I have 91 4G4D EX(D16A6) auto..I haven't done much engine work..just the basics.

aftermarket air intake, new NGK-R plugs (want Iridiums). engine has 120K change oil regularly with 5w30..replaced the fuel filter about 1000 miles ago...timing belt replaced recently, too. I run Chevron 89octane and seem to get only 240 - 265(tops) on a tank... When I first bought the car a few years ago it had 65k on it and the previous owner pampered this thing I have all the papers to prove....I used to get almost 300 miles.

WIRES - I plan on getting newer Spark wires..need suggestions (NGK, OBX, or ACCEL) does it help to have a bigger core (9 - 10mm wire thickness).

TIMING - Is it timing possibly, I've advanced it up a little as it ran slightly sluggish while stopped at a light, the whole car shakes like mad. I haven't scoped it yet.

SMOG - When I got it tested last year it failed...I had to get a whole new exhaust and catayst system to improve the NO2. It finally passed but just barely..the shop said I may be burning on the lean side. HELP HELP HELP

Anyway give me your suggestions as to what I can do to improve the mileage and HP... I cannot afford a swap..plus I love my engine set up(i know I know go B16 or ZC) I will start a donation bucket if you want....

If you read this please bump.





Modified by db_91_4d at 9:17 AM 12/28/2004

 

Don't waste your money on OBX wires, NGK or OEM wires are the best way to go.
If your car is idles too low, you could be too retarded... get a cheap timing light from AutoZone, and set your timing back to stock. (16BTDC) You can advance as far as 18 BTDC if you wish.
Replace your cap/rotor as well, along with the wires... a dirty air filter will also kill fuel mileage, if you have the extra cash get a K&N stock replacment filter, they're great. I also recommend you run a 5w-30 synthetic motor oil, you can gain MPG and engine life with a syn. Before you change plugs and do a tune up, get a bottle of Seafoam. Put 1/3 in your vacuum line @ brake booster, put 1/3 can in your fuel and 1/3 can in your oil, there are many Seafoam threads here on HT.

 

Do you still have the emission readings from your smog tests? Can you post them, that would be helpful. You say the car shakes at idle, how does it run off idle? Is it smooth pulling away from a stop or does it stutter? When did the problem start? Was it after any of the repairs you mentioned? How far did you advance the timing? Did your power and mileage drop after replacing the timing belt?

 

adding an intake is suppose to lower your gas milage. even when the manufacturerrer, "i dunno how to spell..." says that it gets better. Not sure tho, but thats the results my friends and i have.

At least yours is not as bad as mine, i barely get 200 miles per tank, I gotta stop hitting boost too much. BUT IT SO DAMN ADDICTIVE !

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by kewbee7 &raquo;</TD></TR><TR><TD CLASS="quote">adding an intake is suppose to lower your gas milage. even when the manufacturerrer, "i dunno how to spell..." says that it gets better. Not sure tho, but thats the results my friends and i have.

At least yours is not as bad as mine, i barely get 200 miles per tank, I gotta stop hitting boost too much. BUT IT SO DAMN ADDICTIVE ! </TD></TR></TABLE>

thats because it changes your air fuel ratio. Normally from what I have noticed anything u do to the intake side (CAI, intake, throttlebodies ect) generally tends to richen up the fuel curve, and normally when u start moding your exhaust side (headers, exhaust ect) generally leans it out.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by db_91_4d &raquo;</TD></TR><TR><TD CLASS="quote">I have 91 4G4D EX(D16A6) auto..I haven't done much engine work..just the basics.

aftermarket air intake, new NGK-R plugs (want Iridiums). engine has 120K change oil regularly with 10w30..replaced the fuel filter about 1000 miles ago...timing belt replaced recently, too. I run Chevron 89octane and seem to get only 240 - 265(tops) on a tank... When I first bought the car a few years ago it had 65k on it and the previous owner pampered this thing I have all the papers to prove....I used to get almost 300 miles.

WIRES - I plan on getting newer Spark wires..need suggestions (NGK, OBX, or ACCEL) does it help to have a bigger core (9 - 10mm wire thickness).

TIMING - Is it timing possibly, I've advanced it up a little as it ran slightly sluggish while stopped at a light, the whole car shakes like mad. I haven't scoped it yet.

SMOG - When I got it tested last year it failed...I had to get a whole new exhaust and catayst system to improve the NO2. It finally passed but just barely..the shop said I may be burning on the lean side. HELP HELP HELP

Anyway give me your suggestions as to what I can do to improve the mileage and HP... I cannot afford a swap..plus I love my engine set up(i know I know go B16 or ZC) I will start a donation bucket if you want....

If you read this please bump.


</TD></TR></TABLE>

I agree with using see foam, but also do your normal maintenance, plugs, cap wires, rotor, filters and dont forget about the PCV valve. Then possibly look into a fuel managment device like the VAFC to lean out your AFR cuz it sounds like it may be running a bit rich as well. U cannot believe the spectacular mileage difference it made on my wife's Del sol (used wideband obviously).

 

Thanks too all who replied.
I will look into replacing my distributor cap(possibly the whole distributor as it is an aftermarket one). NGK wires and Iridiums...I forgot to correct myself on the oil..I do use 5W30, DUH!!. I will also look into using seefoam. I did use an engine cleaner on my last oil change..thinking that maybe I had bad injectors or dirty valves. Its the kind that you dump into the engine and fuel. ran it for 5 min. and then drain the old **** out.
**
AUTOENG2002SI You don't know what I had to go through to find the paperwork on my smog....OK if you know what your reading here's your test.

NO (PPM
Test MAX AVE MEAS RESULTS
15 mph 835 237 452 PASS
25 mph 774 199 772 PASS

from the looks of it...I just barely passed...this after I replaced the Catalytic convertor and added new catback exhaust sys. nothing else changed up front.

Could it be that I just need to put the stock air cleaner back on for testing? previous posts suggest that air/fuel mixture may be to rich...but the repair guys say that I am burning too lean not enough fuel in the chamber.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by db_91_4d &raquo;</TD></TR><TR><TD CLASS="quote">Thanks too all who replied.
I will look into replacing my distributor cap(possibly the whole distributor as it is an aftermarket one). NGK wires and Iridiums...I forgot to correct myself on the oil..I do use 5W30, DUH!!. I will also look into using seefoam. I did use an engine cleaner on my last oil change..thinking that maybe I had bad injectors or dirty valves. Its the kind that you dump into the engine and fuel. ran it for 5 min. and then drain the old **** out.
**
AUTOENG2002SI You don't know what I had to go through to find the paperwork on my smog....OK if you know what your reading here's your test.

NO (PPM
Test MAX AVE MEAS RESULTS
15 mph 835 237 452 PASS
25 mph 774 199 772 PASS

from the looks of it...I just barely passed...this after I replaced the Catalytic convertor and added new catback exhaust sys. nothing else changed up front.

Could it be that I just need to put the stock air cleaner back on for testing? previous posts suggest that air/fuel mixture may be to rich...but the repair guys say that I am burning too lean not enough fuel in the chamber.
</TD></TR></TABLE>

Can you give me the readings on the other gases (HC and CO), preferably both before and after the cat replacement if you have them? This will help me tell whether or not the new cat is just masking another problem.

 

soon as I get the chance to find it I'll post.
All I know is that the other tests passed this is only section that failed, miserably. the first pass I think was somewhat higher.

 

after you replace cap, plugs, wires and set your timing back to stock.....if you are still getting bad gas mileage I would look at your O2 sensor(s)

 

i have an 89 Honda CRX with a B16 obd0 pr3, and i also cant pass my HC or NO im definatly runnin too rich, but what can I do to pass??? Help Please

 

If you are running too rich your CO should be too high. What do the numbers look like?

 

i lost the numbers but the CO got lowered when i put on a cat

 

HAPPY NEW YEAR 2005 bump..

Still workin to get those first set of test numbers.

 

OK...its been too long since I figured out my problem.....It was a simple fix too. I took so long in answering because I wanted to get at least 2 tank fulls to see if what I was seeing was true....

Replaced the spark plug wires(NGK-blue), spark plugs and and new distributer rotor cover....everything with the distributer is fine.
***
Get this I've gone a min. of 280 miles highest was 310 mi....not freakin bad...If I'd tone it down on my hard driving I would get continuous 300+ miles on 1 tank....Thanks for all your help.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by teler86 &raquo;</TD></TR><TR><TD CLASS="quote">i have an 89 Honda CRX with a B16 obd0 pr3, and i also cant pass my HC or NO im definatly runnin too rich, but what can I do to pass??? Help Please</TD></TR></TABLE>

is your ecu chipped or stock? should be stock if you wanna pass.

Are you using a stock cast iron exhaust manifold or a header? if header, you should use the stock cast iron exhaust manifold; it helps a lot when trying to pass smog. The cast iron does a better job of burning off/absorbing exhaust gases or something of that nature.

your CAT stilll good?

change your spark plugs lately?