Hi my odyssey has the overheat light on, temp guage on cold and its not running properly. It feels like it has a fuel blockage and is using heaps of petrol. Any help would be so appreciated.
Well, it sounds like you have a few things going on here.
- Overheat light on: that means the computer has detected an overheat condition. On some vehicles, that light stays on until it is turned off by a mechanic. Has the Odyssey overheated in the recent past? A parts store can use a code reader to reset it for you.
- Temperature gauge cold: How cold? Does it stay completely at the bottom? Your coolant temperature sensor may be defective. You can test the sensor and the connector using a multi-meter. Make sure you are getting 12V at the connector, and make sure the sensor is producing the appropriate resistance for the expected temperature of the coolant (cold or hot).
- Is the car overheating?: Since you have a light saying it is overheating and a gauge saying it isn't, you need to find out for yourself. When the engine has been turned off for a long time (at least 1 hour), remove the radiator cap and make sure you have coolant. If not, fill it up. Squeeze the rubber radiator hoses so you know how soft they are when the engine is cold. Start the van and go for a 5-10 minute drive. When you stop, turn the engine off and feel both rubber radiator hoses again (don't touch the engine or the exhaust!), make sure both rubber hoses are hard and very warm. If they are, the engine is not likely to be overheating right now. If they are soft, or if one of them is cold, or if there are A LOT of bubbles going into your coolant overflow tank (you can hear this easily), the engine is overheating right now.
- Fuel blockage: there is no way to distinguish fuel blockage from a number of other engine hesitation problems just by driving. It sounds like the engine may have a misfire. This could be fuel, spark or compression. Remove and examine your spark plugs (post pictures here if you can), test the resistance of your spark plug wires, perform a compression test on all your cylinders and a resistance test on all your injectors. You can also perform a fuel pressure test. If your fuel filter is too old, you should replace it.
- Using heaps of petrol: Well, is it using more petrol than before or is it just using a lot of petrol? When you come back from driving, leave the engine on and go smell the exhaust (make sure you do this outside!). If you smell gasoline, the engine is running rich. You may want to examine or replace your oxygen sensors, and make sure your idle air control valve is operating properly.
More clarification would be helpful, but a month later I don't suppose it's coming. However, for future reference this reminds me of working on 1994 and 1995 Honda Accords. IIRC if I got air in the coolant system it would idle up and down, up and down and the temp gauge wouldn't be accurate... it's been a while so it's fuzzy now, but basically -- if you've had the coolant system opened up recently in a mid-90's Honda and didn't get ALL of the air out, it could cause a number of strange symptoms.
So when the car is cooled down, lift the front end with a jack so that the radiator cap is the highest point in the cooling system, leave the cap off and start the car. Let it run at least until the radiator fans kick on. It will make a bit of a mess with coolant bubbling out here and there.