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VS commodore poor fuel economy

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My thermo fan used to turn on at around 3/4 sitting in traffic but apparently it’s suppose to turn on at 2/4. I replaced the thermo fan relay and now it turns on at 2/4 and no longer reaches 3/4. Also I would like to do a compression test on it but when I pull the 15 amp fuel pump fuse in the engine bay to whole car acts as if the battery was disconnected. If I pull this fuse my key no longer unlocks the car, my interior light does not turn on, my doors don’t auto lock/unlock from the driver door lock and most importantly if I pull this fuse the car will not crank over at all I can put it to accessories and that’s it.
 

losh1971

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Pull the fuel pump relay not the fuse.
 

Dunlop

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I’ve had my auto 1996 vs spac commodore for a little over a year and while it’s been very reliable it’s had terrible fuel economy. When I first got it I used to get about 400kms to a tank just driving around (not city driving but not highway) but in recent months I’ve been struggling to get 300kms to a tank. In the little over a year I have done a lot of work I’ve serviced/replaced spark plugs, fuel filter, spark plug leads, cleaned throttle body, cleaned MAF sensor, new idle air control valve, The whole cooling system, oil pressure switch, transmission service with filter, valley gaskets manifold and plenum gaskets, cleaned the whole plenum, both temperature sensors, brand new Bosch oxygen sensors, 6x brand new injectors from sprints, brand new alternator. I have also done about 4-5 oil changes with filters. There’s also a couple other things I’ve done/changed but can’t remember right now. Any ideas on what else to look for? Thanks.
Can you let us how things go as my VR is basically doing the same thing... not sure why yet, but I'm hoping to take it back to a good mechanic who recently diagnosed low oil pressure. A common problem if you aren't a mechanic with years of experience and replace everything you can think of but it doesn't solve the problem...
 
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Okay so I’ve just done a compression test turns out I was pulling the fuse instead of the relay whoops! Anyway here are the results all seems quite healthy.
cylinder 2 165
cylinder 4 160
cylinder 6 169
cylinder 1 170
Cylinder 3 170
cylinder 5 170
 
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Also forgot to add I know some people go foot flat when testing compression I didn’t do this just turned the key.
 

losh1971

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Those are reasonable figures, 200 would be engine just run in, 100 is minimum.
 
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Just another update I have ordered a fuel filler neck gasket and fuel filler neck to tank hose. I will be replacing these along with brand new breather lines. I have also read the Holden service manuals and it says maybe my Transmission Torque Converter Clutch is faulty? My transmission is very unhappy and always has been, the whole car jumps when I engage reverse and sometimes likes to stall when I engage drive. It also takes a second or 2 to downshift if I was to floor it (which I’ve done only like 3 times in my ownership) so maybe the terrible fuel economy is my transmission which would honestly make sense since it’s unhappy.
 

greenacc

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Have you replaced the transmission fluid during your ownership?
 
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