WhiteMonteZZZ Posted April 17, 2005 Report Share Posted April 17, 2005 I wanna experiment with something on my Monte. I bought a shift light on ebay (got it super cheap) to hook up to see just how off the factory tach is (i've read a lot of factory tachs aren't real accurate). Then I got to thinking about actually utilizing the shift light and decided i'm gonna have it come on at about 5500-6000 or so RPMS (the DOHC shifts at ~6300) and use it for fuel economy. I.E. since I have a lead foot and like seeing redline a lot, but since the wallet complains it's going empty fairly often, i'll use the light as a little voice saying "slow down, speedy" 8) Now, to hook this up, there's 3 wires - Positive, Negative, and Signal. I got the first two obviously, but for the signal wire, would I affect the PCM or anything by hooking the signal wire to the tach wire going to the gauge cluster? I'm not thinking so as it's not drawing power or anything like that from the signal wire. Just wanna make sure i'm not gonna blow anything up lol. And don't gimme comments about that 'r' word commonly referring to H*NDAs or anything For those that don't know, my car is modded for a slight 'retro' look, and the light kinda compliments it too. WMZZZ Quote Link to comment Share on other sites More sharing options...
pitzel Posted April 17, 2005 Report Share Posted April 17, 2005 A couple issues which you might want to research: 1) Does the tach wire merely transmit pulses indicating Rev's, or does it transmit digital data indicating revs? Your magic shift light won't work if the data is transmitted digitally. If you have access to an oscilloscope, you might want to investigate. 2) If the data is an analog stream of pulses corresponding to revs, then I don't see any problem with what you are doing. You might have some calibration issues however, do you have any way of adjusting the shift light? 3) Isn't the empty wallet incentive enough to drive a reasonable speed? :oops: Quote Link to comment Share on other sites More sharing options...
WhiteMonteZZZ Posted April 17, 2005 Author Report Share Posted April 17, 2005 Will get back on the data info. I drive a reasonable speed - mainly this is kinda for the retro look i'm goin for w/the car, but somewhat practical too The shift light is adjusted via "pills" you insert. The pills are each for a specific rpm that the light should turn on at. Eg the 5.5 pill kicks the light on at 5500 rpms, etc. WMZZZ Quote Link to comment Share on other sites More sharing options...
digitaloutsider Posted April 17, 2005 Report Share Posted April 17, 2005 The only thing similar to this is someone (on this forum) rigging up the light to come on whenever the ECM sends out a signal to shift. Quote Link to comment Share on other sites More sharing options...
WhiteMonteZZZ Posted April 17, 2005 Author Report Share Posted April 17, 2005 According to one of my sources who knows most of the ins and outs of the wiring harness, he says the signal should be analog going to the tach. WMZZZ Quote Link to comment Share on other sites More sharing options...
1990lumina Posted April 17, 2005 Report Share Posted April 17, 2005 Install a redline buzzer Quote Link to comment Share on other sites More sharing options...
WhiteMonteZZZ Posted April 17, 2005 Author Report Share Posted April 17, 2005 Install a redline buzzer I've already got a key buzzer - no more pansy chime 8) Quote Link to comment Share on other sites More sharing options...
1990lumina Posted April 17, 2005 Report Share Posted April 17, 2005 Lol, this is like no key chime you've heard before lol. I'll try to get a video of it one day soon.. Quote Link to comment Share on other sites More sharing options...
Baddflash Posted April 18, 2005 Report Share Posted April 18, 2005 If you have an analog cluster you have an analog signal directly from the ICM. If you have a digital cluster your tach signal is carried on the aldl serial connection. So if there's a seperate tach input to your cluster it should be just fine to tap in there as it should be analog. Quote Link to comment Share on other sites More sharing options...
WhiteMonteZZZ Posted April 18, 2005 Author Report Share Posted April 18, 2005 If you have an analog cluster you have an analog signal directly from the ICM. If you have a digital cluster your tach signal is carried on the aldl serial connection. So if there's a seperate tach input to your cluster it should be just fine to tap in there as it should be analog. I have an all-analog gauge cluster. My elec. source said that the tach wire going into the tachometer comes straight from the coilpacks/icm. So you're absolutely sure then that I can tap the tach wire to the shift light no prob? Woot! WMZZZ Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted April 18, 2005 Report Share Posted April 18, 2005 dont these cars have a shift light? I know the older gp style clusters had a yellow arrow, and maybe the 94+ ones did too, or was that in a dream? Quote Link to comment Share on other sites More sharing options...
WhiteMonteZZZ Posted April 18, 2005 Author Report Share Posted April 18, 2005 dont these cars have a shift light? I know the older gp style clusters had a yellow arrow, and maybe the 94+ ones did too, or was that in a dream? A: My car's an auto :oops: B: Those lights (seen one in my friends wrangler) are useless Quote Link to comment Share on other sites More sharing options...
Baddflash Posted April 19, 2005 Report Share Posted April 19, 2005 They are for fuel mileage purposes not performance, and are non adjustable. Plus they are only available on vehicles originally equipped with a manual trans, 95 monte was not. Quote Link to comment Share on other sites More sharing options...
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