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Honda Pressure waveforms
Posted to Technical Theory Forum on 11/28/2009 32 Replies

Today I had some time to play around, and I had a 1983 Honda accord in the shop that was headed for the scrap yard. I thought I would grab a few pressure waveforms from the engine before I pulled the trigger on it's long lived life. This car will not run, since it has an ignition problem, and a transmission problem. I have a pressure transducer screwed into the #1 spark plug hole. The green trace is a FLS transducer plugged into the brake booster hose. I could not trigger from a spark plug wire, since the engine will try to start, and there is no practical way to disable the fuel supply. I did hook an ignition probe on the coil wire, which was hooked to a spark tester, and I did get a very good idea of what was wrong with the ignition system. Capture #1 is with nothing wrong with the engine. I put this up so that you can use it as a baseline, and have something to compare the other captures with. [1983 Honda Accord, Engine/Propulsion waveform] Exhaust valve with the adjuster backed out all the way. The exhaust valve is only opening a very little bit. [1983 Honda Accord, Engine/Propulsion waveform] Intake valve that is only opening a very little bit. [1983 Honda Accord, Engine/Propulsion waveform] Auxuliary valve that is not closing all the way. With the engine cranking, the low compression cannot be heard in the cranking cadence. Notice the lower compression, and the difference in the lower portion of the waveform. You can also see the problem in the FLS capture (green trace) [1983 Honda Accord, Engine/Propulsion waveform] Exhaust valve with .025" clearance. [1983 Honda Accord, Engine/Propulsion waveform] Tight exhaust valve. The low compression cannot be heard in the cranking cadence. [1983 Honda Accord, Engine/Propulsion waveform] Tight intake valve. The low compression cannot be heard in the cranking cadence. [1983 Honda Accord, Engine/Propulsion waveform]

Feel free to comment,, and enjoy!

Albin from Washington

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