Nismo280zEd Posted October 4, 2006 Share Posted October 4, 2006 I'd been having some problems with my MS picking up the tach signal and they slowly got worse... The Z has been sitting for about 2 months or so as I've been driving my S14 around town. Went to start the Z today after adding some gas (money is tight) and no pickup to the MS at all. I had this problem before but solved it by unbolting the connection on the neg of the coild and puting it back on. So with more research... I saw that DIY uses shielded wires for the input wire to the MS. Do you guys run shielded wires? could this be the culprit or do i need to pull the box and check for solder cracks? -Ed Quote Link to comment Share on other sites More sharing options...
trwebb26 Posted October 4, 2006 Share Posted October 4, 2006 Are you sure it is the tach signal? What symptoms are you having that make you believe that the tach signal is faulty? Quote Link to comment Share on other sites More sharing options...
z-ya Posted October 4, 2006 Share Posted October 4, 2006 No Shield is required if you are triggering on the "-" terminal of the coil. Do you have a steady RPM when cranking? What version PCB do you have? Give us some more details on you setup. Thanks Quote Link to comment Share on other sites More sharing options...
Nismo280zEd Posted October 10, 2006 Author Share Posted October 10, 2006 my setup details are probably burried in the MS thread by now lol. PCB 3.0 MSnSE 021 code triggering off the "-" of the coil. RPMs steady when cranking.. I don't get a signal light on the box when cranking and yes.. the LED is fully functioning. my VE tables are posted under MAPS in the sticky. Quote Link to comment Share on other sites More sharing options...
Nismo280zEd Posted October 12, 2006 Author Share Posted October 12, 2006 did some investigating today... traced continuity from the neg of the coil to the MS... I have run with one wire from the neg of the coil... then it gets to about passenger side and i split it into two, one lead goes to ms, one lead goes to factory ignition box (transister ignition unit). Everything traced out, so i check the db37 connector... found a ground had broken off of it's solder... re did that, tried to start.. no luck. Tested the coil to see if it has elec. 10.4V while cranking. checked the cap and rotor on dizzy, cleaned the contact on the rotor, no luck. I think i'm going to have to take the MS apart. Might be a cracked solder... on the board. Quote Link to comment Share on other sites More sharing options...
nienberg.11 Posted October 12, 2006 Share Posted October 12, 2006 I was told that shielded wiring for the tach signal was a good thing to have even when triggering from the "-" side of the coil so I'm running coax with the shielding grounded to the car. That's probably a common practice (I don't read in here often). I personally have witnessed how much electromagnetic noise a z can produce and didn't want to take chances. I once had the car sitting halfway in my garage and had the garage door try to come down on my roof after revving the engine. I moved the car forward a little for safety and found that I could consistently activate the garage door just by revving to a few hundred rpm within a few feet. Quote Link to comment Share on other sites More sharing options...
Nismo280zEd Posted October 13, 2006 Author Share Posted October 13, 2006 I was told that shielded wiring for the tach signal was a good thing to have even when triggering from the "-" side of the coil so I'm running coax with the shielding grounded to the car. That's probably a common practice (I don't read in here often). I personally have witnessed how much electromagnetic noise a z can produce and didn't want to take chances. I once had the car sitting halfway in my garage and had the garage door try to come down on my roof after revving the engine. I moved the car forward a little for safety and found that I could consistently activate the garage door just by revving to a few hundred rpm within a few feet. crazy story... but awesome idea for coax. I have a ton of coax cable lying around... i didn't even think about using that. Quote Link to comment Share on other sites More sharing options...
woldson Posted October 14, 2006 Share Posted October 14, 2006 being a cable guy there are varying shielding amts and size of coax. the cable is excellent at passing RF and pwr. you will need to have the inside conductor exposed as little as possible. the out side conductor is the shield is steel brad and alummin foil. take that to ground and make sure you do not short inside to outside conductor with even the smallest piece of Brade. if you have to extend Brade use small stranded copper wire, it is superior RF ground! make sure ground is quiet other wise you will have even a worse problem:). good luck Quote Link to comment Share on other sites More sharing options...
Nismo280zEd Posted October 14, 2006 Author Share Posted October 14, 2006 I do have a scope to see if the signals are clean or not... however... I got it from a fellow board member.. and I'm not an expert on using it.. I know how to test signal and such.. but how do i see if the ground is clean? Put the scope ground to the battery "-" and the probe to the chassis ground point? Quote Link to comment Share on other sites More sharing options...
z-ya Posted October 14, 2006 Share Posted October 14, 2006 Best place to measure noise is at the MS. Ground the scope probe at the MS and probe the input signal on the DB37 connector. The edges should be clean and glitch free. If you can capture a screen shot from the scope, post it so we can look at it. Quote Link to comment Share on other sites More sharing options...
Nismo280zEd Posted October 15, 2006 Author Share Posted October 15, 2006 I think i can grab a pic of the scope read out with my digital camera. Won't be able to try this till tuesday at the earliest. Quote Link to comment Share on other sites More sharing options...
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