i got a 1991 crx hf with a b18b1 running obd0 and it runs great...over 30 mpg....but i cant get it to pass emissions...it has a new cat and oxygen sensor....I only failed carbon monoxide but hydrocarbos were pretty high and nox was a lil high..I advanced the timing and got carbon monoxide closer but not close enough...my fuel pressure was 35 psi with vacuum line connected...would it help more to have it lower or higher....i was thinkin higher for a better spray pattern....like 40psi....or would it be better to drop it to like 30....im running outta trys so i cant keep playin trial and error...i was wonderin if anybody here had experience with this....thanks

 

I would drop the pressure, and add some denatured alcohol to your gas

 

HC = unburnt gas
CO = Bad combustion
Nox = combustion temp over 2500 deg.

Low HC = High Nox so if you are close on both I would not touch the Fuel pressure.
Unfortunately better spray equals more gas too.

I would suggest decarbonization (Seafoam)and or fuel injector cleaner.
Run 87 octane without any additives in it for the test.
Check for vacuum leaks, can cause high CO.
Cap and rotor and plugs if they are old.
Timing should be at spec + or - 2 degrees. if spec is 16BTDC go with 18

 

thanks guys...the cap and rotor looked like new...the plugs are new....the motor only has about 63000....i might get a grip of that sea foam....whats the best way to check for vacuum leaks....any easy way? hc are at 137 and can be 175.....nox are 608...can be 1307...they went down when i advanced timing....so i guess i can have them go up quite a bit.......didnt make sense..? so im not really sure what to do....thanks

 

i would try retarding your timing. and if you advance your timing you must use premium gas. i got a waiver for emissions for my car being too low

 

make sure that your EGR valve is good too.

 

what ecu are you running??

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EF honda EF &raquo;</TD></TR><TR><TD CLASS="quote">i would try retarding your timing. and if you advance your timing you must use premium gas. i got a waiver for emissions for my car being too low</TD></TR></TABLE>

How did you manage that? That would be awesome, I assume that means you also got one of those nifty stickers that allow you to drive in the carpool lane all by your lonesome?

 

i tried retarding the timing and it was a lot worse...i am running a pr4 out of a 91 integra. The motor doesnt have an egr...they are mainly for nox anyways and that is my best category....so i dunno

 

Vacuum and exhaust leaks often cause bad readings.

Last year when I replaced my header I made a screwup and damaged a gasket. It was hissing at the downpipe, and I failed miserably.
Replaced gasket, passed with flying colors.

 

im not really 100% sure if there are no vacuum leaks...but i know there arent any exhaust....i cant hear it...and i seafoamed the car today and didnt see white smoke pouring from anywhere but the tailpipe lol

 

Speaking of emissions, I did mine today. I had a fresh cat put on because I had gutted mine out last year around this time, anyway with the cat on the HC was about 270-280. what I did was took the brake booster line off and held my finger over it alittle to where it was wanting to die. then I got it tested again and the HC level went down to 45-50. So it passed. Only thing is that I knew the people that I took my car to to get it inspected.