When researching 2 seater Honda's, I came up with the following EPA figures:

84 Honda CRX 1.3L 54/67
85 Honda CRX HF 49/54
86 Honda CRX HF 52/57

93 Honda del Sol S 34/38
94 Honda del Sol S 35/41
95 Honda del Sol S 35/41

I ended up with the worst one of the lot from a mileage standpoint.

These figures came from fueleconomy.gov except for the 84 CRX, which I found on the web somewhere. Fueleconomy.gov only shows data back to 85.

So anyway after seeing this I was hell bent on an 84 CRX 1.3L. I searched high and low but couldn't find one that was worth buying. But still, I searched the web thoroughly to try and find out what was so special about the 84 that gave it 12 more (22%) MPG's on the highway and 5 more (10%) in the city. It couldn't be just the smaller engine could it? Finally I stumbled upon the answer when reading an article about the EPA's plans to change the way it tests vehicles. Near the end of the article (which I have lost) it stated that the last time the EPA changed the way it reported test results was back in 1985 where they cut 22% of of highway figures and 10% off of city figures. So the 85 and the 84 were really the same as far as EPA figures go.

But, I still have a nagging question. Why is it that the 86 CRX had 3 MPG higher than the 85 on both city and highway. The car actually got slightly heavier and the only other changes were flush mounted headlights and a fuel feedback system. Is that worth 3/3 MPG?

Similarly, the del Sol between 93 and 94. The 94 is heavier but gets 1/3 MPG better. The only difference i can tell was the addition of passenger side air bags.

So finally my question... did Honda tune the 86 CRX HF and the 94 del Sol ecu's to do better on the EPA tests?

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The 86 hf had no fuel injection, so no ecu, I'll research this for your. Also, all obd1 ecus are the same, I'll look this up too, hard to say though.

All obd1 ECUs are the same? So the p28 is the same as the p07?

Very minor differences among OBD-1 ECU's with the exception of that little gem.

Sorry, if you want to get technical the boards are all almost exactly the same anyway.
But, what I meant was this his p06 is the same as any other p06 he'd ever find (unless it was factory chipped, I've actually found a factory chipped ecu in my time).

EDIT: Sorry I suck at saying what I mean.

Also, I should note that most hondas, especially in your case, are considered a compromise between power, fuel economy, and thrift. Your engine in particular goes to the thrift side of things because it's neither powerful nor economical, it's just there in the middle chilling and being produced cheaply.

Rating all the popular 92-95 civic engines:

D16Z6: Power high, fuel economy low, thrift in production low.
D15B7: Power medium, fuel economy medium, thrift in production medium.
D15B8: Power low, fuel economy high, thrift in production high.
D15Z1: Power medium-low, fuel economy extremely high, thrift in production low.

Note that this is relative to EG civics only, not monster truck v8s.