Hi Mike, Well your to be commended for staying with it. I have been asked several times over the years to fix an engine's faults while being told to ignore a noticeable major fault in the process. I feel bad saying this, but until BB or someone solves the low compression on #3, I would forget about "fixing" or "adjusting" anything else. My main point is that you cannot expect #3 to burn all of the gas it's receiving, since with lower compression it's burn rate is low. This means that probably cylinder 1, 2, & 4, are running lean, i.e. low power, and #3 is dumping raw fuel into the exhaust stream. The above scenario explains why The O2 is coated with soot, and yet the readings from the O2 sensor read in range, .3 - .7 volts-- this is an average of all four cylinders. Therefore with one cylinder running rich, the other three must run lean to compensate. Low power results from a lean condition and from only 3 cylinders producing reduced power with one overrich cycled producing even less power than the other three. Said differently, the ECU believes that it is feeding the engine fuel at the correct amount since the O2 feedback is good. But in reality, the feedback take a all four cylinders into account. In order to successfully run one cylinder 30 lb. LOW, the ECU would have to cut it's fuel ratio separately. The compression issue needs to be solved. Like many on the list I've built engines. Used to do 2 or 3 a week. Putting the rings on so that the gaps are offset, valve set-up and etc., are possible quality control items. If Bob is not a one man shop, then it's not always possible to watch everything that goes on. I feel that you've dutifully double checked your end of the deal and are entitled to have the #3 cylinder taken care, assuming normal circumstances are present. Sincerely, Mark Keller 91 Carat |
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