RoboS Posted October 1, 2015 Share Posted October 1, 2015 Does anyone know what could be wrong with my new VDO rev counter. The dip switches are set correctly but the needle shows the gauge is over revving. Am i missing the point somewhere? Thanks Rob Quote Link to comment Share on other sites More sharing options...
Welly Jen Posted October 2, 2015 Share Posted October 2, 2015 Hello Rob, Can you give us some more information please? How much is it over reading? What sort of ignition system is it connected to? Traditional points, wasted spark driven by an ECU? If ECU, which one, what pin and how is it programmed? How are the dip switches set on the tacho? I ask because a wasted spark set up can give twice the number of ignition pulses other set ups can give. This might be compensated for in the ECU, or at the rev counter. If it is currently idleing at an indicated 2k rpm or so that may be your problem. If so easiest way round is to set the dip switches for double the number of cylinders, so halving the indicated revs. Jen Edited to add, just seen you have an Seight. Sorry, was using the mobile version of the site where that is hidden. If so, the setting dip switches for sixteen cylinders probably won't be an option. The other questions still apply though. Quote Link to comment Share on other sites More sharing options...
RoboS Posted October 3, 2015 Author Share Posted October 3, 2015 Hello Rob, Can you give us some more information please? How much is it over reading? What sort of ignition system is it connected to? Traditional points, wasted spark driven by an ECU? If ECU, which one, what pin and how is it programmed? How are the dip switches set on the tacho? I ask because a wasted spark set up can give twice the number of ignition pulses other set ups can give. This might be compensated for in the ECU, or at the rev counter. If it is currently idleing at an indicated 2k rpm or so that may be your problem. If so easiest way round is to set the dip switches for double the number of cylinders, so halving the indicated revs. Jen Edited to add, just seen you have an Seight. Sorry, was using the mobile version of the site where that is hidden. If so, the setting dip switches for sixteen cylinders probably won't be an option. The other questions still apply though. Hi Jen Thanks for the info, its difficult to say how much its out, it reads ok at 2000rpm and then seems to get worse the more the car revs. The ignition systems is a std new electronic V8 distributer. The VDO gauge dip switches are set up as indicated on its data sheet for a 8 cylinder engine. Thanks Rob Quote Link to comment Share on other sites More sharing options...
Mark (smokey mow) Posted October 3, 2015 Share Posted October 3, 2015 1.Where does your tacho signal come from? Is it from the coil or the alternator? 2.What are your current dip switch settings? 3.Are you holding the gauge the right way up when setting the switches so that switch one is on the left and not the right! If not then the coil driven V8 setting of on-on-off would appear as on-off-off which is the setting for a 4-cyl engine. Quote Link to comment Share on other sites More sharing options...
RoboS Posted October 4, 2015 Author Share Posted October 4, 2015 1.Where does your tacho signal come from? Is it from the coil or the alternator? 2.What are your current dip switch settings? 3.Are you holding the gauge the right way up when setting the switches so that switch one is on the left and not the right! If not then the coil driven V8 setting of on-on-off would appear as on-off-off which is the setting for a 4-cyl engine. Hi Mark The signal comes from the coil The dip switches are on, on & off (1&2&3) Yes the gauge was the correct way, i even switched them the opoosite way just in case. Im thinking it may be a faulty gauge Rob Quote Link to comment Share on other sites More sharing options...
Welly Jen Posted October 5, 2015 Share Posted October 5, 2015 Rob, what is the tacho displaying at engine idle? What is it displaying at high revs, as high as you'd normally go when driving? Not sure we understand yet exactly what you are seeing. Jen Quote Link to comment Share on other sites More sharing options...
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