Car help (again)

My dads car is currently returning 10mpg, my parents have no money at all at the moment so they cannot afford to take it to a garage.

The car is running perfectly but the exhaust output is like the car is running cold. It it not burning oil (well it has needed a tiny amount since August when it was serviced) and it is not using any water (again just normal amounts). The oil colour is as it should etc.

The temperature gauge is not working so I have to the conclusion it is related, the Haynes manual hasn't helped me much but there is a big multiplug connected to the manifold which I suspect is some kind of temperature measuring resistor.

Could anybody please confirm where the device that measures the temperature for the ECU is so I can get it out and test it with a multi metre?

I am pretty certain this an ECU fault but because I can't spot anything remotely machnicaly wrong with the car.

 

Can't help you with the car fault, but I would have though that at 10mpg it would be more cost effective to get someone to at least have a quick look at it than to drive it around for long when it costs £4 to drive 10 miles!

Alternatively, break the car and sell the bits on ebay, it's a very popular pasttime these days.

 

Sounds about right - the ECU is thinking the engine is cold, and supplying full enrichment, just like driving with 'full choke' on an old carburtted engine. It might be the wiring to the temp sender, or the sensor itself.

Also, just replace the thermostat - this is usually easy and cheap (<£8 plus your time); it could be reading 'cold' simply because the stat has failed (and they always seem to fail open).

 

If the thermostats are knackered so the engine is running too cold, or if the temperature sensor is bust so the ecu thinks the engine is cold, the fuel economy is likely to plummet. The rich fuel mixture which is costing you a fortune, is also likely to be washing off the oil on the cylinder bores, causing wear, and thining out your oil as it collects in the sump. Can't help on locating the temp probe, or on how to check the stats, but I'd say 100 quid at the garage would be money well spent right now.

 

Non-electronic suggestion - look at the condition of the air filter element, it could be dirty/clogged up. A new element is pretty cheap (as is a temp sensor if it's the bit that's f****d).

 

Change the thermostat, it's easy, just hope no buffoon has stuck it down so tight that you have to break the housing, I've been there. Stick it down with gasket in a tube type stuff. If that doesn't work, it's almost certainly the sensor, or worst case scenario the ECU

 

The air filter was replaced when it was serviced in October, however the element won't have been.

I am right in thinking there is two thermostats? One for the ECU and one for the cooling system?

 

No, just one and it controls the flow of water around the engine, it works much like a radiator thermostat, as it heats up it opens. So if it's stuck open the engine will take a long time to warm up, and may not reach it's proper operating temperature. What's puzzling is that the guage doesn't move at all. Could be worth your while starting it, and letting it run for a while, see if the fan kicks in eventually. If it does the engine is heating up normally and probably the cooling system is ok. The problem then is probably the sensors somewhere. Ring a Ford garage and ask them, they'll tell you. I always used to find the main dealers quite helpful with old cars, they didn't really want to do them as they could turn into such big jobs so they'd give you the info to save themselves the trouble.

 

it could be that your thermostat is stuck open an need replacing, there is nomally only one thermostat but you will have one transmitter for the temp guage and one for the ECU, both should be located near the thermostat

 

The thermostat sounds likely, when my dad went to his parents 100 miles away he said on the motorway the temp guage started to work and the fuel econemey was near normal but it has not moved since and of course it has all been stop start journeys.

 

Get it changed then

 

It is easier said than done when my parents have no money at all.

 

10 mpg?

£4 every 10 miles......£4 every 10 miles......£4 every 10 miles......£4 every 10 miles......£4 every 10 miles......£4 every 10 miles......£4 every 10 miles......£4 every 10 miles......£4 every 10 miles......£4 every 10 miles......£4 every 10 miles......£4 every 10 miles......£4 every 10 miles......£4 every 10 miles......£4 every 10 miles......£4 every 10 miles......£4 every 10 miles......£4 every 10 miles......

How much is a thermostat? I've replaced several thermostats on several cars, some were easy, some were tricky, but I managed them, and I'm no mechanic....