DuoWing Posted June 6, 2014 Share Posted June 6, 2014 I had a quick question to ask. I recently upgraded to the 90's PRW-2 igniter and a Z31 coil in my 76' Z running L28ET and Nistune. Only problem I have now is the tach seems to not work. Last time I ran the car on the stock 280ZXT igniter and blaster 2 coil the tach worked fine. Although it has been a good while since I last ran it. Does anyone have any experience with this? My only other thought might be I have the pins for the coil reversed, and maybe this would throw an incorrect tach signal? Quote Link to comment Share on other sites More sharing options...
NewZed Posted June 6, 2014 Share Posted June 6, 2014 Does it not move at all, not read correctly, or twitch and jump? I had a combination of ignition module and coil that caused my tach to twitch and jump, and only read from zero to ~1500 RPM. An extra condenser (capacitor - the typical silver can from the distributor mount in this case) on the negative terminal of the coil removed the noise. I couldn't explain the details of why it worked, since I don't even really know how the tach works. Quote Link to comment Share on other sites More sharing options...
DuoWing Posted June 6, 2014 Author Share Posted June 6, 2014 (edited) So far it doesn't do anything. I flipped the pins in the connector to the coil and still saw no difference. I tested the wiring from the coil connector up to the resistor under the dash and I had continuity. I guess I may have to pull the tach and check the connections there. The resistor also seems to still be a 2k ohm resistor so that checks out. Also I don't know what it says about the Z31 coil and PRW-2, but I messed with it a bit and it was revving up poorly if you tried to give it much throttle. Got out the timing light and the timing which used to be perfectly at 20* BTDC was now advanced all the way to around 30* BTDC. So I figure I'll adjust the timing back and see where that leaves me. I'm wondering if the newer coil/transistor are just better that they respond so much quicker so I need to retard the timing to make up for the improved response? Also I guess it's not out of the question that my Tach could have just died, much like my voltmeter worked, I left the battery disconnected and the next time I hooked the battery up my voltmeter portion of the gauge no longer worked. Edited June 6, 2014 by DuoWing Quote Link to comment Share on other sites More sharing options...
DuoWing Posted June 16, 2014 Author Share Posted June 16, 2014 Well as far as I can tell I think my Tach may have just bit the dust. It doesn't respond at any RPM. I've obtained some new weird running issues and wired back to original igniter and coil and still had no tach. I got a new autometer sportcomp tach to match my boost gauge, so I guess time to take that apart and put it in. There were times in the past where I would be driving and the tach needle would just completely dip down to 0 and then jump back up with no noticeable hesitation in driving, so maybe it was its time. Quote Link to comment Share on other sites More sharing options...
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