Any of you guys passing emissions with larger injectors? I have been having problems passing with my current set up (see sig). The CC305 cam is on a 112 lsa. I am in the process of changing to a blower cam and am installing a set of Kooks headers with their catted Y-pipe. I considered changing to smaller injectors just for the emissions test, but doing that on a yearly basis would be a pain. I keep failing on the hydrocarbons. 220ppm is the limit and with my current set up detuned and with some fuel additive I got to 280 the last time.

 

My friend's 95 Z28, 383, 224/236/114 cam, AFR heads and blower passed smog no problem here in CA.

 

He passed in CA???

Good thing that I'm exempt here with my 94

And even if I wasn't, I know the right people

 

With my 72lb inj I never can get it to idle any leaner than 12.5 AFR and always fail... I think I had 500ppm HC's. Swap in the stock injectors and tune and it blew a 50 PPM HC. I've had to do it the last two years.

 

That's pretty much the same problem that I've been having. Guess I'll have to do the same and swap injectors for the test.

 

Using 94 NO TOP Z's tunes I have passed with 50's three years in a row. I think the key is changing the fan settings back to stock, I think the fuel burns off in the headers.

 

Flip94TA: What size injectors are you using?

 

50's, I remember you have a hard time last year also.

 

I just looked at your last post and you already answered my question. I don't know how I didn't see that. Duh. You are right. Last year was the first year of testing and I tried to get through 5 times and never passed, so I just gave up for a while until I could get these other changes made. I told my tuner that we have to get it through this year, so we are pulling out all the stops. I'll pass your info on to my tuner.

 

Are you guys running hi or low Z injectors?

I'm assuming "94 NO TOP Z" 's injectors are low Z. You can't get better than 12.5:1 AFR at idle? Jeez...

-Alex

 

94 NO TOP knows more about tuning than me, but I do remember that the injectors are set at 42.67lbs in the tune, they are supposed to be msd 50's but I bought them used and never ran the model number on them, it doesn't lean out so I am assuming that they are correct and the car just runs better at the setting. I think the AFR was 12.2 on the dyno.

I would just try a stock tune with the injector size corrected and idle at 850-900. If you fail HC, it should only be in the 250-500 range, adding about 5-10 bottles of .99 cent drygas will lower the HC more.

What kind of numbers did you see last time?

I been wondering if the ethnol changeover in pump gas will also make it easier to pass on HC.

 

I am running the low-Z 72's. I played with the programming a lot but, have never been able to idle at the correct AFR. Ever since I have installed them the O2's just don't move at idle and the BLMS never move. Could be something simple.

 

I assume this is closed loop? The injector offsets are set and everything?

I'm just hoping I won't have issue idling at 14.7:1 with large low-Z injectors. Trying to understand if this is a mechanical limitation (running high fuel pressure or/and the injectors are simply to large) or if it's a programming issue.

-Alex