fl327 Posted June 10, 2004 Share Posted June 10, 2004 Just followed post1 in its entirety and converted my 75 to z31 action, AGAIN... Too bad the car just sold... Link to comment Share on other sites More sharing options...
lilj Posted July 16, 2004 Share Posted July 16, 2004 There is a difference in the year ECU 84-86 are the same 87-89 have the same pins' date=' but I think the 88-89 years use a 16 bit processors (as opposed to 8 on all others) and are digital, which offers higher resolution and more accurate maps. [/quote'] can anyone verify this? Thanks, -Jon Link to comment Share on other sites More sharing options...
fl327 Posted July 17, 2004 Share Posted July 17, 2004 its true. Link to comment Share on other sites More sharing options...
Guest 2slo4u Posted July 17, 2004 Share Posted July 17, 2004 So what I'm learning so far: I've got an 81 turbo and: -I need to now eliminate the dropping resistors? -I don't have a speed signal for the burnoff?(I've got cruise, doesn't that use a speed signal? -I've got an 85turbo ecu, do I need to reprogram it? Still learning; By the time I actually do the changeover, I'll be Zing wires in my Zleep... Link to comment Share on other sites More sharing options...
Afshin Posted July 18, 2004 Author Share Posted July 18, 2004 -I need to now eliminate the dropping resistors? Yes, however, if you ever decide to go with a 88-89 ecu you will then need the dropping resistors (the 88-89 ecu is set up for high impedance injectors) -I don't have a speed signal for the burnoff?(I've got cruise, doesn't that use a speed signal? yes, cruise uses a speed signal, look at your 81 wiring diagram and see if a speed signal is going to the 33 pin on the ecu, if so follow the write up and the burn cycle should be taken care of by the new ecu. I've got an 85 turbo ecu, do I need to reprogram it? No, it's identical to the 84 unit. However if you want to use larger injectors you need to reprogram it. My 84 set up was working quite nicely, but wanting more as usual I then got a 88 ecu which Bernard reprogramed for larger 370cc injectors and more aggressive timing at low boost. Needless to say, the car has gotten quite fast My experience with Bernard has been absolutely great, and much cheaper than JWT. He is also working on some other features which I will try in the near futur which should make an excellent set up even better. Link to comment Share on other sites More sharing options...
Guest 2slo4u Posted July 18, 2004 Share Posted July 18, 2004 Thanks for the help everyone.... Alrighty then. Time to: -bypass the injector resistors -add wire for burnoff of mas -(Can't find the collar for the bottom of my 83 distributor shaft. Where did I put that pesky thing?) -Chop, splice, solder. -Hopefully the ecu I have actually works -Hope for the best. Can I expect a noticeable increase in horsies right away? I'll definately let y'all know when it's up and running. Link to comment Share on other sites More sharing options...
GrayZee Posted July 22, 2004 Share Posted July 22, 2004 Lastly, to run the air regulator, it was controlled thru pin 108 on the z set up (which control the FPR in the z31 set up) as opposed to pin 16 on the Z31 set up. So I connected the 16 pin/wire coming out of the ECU connector to the 108 z harness wire (black which goes to the air regulator) and now the Z31 ECU will control the air regulator from ECU pin 16 thru the 108 wire. (While ECU pin 108 now controls the FPR) This may be a stupid question but if you swapped pins 108 and 16 because they are reversed on the z31 and you needed a (-) trigger to run the fuel pump relay that much I can understand, but from following the wiring harnesses it looks like the air regulator uses a ignition sourced feed (+) and is triggered by a (-) pulse from the Ecu on both the 280zx and 300zx harnesses therefore wouldn't the air regulator not work if you wired it up this way? Wouldn't that just feed a (+) pulse to a (+) feed wire? Link to comment Share on other sites More sharing options...
Afshin Posted July 22, 2004 Author Share Posted July 22, 2004 Wouldn't that just feed a (+) pulse to a (+) feed wire? No, pin 16 out of the Z31 ecu feeds a negative signal to the air regulator just as pin 108 on the Z ecu sent a negative signal. Also someone asked if you could feel an immediate gain in HP with this set up. Well you do feel some gain in HP (my guess is only about 15 peak HP), but most notable is the greatly improved throttle response and broader power band, so the car runs much better and the power comes on sooner and runs significantly faster than 15 peak HP would suggest. You also get much better metering of air under higher boost to about 12-13 psi where the Z31 MAF maxes out (it happens much sooner with the AFM). Lastly gas mileage improves by a good 3mpg (others had the same experience), that's until you turn up the boost again because the car is running better Good luck with the swaps (it's quite easy to do once you look at the original EFI diagrams and follow/highlight the few wires that need to be switched). Link to comment Share on other sites More sharing options...
GrayZee Posted July 23, 2004 Share Posted July 23, 2004 Thanks for the quick reply! Ok you set my mind at ease. I can't wait to do the swap. Looking forward to the improved throttle response and powerband not to mention the gas mileage! First I have to get the ecu re-programmed as I am using a 89 NA ecu. I was told that the timing advance on a NA ecu would be way too aggressive for a turbo engine. Link to comment Share on other sites More sharing options...
Guest 2slo4u Posted July 26, 2004 Share Posted July 26, 2004 I'm about halfway through the swap and still have to finish the ecu and add the mas. I noticed in Dave's diagram he added a wire to slot 114 of the ecu for 12v memory. I did not notice that your writeup Afshin. Do I need that wire or does it depend on which ecu I'm using? I'm using 85 turbo ecu. 81zxturbo 95slobaru impreza Link to comment Share on other sites More sharing options...
Afshin Posted July 27, 2004 Author Share Posted July 27, 2004 The reason I did not mention pin #114 for the ecu memory is that it is already there in the 83 280ZXT harness, so no modification is warranted. I don't know if the same is true for a pre-1979 model harness. If not you can always add the wire/pin. Link to comment Share on other sites More sharing options...
Guest 2slo4u Posted July 27, 2004 Share Posted July 27, 2004 Mine's an 81. I guess I'll find out if it has a 12v constant on pin 114 in the morning... if it's not raining. Dave says he's using the dropping resistors on his also. I guess I'll leave them on at first and see what happens. If it runs lean, I'll bypass the resistors. 81zxturbo 95slobaru impreza Link to comment Share on other sites More sharing options...
Afshin Posted July 27, 2004 Author Share Posted July 27, 2004 Regarding impedance: High impedance injectors will work in a low impedance system and should not run lean. There will be a very small delay in opening which is unlikely to be detectable. However as usual it is best to fully match the system. So the car will run without bypassing the resistors, but probably better to bypass them. Low impedance injectors will run with proper fuel delivery in a high impedance system, but the higher current flow will overheat the coils, often causing injector failure with prolonged use, so dropping resistors should be placed. Link to comment Share on other sites More sharing options...
Guest 2slo4u Posted July 27, 2004 Share Posted July 27, 2004 I finally completed the labotamy and... IT"S ALYIIVE!.... IT"S ALIIIVE!... I even drove it and it seemed to work ok. I did notice: -I removed the dropping resistors and the computer seems hotter than it should, but still works. -Idles at correct rpm but rougher than the 81 ecu -After driving and warming up, misses a little all the way up to about 4000 rpm when free revving. I did: -swap injector 2 and 5 harnesses -run two extra wires to ecu from ignition coil to ecu 34 and 3 -use the ignition from the key switch(the relay input is extremely low current so I figured it would be ok) after trying pin 20 for the + it did not work. -Wired the mas large ground to the intake manifold where the other computer grounds are. -used the 12v+ from the vcm to power the large 12+ on the mas -soldered all connections -disconnected vcm plugs. Thanks, guys for all of the help! I'll keep y'all posted! 81zxz31turbo? 95slobaru impreza Link to comment Share on other sites More sharing options...
Bernardd Posted August 7, 2004 Share Posted August 7, 2004 Got my z32 maf working with my z31 ecu. I'll be doing some tuning over the next little while to get a feel for how everything works. More to come. Bernard Link to comment Share on other sites More sharing options...
Guest 2slo4u Posted August 7, 2004 Share Posted August 7, 2004 Well, since my last post on this thread, I've removed the vcm and all related vacumm tubing and connectors and made plates to seal off the aac and egr valves out of aluminum alloy left over from a&p school. After putting the block off plates on, the engine would not idle without a little pressure on the pedal. Must have cured two unecessary vacumm leaks, WOO HOO! I then adjusted the idle screw up to perfect idle speed and it idles great. -still has very slight hesitation at 1000 rpm when accelerating -but has great rpm transition all the way to top of rpm gauge! -much better driveability Man I can't tell you guys how much I appreciate the help and your work enough. I knew there had to be someone else that did the same kind of things I didn't have the $ to do. Thanks Dave, Bernardd and Afshin. You guys are great. Maybe one day I'll get to check your wicked rides out and chat a little. I rarely drink, but I'll buy the beer! Link to comment Share on other sites More sharing options...
Guest 2slo4u Posted August 11, 2004 Share Posted August 11, 2004 Hey folks, I have completed the ecu swap from 280 to 300 and wonder if I should change the ignition coil also. Will the 300zx coil and transitor work better? I have a brand new 300zx transistor and a used but working coil. I notice others swapping to these and wonder if it will be worth doing. Thanks everyone. 81zxturbo 95slobaru Link to comment Share on other sites More sharing options...
Guest DA-MAX Posted August 17, 2004 Share Posted August 17, 2004 Insert new pin into slot 34 of ECU connector then connect it to a new wire going to the + coil terminal 3) Insert new pin into slot 3 of ECU connector then connect to a new wire going to the – terminal of your coil. a really quick "duh" question...but you mean run the wires from the ECU(inside the car) to the actual coil terminals(under the hood)? so just cut the wires at the coil and connect the new ones? might sound stupid but just wanna clarify. thanks Link to comment Share on other sites More sharing options...
Afshin Posted August 18, 2004 Author Share Posted August 18, 2004 The wires run from the ecu to the coil in addition to the previous wires going to the coil. Do not cut the original wires going to the coil, the car won't start. Regarding the 300zx coil, I put it in my car because I heard it's a better coil and was very easy to do (payed $5.0) for it. I don't know how much of a actual difference it makes. Link to comment Share on other sites More sharing options...
Guest 2slo4u Posted August 18, 2004 Share Posted August 18, 2004 Afshin, I want to swap to the 300zx coil but am unsure of how to do it. The 280 and 300zx transistors are set up differently. Should I just use the 280 transistor and connect the 300 coil to the two wires (four) I have already. Or should I use the 300 transistor also. I have a brand new 300 transistor and would like to use it. I did not notice in either writeup how to use the 300zx coil/transistor. Thanks for all the help. 81zxturbo 95slobaru Link to comment Share on other sites More sharing options...
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