26mpg...New D15B2

I just got a JDM D15B2 for my CRX (because my other engine was burning oil because of 3 overheats, not my fault :) and I'm wondering about my MPG. It was never "awesome" and never above 30, I usually got around 260-270 miles on a whole tank till empty. I've heard stories of this car getting 32+ so I'm wondering, what's up?? Here's what I've replaced to try to help the situation:

O2 Sensor
Fuel Filter
Air Filter

I'm getting no codes from the odb0 ecu (doesn't mean anything ;) ) and I drive very conservatively, so what left is there to do?? Could my injectors or my crappy old DPFI system be the issue??

EDIT: My alternator has a bad bearing and makes a lot of noise (although the charging system light doesn't come on) could that be related?

you have a jdm d15b2. does your block say d15b2 on it ?

i get about 35mpg with my 1.5 dpfi

I dont know if this will help but you may want to replace your spark plugs and wires. Problems on that end could also be the culprit of your bad gas mileage

Yes, it says D15B2 on the engine, and it's JDM..when I had the engine replaced it also got a new distributor and all parts in that, new wires, new belts, seals...I am stumped on this. The engine though when driving next to a wall sounds very deep and like it's burning rich, but my EG smells fine and the O2 is maintaining mixture...

Yes, it says D15B2 on the engine, and it's JDM..when I had the engine replaced it also got a new distributor and all parts in that, new wires, new belts, seals...I am stumped on this. The engine though when driving next to a wall sounds very deep and like it's burning rich, but my EG smells fine and the O2 is maintaining mixture...

Well if it says d15b2 on it, there is no way it is a jdm engine! So whoever sold you it ripped you off, sorry to say. A d15b2 engine was in only USDM 88-91 civic LX,DX, and CRX DX!!
Sorry...

I dont think the alternator has any relation to it. What do you normally shift at. Are they city miles or highway miles? Could be that the injectors are gunked up, or maybe dirty fuel lines, change the pcv valve. Thats all i can think of
Good Luck

-Andrew

I normally shift at 3,000 rpm...well it doesn't say D15B2, it says D15B on it whether that makes any difference at all. Could it be my vacumm lines or is it possible for the FI's to make that big of a difference? City miles. Thanks a lot guys.

I normally shift at 3,000 rpm...well it doesn't say D15B2, it says D15B on it whether that makes any difference at all. Could it be my vacumm lines or is it possible for the FI's to make that big of a difference? City miles. Thanks a lot guys.


OOOOOOOOHHHHHHHHHHHHHHHhh okay.....Jdm D15B, thats much better!!! hmm for city miles 26mpg is lower than average but not much. Id say dont worry about it. Did you just do the swap. Sometimes it takes a good thousand miles for the ecu to get up to speed and learn how the engine works.

it was done a few months ago, it has about 3,000 miles in my car now, already got an oil change. Another thing is that sometimes when I turn my car off in the drive thru, and about 2 or 3 min later I try to start it and it won't, just cranks, then I turn it off and wait for 20 seconds and it starts just fine...? Had this problem with my old engine too, is there someway I can test the injectors?

you have a jdm d15b2. does your block say d15b2 on it ?

i get about 35mpg with my 1.5 dpfi



That's roughly what I averaged, about 33-35 mpg when my motor was in. It sounds just like yours, JDM D15B block with the DPFI. My car had the 4 spd tranny on it if that makes a difference (I think it would really only make a difference on highway because of the 5th gear).

I'm stumped here guys..could my MAP or MAF sensor have anything to do with my problem, all those things weren't not replaced with the engine, the DPFI manifold and sensors were not replaced. Thanks a lot.

New INFO!!

I checked out my ECU under the carpet, the little red light IS blinking, and it does it 16 times...I read up that it means this:

Fuel Injector System
defective circuit or unplugged / defective fuel injector

I'm guessing this could be the problem, how do I go about diagnosing? Why didn't my check engine light come on? Also....I checked the resistance on my fuel injectors...

Auxillary: 1.3ohms
Primary:8.5ohms

Maybe the Main Relay?

well I found the problem...it was mostly my fault for not seeing the ECU light. It was code 16, and it turned out to be the main relay..bad solder joints. I haven't re-soldered them yet, but I reset the ECU and it runs SOOO much different when it's not flashing, like night and day. I also notice a huge improvement in gas mileage already. I'll just have to resolder it up before it craps out again. Thanks guys.

d15b2... 30+ mpg, all depends on how you drive it, but the b2s are much to drive hard so it all depends on itf you take care of it