Suprash Posted March 1, 2012 Share Posted March 1, 2012 So my NA-T has had the stock dizzy setup dropped and converted to a wasted spark setup from a Ford V8 I believe. The stock dizzy is still in place, but has no king lead or HT leads connected, so its basically just sat there spinning. Now since converting to the coil pack setup the rev counter no longer works. I have pin pointed the rev counter wire on the plug that plugs onto the dizzy housing. Firstly, does anyone know for sure how the rev counter gets its reading through the stock dizzy ? Is there a sensor thats built into the housing that counts the pulses ? Is this why my rev counter no longer reads anything as there is now pulses no going though the stock dizzy ? What is going to be the best way to get the rev counter working again. I run a HKS FCon ECU, so is there a way I could tap into this, obviously the ECU knows what the engine is doing because its firing the coil packs. Failing that, can you buy an aftermarket rev counter sensor and fit this ? I've been told yes, but that would normally be for a HT setup and have been told that fitting that type of aftermarket sensor might struggle to pick up on coils ? Quote Link to comment Share on other sites More sharing options...
Noz Posted March 1, 2012 Share Posted March 1, 2012 (edited) I was under the impression the rev counter works from the ignitor, and not the actual dizzy itself. Otherwise this would make conversions like the 7m CPS include information to connect to the counter, where as it is just purely a sensor for timing. I would say you just need to check the restance values, and also check the wiring. A component may have failed somewhere, and affected the rev counter. Or even maybe a wire has broken down. I would check simply component connection before you try and re-wire the ignition system it may be something real easy. Ref: http://www.toymods.org.au/forums/tech-conversions/46365-solved-jza80-2jzge-tacho-vs-2jzgte-tacho-engine-swap.html QUOTE HOw to mod a NA tach to work with a TT ECU/Igniter Take out the tach and look at the circuit board. See the 33K ? resistor on the top right hand corner. Jumper the resistor with a wire. Put it all back together. Hook up the wire from the TT Igniter A1 terminal (ext) to the blk/wht wire on the Diag connector (tach) and your good to go. Does not cost one dime and works just fine. Apparently the NA tach takes a high level signal developed by the distributor/Igniter circuit. The TT ECU and Igniter put out a low level signal for the tach. The NA tach current limits its high level signal by putting a 33K ? resistor in series with the input. When you jump the resistor the tach is no longer current limited and the low level signal from either the TT ECU (A16) or the TT Igniter either one will drive the NA tach just fine. Edited March 1, 2012 by Noz (see edit history) Quote Link to comment Share on other sites More sharing options...
pedrosixfour Posted March 1, 2012 Share Posted March 1, 2012 (edited) It might be a case of replacing a certain resistor on the back of the rev counter as is the case when converting an NA to TT while still utilising the NA's clocks. It's related to the type of signal delivered to the rev counter from the different ignition types. Edit: Or to put it simply; what Noz just said. I did this bridging mod myself to get the NA clocks to read the 1JZ's signal and it works fine, albeit with a caveat. Edited March 1, 2012 by pedrosixfour (see edit history) Quote Link to comment Share on other sites More sharing options...
Suprash Posted March 1, 2012 Author Share Posted March 1, 2012 OMG !!! Im so fricking useless with electrics/wiring lol. Erm, I have no clue what Noz just said, or even what a caveat is lol. So basically Im my simpleton terms, bare with me lol, I just need to remove the rev counter clock and on the back there will be a small circuit board. Once I've located the 33k resistor, top right hand corner, I jump (?) that with a wire that I connect to ??? I get lost after that part Quote Link to comment Share on other sites More sharing options...
Noz Posted March 1, 2012 Share Posted March 1, 2012 (edited) Ok, lets take a step backwards. That information was just giving details for changing the resistance input to the rev counter, as when you use a TT ignitor the values are different than the NA, therefore the rev counter wouldnt work so was just an example of how the resistance is changed on your counter for different applications. It is possible if your ignitor is not the NA, you would of had to change the resistance to make it work, they may not even be any resistance in the same place due to this. FURTHER step backwards.... this was only reference information and may not apply to you. It will depend on what components your even using. BACK EVEN MORE...... before you try and understand the system & what components you have then trying to find a way around it, lets try and find whats wrong first. I would check all your wires, make sure nothings come loose, after that do a resistance check on wires where you can, something may have broken down where you cant see. After that, you will need to try and understand the system and maybe even draw yourself a simple diagram of where things are plugged in. Parts numbers and photos of what you are running will also help. Also, I assume you have an NA head, do you have any sensors welded into it? Have a look around the top of the engine for any custom components that may have been put there due to the conversion. That will also help us find what or where the problem may be. And a diagram can also help as you can label voltages etc, but this should be done after you've done based checks as something simple won't take as long to fix. Edited March 1, 2012 by Noz (see edit history) Quote Link to comment Share on other sites More sharing options...
Suprash Posted March 1, 2012 Author Share Posted March 1, 2012 Right, the NA head is stock, apart from the Ford V8 wasted spark setup. Wiring is all good, rev counter worked on the stock dizzy, then as soon as we switched to the Ford V8 wasted spark setup it didnt, so its obviously because of the coil pack conversion. I thought I read though, that dizzy is high level signal and coils are low level signal, which is why my tacho cant see the signal, because its switched from high to low now, no ? Quote Link to comment Share on other sites More sharing options...
Noz Posted March 1, 2012 Share Posted March 1, 2012 If you have checked everything, and can't find any issues, the next step would be to try the jumper wire to adjust the signal from the ignitor. Quote Link to comment Share on other sites More sharing options...
Noz Posted March 1, 2012 Share Posted March 1, 2012 (edited) Just a bit of info to help, this peice of information states that waste spark is better than COP (which is what you use). http://news.carjunky.com/how_stuff_works/how_ignition_coil_or_spark_coil_works_ic2315.shtml EDIT: Found this peice of info, this explains what the dizzy actually gives out, explaining there is NO rpm output to the dash from the distributor. It also gives you the pin output on the ignitor to the rpm gauge. http://www.toymods.org.au/forums/faq/10002-toyota-distributor-dli-ignition-systems-explanation-guide.html Edited March 1, 2012 by Noz (see edit history) Quote Link to comment Share on other sites More sharing options...
Suprash Posted March 1, 2012 Author Share Posted March 1, 2012 If you have checked everything, and can't find any issues, the next step would be to try the jumper wire to adjust the signal from the ignitor. Right, but its getting my head around that part of the info that I was asking ??? I just need to remove the rev counter clock and on the back there will be a small circuit board. Once I've located the 33k resistor, top right hand corner, I jump (?) that with a wire that I connect to ??? I get lost after that part Quote Link to comment Share on other sites More sharing options...
Noz Posted March 1, 2012 Share Posted March 1, 2012 Do you understand the jumper wire document mate? Maybe if you try and explain it to me, you will help understand it? Quote Link to comment Share on other sites More sharing options...
Dan_Turism0 Posted March 1, 2012 Share Posted March 1, 2012 not sure if this will help mate but there's a walk through on clubna-t - http://forum.clubna-t.com/showthread.php?t=11088 Quote Link to comment Share on other sites More sharing options...
Noz Posted March 1, 2012 Share Posted March 1, 2012 Read that so many times over the past few months! Good basic guide there, though it's a tad confusing if you've never looked at this subject before. Problem is there isn't any diagram information for the Supra GE in there, only SC. Using the 7m CPS also means you still need the exhaust GE cam. Quote Link to comment Share on other sites More sharing options...
pedrosixfour Posted March 1, 2012 Share Posted March 1, 2012 Sorry buddy, wasn't trying to add to the confusion! A caveat is merely a warning to accompany the resistor bridging method. Namely that this modification carries a very small possibility of a power spike/surge getting to the ECU which may cause harm. As I am using a stock 1JZ ECU I deemed the risk to be acceptable but if I were to opt for a different costlier ECU I think I'd spend the time finding out the value of the proper resistor required to do the job properly and so guard the ECU against possible damage. I didn't spend much time looking for the proper resistor value when I was doing the transplant, with a bit of time and understanding it's probably obtainable in the wiring diagrams somewhere. Below are a couple of shots of the resistor that needs to be changed/bridged in order for an NA clock to read a TT signal. Please bear in mind that this might not even apply to your problem but if, after plenty of research, it does apply then at least you'll know where to go. Also, in the second shot the resistor hasn't been removed, the bridge was carried out on the underside of the card which is less cluttered. Quote Link to comment Share on other sites More sharing options...
Noz Posted March 1, 2012 Share Posted March 1, 2012 A bit off topic, but pedro, whats the 1JZ BPU horsepower rated? Quote Link to comment Share on other sites More sharing options...
pedrosixfour Posted March 1, 2012 Share Posted March 1, 2012 370 - 380 brake at about 1.2 bar as far as I know. Will have actual figures on Saturday. Quote Link to comment Share on other sites More sharing options...
Suprash Posted March 1, 2012 Author Share Posted March 1, 2012 Oh my days This is getting into exactly what I was trying to avoid Time to hand over to an electrical specialist I feel, queue the father-in-law Quote Link to comment Share on other sites More sharing options...
Noz Posted March 1, 2012 Share Posted March 1, 2012 I reckon solder a bit of wire onto the PCB mate it looks easy enough and see if that works. your be well chuffed if you fix it yourself! Quote Link to comment Share on other sites More sharing options...
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