Low CRX HF Mileage

[user removed]

Is your operting temperature high enough. Bad thermostat casues them to run cold and burn a lot more fuel.

How do the plugs look?

regards
Mech

[some_other_dave]

None of the CRXes had lean-burn engines.

Sounds like you're getting good suggestions so far. I would guess that the tires, the ELD, and the exhaust would each cost you a little bit. It might be enough to add up to what you're seeing, but I'm not sure.

Also note that colder weather will hurt your fuel economy--the colder, the worse it hurts.

-soD

[z3pilot99]

Engine was tuned up (wires, plugs, cap and rotor, PCV valve and collapsed PCV hose were replaced). Also done: timing belt replaced, timing set, new thermostat, and a bunch of other little stuff the PO had neglected. I used new honda parts as I have heard that hondas are a bit finicky. I agree tires could be probably the biggest issue.
Car warms up to middle of the gauge and stays there while driving in cold and hot weather.
It was burning a little oil so I replaced the valve stem seals. I also removed the intake cleaned the throttle body and EGR ports. Egr valve was sticking and giving false readings thus a CEL. I cleaned it and now the CEL is gone. Only remaining error is the ELD. It does not trip a CEL light but I can see a code on the ECU. The car runs extremely well. I just drove it to work this morning. It kind of redeemed itself. I thought I was at 110 miles and just about to touch the half line. I drove it to work and it stayed up there until about 160 miles on the Odo. So, maybe it isn't as bad as I thought. I'll have to fill it up soon. I will get a better feeling on how it is doing then. Thank you all for your help.

[MetroMPG]

You should seriously consider getting an MPGuino so you have accurate fuel economy feedback. Better than estimating with the guess-gauge.

[z3pilot99]

That is the next step after I get the codes cleared and running properly. MPGuino to me is a waste of money UNTIL the car is repaired and running properly. Then it becomes a very useful tool. I look forward to that step. However, I have done searches on how to hook up the MPGuino on here and cannot get any real answers. I posted asking and the response is only "that it should work". I am surprised at the lack of info in that regard. I know there are other CRX HFs on here. One thing I have learned in the last week driving the BMW....the factory fuel mileage gauge helps tremendously with throttle modulation. I now use the fuel mileage gauge to watch going up and down hills. I try to keep the fuel mileage at a certain level going up and down hills. I have noticed a huge improvement. I have got the most miles out of a half tank ever this week using this technique. I used to coast down hills and power up hill. Then read somewhere on here that you should use the down hill to accelerate and thus gain more momentum for the up hill. Of course full throttle down hill does not do you any good. But, I try to keep the indicator above 30mpg down hill while accelerating and then keep it above 30mpg going up the hill letting my speed decrease to keep the MPG up. I would have never learned this without the BMW fuel mileage gauge. Also, I guess on the fuel gauge not as a sure thing MPG rating. I just use it to get an idea. When I first started driving the CRX with the improper ECU I was getting 100-125 miles at the half tank reading. I only use actual gallons on fill up and miles (now corrected due to tire size) to figure actual mileage.

[some_other_dave]

I have an MPGuino for my car. Not in the car, but at least it's built...

You hook it up by hacking into the engine management system's wiring harness. Well, hopefully you "carefully and tastefully connect it into" the harness. It needs to be connected to one of the fuel injector signal wires, the VSS wire (on our cars that comes from the instrument cluster), and switched power and ground. I think that's it. You have to find which wire is what, and tap into them. I'm still dithering about exactly how I want to do that...

The fuel gauge in my current CRX and its 1990 Si predecessor is very nonlinear. I can go over 100 miles in the top 10% of the reading on the gauge. The next 100 will take me to the halfway mark on the gauge. The next 100 miles will put me just above the empty mark, and by the end of the last 100 miles the needle on the gauge will no longer even be touching the empty mark. And then it'll take about 9.5 gallons (in my car, that's out of about 11) to the auto shut-off of the gas station's pump.

Oh, and all of my Hondas would have gauges that read lower when first starting the car in the morning, and would read higher after driving around for a while.

-soD

[z3pilot99]

Originally Posted by some_other_dave

I have an MPGuino for my car. Not in the car, but at least it's built...

You hook it up by hacking into the engine management system's wiring harness. Well, hopefully you "carefully and tastefully connect it into" the harness. It needs to be connected to one of the fuel injector signal wires, the VSS wire (on our cars that comes from the instrument cluster), and switched power and ground. I think that's it. You have to find which wire is what, and tap into them. I'm still dithering about exactly how I want to do that...

The fuel gauge in my current CRX and its 1990 Si predecessor is very nonlinear. I can go over 100 miles in the top 10% of the reading on the gauge. The next 100 will take me to the halfway mark on the gauge. The next 100 miles will put me just above the empty mark, and by the end of the last 100 miles the needle on the gauge will no longer even be touching the empty mark. And then it'll take about 9.5 gallons (in my car, that's out of about 11) to the auto shut-off of the gas station's pump.

Oh, and all of my Hondas would have gauges that read lower when first starting the car in the morning, and would read higher after driving around for a while.

-soD

I understand the wire connections. Although the VSS is a bit of a question. We/I have a cable speedometer. It is a 1990 HF. So, do I still have a VSS? I do not have Cruise Control. I think we also need to know the flow rate on the injectors. I have no idea where to find that info. I think we need to know that in order to program the MPGuino. My gas gauge is very inconsistant. Not realted... My last tank was 43 MPG. Not really very good for the HF. Tank before that was 47. That is my frustration. My traveling distance or highway/city% driving does not change much at all. Everything else I have done is now consistant. With my ELD inop if I drive when it is dark and my lights are on can the drag from the altenator be causing a decrease in fuel mileage? That is the only real variable now. I might fill up in the afternoon when it is light and drive the 75 miles home in the daylight. But other times I might fill up by the house and my first stint will be early morning to work, in the dark. That is the only thing I can come uip with now. I am on the freeway about 55miles. The other 20 is country roads. With little traffic yet a bit hilly. I can let my speed vary quite a bit so I will be very light on the gas pedal going up hills and accelerate going down hill as explained earlier. I can handle 45MPG or even 40 MPG if it were consistant. However, if all I am going to get is 40MPG then I might as well get a newer civic or focus. I know they are rated at 35MPG highway but there is a lot to be said for comfort and safety of newer cars.
I am driving in heavy deer populated areas. Northeast central Ohio to be specific. I saw 6 deer along the road running around Monday morning on the way to work. I don't imagine a CRX hitting a deer would be a good thing for either of us.

[MetroMPG]

Originally Posted by z3pilot99

We/I have a cable speedometer. It is a 1990 HF. So, do I still have a VSS?

Might help: http://ecomodder.com/forum/showthrea...html#post77756

I think we also need to know the flow rate on the injectors.

Not really. You can put in a guesstimate and calibrated it from tank fill-ups after. Have a search around the MPGuino subforum.

With my ELD inop if I drive when it is dark and my lights are on can the drag from the altenator be causing a decrease in fuel mileage? That is the only real variable now.

Yes. Curious to see your results when you get that sorted out.

Weather - wind, precip & temperature all have a fairly big effect on fuel economy as well.

[some_other_dave]

Our cars do have a cable-operated speedometer. But there is a VSS inside the instrument cluster that takes that cable movement and converts it into an electrical signal that is sent to the ECU. Your ECU will throw a code with the speedometer cable disconnected (BTDT!) -- it does know about the speed of the car.

And as MetroMPG said, you don't have to know the exact flow. Just plug in a guesstimate number (and numbers that other people use are available out there!) and then tweak it based on your gallons used / miles traveled calculations.

I'm not sure what exactly would be causing your problems, but colder weather puts a hurt on fuel economy in many different ways, from making the air denser to push through, to taking more energy to get the engine up to operating temps. So that could be a factor...

-soD