Quote:
Originally Posted by wheela
Do you have MHD for logging? One way to check for leaky injector(s) is to cruise down the highway and completely lift off throttle for a few seconds. Within a couple seconds your AFR should hit a hard limit of 234.something - I can't remember the specific number, but it's a hard stop with no fluctuation. If it doesn't do that, an injector is leaking. The caveat, I'm not sure of the sensitivity of this test. If it's a super slow leak that must sit overnight to accumulate, I'm not sure if you'll necessarily be able to detect it this way.
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Reporting back on this - Per your post, it must be a very slow leak, because the AF ratio behaves as normal throughout the vacuum range.
When we got this car it had most likely been run with a bad VC / PCV issues for quite a while, as there was oil in the vacuum line that runs to the exhaust flap, and the plugs and O2 sensors we pulled out looked like lumps of coal. Since we've repaired everything I'm almost wondering if it may clean itself up (dirty cat, oil at the exhaust flap), though an internal issue with an injector most likely will not self-repair.
It's possible that it may need a walnut blasting due to neglect, as DI also will not clean itself up if the valves are caked up with carbon. We probably should have done this when the intake was off for the OFHG, but thought we'd get it running first and get a baseline. Oh well, more work...