Reaper

[50LTRv8]

you serious?, I get about 500 out of mine thats a stocko though

[Reaper]

you serious?, I get about 500 out of mine thats a stocko though

I have done 1500km in this car and would be the most expensive 1500km known to VP man!

Reaper

[levymetal]

haha doesn't sound good reaper. no idea on petrol, but my car seems to use as much idling as it does driving on gas. probably needs a good tune (although it was only tuned about 5 months ago), but i just got 185kms out of 48 litres. wasn't too happy at all

[immortality]

i think reaper only knows 2 throttle positions in the VP, boot fully planted and no throttle (and only then because both feet are on the brake ) and thats only when he's not modifying something or rebuilding the engine