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Whoops · 05-12-2008, 07:47 PM

Good golly, I didn't think anyone could make a Honda drink that much gasoline.

All of the advice you've gotten is rock solid. However, here is what your dealing with, from my understanding.

Although you have a D15B6, which came from a Si, so you have been told, the DPFI, is a dual point fuel injection system. The black cover, behind the engine on what looks similar to a carburetor, but is not, is the issue people are giving you flak about.

The Si used a MPFI, which is short for Multi Point Fuel Injection. This essentially meant it had one injector on each intake runner. MPFI was used on the engine's geared for power and the one's geared for super economy. DPFI was used on engine's geared for run of the mill, plugging down the road.

In parallel with DPFI, it used one version of a ecu, or electronic control unit (computer) to control the fuel intake and engine electrical timing. The MPFI uses a different version and then it is refined based upon which engine.

If your engine came from an Si, then their is a fairly high liklihood that they used the transmission from the Si. The Si transmission was geared shorter, for quick start, high torque. The DX, which is probably the flavor of car you have, was middle of the road. The HF was geared very tall, but was matched to a specially profiled engine/camshaft/intake/exhaust system.

Whomever you purchased the car from clearly spent a ton of $ on all sorts of bells, whistles and flashy thingies because someone told him that was what all of the big boys were using. They didn't really know zipidy spitola however, since probably the most basic thing they should have changed was the DPFI, to MPFI. Without making that switch, they were just spending money on flash, with probably a zero return on performance.

What has been suggested is that you replace the engine and transmission with something which is going to get you mileage, instead of flash. Since your engine has lots of flash, you could conceivably get more money by selling the flash, than trying to unmodify whatever someone else did, previously.

Best of luck. I have to say I have never heard of someone having a car decked out with so much flash and DPFI. That is just mind bogglingly a waste, wow.

ps I generally drive a 89 Honda Wagon, which is for all practical purposes a DX. I can get 35-37 mpg, driving reasonably. I generally can get 320 miles or so, before my stomach starts to twitch about running out of gas. The tank physically will hold 11.5 but registers empty at about 9.5-10.

05-12-2008, 07:47 PM	#19 (permalink)
Whoops EcoModding Apprentice Join Date: Dec 2007 Location: Ventura, Ca Posts: 112 Whoop's Wheels - '89 Honda Civic Wagovan 90 day: 39.09 mpg (US) Thanks: 1 Thanked 9 Times in 7 Posts	Good golly, I didn't think anyone could make a Honda drink that much gasoline. All of the advice you've gotten is rock solid. However, here is what your dealing with, from my understanding. Although you have a D15B6, which came from a Si, so you have been told, the DPFI, is a dual point fuel injection system. The black cover, behind the engine on what looks similar to a carburetor, but is not, is the issue people are giving you flak about. The Si used a MPFI, which is short for Multi Point Fuel Injection. This essentially meant it had one injector on each intake runner. MPFI was used on the engine's geared for power and the one's geared for super economy. DPFI was used on engine's geared for run of the mill, plugging down the road. In parallel with DPFI, it used one version of a ecu, or electronic control unit (computer) to control the fuel intake and engine electrical timing. The MPFI uses a different version and then it is refined based upon which engine. If your engine came from an Si, then their is a fairly high liklihood that they used the transmission from the Si. The Si transmission was geared shorter, for quick start, high torque. The DX, which is probably the flavor of car you have, was middle of the road. The HF was geared very tall, but was matched to a specially profiled engine/camshaft/intake/exhaust system. Whomever you purchased the car from clearly spent a ton of $ on all sorts of bells, whistles and flashy thingies because someone told him that was what all of the big boys were using. They didn't really know zipidy spitola however, since probably the most basic thing they should have changed was the DPFI, to MPFI. Without making that switch, they were just spending money on flash, with probably a zero return on performance. What has been suggested is that you replace the engine and transmission with something which is going to get you mileage, instead of flash. Since your engine has lots of flash, you could conceivably get more money by selling the flash, than trying to unmodify whatever someone else did, previously. Best of luck. I have to say I have never heard of someone having a car decked out with so much flash and DPFI. That is just mind bogglingly a waste, wow. ps I generally drive a 89 Honda Wagon, which is for all practical purposes a DX. I can get 35-37 mpg, driving reasonably. I generally can get 320 miles or so, before my stomach starts to twitch about running out of gas. The tank physically will hold 11.5 but registers empty at about 9.5-10.