Failed Emission Test

[blee]

'87 3.2 that has been sitting for aprox. 3-months while I replaced the leaky fuel line and detailed the whole top-end while everything was apart. Started right up but failed emission test because the HC count was 264 PPM at idle. The limit is 220 PPM. It passed cruise HC as well as cruise & idle CO tests. I know the Motronic/DME automatically manages everything. Is there anything I can check or adjust to reduce the idle HC count? One tidbit of information: I drove straight to the testing station after starting it up, which is maybe four miles away. Would bringing the temperature higher make enough difference in the count?
Regards.

[Drew001]

Check this thread. Lots of good information there from banjomike.

[911Freak]

I would SERIOUSLY recommend you ALWAYS do several blasts and blow out the carbon and get the engine running as warm/hot as possible before a smog test..I'm sure driving to the shop like you did wasn't enough to get the engine in optimum temp..and from sitting you didn't get it blown out to do a good test..

I always hot shoe my SC prior to getting it smog'd, a few good hard accelerations on the on-ramps are a good starting place...sustained high rpm is good but it really helps to get good pulls through out the rpm range..

Go on a good spirited drive before retesting..I'd pay the extra $$ and get a "pre-test" done just incase...

[don911]

I've always had the engine fully warm and usually run high rpms before going to the test. My 87 passes with no problem even with a cat bypass installed.

[PatrickB]

I bet if you drove the car for an hour right before you test, you'd pass without doing anything else different. Get that CAT cookin'! Also, if you're close to oil change time, do that too. Sometimes that can help.

[DRACO A5OG]

Originally Posted by 911Freak

I would SERIOUSLY recommend you ALWAYS do several blasts and blow out the carbon and get the engine running as warm/hot as possible before a smog test..I'm sure driving to the shop like you did wasn't enough to get the engine in optimum temp..and from sitting you didn't get it blown out to do a good test..

I always hot shoe my SC prior to getting it smog'd, a few good hard accelerations on the on-ramps are a good starting place...sustained high rpm is good but it really helps to get good pulls through out the rpm range..

Go on a good spirited drive before retesting..I'd pay the extra $$ and get a "pre-test" done just incase...

+1 plus more detail:

Start her up and drive off right away, (siting at idle wil create more carbon deposits) and drive around town keeping her under 3K RPMs then bring her up to full operating temperature at or near 8:00 o clock on your temp guage.

After complete warmup, at stop in first floor it and bring it up to 6.5 RPMs "Redline" 5 seconds yes redline, look in the review you should see allot of carbon deposits blow right out.

She will run smoother to boot.

Break a Leg on your Re-Test

[blee]

Thanks for all the replies - I'll take it for a longer drive prior to getting it inspected again. Wish me luck!

[Otto]

Tighten the intake manifold nuts. We have noticed almost every 3.2 we do needs it.

[rusnak]

omg your gas is too old. It has probably been too old for at least 2 months.

You should drive all of the gas out, maybe add some BG 44K to a full tank, and refill with fresh Premium 91 Octane.

Make sure the car is HOT. Make sure the attendant doesn't let your 911 sit out in the cold for a long time before doing the test. It should go right onto the dyno. You should drive it more than 4 miles. The hotter the better. It'll pass for sure.

[blee]

Woooohooooo!
She passed! Sure enough, the intake manifold was loose, added new gas with a can of detergent, drove it on the freeway for 30 miles (CAT was cookin), gunned-it on the on ramps- what a wicked scream at 5200 rpm! Good times. Thanks for all the feedbacks. Now that I'm good for two years I can finally rip out the cat & stock exhaust and install the new SSIs & dual in/dual outs.

PS - someone gave me an interesting tip: disconnect one of the injector lines before getting tested, supposedly acts like an air pump, resulting in less emissions coming out. Who would have known?