NismoPick

Ok, I think I got it.... to make up for less boost, it advances the timing a lil more. If you are upgrading to an 88-89 ecu, I'm sure that can be reprogrammed along w/ the fuel map. Check w/ the guys @ NIStune... I'm sure they've dealt w/ that. http://home.aanet.com.au/nistune/

duowing

At leas that looks way cheaper than a JWT tune. Is there any advantage to a JWT $500-600 tune vs. just putting that towards Megasquirt?

lifegrddude

Ease of use since it's a basic plug and play application with a fuel map that's been proven to work vs. having to take the time to tune it yourself with a wideband and EGT.

Yeah it can be reprogrammed. My ecu is tuned with the Nistune program, although it was originally an n/a ecu. I run 24* at idle, up from the 20* I had before. Made a night and day difference in how my Z ran under boost. Hopefully I'll get some time to redyno or visit the drag strip soon.

duowing

Actually even on the stock 280ZXT ECU/AFM combo I noticed a good bit of difference by running 24* over the stock 20* and when I accidentally moved the dizzy one time while retightening it and had it set to about 18-19* I could tell that the car felt a good bit slower.

Since I am planning to upgrade I've been looking over options. I see what you mean where the JWT is plug and play and you don't have to tune, but with the Nistune you're then free to play around a little. I'll have to go over my options when I eventually get to swapping over to the later ECU.

duowing

Alright quick question on the Z31 ECU Diagnostics. I went through and ran the procedure. I came back with a few codes. Namely being for the Throttle Valve Switch, and MAF being issues. One thing I wonder is does the ECU need to see a malfunction just once in these parts to throw a code? If so then it would make sense as a couple of times I've disconnected the TPS while the car was idling, and I did disconnect the MAF to experiment.

NismoPick

I'm sure the ecu stores a code if the TPS or MAF is disconnected. You should erase the codes (disconn the battery for a few min), then drive it around for a few (streets / freeway), then check the codes.

duowing

That's what I figured I would do. I have to admit, it is nice though being able to run the diagnostics codes. It gives a little more direction as to where to start. One big advantage to the whole Z31 ECU/MAF swap I think is simply the fact that if the MAF were to completely die, you could still limp the car home, where as the AFM you couldn't run the car at all.

duowing

Hey Nismo I've been trying and trying to figure out why I get off and on hesitation I don't know if it's the swap or what, but I was wondering other than your off idle from your ECU ground wires, did you have any other issues with hesitation, sputtering, popping, etc that was fixed once you redid your wiring. I today was adjusting my MAF per the FSM by making sure the lights are flashing simultaneously to adjust to proper idle mixture ratio. I can't tell if it made it better or worse.

NismoPick

Negatory. I actually did the swap in the first place because of hesitation & running lean. After I got the ground wires fixed it ran better than ever. The only other time I had an idle issue was when I tried to block off the AAC valve. For some reason it didn't like that at all.

At this point I would suggest hooking up a wide band O2 & see what's going on. Then you can adjust the MAF, TPS, CHTS, timing, etc...

duowing

A few thoughts came to mind.

I've never finished the wiring for the fuel pump. I need to go cut the ground from the harness and ground it to the chassis and then unplug the fuel pump modulator, I believe that was the correct way to get the fuel pump to shut off after the 2-3 second prime, right? My fuel pump just currently keeps running, although I don't think that would be enough to cause issues.

Second is my alternator, I'm going to go through and clean the alternator grounds as my idiot lights keep showing up on and off. If my regulator is going bad I'd imagine that could definitely have an effect on my setup. Although I doubt it, but I wonder if the Z31 setup would require a bit more voltage to run it or not?

Third was the ignition since I've never upgraded yet to my Mallory 6AL I wonder if the stock ignition would cause problems, as I've heard that even the Z31 ignition was quite a bit of an improvement as far as the ignitions go.

I guess I'll just have to start cleaning grounds, and trying different things. I'm also thinking while I'm at it I might as well do the GM 1-wire alternator swap.

jmmorriso

I put a nissan Rebuilt ECU in and now the fuel pump shuts off after 2-3 seconds like its supposed to. When I rewired my NA I ran new wires to the fuel pump, new relay and all that so I didnt have to mess with the stock stuff. I also used the 300zx fuel pump modulator and all that. Also I cured my hesitation problem by adjusting the MAF with my wideband to right around 14:1 at idle with everyting connected and warmed up. I have a 60mm TB and have the TPS adjusted to open at .001 throttle opening. I dont know if that helps the stumble or not, but I did it.

duowing

Alright, I'm planning on updating my swap. I want to go to the later setup.

Anyway, I need to know if anyone can direct me to where I can get the bung for the titania O2 sensor. I've been searching ebay, but they're all for an 18mm threaded O2, where I hear the one on the 300ZX was a 17mm thread. I know Heat Rave R at some point got the O2 installed, so I'm curious as to where he got the bung.

NismoPick

Have you tried any local exhaust shops? Technically you don't HAVE to use an O2 bung... you could get a stainless steel (or whatever steel you want) nut w/ the right threads & weld it in.

duowing

Well that would make things even easier. I figured at some point I'd probably just take the car up to an exhaust shop and see.

duowing

Alright, so my car's been acting up, and I guess my crimp connector fix for those ECU ground wires wasn't exactly too good. As I started shaking them and the car would get better and worse as I'd move the wires. Anyway I went to fix them, and ended up cutting way too much of the ground wires down by the ECU plug so I had next to no room to work. I'm getting really nervous at this point as I don't like having this little bit of wire left to work with.

Anyway I pulled out the connectors that came with my Z31 ECU and I started looking at them. On the end where it plugs into the ECU there's a slightly larger middle hole. After playing around with some safety pins, I was able to figure out that using that middle hole I could get the pin in there to push down the little clip on the ECU pin to loosen the pin from the connector and slide it out. So I was able to get the shortened pins out of my 280ZXT harness and replace them with pins that had much longer wiring from the Z31 connectors.

It takes some work to figure out. It helped that I had the connectors partially cut up from when I was taking pins out for the swap originally, but I figured this would be some good info for anyone who messes up like I did and cuts the wiring down way too much.

NismoPick

So it runs better now?

duowing

Yeah, I think the problem was trying to use a crimp with that one wire that's really big, I think things didn't set well in there and kinda loosened up as I would hit the wiring once in a while getting in and out of the car. I'd almost like to get a hold of a new ZXT wiring harness and just pop the pins out and rearrange everything, then you could have a harness that runs from pin to pin with no breaks, splices, or soldering required.

duowing

Well interesting thing to note. I got my 86' Turbo ECU the other day. I went out and plugged it in. Even though I don't have the O2 sensor yet, I ran the car with the old O2 sensor unplugged. Car ran rather well. A bit rich, but as far as I could tell I didn't have any problems in the transition from warm-up to operating temp. I didn't have any issues when restarting the car after getting gas like I do alot of times. Also my fuel pump now works correctly, before where it would stay running with the ignition switch on, it now does the 2-3 second prime then shuts off as it should.

NismoPick

Yeah, the motor should run rich if you unplug the O2 sensor. Did you ever run the old Z31T ecu with the O2 sensor unplugged?

raythenegr0

I hereby undertake this task and plan to make a better write up than Nismo to lose n00b status.

snwbrderphat540

lol.... what constitutes a better write up? picture for each step with detailed explanation for each picture?

raythenegr0

Pretty pictures, smiley faces, rainbows, structure, and really long explanations which could have been summed up in a sentence but because they're longer people think it's better.

duowing

Actually I never did drive with the 84' ECU without the O2 sensor. I'm thinking I may just hook it back up and see how it is using the 84 with no O2. I'm planning to get the bung welded on soon so I can run the 3-wire titania sensor.

NismoPick

That works for SOME college professors.... but if you use filler BS words in a "how to" thread, I'm going to intrawebnet punch you in duh face!

snwbrderphat540

and ill cover the nuts