possible source for fuel mileage
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Joined: Nov 2001
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possible source for fuel mileage
I see alot of posts about fuel mileage, heres one not many think about. A lot of fuel injected vehicles suffer from this and it is hard to find. You would never think a thermostat could rob fuel mileage. Most fuel injected engines use a temperature sensor to tell how warm the engine is. If this sensor is bad it can tell the computer that the engine is always cool. This temperature sensor is the "choke" in the system, if it says the engine is cold, the computer will dump fuel to the engine to richen the mixture. It is supposed to run in this richer state until the engine is warm, once warmed up the computer starts adjusting the mixture according to what it is told by the other sensors. If the thermostat is stuck open or partly open the operating temperature that the computer wants to see may never be reached, causing the same thing. Also if a thermostat of the wrong temperature range was installed it will cause this. Most fuel injected vehicles run 195 deg. thermostats. The man at the parts store should be able tell you what temp. you need. I can't think of a reason why you would run a thermostat other than the factory spec in our trucks. If yours is over heating, changing thermostats or running without one is just a band-aid fix, there is something else wrong somewhere.
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Joined: Dec 2001
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From: Southeast FLA
possible source for fuel mileage
This seems applicable to many people, but perhaps not the 4.9 owners looking for a better running truck.
I've actually just recently read a Ford-related site that gave instructions on how to put a resistor on that electrical line to get a little more fuel to the engines. Since the 4.9's are known to run lean as it is, I believe the site was talking about a 4.9 modification to get more out of it.
(perhaps this is one of those reasons bigbluetruck couldn't think of... an easier way to do richen the running mixture on 4.9's would be to just get a cooler thermostat)
Yes, I suppose the fuel mpg would suffer even with the 4.9, but then some people aren't worried about that too much.
Even if it was bad, it would cause *more* fuel to enter the combustion chamber, not a 'dumping' of fuel (at least not in an uncontrolled sense like a bad fuel pressure regulator will).
I'm not saying I'm an advocate of it, nor have I tried it, but the above info is certainly another point to consider. The one thing I've learned with the ~40 cars and trucks I've owned is that the stock OEM set-up is not always the best running (in some cases), or most fuel economical (in other cases), system to have. (my 4.9's EGR restrictor plate just proved that theory again).
Best,
I've actually just recently read a Ford-related site that gave instructions on how to put a resistor on that electrical line to get a little more fuel to the engines. Since the 4.9's are known to run lean as it is, I believe the site was talking about a 4.9 modification to get more out of it.
(perhaps this is one of those reasons bigbluetruck couldn't think of... an easier way to do richen the running mixture on 4.9's would be to just get a cooler thermostat)
Yes, I suppose the fuel mpg would suffer even with the 4.9, but then some people aren't worried about that too much.
Even if it was bad, it would cause *more* fuel to enter the combustion chamber, not a 'dumping' of fuel (at least not in an uncontrolled sense like a bad fuel pressure regulator will).
I'm not saying I'm an advocate of it, nor have I tried it, but the above info is certainly another point to consider. The one thing I've learned with the ~40 cars and trucks I've owned is that the stock OEM set-up is not always the best running (in some cases), or most fuel economical (in other cases), system to have. (my 4.9's EGR restrictor plate just proved that theory again).
Best,
