nabin

iTrader: (2)

Let me start by saying I am not new to Hondas......

I have owned my car for a little 4 years now, 1995 Honda civic LX sedan (280k on body). When I bought it, it was all stock. Since then I lowered it, put 2000 Si wheels on it, gsr brakes, swapped a gsr on a p72 into it, etc etc........

Recently, I decided that there is no reason to have a gsr in my daily when I drive an hour to work every day. So I bought a d16z6 on a p28 (~170k on it) and swapped it in for the gas mileage. I replaced every gasket on the motor, new timing belt, wp, and all that jazz. gsr brakes and si wheels still on it.

So once it is running I take it out, and fill a tank and use a whole tank of gas and calculate my mpg. it was 29 mpg. Not really what I was looking for, but heck, it was much better than the gsr was getting. The next tank of gas I did the same thing... 25mpg.....next tank, same thing - 25 mpg.......

This has me freaking out, I want the good gas mileage if im going to have this low *** car.

So, HELP ME PLEASE!!!

Here is what I have done so far to attempt to correct the problem.....

-First I put injector cleaner in the fuel tank thinking that may be the problem. It was in those two tanks of 25 mpg.

-next I thought my injectors may be bad and dumping fuel, so i pulled my dip stick and smelled my oil...... it doesn't smell like fuel, just oil. I noticed it had burned off a good amount of oil too. I filled the oil back up.

-someone said that sometime the return line gets clogged, so I blew the line out with 90 psi from the air hose with the gas cap off. There was no clog it actually sprayed gas out of the spout where the cap goes.

-due to the loss of oil, i ran a comp test 175 across the board. while doing this, I noticed my plugs looked white, like i was running lean........... BTW they are new plugs.

-I thought may be pcv valve, so i took it off and the cleaned it, the line that goes to it, the line it goes to and the nipple that comes off the intake manifold with carb cleaner. the pcv valve seems to be functioning correctly.

-i was going to replace the o2, but i am not throwing a code for it and i only have a bosch one at home, i heard they are CRAP to run on a Honda.

-the fuel filter was replaced about two years ago, and i do not think that is the problem since my d is getting basically the same gas mileage as my gsr.......


Some one please help!! anything I haven't thought of or an explanation.

At this point I am pretty much stumped! I'm not the poor kid that is going to cry about needing to replace a part because i have no money, but i also don't want to dump any more money into the car chasing leads that end up getting me no where.

Former User

No mention of most important items with respect to gas mileage:

Plugs, wires, cap, rotor, ignition timing, CEL codes

nabin

iTrader: (2)

ignition timing is perfect. I set it correctly using the lines it should be set on, and then used my timing light to perfect it.

cap and rotor look to be in good condition, but i plan on replacing them today. And if you read the whole post above it says i put new plugs in.

you are right, i need new wires.

nabin

iTrader: (2)

oh and also if you read the whole post i mentioned NO CELs popping on.....

teamXteg

what about the cat? you said it was burning some oil. is there a chance that it has got a lil clogged up?

Former User

Does the CEL work?

Also check for an exhaust leak and whether the engine is running cold.

Former User

Was the service connector jumped when you did this^? Was the engine warmed up and idling to spec?

nabin

iTrader: (2)

im sorry I do not know what you mean by the service connector... you mean the connector that makes the CEL blink??

Yes the engine was at operating temperature when timing was adjusted with distributor.

Former User

Yes.

To set the base ignition timing correctly, the service connector must be jumped to prevent the ECU from altering the ignition timing electronically. See diagram in FAQs sticky.

nabin

iTrader: (2)

Exhaust had a HUGE leak for one of those tanks of gasoline, but I have since fixed the exhaust leak and gas mileage has not changed.

YES, 100 percent CEL works. engine seems to be running at correct temperature according to gauge in cluster.

nabin

iTrader: (2)

oh crap, I have never heard of that!!!! I am going to look into that. any other suggestions?

nabin

iTrader: (2)

I am running a test pipe. no cat.

Former User

I'd say I did pretty well if that's all I missed after reading your novel of a first post.

Better go back and read what you posted. You only said there was no CEL code for the O2 sensor.

nabin

iTrader: (2)

Sorry for the novel, and you are correct sir! Thank you for your help, please continue with suggestions.

jlaustill

I'm having almost exactly the same mileage on a D15B7, which is pretty much the same motor from what I can tell. I have already done fuel filter, air fitler, cap, rotor, plugs, wires, timing, cleaned iacv and set idle, checked tires and wheel bearings.

I've currently suspecting

wheel alignment
a/c compressor drag(think it's starting to seize)
cat plugged

I'll be watching this thread to see what you come up with, but I bought this car FOR the mileage, so I'm not very happy with 25-30 when other people are getting 36-40...

nabin

iTrader: (2)

Yea man I got 28 on the last tank. No real change I don't think.... I played a bit and had a lead foot this tank cause I'm annoyed and dgaf.... I ordered a new cap, rotor, and wires... Even though I saw no issues with the ones I have. Better to put new ones on and rule that **** out.

nabin

iTrader: (2)

Setting the timing with the plug connected did nothing for my gas mileage :/

jlaustill

Out of curiosity, are you running A/C?

Former User

Good idea.

To what mark on the crank pulley did you align the pointer?

Are running an the stock fuel pump, fuel pressure regulator, and injectors?

nabin

iTrader: (2)

stock everything. aligned to white mark while setting timing and middle mark of the three while running at operating temp and idle.

yes running ac, i don't always have it on though.

redcoats1976

im getting around 27 with my del sol si,d16z6 auto.im assuming i would get like 32 with a manual transmission with all else unchanged?and yes,its had a tuneup,new wires,plugs,cap,rotor,fuel filter.i run the a/c all the time.its hot here...

nabin

iTrader: (2)

new cap, rotor, wires (plugs had been one in past 2k miles).... no change in gas mileage.

new issue arose - burning about a quart of oil every 500 miles....

Telecatster

"i was going to replace the o2, but i am not throwing a code for it and i only have a bosch one at home, i heard they are CRAP to run on a Honda".

An o2 sensor can be weak (but not faulty) and not throw a CEL. This may be the issue. Denso is the OEM, just need to replace with correct wire (3 or 4) for your model and year.

Did you calculate your mileage yet and if so, how?

sweesiong78

do a compression test on your engine (rent one from autozone or get one in link below)....if the rings are worn and you have low compression I can see how this might be causing your low MPG and high oil consumption. Before spending anymore more $$ on the engine and throwing parts at it would be wise to check if your engine internals are OK or you are just throwing $$ down the drain.

compression tester

strategy400

He already did that see OP.