What voltage is the signal used between ECU & PTU? Hahahahahahahah lolol lol rofl :rofl::rofl::rofl: roflmfao lawl
It has been said it may be 5V before but I am thinking it will be more like 12V, will measure tomorrow. Are you trying to get this information to assist in choosing semis to do rebuilds ?
Would I need a PTU if I was running diesel.2009>>> If these are 47 Ohm. I'd be guessing it's 3.5-4.5V. Depending on battery voltage.
Power Requirements: Source: 8.6 to 16.5 Volts DC Consumption: 530mA @ 12Volts DC Not sure if that is correct
Errr, ZX_dorift, I think that maybe you misunderstand how the coils and the PTU work. Here?s a general rundown of how the ECU, PTU and coilpack work together to create a spark. Firstly, coilpacks. There are no diodes, and no capacitors or condensers in the coilpacks. They are just a primary and a secondary coil wrapped around the same former (metal bit inside the coilpack). The secondary coil has many more turns around the former than the primary - this determines roughly what the secondary voltage is compared to the primary. The coilpacks all have an earth on one side of the secondary coil (one of the plug connections), and the other side is what is connected to the short coil lead that connects to the spark plug terminal. There is no other wiring connection to the secondary coil. When the ignition is switched on, the ignition coil relay provides 12 volts to each coilpack (centre pin on the connector), and this is connected directly to one end of the coil primary winding. The other end of the coil primary winding is connected to the PTU, with each coil pack being connected directly to its corresponding transistor inside the PTU. Moving to the PTU for a minute, it's just a bank of six rugged transistors (switches) with a little bit of biasing on board, configured in an open collector configuration, by the look of the photos showing the guts of the thick film circuit. I haven?t had a look inside the ECU to see how it drives them, but it wouldn?t surprise me at all to find six smaller transistors in there which will send out a voltage signal ? probably around 5 volts, but it may also be switching to earth. These signals are sent to each PTU transistor?s base connection. Back onto the coilpacks again. The coilpacks are just a transformer. With the engine running and a spark NOT needed by a particular cylinder, its coilpack primary winding will at some stage be energised by the ECU. It does this by sending a signal to turn ON the corresponding PTU transistor. The PTU transistor being ON completes the circuit for the coilpack primary winding like this; battery voltage from ignition coil relay to one end of the coil primary, with the other end of the coil primary connected to the collector of the corresponding PTU transistor, which as it is turned ON, is basically a short circuit from its collector to emitter, and the emitter is connected to ground. That completes the circuit, and allows a reasonably high current to flow through the coil primary winding. Nothing happens except that the current flowing through the coil primary creates a magnetic field around the coilpack former. When this magnetic field has built up to its maximum strength, it just sits there, storing energy. Now, at the exact time that the cylinder we are talking about needs a spark, the ECU turns OFF the PTU transistor(not on!). This opens the primary coil circuit as it no longer has a path to ground, and the magnetic field collapses. The energy in the magnetic field has nowhere to go except out through the coil secondary winding. Because the secondary winding has many more turns than the primary winding, it multiplies the voltage by the ratio of the windings, to a voltage high enough to create a spark at the spark plug electrodes. The coil has changed a high current-low voltage input into a magnetic field, then changed the magnetic field into a high voltage-low current output. Because high voltage will find any way it can to get to an earth (in this case, we want it to get to the spark plug electrode, things have to be well insulated. The best way to do this is to keep the coil as close as possible to the spark plug, and to keep the connection (lead) as clean and as dry as possible. This is one of the big advantages of coil over plug design ? that the spark has nowhere to go except to the spark plug electrode. The other big advantage over traditional single coil systems is that each spark plug has its own coil, so each coil can spend longer building up its magnetic field to give a better spark. This means much better sparks at higher revs, and much higher revving designed engines being feasible. I don?t know the coil primary and secondary resistances off hand, but the primary will always be low (a few ohms) as it has to allow a large current to flow, and the secondary is always a higher resistance (a hundred ohms or so) as it has lots and lots of turns to get the voltage high enough for a spark. The plug lead itself can actually be a bit higher resistance (and it is, in the case of older distributor type ignitions, to minimise electrical noise), but the overall ?high tension? lead (the lead from the coil to the plug) as well as the plug gap actually determines how long the spark lasts for. If you close up the plug gaps, you end up with a shorter, but more powerful spark. Open up the gaps, and the spark lasts longer but its peak voltage is lower, and you also run the risk of teh initial combustion blowing out the spark. The overall spark energy per spark will be roughly the same though. One last thing. A bigger spark isn?t necessarily a better spark. All the spark has to do is to ignite a nice neat round ?kernel? of fuel air mix around the spark plug, which expands smoothly as the mixture detonates. A spark which is too ?big?, ie usually too high a voltage not only runs the risk of tracking to earth before it gets to the spark plug resulting in a misfire, but it can also arc past the two spark plug electrodes, down to the piston crown or cylinder bore. This can cause unreliable ignition and pinging, and it can even cause a misfire as well, as the high energy of the spark can blow the fuel air mixture away from it, so it doesn?t get ignited. Getting back to your question, If the ECU controls the PTU via open collector transistors, which is the usual way to do it, then the question of voltage is irrelevant. The ECU either grounds the wire or it doesn't. I think you may have also misunderstood Tassie's comment about " The PTU is there to isolate the ECU from the noisy and back EMF prone ignition coil system " too, as you refer to the PTU reducing RFI. RFI (radio frequency interference) is not the same as back EMF. The PTU does not stop or soak up any RFI at all, but it does act to isolate the rather sensitive and delicate ECU against back EMF. Back EMF occurs when the coil secondary dumps its energy into the spark plug, but some of this energy reflects back through the primary winding, which can result in a high voltage spike (or several spikes if it resonates) back at the PTU. Better the PTU deals with the voltage spikes than the ECU.
4.85V to be precise (ECU to PTU), also notice the very small blip of 5 other cylinders firing on different wires, that is inducted noise, but being a logic signal input they will do nothing, BUT I would not like them on my MAF signal.
Eerrrrmmm DORIFT.... Jeezuss M8 you latch on like a pigdog and wont let go will you.... For a start, this is a thread about series 1 PTU REPAIRS, not about coil electrical properties. Your an electronice injunear. This basic 2nd year apprentice motor mechanic crap should be bread and butter to you given inductance is such a generic element of electronics. However, just to humour you, AND in addition to Dangerous's pretty good and thorough synopsis, AND to give you some reseach pointers....actually, an electronics injunear should be very well versed in the issues of induced RF noise and back EMF supression in typical step up (ignition coil) and step down transformers so... welll.. (Ill let the forum make up its own mind...) Just foir shits and giggles, Ill provide a few details which are freely available anywhere and any self respecting electronics engineer should already know.....Give you some ammunition if I get it wrong eh....? Due to high back EMF (<>500V) induced in the primary windings of the coil after primary current switchoff........... Oh yes, typically in Nissans is a 0v-+5v-0v squarewave and triggering off the falling edge,... actually, why are you asking.??? Surely as an electronics ingenue, you have, or have direct access a small portable 'scope that you can have a quick look at the ECU output waveform and voltage on your own Zed.... SURELY? Ignition systems use resistive lead, plug caps, and/or resistor plugs for a very simple reason. To suppress radio interference........ in radios and other sensitive electronic devices. You SHOULD already know this as an electronics injunearar'er!!!!!!!! Typical coil primary resistance is bugger all. Typical secondary winding resistances around 10Kohm but will vary from make to make. HT lead resistances around 8Kohm and resistor plugs 5kohm. Again will vary. there are many zero resistance HT leads available as well. capacitance in an HT lead is a real issue, as you KNOW but i think its safe to ignore that here for the purposes of this exercise. You can view the coil as generating a voltage output that for the purposes of the exercise, resembles a Bell curve..... well not exactly but it serves to illustrate for those who are not as savvy (electronically) as you. ALL the suppressed leads, caps and or plugs do is, in essence limit/attenuate off the voltage that can be applied to the plug gap. So instead of a nice little voltage rise/spark voltage fall, you get more or less nothing to the plug gap untill the voltage is high enough to overcome the lead/cap/plug resistance and this simply "squares" off the pulse waveform. reduces/eliminates RF noise or very simply, static. Is that simple enough for the plebs? You and i both KNOW its not nearly as simple as that but it should serve to illustrate...no? Most electronic injunears would know this as a matter of course which makes me wonder why you ask such fundamental and basic electronics question on an automotive forum when youd have legions of high end references to look up.....No? Is it because your not a very knowledgeable electronics injunear, (remember, who couldnt conduct a simple resistance check of a typical step-up transformer) or is it that you are REAL smart and are just trying to elicit an error out on one/several of use "nuts and bolts" men and giving urself some ammunition to give us a verbal technical hiding when one of use posts something either mistaken or indeed incorrect.....??? Over to you electronics engineer. E
So are you telling me I should have no trouble measuring the resistance of the secondary winding? That is between the ground terminal and high tension output. Because if I should be getting a reading, there must be something up with this multimeter. The only reading I am getting is a diode forward voltage. Thanks heaps for checking this. That's what I thought. Then I saw this. http://z32.wikispaces.com/file/view/ECCS_colored_m.gif AFAIK each channel is input into dropping resistor, zener diode then what appears TTL gate. At least 2 transistors per channel here. Perhaps, but I was only using this comment in context. AFAIK EMF causes RFI. Affirmative, however I haven't bought a clutch kit yet. Therefore the gearbox and starter motor are out of the car. Engine ground is disconnected. Battery tray rust to attend to. Hence battery is out of car. Too much going on, panels coming off for repainting etc. Thanks everyone for your time.
OK. I'm gonna try. I like your enthusiasm (don't lose it!), but I'm head scratching about some of your diagnosis methods (1) To measure the secondary winding resistance of the coil, you need to measure from the connector terminal on one end of the coilpack connector (dunno if it's left or right, but it will be the one for which all coilpack connectors is the same colour) to the output of the coil. Don't measure to the ground, and don't measure using anything else but the ohms range on your meter - maybe that's where you're going wrong . To do this, you'll need to remove the short coil lead (ie wrench the bottom off the coilpack so you can get to the carbon connector sitting just below the coil setup. It will be pure resistance, as it's just a long bit of copper wire, maybe with some reistance built in. It should be around 8,000 ohms (the primary should be less than one ohm). By the way Briz - nice data shot - I presume that was straight off a single PTU input at idle? It's a very short pulse. (2) The PTU diagram. Nothing surprising there, the diagram is just a Darlington pair transistor setup - good for fast response and clamping ON. On the PTU connection diagram, all it's saying is that the 3 is the earth, all of the 2s are the inputs from the ECU, and all of the 1s are the outputs. Truly truly really, if you are an electronic gingerbeer, you should have known all of that without asking - why is that? (3) Inside the ECU, if there are any zeners on the PTU outputs, they would be to sink any of the residual spikes or back emf that got past the PTU. Yes, the PTU transistors could be driven by TTL, especially if they are darlington pairs (by the way, that makes a mess of the remanufactured PTU being a good design, as it probably wouldn't switch as fast or as hard as the original design). (4) EMF does not case RFI. EMF is a leakage of a high voltage spike back into the low voltage part of the circuit. RFI is high frequency electric noise caused in this case by either (and by far most likely) the high number of sparks happening per second, or (far less likely) the primary resonance if the emf gets into the primary circuit and the primary circuit has some capacitance.
Thanks ! Yes you are right single input at idle, but do the math on the interval, 800RPM should be once every 300ms, this is once every 150ms. Look at the "simultanious injection" on page EF&EC-22, talks about fueling twice per cycle, I always though that was purely for startup. Why would there be spark twice a cycle when idling cold ? I will do A&B channel of coil and injector to see if its firing fuel on the exhaust stroke.
Nope. Multimeter is telling me no connection. I have been taking measurements with coil removed from engine. They are 22433-30P00. I didn't realise the Series 2 PTU wiring arrangement was different to that of the Series 1. You knew I didn't know. You just like watching me squirm. Help starting?
If the coils are firing twice per cycle on a Z32 when it's cold (or any time), it is probably to keep the spark plug electrodes clean, and ready for the next 'real' ignition. From memory, the theory is that the exhaust gas, including bits of carbon, unburned fuel etc can collect on the plug electrodes as they exit the cylinder, and a spark at that time will clean them off the electrodes - it doesn't need to be a full spark, as there is no compression to deal with, so the spark voltage is much lower. You might see on your beaut little machine that the exhaust spark dwell stays much shorter than the ignition spark dwell. This is a bit different to a lower tech engine which fires a spark during the exhaust stroke, which is called a "waste spark". I'm pretty sure the Holden V6 engine used in the VN onwards was a waste spark setup. It wasn't so much to keep the plug electrodes clean, but it allows a simpler (cheaper) ignition system. From memory, the VN V6 had siamesed coils with the pair being arranged so that when one fires on an ignition stroke, the other coil fires the cylinder which is on an opposite exhaust stroke - both coils are fired by the same signal from the ecu. That way, you only need three connections to the coil primaries, and the ECU only has to worry about firing three times to get all six cylinders to ignite. If the injectors are all firing, it's usually to start the engine, and keep a rich mixture when it's cold. It's like an electronic choke to keep the fuel mixtures rich. Knowing the overengineering that went into the Zed though, and the fact that it was to be sold in many countries with many different pollution requirements, cold climates, etc, - and if what you are saying is correct, and the ecu not only fires the plug but also the injector on the exhaust stroke - it wouldn't suprise me if the Zed was designed to ignite some fuel on the exhaust stroke for a short while to heat up the catalytic convertors so that they start working straight away. Just a theory though.
Might be overanalysing this. Id be suggesting that the ignition system is not fully sequential and in fact IS running in a wasted spark mode. Ie: triggering 2 cylinders together despite there being 6 output channels from the ECU. Brisz might do a few more tests to determine if this is the case. I think its extremely doubtful there would be a second "wasted" weak(er) spark to help keep electrodes clean. Spark energy is so low and such short duration I cant see a reduced energy spark achieving anything. There are a few injector triggering strategies. Almost universally, injectors are triggered in either "bank" or "batch" mode during initial startup. Bank being, say one side of the motor, or a group of injectors at a time and batch being the whole lot. Nissan often employ a start signal (Black/Yellow) directly from the key to the ECU to invoke "Cranking" tables which are totally different to other running tables and trim tables. The ECU usually tries to start only from the crank table and ignores running and trimming tables. Other ECU's simply use an RPM range to determine if the engine is cranking which is usually in the vicinity of 175 to 200 rpm. This is almost always the case with aftermarket ECU's The ECU will switch over from "Cranking" tables to "Running" and trim tables at a preset crossover rpm. This will also assist recovery if the engine is nearly stalled. E
So how come dangerous is the only one telling me to measure the secondary resistance this way? Why does not the manual specify the technique for measuring the secondary resistance?? And why has someone posted this on Wikipedia??? Now to rebuild a PTU we need to properly understand exactly which signals are going on. This is why I have been asking all these questions. So lets just cross our fingers because the secondary coil is directly connected to engine ground is it??? http://z32.wikispaces.com/file/view/ECCS_colored_m.gif No! When the primary coil is turning on it induces a current in one direction. When it is turning off it induces a current in the other. This is why we have a diode here.
YES!!! Look at the diagramme. It CLEARLY shows the secondary windings grounding straight to engine/chassis/ptu AND ecu!!! Pretty clear. E
