What is its function ?

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Aug 28, 2011 | 12:54 AM

MainePorsche

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From: North Country

What is its function ?

Guys,
Pardon my ignorance, but what is the function of those two non-linear thin metal tubes with the blue caps on each side at the rear of the engine ?
Thanks

Aug 28, 2011 | 12:57 AM

James Bailey

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Test ports for emission sampling on 85-86 cars.....

Aug 28, 2011 | 01:02 AM

MainePorsche

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Thanks Jim, I always wondered what they were. I'm an 87. Best wishes with the 'Show'.

Aug 28, 2011 | 01:29 AM

blown 87

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Quote:

Originally Posted by MainePorsche

Thanks Jim, I always wondered what they were. I'm an 87. Best wishes with the 'Show'.

Yes, they are on the 87's also, they are used for setting the CO levels.
Nobody seems to use them anymore, most are rusted out and are NLA I think.

Aug 28, 2011 | 05:26 AM

jon928se

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Quote:

Originally Posted by blown 87

Yes, they are on the 87's also, they are used for setting the CO levels.
Nobody seems to use them anymore, most are rusted out and are NLA I think.

Carried on until '88.

Only useful purpose is if you have Cats but no O2 sensor - lets you sniff the real mixture to set it using the potentiometer fitted to no Cat cars.

DELETE.

Apparently an old lug nut fits the port on the downpipes perfectly. Alternatively put a 1/4" ??? ball bearing where the pipe used to be in the brass union nut and seal the hole with that.

When they are rusted out and broked they make an interesting rattle that is completely unfathomable until you eventually find it, they also sound like a small leak from a manifold gasket.

Aug 28, 2011 | 07:55 AM

the flyin' scotsman

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Test ports for exhaust that indeed were used through '88 and perhaps beyond?

I removed them from the manifolds and capped them, 1/4" pipe thread IIRC.

Last edited by the flyin' scotsman; Aug 28, 2011 at 12:31 PM.