very bad fuel economy

[moocow]

hey guys c:

my car is a 1995 vs berlina with a vt engine. I'd been noticing my fuel economy get worse and worse for a little while now. lately it has been really bad. a tank of fuel would be lucky to last me a week with light driving to work and back and the occasional other trip. a large amount of soot comes out of my exhaust. when I stop the car after driving around it sometimes shudders as if it's not getting enough revs. the engine still runs really well and gives a fair amount of power, however I think it isn't producing quite as much power as it used to and it can be a little sluggish at times. it also tends to miss when it's cold. it makes a sort of hissing noise but it isn't always noticeable. I've replaced the O2 sensors and re wired the earth but this hasn't changed anything except that now the t2 diagnostic machine thing gives the correct reading of both banks running rich. I'm a bit pressed for money atm and I need to get this sorted. could this be maf sensor issues? or maybe something to do with the injectors? any help is much appreciated =) I really want to get my baby healthy again!

 

[Shaun m]

hey guys c:

my car is a 1995 vs berlina with a vt engine. I'd been noticing my fuel economy get worse and worse for a little while now. lately it has been really bad. a tank of fuel would be lucky to last me a week with light driving to work and back and the occasional other trip. a large amount of soot comes out of my exhaust. when I stop the car after driving around it sometimes shudders as if it's not getting enough revs. the engine still runs really well and gives a fair amount of power, however I think it isn't producing quite as much power as it used to and it can be a little sluggish at times. it also tends to miss when it's cold. it makes a sort of hissing noise but it isn't always noticeable. I've replaced the O2 sensors and re wired the earth but this hasn't changed anything except that now the t2 diagnostic machine thing gives the correct reading of both banks running rich. I'm a bit pressed for money atm and I need to get this sorted. could this be maf sensor issues? or maybe something to do with the injectors? any help is much appreciated =) I really want to get my baby healthy again!

My vt had a fuel smell, it seems to be the injector o ring **** itself, that can reduce fuel economy. Or replace maf

 

[moocow]

ok, so I unplugged the maf sensor and went for a drive. the only thing that was different was the check engine/power train light came on. no difference in fuel usage. plugged it back in, light went away. tried a different maf sensor, still no change.

 

[meady_183]

have you given it a really good service mate? like i mean give it the serious once over.
- oil
- oil filter
- air filter
- fuel filter
- bottle of injector cleaner
- clean out your plenum/throttle body
- replace oxy sensors
- new plugs and leads
- check the connections of your coil packs. take them out, spray on some electrical contact cleaner, and
reconnect them to ensure the motor is getting adequate spark
also check the little hose under the throttle body is still on. the name of it escapes me,
but make sure it hasnt come out of its hole. and any other hoses around the intake area
that may look like theyve escaped from somewhere. your car is running very rich by the sounds
of it (with the black out the exhaust, like a diesel), so the computer may be getting a poor
reading from one of the sensors around the intake. Good Luck mate

 

[Tree cutter]

I agree that it is running rich because of the black smoke out the exhaust. Your fuel pressure regulator might be faulty or the vacuum hose might have fallen off it which will mean you have high fuel pressure.

 

[moocow]

I have recently done most of those things except for the air filter and throttle body. I'll check the hoses tomorrow. how would I check the fuel pressure regulator?

 

[moocow]

I just checked the vacuum hose that goes to the regulator and it looks like there is moisture inside it. could this mean a faulty regulator?

 

[vyseriesII]

O2 sensors been replaced recently?

 

[moocow]

just last week actually

 

[moocow]

just replaced the fuel pressure regulator. nothing changed >_<