I currently running the stock d15b1 in my hatch and nothing major is done to it. Just I/H/E and thats it. And I'm still running the DPFI. I've recently done a tune up to it(plugs, wires, cap and rotor) and that just made it run better. I'm getting anywhere from 230-270 miles to a full tank. I do a lot of city and freeway driving but I shouldn't be getting this amount of horrible mileage.

Any ideas?

I also recently did a 5speed trans swap with the 5speed ecu. And that came out of my wrecked hatch that got 320ish to the tank.

 

throwing any codes? could be a coolant temp sensor (the one to the ecu) could be bad sending a cold signal to the ecu causing it to run on cold fuel maps all the time thus using more fuel. check the plugs after a drive and see what they look like

 

Plugs look find. Coolant is is at 170ish. My temp gauge is never going over half or near it. I used both clusters I have. Both read the same.

 

no man i mean the temp sensor that goes to the ecu, not going to the temp gauge theres 2 diffrent ones

 

you might have some bad injectors...i use to get the same amount of gas mileage like this but when i changed out the complete dpfi throttle body with injectors and sensors my gas mileage improved big time...!!!

 

Repeating the first question from 'blaster' - are you getting any ECU trouble codes (Check Engine Light on?)

 

yeah was your wrecked hatch a dpfi model? si or hf? if so that explains it, the duel point gets better gas milage

 

Im throwing no codes what-so-ever. My old hatch was a DX so it's DPFI as well. I really wish I could source some MPFI swap items, I'd be alllll over that ****.

 

I'm having the same problem. Except I got all stock b15b6.
Getting about 220-240 a tank or so..
No CEL. And I don't mean to hijack your thread.. but maybe I'll find an answer here too.

 

Vacuum leak?

 

no surging idle or any of that.

 

The car can run rich without having a surging idle, make sure the lines running from your map sensor are in good nick.

 

Where would my map sensor be at?

 

it's mounted directly behind your intake manifold on the firewall with hoses going into it...!!!

 

Do a 10 speed swap and drive a damn bike.. better mileage guarenteed

 

Alright happy *** lol. I'll go look at it right after I get my MKIII Golf lip. :D

 

 

 

Miles per full tank is not a very accurate measurement. Have you actually calculated your gas mileage? Reset the trip odometer at each fill-up after you calculate the MPG.

IIRC there were 11 and 12 gallon tanks. The float lever could also be bent leading to inaccurate fuel level display. As previously said the ecu may be in enrichment mode due to too low water temp(thermostat stuck open, etc.) or a bad ecu ect sensor. How do you drive - do you drive like a granny or do you beat on the car all the time? I have seen a change from 26 to 46 mpg just by a change in driving habits. This past summer I have gone up to 480 miles per tank.

The HF I believe had the best fuel mileage. 1.5L, 8v, MPFI, low weight, tall gearing and low red line = 50+ mpg highway.

Good luck.

 

I'll get on my car every now and then, just like a 2nd gear spirt. Other than that, I'm never really shift over 3k. I fill my tank up everytime I get gas. And it's almost always the same amount of gallons, about 10.3ish

 

so you're getting about 26mpg. do you do mostly city or mostly highway driving? i can only average 28 around town in my si, but since i'm mostly highway 90% of the time i'm averaging about 33mpg.

 

It's about equal. When I go to school I take the back roads which is 55mph there. This tank of gas I got 249 miles....

 

WOW, this is the thread I've been looking for E-AT_me ! What we've been talking about right here.

I have an 87 CRX-HF with the 1.5 carb/5 spd. Former owner got as much as 60 mpg till something went haywire and he never could figure it.

I checked mine by filling the tank till it was about to run over and driving a few days with the trip odo zeroed as I pulled away from the pumps. It shows I'm now getting 40-41 mpg. That's up from 30+ before when I got it.

Main problem then was a bad radiator fan control switch, squealing belt and alternator brushes burning out. Now with the valves adjusted, plugs regapped to .040, valve cover & breather cleaned, alternator belt tightened properly so it doesn't squeal, so it's now running without rpm surge.

What it is doing is dropping rpm below 500 and then bouncing up to 750+ till the engine finally falls below 500 rpm and dies. Then sometimes it idles properly. Intermittent problem.

Otherwise the plugs are a nice tan but the tail pipe is black and sooted

The heater is warm but not real hot, and the engine seems to reach op temp so I'll have to check it with a temp gage.

One other thing. When I got it the auto choke butterfly was wired wide open with a paper clip.

I've been suspecting the Oxygen Sensor (5 wire heated sensor)

E-AT_me and I have been kicking this around in IM's but any other views on the problem source would be appreciated. I'd like to get it back to at least 50+mpg. (I don't know if it will ever see 57 mpg again unless the Jet Stream dips down behind it)

 

QUIT TRYING TO JACK MY ****ING THREAD!!

 

lol. Angry much!