1988 honda crx HF gas mileage decreasing

[88crxhf]

I just purchased this from a lady who said it was sitting for the last 2 years with 1/2 tank of fuel, the transmission was blown up, almost looked like the transmission oil was never changed. I hunted down a HF transmission after going through a few of them trying to find the HF model 5 spd. I also had the Oil light come on when first driving the car, come to find out, there was alot of thick sludge plugging the oil pick up tube and alot of sludge in the oil pan. Oil was thick and black.

The car started first try and idled fine with the old fuel that was still in it and so I topped it off with regular gasoline. I have never ran it down past 1/4 of a tank. The first part of the tank I got 44.1mpg, second i got 37mpg and the last time I filled up i got 33mpg. I was thinking the thermostat was bad as it took almost 10 minutes to warm up from being cold, so I replaced it and then replaced the fuel filter.

With every tank of fuel I have added fuel injector cleaner and Red HEET gas-line antifreeze with injector cleaner. I was thinking cap and rotor next and spark plugs also. When I checked the plugs they looked alright but just for saftey measures I was going to change them.

Last fill up the car started running a little weird about 1000-1200rpm. I noticed it when shifting from 2nd to 3rd mostly. The green shift indicator light works great and comes on about 1800-2000 rpm. I have tried to shift every time when the light comes on, trying to get the best fuel mileage.


Any ideas or suggestions? Anything would be greatly appreciated. Thank you

[IndyFetch]

Seafoam the engine. Drop the oil pan and clean the sludge out of it. Fill the crankcase with 1/2 qt high-detergent ATF, and then fill the rest with regular oil. The ATF will help to clean the sludge out. Check for exhaust and vacuum leaks. I would drain the fuel tank if possible. If not, run all of that crap fuel and treatments out of it, then re-fill with gasoline only.

[JanGeo]

Sounds like the gas in it was concentrated btu gas ... All the low btu components had evaporated. The oil light coming on is not good! Also sounds like you had a prior owner who didn't know about oil changes. A mechanic friend has met people like this that do not know the engine oil needs changing and just keep driving it until the oil congeals.

[GasSavers_gashog]

I have seen 2 cases of someone putting ATF in a crankcase and both resulted in major destruction of the motor, One of them was me by picking up the wrong bottle that looked almost the same. Made the car start using oil bad. Another was a guy in California state park. He had to replace the motor on his S10

[IndyFetch]

I had a bad lifter tick when I bought my truck (it had sat for a long time) I added 1 qt ATF and 1/2 qt Lucas oil treatment to the crankcase. It cleaned out the lifters and the tick went away. I changed the oil after about 500 miles, and when I re-filled, I used 1/2 qt of ATF and 1/2 qt of Lucas oil treatment. When I change the oil again, I intend to use no ATF (it is running smoothly now) and no oil treatment. I didn't use straight ATF; it was a relatively weak blend of 20% for 500 miles, then 10% thereafter. I have not had any ill effects thus far. If I do, I will be sure to let everyone know.

[Rusty94cx]

I would think that the problem is not in the fuel run a couple of tanks of premium to help but I agree check for vacuum leaks check all hoses and the carb it has one right probably needs rebuilt. Sitting is bad especially if not done properly. Could even be a bad 02. Check for mouse nests in air box. Ie restricting air flow poor performance. I've seen it all. Start with basic tune up stuff. Any check engine light?

[88crxhf]

no check engine lights, only when the oil light was on and i changed the pick up tube and oil pan. i dont understand why it would go from 44.1 mpg to 37.0 mpg to 33.0 mpg. I filled up again today with another 33 mpg fill up.

[GasSavers_Erik]

Also check the brakes to be sure they aren't dragging.

[JanGeo]

I am sticking with the gas as the cause. The old gas just had more energy in it or was thicker and affected the air fuel ratio. Uh unless you calculated wrong?

[88crxhf]

Brakes are brand new, no drag. Kinda hard to mess up basic division.