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Z31/300zx ECU/MAF to 280ZXT swap guide


Afshin

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  • 1 month later...
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I hope someone sees this soon, cuz Im running out of parts to change. Ive got the swap done, 85 NA ECU harnes maf etc... on an 81 na. everything is hooked up and working right, just replaced CHTS with one for a 300zx and new thermostat. timing is set ant 20 BTDC 60mm throttle body too

 

Car stutters and jumps bad when cold coming off idle, once past 2k its awesome, no popping, no missing, perfect. its better when warm. but still does it from a standstill. for some reason it doesnt seem nearly as bad when the car is moving, but I think thats just voodoo. Also she free revs awesome with the CHTS disconnected, but doesnt have a lot of power. I re adjusted the TPS to open as soon as you breathe on the throttle, thinking the added whoosh off idle from the big TB was playing havoc, no change. Does anyone know if the boos sensor is supposed to be hooked up to the ECU on the NA cars? I cant find any reference to it, but it was on my donor car.

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  • 4 months later...

I dont know if you can help, but here goes. I have an 82 280zx that has an old flapper style AFM, i used to have an 86 300zx and I liked the MAF on it versus this one. is there any way to change them out? i understand that you had a turbo, mine is not, which sucks, but none the less i want to change out that old AFM. would i have to change the ECU or anything else? or do you know of any conversion that is offered? i have looked with no success. thanks for ur time. ZXWilly

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Its been a long time since I was on the boards and just about as long since have had to mess with the car. Read this entire thread and maybe check out a similar thread on zdriver.com You will need quite a few 300zx parts and some time to do the swap properly, but it feels like it is worth it as far as power goes, and its definitely more fun to drive. You will need a the following parts from a 300zx na ECU, MAF, CAS wheel, MAF pigtail, CHTS, O2s, I used a complete 300zx harness to do the swap because an NA car wont have the right ECU connectors to do the swap,plus I wanted the functionality of all the stock EGR and FPR solenoids.

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  • 1 month later...
8994cas1-thumb.JPG

 

The chopper wheel on the left is from the 280ZXT, the one on the right is from any Z31, or similar year maxima. The holes should look like this when being dropped into the distributor. If you flip it over, then it will give the wrong reference point and run poorly.

 

Does anyone have this picture available or can describe me which way you should put the chopper wheel? I have chopper wheel from z31 which has two holes in middle. Should I put the second hole to the right side or the left? The other one clerly goes to the clip...?

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afshin do you have to hook up pin 34 to the + side of the coil for the car to run and is it the same for pin 3 to the - side of the coil, cause i did everything you said but never connected pin 34 and 3 to the coil and my ECU turns on but the green light and red light are showing together and my fuel pump wont come on and i dont get any spark, also i have a 5 pin bosh style fuel pump relay wired in my car how would you work with that??? please let me kno i want better maping:(

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If you haven't tried already, I'll check my dizzy this weekend and let you know which way is which.

 

 

I haven't had the change to try. My engine is still in piece. I though that I fix my distributor before I get pieces from machine shop. If you can, could you check it? I would be very grateful.

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afshin do you have to hook up pin 34 to the + side of the coil for the car to run and is it the same for pin 3 to the - side of the coil, cause i did everything you said but never connected pin 34 and 3 to the coil and my ECU turns on but the green light and red light are showing together and my fuel pump wont come on and i dont get any spark, also i have a 5 pin bosh style fuel pump relay wired in my car how would you work with that??? please let me kno i want better maping:(

 

I ran the wires from the ECU to the coil. I believe that's the problem you're having.

 

Blobber, you're welcome and good luck with the swap!

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  • 6 months later...
  • 2 weeks later...
  • 2 months later...

Hoping someone can help. I just finish the z31 ecu/maf swap into my 82 l28et. Im having a poor cold start issue, fires up then stumbles and dies, unless I give it some throttle. Also when fully warmed up, intermittanty it will stumble and die out when im at a stop.

 

I've read some where that after this swap there is a lean cold start issue. I don't have a cold start injector, my timing is at 24 btdc, fuel pressure is at aprox 35 psi. I wired up the ecu and maf accordingly and swapped out injector 5 and 2.

 

Anyone have any suggestion?

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  • 2 months later...

I have a few ?'s. First off, I have an '82 zxt and have already removed the idle air valve and most of the bcdd stuff/ Will this throw the '88 turbo ecu into "limp" mode if these things are missing and the electrical connections are just disconnected? Do I need to put this stuff back on? I only took this stuff off to clean up the intake area up a little so I don't mind if I have to. Also I have an n-42 intake mani w/ 60mm t/b I'd like to install as well. Is there any unforseen issues with this? I have the 295cc n/a supra yellow tops with a palnet rail, besides needing the resistors in place does anyone know if these squirts will be ok? Also, in the write up, what color does (y/l) stand for, is it yellow w/ blue line? The '88 maf "A" had a pin on it but the connector side was blank. Do i still need to insert a wired pin into "A" location of the maf connector to make a connection to the maf? Or is there something not needed for the '88 maf that the car that this stuff came off of doesn't need anymore? Any new updates would be greatly appreciated. Oh and one other thing, is the 83zxt's O2 sensor fine with the '85 ecu or do you need to get the '85 O2 sensor w/ the tree wire set up. I read that they have the same diamiter thread type and are the same kind, but I wasn't clear as if the single wired O2 from the '83 zxt will work or not.

Thanks,

J.

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I have a few ?'s. First off, I have an '82 zxt and have already removed the idle air valve and most of the bcdd stuff/ Will this throw the '88 turbo ecu into "limp" mode if these things are missing and the electrical connections are just disconnected? Do I need to put this stuff back on? I only took this stuff off to clean up the intake area up a little so I don't mind if I have to. Also I have an n-42 intake mani w/ 60mm t/b I'd like to install as well. Is there any unforseen issues with this? I have the 295cc n/a supra yellow tops with a palnet rail, besides needing the resistors in place does anyone know if these squirts will be ok? Also, in the write up, what color does (y/l) stand for, is it yellow w/ blue line? The '88 maf "A" had a pin on it but the connector side was blank. Do i still need to insert a wired pin into "A" location of the maf connector to make a connection to the maf? Or is there something not needed for the '88 maf that the car that this stuff came off of doesn't need anymore? Any new updates would be greatly appreciated. Oh and one other thing, is the 83zxt's O2 sensor fine with the '85 ecu or do you need to get the '85 O2 sensor w/ the tree wire set up. I read that they have the same diamiter thread type and are the same kind, but I wasn't clear as if the single wired O2 from the '83 zxt will work or not.

Thanks,

J.

 

Thats a lot if text in one spot... My '86 NA2T Z31 is running fine, not in limp mode, without the idle controls. They certainly are not needed.

 

Also, when using a Z31 ECU these days, a good thing to consider might be Nistune, stock turbo Z31 injectors are 260cc so you MIGHT be able to get away with 295cc, but i can't say you would for sure :P

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Thanks for the reply and sorry for all that txt.

By the way, does anyone know where I can find a good clear pic of the wiring schematic at the ecu? I need to find out where pin 108 is. I have searched with no avail. RUNZ supplied a pic but txt too small and a bit blurred. I tried to resize the pic but no good.

Thanks,

J.

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Thanks for the reply and sorry for all that txt.

By the way, does anyone know where I can find a good clear pic of the wiring schematic at the ecu? I need to find out where pin 108 is. I have searched with no avail. RUNZ supplied a pic but txt too small and a bit blurred. I tried to resize the pic but no good.

Thanks,

J.

 

Know how to read a service manual? The factory service manual for all years, 84-89, is available at http://xenonz31.com > click on References

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