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Old 04-09-2009, 03:45 AM   #8 (permalink)
EcoModding Lurker
Join Date: Mar 2009
Location: Vancouver, WA
Posts: 48

Active Learning - '93 Chevy Suburban Silverado
90 day: 10.67 mpg (US)
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Originally Posted by dcb View Post
I don't know, I just measure it with the gas pump

There's lots of variables as I said. I would just top off the tank and fudge usPerGallon so that mpg looks about right, then true it up at the next fillup.

But in essence, it is the pressure drop across the injector that determines the flow. If you know the operating pressure drop and adjust the published flow rate for the operating pressure drop in your vehicle, you can multiply that by the number of injectors to try and predict how much flow per time total.

Also, you did not mention what vehicle you have. There is a known issue with peak and hold. Just as a precaution you might want to unplug an injector and measure it's ohmage, if it is above 10 ohms you should not have a problem.
So sorry for being absent for so long. I have been having a rough time trying to get a tank reading. the mpguino unit locked up twice on me out of the clear blue. no hint either time. I refilled and reset it and got almost half way through another tank when I acidently hit the two reset buttons together.. ugh. But I am sitting at 312 miles and still havent hit the half way mark so I dunno if I broke my guage or im doing something right. Im leaning towards the guage being bad lol. because I cant get that silly guage to make much sense. Sometimes it says im getting 14 mpg on fairly hard acceleration but only 9 on a gentle throttle. Then there is a really touchy spot where it will jump up to 23 mpg. If the road is level you can keep it there usually. One hair more throttle and it will drop straight to 12 or 13 mpg. Coasting very rarely gives more then 24 mpg unless I stick it in neutral at about 55 and i can get roughly 34 mpg once 40..
I got to get a wideband on this thing.
It is a 1993 suburban with the 350 engine. I am thinking of building a new engine for it, that would have the benefit of 10 to 1 compression and better breathing and valve timing.
But it just wont DIE, without which the wife wont approve the funds..
Course I could just let her drive it more hmmm I got a personal junkyard with cars shes driven.. hmmm
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