Had a mechanic tell me he'd adjusted the fuel mixture (made it a little richer) so the engine wouldn't run as hot and the engine would be better off/last longer don't know why I didn't really ask him about it but now am told by the dealer service reps that the fuel mixture is not adjustable, at least not by mechanics, of course I know it probably is constantly adjusted by the computer but I would like to know if one can go into the car's computer system and reset the fuel mixture so's the engine runs richer? He was plugged into the car with his computer/tool when he was telling me this.....I noticed afterward, on the long trip home, that the mileage seemed about 3-4 mpg less than when we took it in...
I am not aware of any way to adjust fuel mixture via an engine ECU adjustment. The Prius engine is not known for running particularly hot, and that would be one of the last things I would personally worry about - even living in the desert Southwest where summer temps are ~110 degrees.
I'm sorry to say I think the only thing that was adjusted was the contents of your wallet. John (Britprius)
Absolutely not! The mechanic is an old friend I've known for over 25 years, he was at my wedding, he's from Japan where he was adopted as a young child by a Toyota mechanic and began wrenching as soon as he could hold one. He's been working on Toyota's for over 50 years; however, I do have trouble understanding him and I think that was the case and why I've never really be concerned but it came to mind recently and I thought I'd check with someone else but now I will call him and see "what up"
This is not something you mentioned in your first post, or I would not have made the comment and withdraw with apologies it in this instance. It is I'm afraid all to typical of many "not all" dealers and workshops. It is still a fact that mixture adjustment on the Prius is not some simple quick fix like turning a screw and at best is left as is for both economy and longevity of components such as the catalytic converter. Cylinder and ring ware along with oil contamination could also be affected by increasing the amount of fuel injected. John (Britprius)
