96 vs ecotec 250ks to a tank need help

[calais_8]

Hi I got a vs ecotec and I can only get 250 300 ks out of a full tank I have replaced the injectors with new ones and also changed the o2 sensors the car idles and drives fine just running rich any help would be appreciated thanks

[brend94vr]

hey many ks did you used to get? in mine i get around 350ks

[Krilnik]

I too get about 350. Used to get 300 before I bought a new air filter.

[hsv91ss]

I get about the same 300 -380ish around town. and 600ish on freeway.

[PanthaVS]

with the standard 59ltr tank, i used to get anywhere between:

- 400km (Hard driving) = 14.75 ltr/100km
- 500km (gentle driving/freeways) = 11.8 ltr/100km

I now have a 73ltr tank and I'm averaging about 600km to the tank. (12.1 ltr/100km)

My car has 250,000km on the ODO. (so it's not a "fresh" engine either)

How long has your car ran such poor milage? (before you changed the injectors)
reason i ask, When you replaced the injectors, what colour were they? they could have been the wrong injectors to start with?

I have heard of people who put the supercharged engine's injectors on thier car, but if they don't tune the computer to control the higher flow rate, then their car will run VERY rich!

There's a thread somewhere in here about things to do to your car concerning economy... do a search... it involves things like tyre pressures, regular oil change, etc....

[calais_8]

mine has 194000ks always serviced it use to get around the 400, 500ks mark just cruising and just slowly got worse then i changed the o2 sensors made no difference then injectors (blue tops standard) then i changed the airflow meter for a second hand one no difference car has a 2 1/2 cat back exhaust and k&n flat panel filter apart from that its stock also when i rev it blows abit of black smoke and has black shit on the bar all the time

[RX25SE]

Clean/ test AFM?

[PanthaVS]

mine has 194000ks always serviced it use to get around the 400, 500ks mark just cruising and just slowly got worse then i changed the o2 sensors made no difference then injectors (blue tops standard) then i changed the airflow meter for a second hand one no difference car has a 2 1/2 cat back exhaust and k&n flat panel filter apart from that its stock also when i rev it blows abit of black smoke and has black shit on the bar all the time

Considering that it slowly got worse... on the ecotec, the fuel regulator (on the exit of the fuel rail) is vacuum controlled from manifold vacuum in the plenum chamber. perhaps you have a cracked/perished vacuum line to the regulator. i believe (someone please confirm??) that when there is a high vacuum in the plenum, the regulator senses that and assumes "idle". but when you open the throttle up, the vacuum in the manifold drops, and the regulator increases fuel.

So, if you are following my line of thought here... say that vacuum line from the plenum to the regulator was cracked/cut, then the regulator would think you are at full throttle all the time, and the fuel management computer would go into a "safe" mode... making it run rich?

it's maybe an idea? i could be completely off the mark... but check all your vacuum lines? (they are plumbed into the rear of the intake plenum)

[klampy]

if hypothetically your 2pin temp sender has crapped out then the engine will always be reading cold and run rich?? just an idea. and a fairly cheap item to rule out.

[brend94vr]

i need to get mine looked at im on half a tank atm its done 113kms :/

[Cpt Awesome]

wow i get about 550-600ish normally round town on a 59 ltr tank nd 450 if i drive like hooligan Hmmm i found i got heaps better economy & power on both my ecotechs (old one then replacement one) when i used that $3 carby cleaner from auto one, coventreys to clean out the plenum chamber and throttle butterfly. I buy fuel every 2 weeks, and usally i have under a quarter of a tank left but since that carby clean stuff i've had between 1/2 and 3/4 a tank left with no extra driving or hooning. i reckon it'd help a little.

[VS_Pete_1]

Clean/ test AFM?

x2. You can get a film of oil from the K&N filter over time.
http://www.youtube.com/watch?v=vPT8rL0noYg
Do a scan.
Checking error codes VR/VS (Revised)

[VS_Pete_1]

if hypothetically your 2pin temp sender has crapped out then the engine will always be reading cold and run rich?? just an idea. and a fairly cheap item to rule out.

The temp sender goes to the temp gauge.
The temp sensor goes to the ecu.
It`s the nice shiney one.

[FstStig]

Have you done your Fuel Filter? New Air Filter? What are the spark plugs like?

[Cracka]

Start with fault finding, obviously something has gone wrong.

How many k's on your car? do you carry allot of lead around with you all the time?

A few of the above are great ones, and ensure that your o2 sensore are earthed correctly too, there is a thread in the How To section I think. You should probably start with the basics, do you have a fuel leak? check near the tank if it looks suss, replace the filter and hoses, infact if your not sure how old the filter is just do it anyway.

Next go over the ignition system, coils, leads & spark plugs, if you own a gregorys or a haynes manual it will tell you the resistivity that you need for each component, you will however need a multimeter. If any of these parts fail, replace them. oh and get your spark gap to 1.5mm

Next parts to look at Air intake system, is the filter clean? using the manual again there are test methods for the associtated sensors, test them all.

How do you drive it by the way? if you flat foot it everywhere you wont get very good economy at all.

[klampy]

The temp sender goes to the temp gauge.
The temp sensor goes to the ecu.
It`s the nice shiney one.

at the end of the day, the one that controls the ecu is the two pin one. sendor/sensor, both detect temperature. i suggested it coz if actually had one fail on my VN after swapping the motor from one body to another. took me months to work out why i was only getting 250kms to a tank where in the other body it would get 600. was just a simple little sensor. shat me to tears.

[The1]

plenty of things can cause bad fuel eco, check fault codes first Checking error codes VR/VS (Revised)

[VS_Pete_1]

Thanks klampy.
Know your pain mate.