D15b 18 MPG-- What could do this?

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Sparks and cords I will check tomorrow and get back to you,
I do not know what benzin smells like but the inside of the exhaust tip might have been painted black or it was what you were talking about, there is very little silver inside the exhaust, and the corner prior to the muffler, the inside of that pipe is mostly black, what does this mean? air filter is a few months ago
I cannot figure out how to tell which chip is which after I open the cpu (have not actually openned it yet, this is from pics on google I am confused)

thanks in advance
-Chris


How do your sparkplugs look? Does the exhaust smell like benzin? How old are the sparkplugs and wires? How old in the air filter? If you look into the muffler with a flashlight, does it look like it's been coated with black paint? Check all of this and report back.

Sounds to me like the tune. Well, actually it sound like you don't have a tune, heh. I was getting 22mpg before I tuned the engine. Now, I make 133WHP and I get over 30mpg, while driving like a jackass (100mph+ on the Autobahn).

Open up the ECU, and see if there's a chip in the place where a chipped ECU's chip would go, you'll want to google this. If not, you need to tune it. Pronto.
 
I think Hondata tuning chips are colored and say HONDATA right on it.
 
Hi new here. I am going through the exact same problem right now. I swaped in a d15b motor and am getting some real crappy milage like 250km per tank. I have a p28 ecu in mine and the guy who swaped my motor said this is the right ecu. the p28 is not chipped. I am mecanically inclined and have exuasted many avenus, and I am starting to lean towards the ecu. I have a p08 ecu as well, that I might try putting in for a week to monitor the gas. Does anyone see any problems with this?
 
This should be a new thread but I'll answer anyways:

P28 will run a D15B but it's not the right ECU, P08 is. Go ahead and put that ECU in.

Also, P28 uses 4-wire O2, while P08/JDM D15Bs use 1-wire O2; you'd think that wouldn't cause issues but we came across bad mileage due to that(though, CEL was on).

Other things to check are simply tune-up stuff like spark plug/wires, fuel filter, air filter, etc.
 
How does it idle? ..Rough? (could be a vacume leak)
Check under the dizzy cap, does it look like red dust covering everything? ..(It shorts out and messes up the firing order.)

Take a look in toward the throttle body opening. Is it all 'gunked up'? If so, clean. The carbon/sludge keeps the butterfly open)

Check your grounds. There might be some that are not there or missing.

E
 
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