Quote: Originally Posted by Munro- if it was the thermostat it would be a very simple and quick thing to diagnose and it really doesnt have much bearing on fuel economy unless its opening way too early but I havent really heard of one of those since the bad batch they put out a few years back that opened when u farted on them, but it really is only a minor thing because eventually they get up to temp just takes longer. If it doesnt open well then thats another story and we both konw that it ends badly... Neways back to the point. There is a lot wrong with that car and Im doubting its just one big thing. Doesnt behave like osmething something can cause... I'd be interested to take a look and see just what is happening. Can you take a video of it running on a fone or somethign and host? Actually i think you'll find there are quite a few vl getting around out there with jammed open thermostats, mine was and on highways the temp gauge would sit below the first line. replaced it and fuel consumption dropped by 30%

I have a fair few mates with VL's and I dont know any with thermo's stuck open. Most people konw if your not getting 400k's to a tank then something is drastically wrong and you start the process of elimination.....

i had that trouble a while ago with the fuel economy, canged the fuel pressure reulator and all ran well, until recent prob, but thats different. i suggest changing te FPR Quote: Originally Posted by Munro- I have a fair few mates with VL's and I dont know any with thermo's stuck open. Most people konw if your not getting 400k's to a tank then something is drastically wrong and you start the process of elimination..... can you write the process of elmination down please as i am only getting around 320-350km per tank . cheers Some original photos have not been recovered yet.

Assuming the AFM cal is set as per service manual procedure and it seems to idle ok and runs with the red/green lights flashing together when on no load at 1800rpms, then the two top items to check for fuel economy are:- a. Thermostat as mentioned b. Coolant temp sensor and its associated connector, loom and ECU connector. To test the thermostat, Remove it, good chance to inspect it Place in pot of cold water, it should be totally closed Warm up water with a thermometer and note the temp at the point when the valve just starts to open, Note: When doing this on a stove keep moving the water around, otherwise the heat is not evenly distributed and the thermostat can open at what appears to be a low temperature because (ostensibly) the thermostat is touching the hot bottom of the pot while the thermometer is registered cooler water... The VL service manual suggests the thermostat opens at 76.5 deg +- 2 deg C and gets fully open at 90 deg C. I would recommend you do the test a few times, and add cold water to the pot slowly to see it closes fully then warming up again, this way you will be able to check if it gets stuck due to slow change in temperature, whereas dumping cold water in is not what happens in an engine and can thermally chock the thermostat which can mask a fault due to slow change in temperature. As for CTS, check/clean connector and loom and check/clean ECU connector. If you have a multimeter then you can remove the CTS and put the body in water (not the connectors) and measure its resistance with a range of temperatures, this is the table of data from the service manual:- Deg C Resistance range (Ohms) -10 7000 to 11400 20 2100 to 2900 50 680 to 1000 80 260 to 390 100 180 to 200 The lower the better (for economy), this is why the connector and loom is so important because if these add resistance then the ECU will think the engine is not warmed up when it has and this will use up a lot of fuel.

Quote: Originally Posted by Niche Assuming the AFM cal is set as per service manual procedure and it seems to idle ok and runs with the red/green lights flashing together when on no load at 1800rpms, then the two top items to check for fuel economy are:- a. Thermostat as mentioned b. Coolant temp sensor and its associated connector, loom and ECU connector. To test the thermostat, Remove it, good chance to inspect it Place in pot of cold water, it should be totally closed Warm up water with a thermometer and note the temp at the point when the valve just starts to open, Note: When doing this on a stove keep moving the water around, otherwise the heat is not evenly distributed and the thermostat can open at what appears to be a low temperature because (ostensibly) the thermostat is touching the hot bottom of the pot while the thermometer is registered cooler water... The VL service manual suggests the thermostat opens at 76.5 deg +- 2 deg C and gets fully open at 90 deg C. I would recommend you do the test a few times, and add cold water to the pot slowly to see it closes fully then warming up again, this way you will be able to check if it gets stuck due to slow change in temperature, whereas dumping cold water in is not what happens in an engine and can thermally chock the thermostat which can mask a fault due to slow change in temperature. As for CTS, check/clean connector and loom and check/clean ECU connector. If you have a multimeter then you can remove the CTS and put the body in water (not the connectors) and measure its resistance with a range of temperatures, this is the table of data from the service manual:- Deg C Resistance range (Ohms) -10 7000 to 11400 20 2100 to 2900 50 680 to 1000 80 260 to 390 100 180 to 200 The lower the better (for economy), this is why the connector and loom is so important because if these add resistance then the ECU will think the engine is not warmed up when it has and this will use up a lot of fuel. Are you a science teacher?

Quote: Originally Posted by whtbt1.88 Are you a science teacher? <cough> no, im an engineer, though I did teach programming at uni for a few years in the bachelor of business course in perth, long time back 79 to 82 or so but I grew out of it Some original photos have not been recovered yet.

Hey guys, im still reading this thread, just havent had a chance to look at my car since saturday with work/study. But at the moment, it is still going good, i got roughly 200 km out of around 25 litres of fuel.

Hmmm... my car is doin very similar things, after putting sum fuel in at shell my car started running extremely rough and spitting black smoke. From that night i have noticed it almost stalls on 2-5% throttle and fuel ecomey is abour 20L/100km. Im going to go through through the advice as stated above and run sum injector cleaner through it aswell. Bloody shell fuel i will never use it again will comment later

i had the same problem too mate. my car was running rich and blowing soot everywhere. over the bar and on the ground. i ended up changing the 02 sensor and the coolant temp sensor. as for fuel economy you can at least knock out the simple things that may cause it. say plugs need changing. possibly leads. all those little service aspects add up in the long run. hope it helps just my 2cents

With all these fuel economy and rough running issues concentrate on the item that has the highest influence first, dont do more than one thing at a time or you will get misled and pass on that misunderstanding to others... These are now old cars and bear in mind the ECU gets two important analog signals that can be affected by old wiring and old and inconsistently corroded connectors and its these two issues that seem to be the most important and subject to lots of confusion. Both the AFM and CTS have high influence, so fix those connectors and check wiring to those first. This includes the ECU connector as it can get condensation from its position in the cabin despite fact its behind a kick plate, some people even have water dripping over it from leaks around windscreen Ground connections on block are important, there are 3 or 4 together on the engine mounting under inlet manifold, check there is no acid corrosion from battery splashes etc Next is any part that moves, such as fuel pumps, fuel pressure regulator etc. Next is the O2 sensor but, as you would be looking at AFM and CTS it makes sense to put the O2 on that same list as its also an electrical item, especially if you are sure its not leaning out... On the subject of electrical, make sure the spark leads are at least 1 to 1.5 inches away from *any* signal leads this means things like, TPS, injectors, CAS, AAC, CTS and if you move the AFM then definitely keep that as far away as possible and dont let spark leads touch any metal parts of engine they must be on insulated holders so they cant cause corona discharge to pass through a metal grounded part which affects ground currents for a sensor etc... edit: On the subject of very rich running on odd occasions, I have found that turning engine off, unplugging and plugging in AFM a dozen times is often enough to wipe off any superficial corrosion on the connector spades. Its also worth "teasing" the wires that go into the AFM loom connector, this means gently pulling and twisting. If you can do all this while battery negative is off so ECU can reset then all the better Some original photos have not been recovered yet.

Well my car is running fine now, I reset the ECU by uplugging the battery (i got a new one while i was at it), replace all spark plugs with bosch super 4s (which i got for a 1dollar each, dont ask), and ran sum fuel treatment through it. the car is running perfect, no missing, no smoke, very smooth.

mine did this a while a go and it was a blocked fuel return line. took the fuel cap off and blew air from the engine end of the return and it ran beautiful after that. getting nearly 550 or 600 k's from a full tank

tru, i normally get 400-450, but im not easy on the throttle. i think my problem was the spark plugs though cus when i took them out they were completly black and 2 actually snapped/crumble when we took them out, the new plugs are working great.