88 CRX HF, bad fuel mileage
 

Bought a one owner crx hf about a year ago, at first it was getting mid 20 mpg. It was really hard to start in first gear and kept losing power above 65mph I changed the plugs and wires, O2 sensor, the egr valve, after egr valve I started geting mid 30's. I recently adjusted the timing to full advance and it got 48 first time I refilled. It seemed like the car had really come to life at first, wasn't hard out of first and buzzed along great on the interstate over 70. Now I'm not so sure. I'm starting to think the timing belt may be on wrong because when I use the timing light on the engine nothing ever lines up which is why I put it to full advance cause it seemed the closest to getting the 3 and 9 o'clock marks flat with the head. The fuel mileage on my second fill-up went back down to 33 and I was really babying it. Its pretty frustrating getting such bad gas mileage in a car I hear regularly gets 50 mpg. the car has 136,000 miles. I know the previous owner changed the gas tank, and the fuel injectors. I also changed the fuel filter. I'm planing to change the spark plugs again soon.
I bought another crx, a 90 hf, just a couple weeks ago with 312,000 miles and a blown head gasket and warped head. Driving it around the block it seems like it would probably get better gas mileage. (I didn't drive it until I used the block and gasket repair liquid)

find out who changed the timing belt and water pump, if it hasn't been done then do it, but I suspect that it has been done and that is when they screwed things up, those heads have a number of marks on both the head, and the cam sprocket and you have to read the book to learn what mark to line up with what, if the mecanic figures that the biggest mark is what gets lined up with the top of the head then it will do exactly what you are having happen, so spend $15 on a book for it, and fix it, or buy the book and expalne the mistake to the person who is going to fix it.
also, how is the car running otherwise? my crx hf has had the tranny swaped to a tranny from a DX and it revs 1,000rpm higher now, giving it poor mileage, you might also have a back presure test done, to make sure you cat isn't cloged, and doing a normal full 60,000 mile tune up with a check list (shop manual has this) should help you alot!

I would wonder if they replaced the injectors with 240cc injectors instead of 190cc, do you have any way to find out who did the work in the past?

I have all the manuals for it, helms, haynes, and mitchell. I don't know about the injectors. I could call the guy he was pretty nice but I don't think he'd remember what type of injectors. He said they gave him the wrong ones the first time, he did it himself. When I lost power over 65 on the interstate it seemed it may have been flooding cause there was a "sweet spot" in the pedal and above that it bogged and lost speed.

on the cam sprocket there are 6 marks and an "UP" marking. there is a line at 3, 6, and 9 o'clock when "UP" is up. Then 2 numbers and a D. None of my manuals specify anything other than 12-16 degrees BTDC @ 650-750rpms at running temp with the jumper hooked up.

That was my first thought as well.

As for the 90 CRX HF, you can get a fairly new engine for around $500 shipped to your door from an importer. Might be worth looking into.

Sounds like your cam timing is off a tooth to me. You can often get away with adjusting it by simply loosening the belt tensioner and slipping the belt off the cam gear. Beats trying to remove the crank pulley.

Are the injectors the same in the 90 model? maybe I could switch them out, at least I could know if that was it or not.

I think all HF injectors are the same, so go for it.

03 Si
 

Yeah, my dad has a 2003 civic Si, the hatchback made in the UK, and hes got 120,000 or so on his. My 88 was parked by the previous owner for probably 5-8 years and then I drove it 120 miles round trip to and from work for a few months with that bad gas mileage and no a/c. The owner worked on it and another guy that was supposed to buy it worked on it... so its hard to know what happened to it. I didn't have time today, but I'm gonna pull those injectors from the 90 sometime this week. If that doesn't work I'll be attempting to move the timing belt, but I'm not sure which way to move it a notch. Am I correct in saying that the 3 and 9 o'clock marks are supposed to line up with the head? I don't know why I can't find documentation on which timing marks to use. Is there writing on the injectors that you can distinguish which ones you have? When I look them up online they only specify by model not by what cc they are.