Unmodding my '91 Civic DX

[ohmycivic]

Thanks for the advice, guys... BTW, whoops, it IS a d16a6 according to the identifier on the engine itself.

I've got someone interested in trading an '89 CRX si for it, which I'll probably end up doing if they don't change their minds.

[getnpsi]

I would register on one of the honda forums, and see if there is a locals area for where you live. See if you can work some sort of trades of parts + cash sort of thing. I personally would keep the rig running and leave the si engine, just make it factory stock specs. Otherwise if you want the whole shebang there should be plenty of kids in your area with the low end models trying to upgrade.

[John L.]

The larger fuel pump is wasting energy as it sends all that additional flow right back into the tank at low load conditions where the fuel isn't needed (or rather the pressure regulator sends it all back to the tank). The cams will hurt economy if they aren't in their ideal range at cruise speed which I'm guessing they're not. The FPR (fuel pressure regulator) might be adjusted higher than stock which could be a big contributor to poor economy, adjust to stock FP but keep the regulator if you think you might want to experiment with leaning the mixture (potentially dangerous to the engine though) later on. The fuel system may have been necessary with the nitrous but dump the nitrous if you want to save gas, nitrous provides more oxygen which needs more fuel to make more power. Of course you could do what these guys are suggesting and just get rid of the car and get something with better economy from the start. 15 mpg is still pretty absurd for any Honda though, you could do better even with the parts you have, just needs tuning.