Newbie with a 1989 Civic DX

[Grizzlywon]

So, I just purchased a 1989 Civic DX hatchback last week. My main goal is getting the best MPG without spending too much more. The car was only $2500 (cheap for CA!) but has low miles, 150,000. Pretty much stock other than some SI seats and door panels.

Here are my questions. Other than simple things like tire pressure, and driving technique, what would you guys recommend? I was thinking a non CA ECU (after I smog it) and a ScanGauge (but I'm thinking I can't get one for this car as it's too old) I realize it's just a gauge to watch what's going on, but figured it would help me learn how to better drive

Other tuning? Chips etc?

I'm Here to learn, thanks in advance!

[MetroMPG]

Welcome to the forum, and congrats on the car. That's an old girl right there.

You're right: too old for a ScanGauge.

I'm not even sure if it's fuel-injected (but I suspect not). If it IS, then you could install an MPGuino for real time MPG monitoring.

If it's not, well you'll have to go old school: vacuum gauge would help.

You could also try to finely calibrate your fuel tank's sending unit against a digital multimeter to get reasonably accurate trip-level fuel use (assuming you park in the same spot each time you check it).

You're right that driving style has the biggest impact, and changing that is free. But there are also a bunch of easy mods you could do, too.

Some light reading, in case you haven't seen these yet...

100+ Hypermiling Tips
65+ Efficiency Mods

How wide are those tires? They don't look stock!

[user removed]

Pretty sure the 89 was throttle body injection, which means a mpguino would be your best choice for MPG readings.

Keep the revs as low as practical for acceleration, shift as soon as practical, probably shift at 2500 RPM max, at least until you get some mileage data recorded.

Welcome.

regards
Mech

[MetroMPG]

Yup: make a garage entry and start a fuel log for sure. Add new vehicle

[some_other_dave]

The DX had what they called "DPFI", Dual-Point Fuel Injection. There were two injectors at the throttle body. MPGuino is your only real option for real-time economy monitoring. You can also do fairly well over a much longer term just using the odometer and your fuel fills. I did in my CRX...

The non-CA ECU won't really give you anything, IMO. You might gain a little from an MPFI swap (changing to the Multi-Point Fuel Injection that was used on the Si and EX models), but that is a more complex swap than just the ECU.

Short of going with a programmable setup and running the mixture lean at cruise (you'll want a wide-band O2 meter if you try that!) or swapping in a CRX HF motor, that's just about it for any benefit from modifying the engine.

You've got decent gearing, so unless you find a CRX HF transmission you probably won't get much from gear swaps, either.

Aero can work, but many of the effective changes will also change the appearance of the car.

-soD

[Grizzlywon]

Thanks guys for all the help so far! And yes, it has DPFI.


So, my first fill up showed 37mpg and thats with about 150 miles with no muffler, a broken Cat and me relearning to drive stick.

I now have a new Cat, muffler back on it (can't believe the previous owner just cut it off!) and I'm getting the hang again of first gear (getting better at my starts while not revving the engine up to high). I'm really sad it doesn't have Tachometer in it stock.

I also put in a new thermostat (it didn't even have one in it when I got it) and will be putting in a new starter. It has been very finicky about starting once it's hot. AutoZone tested the battery and alternator as good.


Next steps:
It's also idling poorly, RPM's getting pretty low (almost to the point you think it will die) then corrects itself.

And I'll look into the MGuino. Looks like a good deal for the price. I'm just not seeing any instructions on their site or even the links they posted.

[NachtRitter]

Hi Grizzlywon...

Welcome to the site. Once the '89 DX is smogged for the ownership xfer, it no longer needs to be smogged since it's 25+ years old, right? I forget when the cutoff is...

I'm selling my VX which has an MPGuino in it; if the new owner does not want it, I'd be happy to send you mine for the cost of shipping... this is what it looks like: http://ecomodder.com/forum/showthrea...tml#post187715

If that doesn't work out, it should be pretty easy to put together your own using one of the more modern Arduino boards; wiring details for the display, buttons, and connections to the car are here: MPGuino - EcoModder. Also check out the latest software updates here: http://ecomodder.com/forum/showthrea...ead-26469.html

[Gasoline Fumes]

As far as I know, the MPGuino won't work with DPFI.
http://ecomodder.com/forum/showthrea...tbi-11899.html

[NachtRitter]

Drat...

[Grizzlywon]

That stinks!


Well FML. It failed smog today, even with a brand new CA approved Cat. The timing is off by about 3x retarded of what it should be. The speedometer and odometer also stopped working right after the smog. I went back to the shop and the shop owner said he didn't touch it! What can I do now? :/

Gonna have my auto mechanic take if for the week and see what he can do. So frustrating.