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Old 08-25-2010, 02:29 AM   #53 (permalink)
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Join Date: Jul 2010
Location: Melbourne, Australia
Posts: 236

bugler - '91 Mazda 626
90 day: 35.89 mpg (US)
Thanks: 15
Thanked 25 Times in 22 Posts
Looks like your using your free time well, I am employed but still look on the forums while im at work but hard to do mods while im working though.

As for your rich warm up, this may well be worth looking into. I had initially thought mine was ECU controlled so I had 2 ideas of how to "fix" it they are
- Interrupt the idle control valve signal (this is just a pulsed 12v signal that gives variable voltage to the solenoid in the idle control valve) I was going to make a circuit that could give a variable voltage signal based on a control knob. Have this switched in instead of the ECU control signal by a switch on the dash board. This would have been a relatively easy mod for me since im an electrical engineer, not sure of your background but id be happy to guide you through making this if your interested
- The other option was to "fool" the ECU by interrupting or influencing the signals from the temperature sensors this would involve finding the signal for temperature and check the voltage when car is at temperature then check when cold and add a resistance or voltage that could be switched in or controlled by a control knob setting in the cabin. Only issue with this is that your scangauge may go a bit crazy, I don’t have one so I don’t know how sensitive they are.

If you want to see the benefit you will get out of "fooling" your ECU I recommend doing a run into town when the engine is cold and a run into town when the engine is hot and compare the fuel used. This will tell you if its worthwhile
For me it saved at a guess about 10 or 20% off my short trip to work

regarding your PS pump and alternator and AC, if you think you might not use the PS and the AC you might make some good savings in efficiency if you change the belt length so only the alternator runs on it. If your alternator does not have the screw to set the tension of the pull you may need to use an tensioner wheel which could be a bit of work. On my car the AC was the tensioner on the PS and AC belt. If your AC is the tensioner then you might be able to remove your PS pump from that belt and change the belt size.
Maybe a more mechanically inclined person can give you ideas on that one.

Ill have to digest those numbers a little bit more later and compare to mine. If you can idle lower then you will make a saving when coasting and when in town at traffic lights. have a read of the wiki I set up on car idle reduction if your interested.

Ill have a bit more of a think for other tests you can do.
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