Z31 ECU upgrade for teh 280ZXT

[Guest ZmeFly]

does anyone know if there is a how to somewhere that someone has done?

 

iv e been searching for a while with no results

 

anybody

[SleeperZ]

I haven't done a "how-to" because I took the hard way, and didn't want anyone to have to repeat it. But this is the method I took.

 

I bought the Chilton's manual that covers all Zs and ZXs through '89. It has all the ECU wiring diagrams with pin numbers for each year. I mapped my '82 wiring harness to my '87 (I converted to an '86 later) ECU, then cut the ECU connectors off, and rewired all the signals to the right pins on the Z31 ECU. It was time consuming, most of the connections didn't need to be cut and rewired, but it was easy. I had to add quite a few wires that didn't exist before, such as ignition signal wires, heated O2 wires and a new fuel pump control logic. I hear some people got theirs up and running with the original 280ZXT connectors, but it left so many things out, and I wasn't sure how the ECU would operate without them.

[Bernardd]

When I removed the POS idle control system to vcm it left me with enough spare wires to convert everything without cutting or splicing except for under the hood. IIRC you have a - and + to the coil added as well as the self clean to the maf. I also ran an extra wire across the dash (underneath of course) for the fuel pump circuit. I can't remember why tho. Someone was nice enough to provide me with a nice spreadsheet that made it a snap.

[SleeperZ]

When I removed the POS idle control system to vcm it left me with enough spare wires to convert everything without cutting or splicing except for under the hood. IIRC you have a - and + to the coil added as well as the self clean to the maf. I also ran an extra wire across the dash (underneath of course) for the fuel pump circuit. I can't remember why tho. Someone was nice enough to provide me with a nice spreadsheet that made it a snap.

 

That may have been my spreadsheet.

[Bernardd]

That may have been my spreadsheet.

You should really post that somewhere on this site seeing that the conversion gets asked about fairly frequently.

 

Nice time in your sig. When did that happen? With no boost increase??

[SleeperZ]

That may have been my spreadsheet.

You should really post that somewhere on this site seeing that the conversion gets asked about fairly frequently.

 

Nice time in your sig. When did that happen? With no boost increase??

 

I posted this Friday night. No boost increase, just a better clutch and differential mounting.

 

http://www.hybridz.org/phpBB2/viewtopic.php?t=26831

 

And really, I suck at "the internet", and don't know how to post a file for download, or how to make a page documenting it. I can upload pictures, that's about it...

[Sean73]

I just got the whole engine wiring harness out of a 84 Z31 turbo. Then, I took the wiring harness inside the house, and checked every connection (using the wiring diagram in Chiltons). It made for a good project in front of the TV. I deleted unneccessary wires, and cut off all the connectors.

 

Now the harness is cleaned up and installed in the car, with the ECU on the driver's side kick panel. The wires were way too long, which is a good thing, I'll trim them down to a precise fit and re-splice the connectors.

 

Granted the car is not running yet, I am happy I did it this way. By custom tailoring the wiring harness, I know every wire and where it goes, which will make troubleshooting easier, and eliminate surprises.

 

Like SleeperZ said, the Chiltons manual is the way to go, because it has the wiring diagrams for all Z's 1970-88. I copied the 73 and 84 wiring diagrams, and pasted them together, then drew lines to the connection points.

 

I can imagine that modifying an 81-83 wiring harness to accept the Z31 ECU is complicated enough that your not going to find a cookbook procedure in these forums. The wiring diagrams will illuminate what you need to do.

 

Sean

73 240Z L28ET, T3/T04E, NPR IC, 84 ECCS, Custom DP, 3" Exhaust.

[Afshin]

Hi Sean, since you are doing the mod now it would be useful to many members if you could make note of what you are doing and then post a "how to do" on it. The topic of 300zx ECU comes all the time on many forums, and to date no one has ever posted a how to do article. I'm sure many including myself would appreciate the extra time you spent to document it. Good luck and let us know when it's running.

[Bernardd]

If you're going to do a write-up I'd like to contribute. If anyone would be interested in a " what I know about the rom and where the data is located to modify for larger injectors, maf, etc etc". I could really piss off anyone that's bought a JWT ecu lately. ( They probably are anyway )

[Guest ZmeFly]

i want to do the upgrade but i dont have the kind of cash that they want.

 

please please help

[SleeperZ]

If you're going to do a write-up I'd like to contribute. If anyone would be interested in a " what I know about the rom and where the data is located to modify for larger injectors, maf, etc etc". I could really piss off anyone that's bought a JWT ecu lately. ( They probably are anyway )

 

[turbobluestreak]

Bernardd I would like to now more about the rom, I last I knew you still had it set up and was testing it. How did that turn out?

 

 

 

 

 

 

 

tbs

[fl327]

If you're going to do a write-up I'd like to contribute. If anyone would be interested in a " what I know about the rom and where the data is located to modify for larger injectors, maf, etc etc". I could really piss off anyone that's bought a JWT ecu lately. ( They probably are anyway )

 

I dont think doing the z31 efi setup is an upgrade by itself. If you run it with stock injectors and whatnot, your limitations on hp are still going to be the injectors. Hp and 1/4 times are identical between the two setups with the stock cc injectors ( a commonality between the two). Having ran the setup for a little while, I do know that with the maf sensor in place of the afm, the car does seem to move along just a little quicker than the afm, thats for sure. I ran into some drivability issues ( When I first put the car together I was not into fuel injection and completely unhip to turbochargers at all and immediately blamed the z31 for something really dumb) that were bugging me so bad I just put the setup back to stock and left it there a year ago. It does take very little to make it work since it is so close to the s130t setup, but definitely not plug and play. Im not saying I wouldnt do it again, but I dont think I would run any better unless I could get in there (ecu) and switch some things around and tune the sucker, along with bigger injectors . Now, breaking the code and getting it to work with bigger injectors is another thing, now your talkin! Sleeper did get the 370cc injectors to work well with his setup and is making great power with it, but wouldnt the bypass pipe setup work as well with the afm setup? Im not trying to take anything away from Sleeper, the bypass pipe is an awesome concept is working well in practice.

What I am saying is that if all you want to run a z31 setup for is to say you have a maf and a stock ecu from another car, it may not be the best reason to do it.

 

I would be into helping with a writeup, I did the swap an entirely different way from what Sleeper described ( I do think that is the right way though, utilizing the full z31 system). I simply cut off the plug to the afm and soldered in the plug to the maf, after rewiring one of the pins to chassis ground and wiring up the burn off. I did some work in the motherboard as well, but the way sleeper did his, you wouldnt have to do anything like that, since he found a way to give the ecu the right signals, where I bypassed quite a few of them. Anyways the car did run well, and did idle better than I could ever get it to currently with the afm system.

[Bernardd]

Now, breaking the code and getting it to work with bigger injectors is another thing, now your talkin!

 

I've done that with three different setups. An 86 ecu with 370cc injectors, and 87 with 370cc injectors, and the 87 with 420cc injectors. I've also used a rather arrogant and PITA to deal with tuning company's code on the 87 retuned for 370's and it works fine. All for the cost of an eprom burner and eraser and a pile of determination (started out almost 4 years ago) and time. I've also fudged the stock afm with good results but all you can tune is the base timing and afm door. I've since found you could tune your accel enrichment by changing the values of the little resistors on the small board inside the afm. You would still have all the other little issues the stock efi brings with it, but you would have somewhat tuned fuel for a bigger turbo and/or more boost. SleeperZ setup is the way to go on the cheap. Mustang guys can actually buy recalibrated maf's for a specific injector size. There are many different ways of doing this. Now if someone where to get a burner (or get his going again) I'd certainly help them out in any way I could. I've thrown around the idea of selling chips but humans being what they are , expect the full dyno tuned chip for their car via mail. JWT can't do it, and I can't either. If I didn't know better I'd say that was almost a rant...........

[yo2001]

I dont think doing the z31 efi setup is an upgrade by itself. If you run it with stock injectors and whatnot' date=' your limitations on hp are still going to be the injectors. Hp and 1/4 times are identical between the two setups with the stock cc injectors ( a commonality between the two). Having ran the setup for a little while, I do know that with the maf sensor in place of the afm, the car does seem to move along just a little quicker than the afm, thats for sure. I ran into some drivability issues ( When I first put the car together I was not into fuel injection and completely unhip to turbochargers at all and immediately blamed the z31 for something really dumb) that were bugging me so bad I just put the setup back to stock and left it there a year ago. It does take very little to make it work since it is so close to the s130t setup, but definitely not plug and play. Im not saying I wouldnt do it again, but I dont think I would run any better unless I could get in there (ecu) and switch some things around and tune the sucker, along with bigger injectors . Now, breaking the code and getting it to work with bigger injectors is another thing, now your talkin! Sleeper did get the 370cc injectors to work well with his setup and is making great power with it, but wouldnt the bypass pipe setup work as well with the afm setup? Im not trying to take anything away from Sleeper, the bypass pipe is an awesome concept is working well in practice.

What I am saying is that if all you want to run a z31 setup for is to say you have a maf and a stock ecu from another car, it may not be the best reason to do it.

 

I would be into helping with a writeup, I did the swap an entirely different way from what Sleeper described ( I do think that is the right way though, utilizing the full z31 system). I simply cut off the plug to the afm and soldered in the plug to the maf, after rewiring one of the pins to chassis ground and wiring up the burn off. I did some work in the motherboard as well, but the way sleeper did his, you wouldnt have to do anything like that, since he found a way to give the ecu the right signals, where I bypassed quite a few of them. Anyways the car did run well, and did idle better than I could ever get it to currently with the afm system.[/quote']

 

I've improved on my time and HP with just Z31 swap with stock injectors. It give alot better A/F across the powerband

[Bernardd]

Basically you take the fuel map and multiply the values in it by the factor of the larger injectors. 270/370=.73 This will only give you the factor. You have to calc the fuel map multiplier first then multilply that factor by the .73 factor, then reverse calc the factor to find the new fuel map value. This will give a stock fuel map with larger injectors. From there it's all tuning for the mod's you've got on your car.

 

There are also warm up maps that should be adjusted based on water temp.

 

It is easy to run whatever maf you want, just change the voltage quatifier map for the particular maf you wish to run. This will also change the way the fuel map is accessed so more calc's are required. The maf is part of the equation for the fuel pulses.

 

I have to figure out how to lower the voltage at which the ecu sees the maf. That way the maf has a wider scale. The stock maf starts at sending voltage at 1.6v but the ecu will only start calc'ing at 2.2v. This is easy to do I just haven't done it yet. Next summer I will be using a cobra maf or z32 maf as I'm maxing out the stock maf by 3.8k or so. The ecu will calculate higher pulsewidths but you have to expand the load scalers. There is a way around this but that will remain my little secret. It is also possible to raise the hp value of the maf by allowing the ecu to use more than the standard 5.12 volts that the ecu uses as it's max. I'll be doing this on my ecu when I lower the activation point. It's a matter of changing the values of some resistors. The stock maf actually goes up to 5.69 volts (at least mine does) so it's not hard to do.

 

I don't think there's an air flow limiter in the code but I'm not entirely positive about this yet. Test bench season will begin in earnest after this weekend.

 

Ok so now I've given out some of what I know. I need some of you guys to get off of your northends and buy some equipment. Or someone with a background in assembly code for the 6802 mcu.

At present I'm using an arrogant and PITA tuning company's code in my 87 ecu. It was very easy to tune and requires less work to get a nice idle and better top end. That's it. Comments, suggestions, flames.......

Bernard

[Sean73]

When I get this thing running I'll have a full website of articles.

 

For someone like me who is building a turbo motor from scratch, and installing it in a 240Z, it makes very little difference to use the Z31 harness, ECU etc... compared to the S130 harness ECU, etc... Both harnesses are fairly self-contained, and require very little wiring to integrate into the 73 240Z.

 

Wire lengths of the Z31 and S130 are different, but it makes no difference to me because I'm splicing new connectors everywhere anyway. I'm in a much easier position to make mods now compared to someone that has already done a turbo swap, and wants to make the Z31 ECCS switch.

 

Even if there is little or no HP gain with the Z31 ECCS, I would still do it anyway, to get rid of that s130 AFM, which is a hulk. The Z31 MAF is nice and portable and I won't have any problems with installing it. I also noticed that some Maxima's use the same MAF, which makes it easy to get spares at the junkyard.

 

I'm also using 84 Z31 Turbo injectors, which are the same as the 280ZX turbo injectors, but newer because of the recall campaign (1995, I think). I got 270 cc out of these injectors on a test bench.

[fl327]

I dont think doing the z31 efi setup is an upgrade by itself. If you run it with stock injectors and whatnot' date=' your limitations on hp are still going to be the injectors. Hp and 1/4 times are identical between the two setups with the stock cc injectors ( a commonality between the two). Having ran the setup for a little while, I do know that with the maf sensor in place of the afm, the car does seem to move along just a little quicker than the afm, thats for sure. I ran into some drivability issues ( When I first put the car together I was not into fuel injection and completely unhip to turbochargers at all and immediately blamed the z31 for something really dumb) that were bugging me so bad I just put the setup back to stock and left it there a year ago. It does take very little to make it work since it is so close to the s130t setup, but definitely not plug and play. Im not saying I wouldnt do it again, but I dont think I would run any better unless I could get in there (ecu) and switch some things around and tune the sucker, along with bigger injectors . Now, breaking the code and getting it to work with bigger injectors is another thing, now your talkin! Sleeper did get the 370cc injectors to work well with his setup and is making great power with it, but wouldnt the bypass pipe setup work as well with the afm setup? Im not trying to take anything away from Sleeper, the bypass pipe is an awesome concept is working well in practice.

What I am saying is that if all you want to run a z31 setup for is to say you have a maf and a stock ecu from another car, it may not be the best reason to do it.

 

I would be into helping with a writeup, I did the swap an entirely different way from what Sleeper described ( I do think that is the right way though, utilizing the full z31 system). I simply cut off the plug to the afm and soldered in the plug to the maf, after rewiring one of the pins to chassis ground and wiring up the burn off. I did some work in the motherboard as well, but the way sleeper did his, you wouldnt have to do anything like that, since he found a way to give the ecu the right signals, where I bypassed quite a few of them. Anyways the car did run well, and did idle better than I could ever get it to currently with the afm system.[/quote']

 

I've improved on my time and HP with just Z31 swap with stock injectors. It give alot better A/F across the powerband

 

 

You may have improved your times, but wouldnt adding more boost and using a hybrid turbo result in the same times anyway????? You were running l jetronic with a knock box and fmu setup right? Of course your a/f and hp was going to increase, you advanced timing on a z31 setup and ran more boost and took it to a dyno, thats a no-brainer that you werre going to get more ideal ratios. Im still not convinced its any better in stock form than the afm setup. They both max out at the same hp on stock injectors. We have swapped setups in between rounds at the track and showed no difference.

 

Sean-yes the AFM is big. It would be worthwhile to get the car up and running with the z31 setup and it would be fun as well.

Bottom line to me is simply changing over to a maf isnt going to give you very much, if any more power, unless you go Jwt or get inside the box and alter parameters, then I like it alot.

[SleeperZ]

You may have improved your times, but wouldnt adding more boost and using a hybrid turbo result in the same times anyway????? You were running l jetronic or something before right? now I think you are running a degree or so advanced with the z31 fuel and ignition curve, which is pretty close to zxt eccs curve, WOW.

 

I wonder what the curve, or A/F ratios, for Z31 vs. 280ZXT ECCS would look like on a dyno. I got a much improved throttle response from the Z31 vs. my old 280ZXT ECCS - same ignition timing, same injectors and fuel system, same everything. I didn't dyno the difference, but it felt quicker, ran much smoother, and my fuel mileage improved by nearly 25% (from 21-22 to 27). To me, that's an upgrade, and it cost about $100. Of course once the Z31 ECCS is up and running, tuning is another advantage for me. I was able to retain all the driveability benefits after adding the 370cc injectors, and this machine feels incredible on throttle.

[fl327]

I would like to see the curves as well, I dont think they would be too different, if it all. 27mpg is pretty good, I average 24mpg and drive 500 miles a week average with most of those miles at 8hg doing 90 on the freeway, my 2+2 averages 22.1 on 87 octane and its in upper 20s with 91, stock. It may have cost you 100.00, I dont think it would apply to everyone.