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darcy wrote:Have you cleaned your MAF?
Carby cleaner or contact cleaner will work ok.

A dirty MAF will over-report airflow and cause the ECM to over-calculate fuel.

I'm getting a Service and Transmission service done tomorrow. Will ask the Mechanic to do this.

Hopefully it will help.

whats the driving conditions, around town or country or what ?

i flog the piss out of my car and about 50/50 town and country and i get 10.5!

Holden202T wrote:whats the driving conditions, around town or country or what ?

i flog the piss out of my car and about 50/50 town and country and i get 10.5!

Generally Suburban Sydney. I do around 40km a day, with a mix of main roads and back streets. Maybe 15 Sets of lights, but i generally don't get caught at each one.

I normally put the car is engineering mode, keep the revs around 2K rpm and try to keep the fuel usage less than 12 litres l/h

Yeah it's disheartening... Especially when brothers tuned LS1 get's better mileage than i do....

dmenace wrote:

Holden202T wrote:whats the driving conditions, around town or country or what ?

i flog the piss out of my car and about 50/50 town and country and i get 10.5!

Generally Suburban Sydney. I do around 40km a day, with a mix of main roads and back streets. Maybe 15 Sets of lights, but i generally don't get caught at each one.

I normally put the car is engineering mode, keep the revs around 2K rpm and try to keep the fuel usage less than 12 litres l/h

Yeah it's disheartening... Especially when brothers tuned LS1 get's better mileage than i do....

Maybe you need to flog the piss out of it more often? give it the old Alfa Romeo tune up

does your dash tell you the same instantaneous fuel consumption as it used to when it was getting better mileage?
if it does it could be something like an injector stuck open

charlay86 wrote:Maybe you need to flog the piss out of it more often? give it the old Alfa Romeo tune up

does your dash tell you the same instantaneous fuel consumption as it used to when it was getting better mileage?
if it does it could be something like an injector stuck open

No i haven't noticed any difference in read outs.

What i did notice when i changed the TPS is i guess the "powerband".

The spread of power/torque down low is better i guess. The engine isn't reving as much to get the same speed during acceleration.

Could it be the Fuel Pressure Regulator? Are they common?

i think if its the fuel pressure reg you'd see other issues, like flat spots or very poor running.

it would have to be a sensor like a coolant or iat etc that would just slightly offset the tune a bit.

without some sort of data logging to see whats happening you really are playing darts in the dark!!

Ok,

Received a call from the Mechanic.

He has down the following:

Genuine Temp Sensor
Genuine Thermostat
Cleaned Air Flow Meter
Genuine Fuel Filter

+ Oil, Filter, Plugs, Coolant and Auto Service.

He said hopefully this will sort out what is happening as the thing runs and drives too good as it is.

Fingers Crossed.

Holden202T wrote:i think if its the fuel pressure reg you'd see other issues, like flat spots or very poor running.

it would have to be a sensor like a coolant or iat etc that would just slightly offset the tune a bit.

without some sort of data logging to see whats happening you really are playing darts in the dark!!

a bad reg can push fuel in via the vac line though and drip in fuel to the two rear cylinders. Maybe not enough to run bad but use more fuel, so id still check the vac line.

13 is terrible should be getting around 7 to 8 per 100km.

seeing what you already looked at.

look at:
CTS
stuck open thermostat
dirty MAF
bad leads and/or plugs
holes/cracks in air intake from MAF to TB ( seen this happen before)
Exhaust leaks before the O2 ( possible as they don't have a exhaust manifold gasket at all)
Fuel reg leaking or too high pressure.
Leaky injectors? could be possible for bad economy?

that should get you started/

vlad01 wrote:13 is terrible should be getting around 7 to 8 per 100km.

seeing what you already looked at.

look at:
CTS
stuck open thermostat
dirty MAF
bad leads and/or plugs
holes/cracks in air intake from MAF to TB ( seen this happen before)
Exhaust leaks before the O2 ( possible as they don't have a exhaust manifold gasket at all)
Fuel reg leaking or too high pressure.
Leaky injectors? could be possible for bad economy?

that should get you started/

Done the following
TPS (Genuine)
Temp Sensor (Genuine)
Thermostat Replaced (Genuine)
MAF Cleaned
New PEC o2 Sensors (Could they be the not 100% Compatible?)

Stil Need to Check
Spark Plugs Leads
Coil Packs?
Fuel Pressure Regulator


What i have noticed which may contribute to what is happening. If the car sits for more than 2 days or so it will develop a miss on startup for say 5-10 seconds.

Anyone experience any similar issues?

Going to buy a ALDL Cable and find out what is happening.