Davidd408

I bought a 90 civic si not too long ago with a bad block and swapped in a sohc zc non vtec. I noticed im getting 16-18 mpg. I bought a new cat and replaced the dizzy. Nothing changed. I noticed a fuel smell when driving and i also noticed i can only fill up to 9-10 gallons.(yes its still 16 mpg with 9-10gallons). Aren't i suppose to fill up to 11.9? Also my car tends to die if i let it coast. I read that may have to do with the main relay though. I plan on sea foaming the engine and replacing the o2, and doing a full tune up. Hopefully this helps. What other things should i look at if what i do doesn't help? Its not throwing any codes, but the cel came on like 2 times in the last month though but went away within 5 seconds both times. Any info would be helpful. Thanks.

zrickety

iTrader: (1)

11.9 gallons would be bone dry with you on the side of the road. You need to check the LED on the ECU and find out what codes are in there, even if the light went out. Have you checked the timing and checked for any gas leaks? Maybe a dragging brake?

Davidd408

my car kept turning off with my needle being right at E so im assuming it had no more gas left. I was only able to put 8.8 gallons this time before it starting overflowing. I also forgot to mention. I usually always get 100 miles right when the needle is at the middle. It doesnt make sense because i only have 60 miles left(which isnt half a tank accoring to the 100 miles) before im completely out of gas. Could it be the fuel pump? Floater? Fuel pressure? Besides that, i checked the ecu and it didnt throw any codes even after i reseted it. I didnt think about the brake dragging but i'll take a look at that hopefully this weekend. Thanks for your input.

Davidd408

So i tried locating the smell today. I thought it would be near the engine bay but it's coming from the exhaust. It kinda smells like raw gas. What can cause this? Anyone?

95accordCE6

Check the spark plugs, make sure they're gapped properly and the porcelain isn't cracked...is the engine running rough like a misfire?

br8crumb

i just wanna throw this out there... check and measure the tps?? once u start driving it works to adjust the air/fuel along with idle rpm etc.... could be putting in too much gas if its not calibrated or bad/on its way out

Davidd408

Gap is fine. All at .40, they are black tho. Its not really misfiring, it's just really smelling like gas

Davidd408

thanks i'll check it out tomorrow.

chettej

did you ever find out what this was?? I just got a 91 civic hatch and it is doing everything that yours is doing to a T. the smell of gas, horrible 15 mpg, the only difference is my civic is throwin a code 5&16.
but she runs and drives fine.

sstupid

Good luck with this one guys. I had a1991 hatch for 3 years and had raw fuel smell from exhaust for the whole time I owned it and got about 26mpg no matter what. I couldn't drive with a window down. It was that bad. Changed plugs, wires, MAP, cat, O2, fuel filter, and air filter. Never figured it out and sold it. A valve adjustment helped the most but didn't cure it.

chettej

ddannnnggggggg!!! everything you just listed off was what I was gonna do this week to try and fix the problem sstupid. that really really lets me down. I honestly don't know where to go from here. I don't want to waste all this money on parts and it not fix the problem. id say the only different is my smell of fuel isn't so bad that I cant roll my window down. any suggestions from anyone else on how this can be fixed besides the tuneup(plugs,wires, cap),MAP, Cat, o2, fuel filter, and air filter.

zrickety

iTrader: (1)

If you are in the snow belt, check for rusty fuel lines under the back compartment inside and by the tank outside.

chettej

I don't know the history of the car where its bee the past 20 years, but im in Alabama.
but I will check the fuel lines in back and near the tank.
thank you zcrickety

chettej

hey guys I was just throwing out there that ive now replaced the fuel filter, pcv valve& hose, o2 sensor, valve cover gaskets, tuneup (plugs,wires,cap), MAP sensor. I plan to put a tps this week and see how much all this helps. I just filled up and ive only gone 11 miles so I cant really see if all these parts have helped with my horrible 15mpg I was getting. I was throwing codes 5 & 16. that's MAP sensor & injectors.

well after putting all the new parts on I reset the ecu and now code 16 has gone away soooo im guessin the fuel filter was just sending bad fuel to the injectors & throwing the 16 code. Sadly even after replacing the map sensor code 5 is still showing... ive checked hose #21 its good with no cracks or tears, so for code 5 the only thing left to replace would be the throttle body or ecu itself. correct??

I will say the car does seem to run a little smoother now, but when I crank it she still sends out some white smoke for a minute and the smell of raw gas is still very apparent. what else should I look for ? ive seen rusty gas lines so that's goin to be next along with the new tps. ANY help would be great!

Lastly when I pulled the valve cover & replaced the gaksets, I noticed the white milky moisture substance in the valve cover and on top of the motor. the car sat for a month so I believe its just moisture, am I right ?

baller status

So it sounds like there were three people in this thread, all with a similar problem, none looked for a fuel leak or had the injectors serviced. The first guy sounds like a great candidate for a plugged or bypassed charcoal canister. Check the fuel tank return line and hoses. It's not your main relay, it's not a brake dragging... I wouldn't bother checking the plugs yet. Sell the car; great. Problem solved.

Second and Third guy: Did you buy your car off the first guy? lol Test the fuel pressure and have the injectors serviced. It's difficult to confirm whether injectors need service, but it's safe to assume that they need it every 100k miles and none of them ever get it. Don't replace them btw, especially with aftermarket. Used Honda injectors are better than most new aftermarket injectors.

Confirm that you have the original injectors, and fpr. Idiots used to (and still do) upsize these things when it isn't needed. Then your engine runs rich and you lose a ton of power, cause bore wash, sell the damn car and the next person has no idea. You don't need to upgrade your fuel system unless you're running forced induction.

Don't replace any parts without confirming they're bad. O2 sensors, MAP sensors, TPS sensors, distributors, cat converters, spark plug wires can all be tested and confirmed good or bad. For the price of replacing these parts, you can pay a professional to fix your car properly.

chettej

thanks baller status. im goin to look into get the injectors cleaned and check the fuel lines as soon as I can get it up on some stands. and see if that fixes my problem. thank you for letting me know!