Leak Down: Not Ready Yet

[Lee Ann]

Hey All-

RE: 1997 Saturn SC2, 1.9 L DOHC

Visited my local independent shop today to do my leak down test. The owner asked to see my compression test results, which were gathered using an Actron compression tester from Autozone. Well, he offered his Mac compression tester so I happily repeated my compression test. Result: 190 psi cylinder 1, Dry test @ normal operating temp. If you had been following my journey, you’ll remember that I had a 10% wet test difference between cyl 1 and cyl 4 (211 psi and 234 psi, 204 and 215 psi, dry test at operating temp).

My local shop owner gave me some great information about the possibility of carbon build-up which may be causing my values to be a little higher than one would expect for a vehicle with the kind of mileage it has (188,000 mi). He also offered some suggestions as to how I can deal with the carbon build-up, DIY style.

Then he suggested that I replace my exhaust system (from the cat flange back, which was on my list of things to address) before I move forward with my leak down test. If I remember correctly, and please correct me if I am misunderstanding, he said that back pressure due to a compromised exhaust system can cause valve float(?) which might explain the machine gun sound in my exhaust at idle. At least that is how it sounded (and the picture I was seeing in my mind) as he was describing it.

So yeah, I guess next on my “To Do List” is the exhaust.
Thanks for reading and for any suggestions/comments you might offer.

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