Dear Car Talk:
I live in Kigali, Rwanda. I have a 1995 Toyota RAV4 two-door with an automatic transmission with 132,000 kilometers on it. It had, at some point, been converted from right-hand drive to left-hand drive, before being imported. It has crazy gas consumption – I get one kilometer per liter. The air is really dusty here; the car is covered with red dust all the time. Could this dust be clogging the filters and causing increased gas consumption? Could the odometer be running slow, so it is not recording accurately? Any thoughts, suggestions or advice? Help! – Anne
Wow. That’s some epically lousy mileage, Anne. Congratulations. According to our metric-to-English conversion chart, you’re getting about 2.5 miles per gallon. That’s low enough to make a 2003 Escalade jealous.
We don’t work on a lot of African RAV4s, Anne. While all the RAV4s we see are fuel-injected, it’s possible yours is carbureted to make it simpler to fix. We don’t know.
But here are a few things that come to mind: If you have a carburetor, one thing I’d suspect is a very filthy air filter. That won’t affect your mileage if the car is fuel-injected, but without computerized engine management, the dust could clog up the air filter enough to throw off the fuel-air mixture and cause gasoline to pour into the carburetor. If you remove the air filter and hold it up to the sun, you should be able to see light coming through it – looking the long way. If you can’t, it’s plugged up.
Then you’d call Kigali Toyota and get a new filter. Or, if that’s not an option, you’d find someone with an air compressor, blow the dust out of the filter and reuse it. You may have to do that every few weeks if it’s as dusty as you say it is.
It’s simple enough to try that as a test. You replace the filter, or clean it well, put it back in and see what your mileage is.
But do resist the temptation to take out the filter and leave it out. Because then all that red dust will scratch your cylinder walls and ruin the engine. Then, for every kilometer, you'll be burning one liter of fuel and one liter of oil.
If the air filter’s not plugged up, then the mechanical fuel pump could be the culprit. The diaphragms in those pumps can fail, sending 25 percent of the fuel to the carburetor and the other 75 percent onto the ground. And the stuff that’s on the ground won’t help your gas mileage.
If your RAV4 is indeed fuel-injected, then you’ve got to look for a leak somewhere.
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