RVI rev counter bounce
Posted: Wed Jul 27, 2005 6:42 pm
Sorry to drag this up again. My Elan S3 has Lumenition and a Smiths RVI tacho, used to work OK now it bounces over 4000 rpm. I know I could have the tacho internals replaced for a cost but I am intrigued to fix mine, I have experience of electronic design and have a scope and other test gear.
My tacho works fine all the way to 8000 rpm if you remove the optical sensor from the distributor and test trigger the lumenition with a toothed wheel on the end of a small electric motor. I am obviously doing this without running the TC engine. Is this an indication that the problem must be interference from the generator/regulator through the tacho supply line? Seems likely to me. If so it should be easy to fix with a decent earth wire and filtering on the tacho supply line? I would try it right now... but its raining. Any one out there tried this?
My tacho works fine all the way to 8000 rpm if you remove the optical sensor from the distributor and test trigger the lumenition with a toothed wheel on the end of a small electric motor. I am obviously doing this without running the TC engine. Is this an indication that the problem must be interference from the generator/regulator through the tacho supply line? Seems likely to me. If so it should be easy to fix with a decent earth wire and filtering on the tacho supply line? I would try it right now... but its raining. Any one out there tried this?