Can anyone help me out here? I changed my cat (I already had a new one), but they changed it anyway... And now it actually did worse! The HC and NOx was in the failing region (as opposed to before) it was on the NOx. I'm about to go back and have a high flow cat put on, they say thats better so I will do that... Any suggestions?? Thanx

The motor is a 94 gsr 60,xxx on bottom end and about 1000 on head since rebuild
It has new valves
New valves seals and guides
ITR Dual valve springs
ITR cams (Could it be the ITR cams??)

Should I change my O2 sensor? (it used to run rich, maybe that messed it up)
I already changed spark plugs, should I get some better ones?? Should I change oil?
WTF can be the problem? Plz help, I've just about had it with this car... :wtc:

 

Actually a high flow cat does worst as far as smog standards. The HFC doesn't operate as hot as the stock cat does in which burns/filters less (some smog guy was telling me).

Since they've rebuilt it, check to see possibly the timing is off (timing light).

 

My friend and I have rebuilt it... He never had any problems with any of his motors... Timing is at 16 degrees... EVERYTHING works fine, the smog guy told me... They keep telling me its the cat, wtf I just had it changed. Went through 2 new cats, now I will either clean or replace my o2 sensor since running rich might have effed it up... Any other suggestions?

 

I'm with FOOD on that one. If ur going to put a new cat on then dont put a high flow cat, that will make hydro carbons go up even more so.

 

Well, we all know the cat can be lazy, however if it failing completely then you would have a CEL. You would also have a CEL if the 02 sensors were bad. These don't get lazy, they work or they don't. I do not think it is the ITR cams since the smog dyno does not even take the rpms up high enough to engage the changeover point. However, if the valve adjustment was not done to full spec. the motor may not be running right. High HC means that "all" hydrocarbons within required spec. are not being burned off. So stop looking for the stuff w/no CEL's. If you have not already done so, I would adjust the valves, do a full tune up and run a honda top end cleaner through and see where you are. Have you ever used race fuel? Just asking...

 

Damn man, sorry to hear. You've been trying for a long time...

What kind of plugs are you running? Exact model number...

 

I have always heard that an O2 sensor can fail, but will not always trip the CEL. From what I recall, if a failure occurs they are designed to make the engine run slightly richer instead of lean to protect the engine. A sudden drop in gas mileage is an indicator of this condition.

Has anyone else heard of this condition?

 

Is the cat ment to be broken in?? This new one I have had about 90 miles on it today before I failed and did worse than the old one overall... However it failed 15mph and passed 25 mph, just like before. I'm running the ngk v power plugs. Would you guys recommend bosch plugs? I'm also thinking of running "guaranteed to pass smog", the fuel additive. I have never used race fuel, I just run 91 octane. I'm out of ideas. So ANY help is appreciated. Thanx

 

As for the valve adjustment, I have done that myself about 1000 miles ago, when I dropped the motor in after the rebuild. It was my fourth valve adjustment, used the b18c1/c5 specs from the helms manual. I double and triple checked the clearance between the lobes and lifters and the torquing... I doubt I made a mistake there. I AM running FERREA valves, but that can't be it, since many of my friends have used them and passed w/o problems...

 

put a stock cat on (just for the test) and a new o2 sensor and just double check to make sure your timing is correct. i had the same problem with my ls/vtec, change my cat to stock for the test with a new o2 and got low numbers across the board!!