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z3pilot99 · 11-22-2010, 02:50 PM

Didn't know quite where else to put this. I have a 1990 CRX HF. I purchased it knowing it needed a little work. I have replaced nearly all suspension bushings, front wheel bearings, EGR system has been cleaned, PCV parts all replaced. Valve stem seals replaced. Found a PO had put a Si ECU in the car. And, have since replaced it with the proper HF ECU. Car has a header/no cat. Has passenger side mirror. Also, it has oversized tires(185/60-14) where as it should have 155/70-13 I think. The electric load detector (ELD) is bad according to the ECU. That is the only code it is giving me. I am working on replacing it now. My mileage is all over the place. I have a 2001 BMW 325xi wagon that I can get over the rated milage on driving the same roads as the CRX. I do not expect the CRX to get the 50 or so that I have heard tales of. But I was hoping a consistant mid to upper 40's. I just cannot believe that the tires could cause that huge of a drop. I am getting mid to upper 30's. I drive the car very gingerly. Always aware of the MPG and my goal of the mid 40's. Last fill up was one of the best at about 45 mpg but I drove it last week and it has dropped. Where as I was getting 150 or more out of a half tank I am now at 110 at a half tank. I know how to check mileage. I drive to about 1/4 tank left, fill it up and divide mileage since last fill up by the amount of gallons needed to fill it up. The is getting very frustrating. I bought the CRX because I have about a 150 mile round trip commute. The BMW is real nice and of course much nicer to drive. But could not afford to drive it everyday @ 23 mpg. Can the ELD make much of a difference? I was thinking it might as it might cause the alternator to be switched "on" by the ECU when it really is not needed. Thus causing more load on the engine at highway speeds. Tires I thought might make a 3-5 mpg difference. I just bought the tires. I keep them inflated to about 40psi. They are not LRR tires. The PO had put 14" wheels on the CRX. So, I stuck with them when buying tires. That may be my big mistake. I would just expect mileage to be consistant. If it were consistant then I could start to knock down issues and figure out where I need to go next. The CRX runs great. Any ideas?

11-22-2010, 02:50 PM	#1 (permalink)
z3pilot99 EcoModding Lurker Join Date: Sep 2010 Location: Apple Valley Posts: 19 Ford Focus - '12 Ford Focus 5 Dr - SE 90 day: 37.36 mpg (US) Thanks: 0 Thanked 0 Times in 0 Posts	Low CRX HF Mileage Didn't know quite where else to put this. I have a 1990 CRX HF. I purchased it knowing it needed a little work. I have replaced nearly all suspension bushings, front wheel bearings, EGR system has been cleaned, PCV parts all replaced. Valve stem seals replaced. Found a PO had put a Si ECU in the car. And, have since replaced it with the proper HF ECU. Car has a header/no cat. Has passenger side mirror. Also, it has oversized tires(185/60-14) where as it should have 155/70-13 I think. The electric load detector (ELD) is bad according to the ECU. That is the only code it is giving me. I am working on replacing it now. My mileage is all over the place. I have a 2001 BMW 325xi wagon that I can get over the rated milage on driving the same roads as the CRX. I do not expect the CRX to get the 50 or so that I have heard tales of. But I was hoping a consistant mid to upper 40's. I just cannot believe that the tires could cause that huge of a drop. I am getting mid to upper 30's. I drive the car very gingerly. Always aware of the MPG and my goal of the mid 40's. Last fill up was one of the best at about 45 mpg but I drove it last week and it has dropped. Where as I was getting 150 or more out of a half tank I am now at 110 at a half tank. I know how to check mileage. I drive to about 1/4 tank left, fill it up and divide mileage since last fill up by the amount of gallons needed to fill it up. The is getting very frustrating. I bought the CRX because I have about a 150 mile round trip commute. The BMW is real nice and of course much nicer to drive. But could not afford to drive it everyday @ 23 mpg. Can the ELD make much of a difference? I was thinking it might as it might cause the alternator to be switched "on" by the ECU when it really is not needed. Thus causing more load on the engine at highway speeds. Tires I thought might make a 3-5 mpg difference. I just bought the tires. I keep them inflated to about 40psi. They are not LRR tires. The PO had put 14" wheels on the CRX. So, I stuck with them when buying tires. That may be my big mistake. I would just expect mileage to be consistant. If it were consistant then I could start to knock down issues and figure out where I need to go next. The CRX runs great. Any ideas?