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post #1 of (permalink) Old 05-30-2001, 10:44 AM
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Emissions problem

I'm oh-for-2 on passing emissions. The first time I went in 'raw' (unprepared, just hoping) and my CO was 4.02 and my HC was 281 (passing is 1.80/200 at 15 MPH). I knew I was running rich, so I adjusted the carb much MUCH leaner (maybe to a fault) and replaced my spark plugs. I'm now 3.04/219. This is better, but I'm not really all that close.

Any advice? I think my EGR is suspect... It does not hold any vacuume if I hook up my hand-vacuume-pump.

Thanks guys,
Sam88Jeep

'88 YJ 4.2L, 32/36 Weber, Jacobs Ign, 2.5" spring lift, 31" BFG ATs.
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post #2 of (permalink) Old 05-30-2001, 11:14 AM
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Re: Emissions problem

EGR will not help your CO or HC levels, only NOx.. Here are some sites to check out:

http://www.motorage.com/edindex/1200feat1.htm

http://people.ucsc.edu/~kbrandt/mustang/smog.shtml

http://www.myzero.com/engine/egr.html



Mark
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post #3 of (permalink) Old 05-30-2001, 11:32 AM
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Re: Emissions problem

Well, if you're losing vacuum if the EGR is bad, then I would think it 'would' hurt you either way. Replace the EGR, and try again.

For what it's worth, and I don't know the numbers or I'd post those too, I passed my dynomometer emissions test here in MA with my 88YJ, 4.2, auto, weber 32/36, with a PCV and an EGR, no pulse air system. It wouldn't pass with a bad EGR (high NOx), and I had to replace it.

How old is your cat? Might be time.

Good luck
Pete

88 YJ - trails/beach trips only![img]/wwwthreads_images/icons/smile.gif[/img]
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post #4 of (permalink) Old 05-30-2001, 11:36 AM
 
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Re: Emissions problem

It may not be the correct method but run regular in the tank and put 2-21/2 bottles of rubbing alcohol in the tank. the regular will burn better than higher octane fuel and the alcohol will dilute it causing lower HC. Just remember to drain the tank and throw in some dry gas afterwards to get the water out(rubbing alcohol is 70% water).

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post #5 of (permalink) Old 05-30-2001, 11:39 AM
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Re: Emissions problem

Just slap on a new cat, It will pass. You can have one that fails miserably and a fresh cat will pass it no problem.

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post #6 of (permalink) Old 05-30-2001, 12:33 PM
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Re: Emissions problem

My '88 seems to have more miles on it than a jumbo jet... 203,000! Now that you mention it, I'm sure the cat is probably shot. That's probably where I need to start. Thanks for the tip.

Actually I'm getting all kinds of grief about the Weber carb. The air cleaner doesn't take the hot-gas-warmup "stove pipe". Plus, and the emissions guy didn't see this, most of the vacuume lines associated with the 'pulse air' have been yanked. The pulse air is still there though... sucking air endlessly (the on-off check valves are gone). Would it be better for emissions to plug the tubes up?

Also, I'm wondering if the DEQ Certified Emissions place is going to pitch a fit with those changes. Got knows there going to just LOVE the changes to the ignition.

Sam88Jeep

'88 YJ 4.2L, 32/36 Weber, Jacobs Ign, 2.5" spring lift, 31" BFG ATs.
post #7 of (permalink) Old 05-30-2001, 02:29 PM
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Re: Emissions problem

Sam,

I have removed the entire pulse air system, and plugged the exhaust manifold, and the connection at the cat. I found that with the cat sucking air all the time, it gave too much air to the cat, and it got really really hot (the air helps the cat do it's thing - so it was burning off too much stuff (?)) Anyway, it was glowing red.

You can get adapters to adapt the weber to a standard 4" diameter air cleaner if you want, and maybe connect the orig air cleaner (?) and some more of that hot air stuff. I just left mine with the standard supplied square one.

I run the weber and a GM HEI, and I passed the dyno test on my 88.

I've still got you beat, though, 207,000 and counting (but the motor and axles are new - the tranny and transfer has that mileage, though.) [img]/wwwthreads_images/icons/wink.gif[/img]

Not saying this is the way for you to go (legal disclaimer), but it works for me. I passed the sniffer, and that's what should count, not what's under the hood.

Good luck
Pete

88 YJ - trails/beach trips only![img]/wwwthreads_images/icons/smile.gif[/img]
79 4WD F250-hauler/tower of my toys
70 Jaguar E-type - the best car England ever made. [img]/wwwthreads_images/icons/cool.gif[/img]
90 Honda CRX - Daily pavement-pounder. 42 MPG. [img]/wwwthreads_images/icons/cool.gif[/img]
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