Ok, here's what I got, ZZ4 cam, stock TPI, no EGR, basically a stock chip with a little timing added, brand new hi-flow cat, new O2, 64cc polished heads, fp at 40# line off.
I passed the high speed with flying colors, only 7 HCs out of 220.
But at idle, it blew 340 of 220 allowed.
Any suggestions of what I can do?
I know I can lower the fp, but I don't think that will get it down far enough.
Base timing is 7 BTDC, should I increase it a little to give the gas more time to burn.?
Use lower octane gas since it burns faster?
Any additives I should add to the tank?
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I could get a chip chip burned with shorter injector pulse widths at idle, but I need this done fast.
EGR is not functional at idle I don't believe so not having the EGR isn't the problem I don't think.
Thanks

 

I forgot to mention, the CO % was fine, on the low speed idle which I failed, the CO% was .25 out of 1.20% allowed.
So only the HC was outof range.
I suspect the larger ZZ4 cam is the problem.
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How about any additives or NAPTHA? What ratio should it be mixed and how much gas?

 

I would decrease the timing to 4 degs btdc, put 87 octane in and get the motor HOT!!! before pulling up to the test station. You may also want to lower fp to 38#'s. I wouldn't add anything like Naptha but I've seen additives at the parts store that are supposed to help lower emissions. Good luck! This is exactly what I did to pass the Illinois emissions test with my stroker motor.
www.geocities.com/dzperf

 

If your state doesn't have a visual inspection you could always unhook the PCV valve to create a large vacuum leak and lean the motor out some.

It worked like a charm 10 years ago when MI had the tests.

 

Retested today and PASSED!! :lala: :lala:
At idle, had 18 HCs and .01 CO%
High speed, had 8 HCs and .01 CO%
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What I did was filled up with 87 octane instead of 93.
Adjusted fp down to 35# from 44# with line off
Upped base timing to 10 degrees from 7
Then just screwed in the IAC adj screw till the idle speed was about 1100, it was 650, max allowed for the idle is 1300 rpms.
I did not reset the TPS, it was at .75, because the higher reading TPS will cause the timing to further advance, thus giving more time for the gas to burn.
My Short term integrator counts were in the high 80's before, and now they are in the 115-118 range, big difference.
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Motor runs terrible with it like this, no power and a little detonation, so now I have returned it back to the way it was for now until I can get a chip that works.