Im running an obd1 b18c on stock usdm p72 ecu that gets a good 17-20 mpg if i never go into vtec. The motor performs very poorly and my gf's toyota TC would probably beat it in a straight line. The motor has roughly 30k miles on it and i do not burn any noticeable amount of oil when i do an oil change. My temperature guage is most often halfway between cold and the middle line; when i am cruising on the freeway the needle sits on cold or below. Please help and point me in the right direction as to why i am getting such horrible mileage with the motor. I wonder if it is a faulty ECT causing the ecu to dump a rediculously amount of gas into the car. Already swapped out for another ecu so i do know my ecu isnt bad. All of your input is greatly appreciated.

edit: replaced the thermostat, car is getting around 30mpg now.


Modified by andrew714 at 12:16 AM 1/3/2008

 

is there any codes. if its a swap are your secondary butterflies hooked up

 

No cel and secondaries are hooked up. I doubt secondaries would affect gas mileage because I'm driving and shifting at 3k

 

Do a compression test and post the results

 

try a warmer thermostat. your motor needs to be at a set temprature for the the ecu to adjust accordingly. that could be it if it runs cold alot. does it blow good heat

 

it blows heat but not that great, still wearing a sweater with the slider all the way to the right and fan at four.

ill check out the thermostat next week and update the thread. no money right now, gotta go xmas shopping. now i wouldnt be surprise if there was no thermostat in there.

 

also check to make sure the heater core isnt stoped up. let the motor warm up then feel both hoses. they should both be warm. that could affect the heater and cooling system.

 

both hoses are warm, hot if i grip it for a couple of seconds