duowing

Alright, I still need to get ahold of the wiring harness part for the MAF and I need to get the chopper wheel from the Z31 Dizzy still. Anyway I wanted to go ahead and ask a few questions.

I've been looking at threads and reading diagrams, mainly I can't figure out why you need to swap in pins into the connectors. Do you only swap in the pins if you're using the existing S130 ECU Connectors? I was thinking that if I just used the connectors that were from the Z31s harness all that would be required would be splicing all the wires together, right? I figure it's probably easier/faster, and there's less wire splicing by adding pins.

I've also read that you can use the original 280ZXT CAS instead of swapping to the Z31s Chopper wheel, is this true? Also if I'm not mistaken you can pull the chopper wheel from any Z31 dizzy, turbo or non, right?

Finally if anyone has the wiring harness for the MAF, or a known working chopper wheel on hand and they'd be willing to sell it to me, that would be helpful. I'm really interested in doing this swap as I've heard that it's pretty much a night and day difference?

Thanks for all the help guys.

NismoPick

Yes, you only add the pins if you are going to keep the stock 280zxt ect connections. Some people have chopped out the 280zxt plugs & connected up the Z31 plugs... that seems like way too much / un-needed work.

Some goof on Hybridz says you can still use the 280zxt chopper wheel. I haven't tried, but since the degree holes are different, I don't see how it will work PROPERLY.



Indeed it is night and day difference.

duowing

I actually found that thread where you questioned that guy on HybridZ, but I figured I'd ask again if there was something I had missed where someone had confirmed whether it worked or not.

I've been reading the write up on HybridZ and I've been looking at the Tables you had made. It just says about swapping pin 16 with pin 108 for the FPR and Air Regulator controls, can you just simply do this? I was reading on HybridZ about how you need to cut the wire before it goes into the FPR and wire that into pin 108, and then he said he just took old wire 16 and just put it into a positive source. This is just the most confusing part to me, but from what I can tell is that what you wrote up in your table about switching 108 and 16 for the Air Regulator and FPR should work, because then you have pin 34 just connected to a positive source?

nismo619

Im begning to think the Ecu swap seems pretty eazy install i wonder if nismopick has any pictures ;-) of his install... hey nismopick did u really gain over 40 hp off the swap ? 180 hp stock 280zxt and 220 hp on the 300zx turbos? 1984-1989... z-31's ? all u really need is the ECU the the chopper wheel and the MAF ? drop in isntallation .

duowing

Man I keep finding more stuff to ask, at least there's a thread for it. Anyway I was going through that thread and I was curious if you did the wire swap for Injector #2 and Injector #5. It was mentioned that the Z31 uses batch fire
when:
-engine is warm
-RPM is less than 3000
-injector pulse is short (defined as less than 6.5ms. e.g. part throttle, crusing on the highway...)

and all other times it just fires all 6 at the same time. I was curious if you switched these in your swap?

NismoPick

Yep... just run connector pin# 16 to the cut 108 wire that goes into the efi harness. Then run a wire from the fuel pump relay ground wire to ecu connector pin# 108.

Then add a pin wire to empty slot# 34 (hook to + fused source), #12 (goes to cut harness wire 33 y/l), and #3 if you are using the Z31 ignitor).

Hook up the new MAF plug, ground the fuel pump to the body, and you are done.

I have pics in the thread I made about the swap. And the Z31T was rated at 200hp I believe... yet I have tons of other mods as well. If my Z ran, it would be around 250whp & 300ft/lbs torque.

NismoPick

No... you do not touch the injector wires.

duowing

Oh one thing I forgot to ask. Since after looking over all of this, I agree it looks like way less work and alot easier to just add the 3 new pins, since then I only have to splice two or three wires together inside the car where as all the rest would be out by the AFM connection. Anyway, so for adding the new pins, I would just cut open the ECU connectors that I have with my Z31 ecu and pull the pin connected to the wire out? Do they just pop right into the 280ZX ECU Connector, or would soldering need to be done?

NismoPick

Cut them out of the Z31 plugs... pop them in the 280zxt plugs.

I used a dremmel to slice open the Z31 plugs, and I used the same pin wires that really control the items on the Z31 so there is no confusion.

duowing

Cool, yeah I planned on using the original color Z31 wire pins just so it'd make it easier, but I didn't know if it was as simple as popping the pins in. I've made a little write out so I can do everything in order, and made diagrams, just to make it as easy as possible for me, and I think I'm ready. Thanks for all the help.

PooFlinginMonke

Why cut them when they are removable?

duowing

Well I've not had much time, so I've been putting it off, but I do have everything so I'm going to go ahead and do the swap this weekend. NismoPick, if I'm not mistaken it was you who was having some odd issues with your ZX running all the stock stuff that you couldn't figure out and then when you swapped over the Z31 ECU/MAF/Chopper it seemed to straighten the problem out?

NismoPick

Yeah, with the stock ecu / afm my motor started leaning out REALLY bad at full throttle. I had 35psi fuel pressure, and no matter what level of boost it would lean out. I adjusted the afm several times and always got different results. So I think it was the afm... but I just got pissed and did the swap. The car runs MUCH better w/ the Z31 ecu & maf.

duowing

Alright, I've got most of everything wired up. Gonna finish it up when I have light in the morning. Now my main concern is how do I know which way to install the chopper wheel?

Sorry about image quality:



or

NismoPick

Did you not remove it yourself? You should still be able to tell how the mounts go on from the outline left on it from the previous install... otherwise you might have to guess (or if someone here has a Z31 distrib handy).

duowing

Well I actually haven't removed the chopper wheel yet, that's just the image of the chopper wheel I got from Hoov. Anyway I was looking through my car and I remember seeing that the previous owner had replaced the crank angle sensor, thinking that was the problem with the car and I was looking through the box with the old part and I found two other chopper wheels, plus there's another chopper wheel still inside my dizzy on the car...



You said that the Z31 chopper wheel was different from the 280ZX chopper wheel right? This is weird, and I'm wondering if the chopper wheel that's already in my current dizzy is a Z31 wheel...

duowing

Alright, I got everything wired up, got my MAF and ECU in, got my rotor plate in. Car started right up, seemed to idle good, revved freely. I just need to take it for a run around now.

There's only one issue that I know of at the moment, when I turn the key to on, the fuel pump comes on, and just keeps running. It doesn't seem to do that few second prime. I don't know if that's a bad thing or not.

Also, one really weird thing, the wiring harness that I got with my MAF was for some reason missing one of the pins. The connection for connector point A or something like that. Anyway I cut up my old AFM connector, stole a pin and popped it into my MAF connector.

duowing

Alright, snw was asking about the swap in my marketplace ad, and I figured I'd just add to this. Anyway here's everything I have to at least say about it.

Impressions: Swap seemed to go pretty good, car fires right up, and idles fine, revs fine, and drives fine. Although I'm not sure if the throttle response feels better or not. Anyway my car seems to be able to pull a bit longer, almost to 6k instead of the 5500-5600. I know not much more, but hey that's still something. The power to me seems to come quicker and a bit smoother.

Problems Corrected: It seemed to rid me of something I had noticed where when I'd be coasting along, when the revs would drop to about 1500 or so, the RPMs would suddenly jump towards 2000, then would drop, then jump, maybe do it once or twice. I couldn't get it to happen tonight after doing the swap.

Issues/Concerns: My only issue is like I said, with just slower regular around town driving it doesn't seem to feel much if really any different, this may be normal though as I guess with slower driving or not getting on the power much, it wouldn't really matter as I guess the ECU would still be doing batch fire anyway and running relatively similar to the 280ZXT. Also as I posted my car when you switch to on doesn't do the 2-3 second fuel pump prime, the pump comes on and just stays on. Not a big deal, but a little odd.

Finally, Nismo, you said that if the rotor plate is installed the wrong way the car won't idle or run well, am I correct? If so I guess I got the rotor plate in correct on my first try.

As far as doing the swap it's really not that hard. All the ECU wiring is generally pretty easy. I couldn't believe at first that adding pins was as simple as just popping them into the ECU connectors. In my opinion the hardest part of the swap was the FPR. Cutting the ground wire, and connecting it to a new wire to run to the ECU pin 108 was a huge pain, mainly because of the location of the relay and the small space of the area behind the glovebox.

For anyone planning to do the swap:
Download the ile nismopick put together with his spreadsheet and the wiring diagrams for the Z31 and 280ZX.(I'll add the link when I can find it again)

Read through the step by step instructions on HybridZ: http://forums.hybridz.org/showthread.php?t=91250

Look over all the stuff until you understand what goes where and sort of how it works, that helps a lot, or maybe draw out a diagram to visualize it. Also make sure you have everything before hand.
- Z31T ECU from 84-85 300ZXT
- Any year/model distributor chopper wheel/rotor plate(I have pics in this thread)
- Any year/model Z31 MAF
- ECU Connectors with a bit of wiring from the Z31 ECU, to cut up and get the pins for the 280ZX ECU connectors
- Z31 MAF Connector harness

Overall was pretty easy, the MAF is nicer with how it takes up less space and can be pulled out really easy unlike the huge clunky AFM.

EDIT: One Quick thing I forgot to throw in. Now that I've changed the rotor plate, ECU, and the way it measures air flow, will I have to re check/redo my timing? I completely forgot that the timing might be affected, but then again it may not be, but since timing is primarily controlled by the ECU I figured different ECU, different timing. Hopefully Nismo can respond with his insight, if not I'll check my timing and update this post tomorrow.

NismoPick

w00t! Another successful conversion! Just to be safe you should check your timing, since you prolly moved or removed the distrib when replacing the chopper wheel.

duowing

Yeah my timing used to be a around 22-23* before TDC now it's sitting at dead 20*, gotta push my timing back to 24.

This really does make a difference, because I could tell the difference between 20* and 24* on the old setup, and at 20* it's running just as good if not better than it was at 24* on the AFM.

Now that I've been driving it more though, I'm definitely noticing the benefits, power does seem to come on quicker, the power delivery just feels better, and things just seem to feel smoother, although I did notice one odd thing. It seems like my vacuum at idle in neutral and my idle in Drive seem to sit about 2-3inHG lower than they used to, I don't know if this is a weird coincidence that I suddenly got a vacuum leak, if it has something to do with the weather being really cold all of a sudden, or if it's related to the fact that the MAF is more open where maybe with the AFM's door it would have been more closed at idle allowing for more vacuum? My idle also sits lower too.

Oh one last thing, I was reading through the HybridZ thread on the swap and I saw the guy say that you should disconnect the VCM since the Z31 doesn't control it properly or something?

NismoPick

Yes, you can remove the VCM completely... just make sure you block the vac lines on the turbo boot. I have an aluminum filter to turbo pipe, so it was easier to block off the VCM vac ports.

duowing

So basically does the Z31 ECU just keep it always activated or it doesn't activate it or something? Would that possibly be the thing responsible for my loss of vacuum? Anyway, I'd assume I'd just run the vaccum hose that comes off the metal line that the factory boost gauge attaches to, to the metal line for the AAC valve, and plug off the turbo boot? The EGR doesn't matter as I have that removed.

NismoPick

The Z31 ecu uses a different setup to control the AAC & EGR, which for the most part isn't compatible w/ the 280zxt setup. So neither the AAC nor the EGR will receive a signal now (thus the reason for the lower idle... the AAC valve no longer works). Leave the AAC actuator hose unhooked, or remove it completely. You don't want it attached directly to vacuum or it will lower performance while driving.

duowing

Alright, cool. Thanks for the info. I'll probably just go ahead and pull it out then, just to free up some more room. Advance my timing, and look into where my vacuum suddenly went, although I'm not too worried as boost seems to read fine, and the car is running good. By the way what do you set your timing at?

duowing

One last thing I wanted to mention, even though you said the Z31 ECU controlled the VCM a little bit differently and generally wasn't compatible, does it still operate the VCM on our cars? Because it seemed like from time to time, I'd have weird little things happen, like I'd slow down, and my idle would be sitting just under 1k RPM, then all of a sudden my idle would just drop to about 700-750-ish and stay there, then my vacuum would be reading normal. Maybe I have another issue, but I was thinking my lower vacuum readings along with slight little issues at lower speeds might be the ECU operating the VCM, only just kind of random and wacky? I went ahead and unplugged it, until I remove it all, should I unplug the vacuum hose that goes from the VCM to the AAC line, or it won't matter if the VCM is unplugged?