yankeedoodoo Posted January 22, 2002 Share Posted January 22, 2002 I have now connected the tach and speedo (JPE gauges) and they seem to be reading @ 1/2 the rpms and actual speed. Does anyone have some idea of what stupid thing I have done now? Thanks for all help/suggestions offered. yankeedoodoo Link to comment Share on other sites More sharing options...
Chelspeed Posted January 22, 2002 Share Posted January 22, 2002 Your only going half as fast as you thought you were.... You've wired them in series instead of parallel and they're only getting 6V each... Trying to be serious for once, the usual culprit for a 1/2 reading tacho is that you have wired the tacho to a wasted spark ignition and each coil only fires half as often. Most aftermarket tachos have a dedicated tacho output that reads full revs. Or its a V8 speedo and you've fitted it to a 4 cylinder engine. No idea why a speedo should under-read that far. Give us some more details: What car do you have? What engine? What ECU? Where have the speedo and tacho come from? Are they from a Caterham JPE? Did they work OK before? Is it a cable speedo or electronic? If cable then what tyres, diff, gearbox now and on the car it came from? If electronic then where is it triggered from, now and on the car it came from? Link to comment Share on other sites More sharing options...
EFA Posted January 22, 2002 Share Posted January 22, 2002 "Most aftermarket tachos have a dedicated tacho output that reads full revs" You meant: "Most aftermarket ECU's have a dedicated tacho output that reads full revs" Fat Arn The NOW PROVEN R500 Eaterid=red> See the Lotus Seven Club 4 Counties Area Website hereid=green> Link to comment Share on other sites More sharing options...
Chelspeed Posted January 23, 2002 Share Posted January 23, 2002 You're right of course, my brain works faster than I can type... Link to comment Share on other sites More sharing options...
yankeedoodoo Posted January 23, 2002 Author Share Posted January 23, 2002 More info cheerfully supplied: The car is a new slr and the JPE gauges came with the car from caterham, zetec/wasted spark, standard 3.62 diff/caterham 6 speed, and pectel T2 which was allegedly designed specifically for the zetec. More clues to follow as requested. yankeedoodoo Link to comment Share on other sites More sharing options...
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