1986 crx hf questions
 

i just bought this car and have some questions. the main question i have about it is the fuel mileage. it gets about 35 on the highway but I know these are supposed to get much better fuel mileage. it's a manual trans. and it's the carb model and it seems to run fine but I'm not used to this car so I could be wrong. Is it normal for this to get such low mileage? It has the original engine and transmission (about 150k miles). thanks

Could be a bad oxygen sensor. How do you know its the original HF engine/transmission?

The HF engine should have a plastic valve cover.

How many rpms does it turn at 60 mph? If its really the correct HF transmission, it should only be turning about 1950.

Also check the air filter to be sure it isn't clogged.

One more thing- check to be sure the brakes aren't dragging.

Vacuum leaks are a big problem with the carbureted CRXs. The quickest tell tale is a pooking sound at the tail pipe while idling. Sitting in the vehicle very slowly increase rpm from idle to 1500 rpms. The number of times it pooks will decrease, but the intensity may increase. If you detect this, there is a good chance that it has a vacuum leak between the isolator block and the carburetor and/or the isolator block and the intake manifold. I like to spray some carb-cleaner around the bottom of the carburetor while it is idling. If the engine all of a sudden runs very smoothly, you know you have a leak. The isolator block can be purchased through rockauto.com for an amazingly low price of $42. Others charge around $78. Throttle shafts can, over time, oval the base plate and generate vacuum leaks. The only fix is to get your carburetor rebushed and rebuilt, or replaced. nationalcarburetors.com is a possible source for you. Since you are getting very bad mileage (you should be getting a minimum of 48 mpg with responsible driving habits and/or 50+ with hypermiling), you need to remove the short section of exhaust pipe that travels from the CAT back to the flex ball joint and with a flash light look up into the catalytic converter to confirm that it isn't completely melted and looking like lava. It should be a nice uniform matrix like the pattern of a screen door. There are many diaphragms on and around the carburetor that should be checked with a vacuum pump. Another source of vacuum leaks is the power brake booster. If you step on the brake and the engine starts to run rougher you will know you have a leak in the booster. It would need to be changed. Locally I purchased one for $82. There is a core charge in addition for rebuilts usually.

As Erik stated, dragging brakes are definitely possible. I had them. With the tire lifted off the ground, when adjusted properly, you should be able to spin the rear tire by hand and have it free-wheel for quite a while and still have a nicely working parking brake.