Hi everyone,

I went to get my emission test done today, and my car failed due to high HC ppm at ASM2525 (whatever that means, i guess during driving). Did anyone have this problem before and know how to fix it, any suggestions?

my test results

ASM2525 TEST
________Limit_____ Reading ___Result
HC ppm __ 55_______109______fail
CO% ____0.31______ 0.18_____pass
NO ppm___612______547______pass

rpm 993
dilution 12.3


CURB IDLE TEST
________Limit____ Reading___ Result
HC ppm__ 200_____ 116______ pass
CO% ____1.00______ 0_______ pass
NO ppm___ n/a____ n/a________ n/a

rpm 679
dilution 10.7


thanks for your help everyone

pat

 

ok, so you've got a 1988 LB9 there, from what i've been able to find out.

Any modifications? Any trouble codes in the ECM?

 

time for a new pistonrings

 

i have the 34 code popping up once a month, as for mods the car is stock except for a high flow cat and flowmaster exhaust. The car has been sort of bad on gas lately (appro. 15 m/g), and running a little rich.

Is that a sign of a o2 sensor gone bad, the one I have in right now is about 5 years old (bosch).

Any suggestions?

Thanks again for all your help.

Pat

 

HC means Hydrocarbons, which are that black sooty smoke that appears out the the exhaust on some cars. It's unburnt fuel and oil.

You probably need a ring job if your car is using oil.

code 34 means MAF - it could be that your car is reverting to stored fuel/air values and not using the values from the MAF. When it does this the ECM errs on the side of caution and thus runs rich (rather than lean which burns holes in pistons). If this is the case - fix the MAF problem and you will probably get down low enough to pass.

Number 1 - find out if/how much oil your car uses. If its more than a 1/2 - 1 quart or so per oil change, then stop and find something else to drive that'll pass emissions and get you to work and whatnot. You won't easily be able to fix high HC due to burning oil without tearing it all the way down.

Number 2 - fix your MAF problem! New MAF or MAF relay (more likely). Check EGR too, if its stuck open your ECM will see less O2 and richen the mixture further. That won't jive with the MAF reading so it'll throw the code and richen again.

All else fails - as long as your not burning oil ----- denatured alcohol has very little hydrocarbons... I won't say more because I love mother earth.

CAT does nothing for HC. You're passing on NO and CO because your catalytic convertor is working fine.

Looking again at your test results. I wonder if your EGR is working at all. your driving test and your idle test are almost identical for HC, about 110. When doing the driving test your at part throttle which "should" actuate EGR, recirculating part of your exhaust through the intake. THis normally reduces HC. Worth looking into.

 

I'd do valve seals before worring about piston rings. A leakdown/compression test will let you know if the rings are bad.

I'd put my money on bob doles' suggestions about the MAF.

 

thanks to all for your help and suggestions

i did a complete tune up on the car; the timing was reset to original settings and i have replaced the following

spark plugs, wires, distributor rotor and cap, 02 sensor, pcv, fuel filter, serpentine belt, heater valve, engine flush & oil change, air pump valve, coolant sensor, by-pass hose and intake manifold gaskets, thermostat.

(the thermostat, gaskets, and especially the by-pass hose just needed to be change)

the car still failed but then........

i changed the high flow cat and ...................

the HCs dropped to 52 from 108 below the 55 limit on LOAD and my car has PASSED emissions (finally three weeks later)

thanks again to all for the help and suggestions