SHADY280 Posted October 21, 2009 Report Share Posted October 21, 2009 so i finally started my truck back up today after a few upgrades. nothing major, 280zx alternator, and i pulled the dash to fix the broken plastic surround (thanks bleach) and installed a tach. i ran it for a minute or so, with the tach just temp hooked up, and the dang truck wont shut off with the key. i tried pulling the batt posts, but no luck, pulled the wires off the ig. switch, no luck, pulled the wires off the tach, no luck, so i pulled the wires off the fuse panel, that did it! so what should i look for that is causing this???? does the 280zx alternator need something done to it to make the truck stop? and the charge light is on, but the alt is clearly charging based on voltage. any thoughts are welcome. Quote Link to comment
hang_510 Posted October 21, 2009 Report Share Posted October 21, 2009 IF IR alt, a 1N4001 diode is likely required on the 'sense' (red???) wire Quote Link to comment
SHADY280 Posted October 21, 2009 Author Report Share Posted October 21, 2009 ok, that will take care of the light, but would it fix the truck not shutting off, and where do i get one of those diodes, and place it so it keep the volatge away fro mthe alt? Quote Link to comment
hang_510 Posted October 22, 2009 Report Share Posted October 22, 2009 ok, that will take care of the light, but would it fix the truck not shutting off, and where do i get one of those diodes, and place it so it keep the volatge away fro mthe alt? yes. install in-line on the sense wire [directional] radio crap(shack) or equivalent ($0.19 ea) the DQ 'how to wire your IR alt' has better details... i had to on mine. freaked me out too. goin like the energizer bunny with the keys in my hand :lol: Quote Link to comment
SHADY280 Posted October 22, 2009 Author Report Share Posted October 22, 2009 yeah it freaked me out too, was running around trying to find a solution. i didnt want to dump the clutch as the truck doesnt have wheels on it right now and its on jacks. that would suck worse if it came off Quote Link to comment
Cuts metal like mad Posted October 22, 2009 Report Share Posted October 22, 2009 just a tip for "next time", can't run with no coil power... pull the power wire on the coil. Quote Link to comment
banzai510(hainz) Posted October 22, 2009 Report Share Posted October 22, 2009 http://datsun510.com/photopost/showphoto.php?photo=124&size=big&papass=&sort=1 you can do as the photo with the old volt reg plug or just make a jumper using wires not to cut the old volt reg connector as those volt regs are getting expensive. most time a car dont shut off is the external volt reg is bad. if you disconnect it the car should shut off wheen key swithc is off. but I have seen a stock extnal and IR alt installed but car still shut off but wondering voltage. I dont know if the diaode is needed as this setup aove has worked b4 in other peoples rigs. Quote Link to comment
impala_631 Posted October 22, 2009 Report Share Posted October 22, 2009 is the tach hooked to a constant power causeing the coil to have constant power? Quote Link to comment
hang_510 Posted October 22, 2009 Report Share Posted October 22, 2009 I dont know if the diaode is needed as this setup aove has worked b4 in other peoples rigs. its what i had to do. may be due the differance in ALT's, mine was for a Z24. Quote Link to comment
izzo Posted October 22, 2009 Report Share Posted October 22, 2009 the diode your talking about. is it just the diode with a wire or two that goes on the alt itself? if so there is one on my truck as well. the napz motor. i didnt put it on, and it wouldnt start, so i put it on. still wouldnt start. I had a shitty connection to the battery. oops :o Either way, its on now and everything works as it should Quote Link to comment
72240z Posted October 22, 2009 Report Share Posted October 22, 2009 I know some z guys need to add that directional diode as well due to the same problem when upgrading to a zx alt. They use a "1N5402" diode from radio shack, keeps the power from back tracking. Quote Link to comment
SHADY280 Posted October 23, 2009 Author Report Share Posted October 23, 2009 i didnt get a chance to play today on the truck, im going to try just unplugging the connector to start, just to see. the tach was hooked to ground, lights, constant+, and the neg. of the dizzy. when it wouldnt shut off at first i pulled all the wires off everything, and it didnt help. none of the wire were perm attached, just wrapped by hand. nice having a tach tho, that little l16 revs quite nicely. i dont mind cutting wiring splicing and all that, just want to do it once so it works, i really dont even care about the light on the dash as i may put a volt guage on. on the 280zx's i think one wire goes to the guage and the other loops from the output to the main connector on the signal. i cant remember as my z has a gm alt now. i just know that i dont wanna put batt voltage to the "L" terminal or i blow the alt. heck i cant even remember how the alt is labelled at the moment if its "L" and "S" or "E" and "I" Quote Link to comment
Six_Shooter Posted October 23, 2009 Report Share Posted October 23, 2009 is the tach hooked to a constant power causeing the coil to have constant power? Even if it was connected to constant power (which after the last reply it was), it would NOT keep the engine running. The Tach connects to the negitive side of the coil, for signal. If, in some messed up way the tach did supply 12v on this wire, it would likely cause the engine to not run. The Diode in this case is needed to keep power (proper term term for volts and current ;) )from being back fed to the ignition switch, or more speciically to the ignition wire, that is also attached to the positive side of the coil. Most newer alternators have this built in, but older alternators, don't an can cause the situation that was the cause for this thread being started. I'd have to look at some wire diagrams, but it will be the wire that supplies 12V to the alternator to turn it "on". Cut this wire and install the diode with the stripe towards the alternator. Either of the diodes listed above will work, along with many others. As long as it's not a Zener or Geranium diode, it will work fine. Quote Link to comment
72240z Posted October 23, 2009 Report Share Posted October 23, 2009 (edited) Ya, I believe thats the vertical pin "L" on the T plug connector. Edited October 23, 2009 by 72240z Quote Link to comment
SHADY280 Posted October 23, 2009 Author Report Share Posted October 23, 2009 yeah ill get a diode, wish i had kept some around, they are always handy to have. my last job we had strips of them. Quote Link to comment
ggzilla Posted October 25, 2009 Report Share Posted October 25, 2009 You don't need a diode with a stock Datsun IR alternator. But if you wire it up wrong, a diode will "fix" it. Otherwise just re-wire it and it'll shut off without the diode.... Quote Link to comment
SHADY280 Posted October 26, 2009 Author Report Share Posted October 26, 2009 i unplugged it today, truck shuts off now. there is the typical yellow wire on top and white wire below. sp what is the better way to do this, re-wire or diode? ill do whichever is proper. not what is easiest Quote Link to comment
72240z Posted October 26, 2009 Report Share Posted October 26, 2009 I'm curious to know how it can be wired in a way dieseling will not happen. Zcar, hbz, datsungarage etc.. all say the diode is needed when you swap an internally regulated datsun alt in. All are write ups on the s130 60amp alt being used too. What did they miss? Quote Link to comment
fisch Posted October 26, 2009 Report Share Posted October 26, 2009 Totally unrelated to your issue, but years ago I bought a Subaru that would start itself up! No keys in it! If freaked me out. Turned out the PO had installed a remote starter, and didn't tell us and didn't give us a remote. It was malfunctioning! I thought it was haunted! Quote Link to comment
ggzilla Posted October 26, 2009 Report Share Posted October 26, 2009 (edited) Dieseling is a different problem. It can occur with old or new type of alternator. Dieselinng is when the engine "runs-on" when the power is cut to the ignition. Alternator wired incorrectly keeps power to the distributor when the ignition is cut. When Datsun fitted the internally-regulated alternators, they didn't fit an external diode. At least not to the regular Datsuns. Maybe they did with the later Z-cars??? My experience is with the Hitachi LR-series 1978-up When you wire it up: * Be sure to remove the external regulator * connect the "L" (Light) of alternator harness to "L" (Light) of the wiring harness You can see the "L" on the back of the old alternator. The new one will not have "L" but instead "S" and "I". Edited October 26, 2009 by ggzilla Quote Link to comment
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