DuoWing

From what I've heard, the N/A 280ZX 5-speed is strong enough to handle the stock Turbo engine. It sounds like if you decide to start pulling more power from the L28ET, then you may want to look at upgrading to the T5.

Your wandering idle is most likely from the AAC failure. What's happening is the VCM is turning vacuum to the AAC on and off to try and control the idle, but the diaphragm is most likely shot. So it adds vacuum to try and close the valve, but it won't hold vacuum and eventually reopens, etc. You can remove the AAC, and use a block-off plate. You will then need to up your idle by adjusting the throttle stop screw on the side of the throttle body. It's locked into place with a 8mm nut on the underside of the throttle body. You can adjust the nut with a small open end wrench and that will turn the screw as well. Or at least it was turning the screw on my throttle body so I was able to adjust my idle up and bring my car to a much more stable idle.

I'm wondering if an ECU that keeps the fuel pump running is an indication of a bad ECU? My car runs pretty darn good just about all the time. I still have some hesitation before it warms up. I did some searching and I came up with some solutions, people having the same issues with their 300ZXs. Turns out alot of these had this problem from the factory. So in some case it relies on the mixture, but at the same time the ECU is just messed up. You either need to find an early ECU that doesn't have the issue, or just upgrade to the later ECU.

One thing I was wondering, you said swapping the ECU was what finally corrected the Fuel Pump staying on issue. You mean swapping the ECU so that it was the same year as the MAF? I don't know if having an 86 MAF with an 84T ECU would matter or not.

My ZXT had the breathing thing going on when I didn't have the vacuum lines for the VCM hooked up correctly. As I've learned you don't need any of those. I've blocked off pretty much everything on the ZXT intake. With the N42 being so limited in vacuum ports all you really would need to have hooked up is the Fuel Pressure Regulator, Brake Booster, and the optional charcoal canister if you don't want any extra gas fumes. One thing that just came to mind, if you didn't hook up the charcoal canister, there is a little port on the underside of the throttle body for hooking up one of the charcoal canister lines. If you don't happen to have anything hooked to it, there would be a vacuum leak.

What have you done to the car besides straight pipe and the N-42 intake? Also have you tried spraying brakleen around the intake manifold to see if you have any leaks?

As far as performance there wasn't any difference. My Air Regulator apparently doesn't work too well. It seals, but it takes a long time to close. I noticed that when it's completely closed vacuum hovers right around 16, if not a little closer to 17 so the drop really isn't much different. I think the cooler temps at night just make everything take a bit longer to warm-up as my drive to work and back takes maybe 5 minutes. I can't seem to find an air regulator that actually closes normally. One day it was about 75 degrees out. My O2 sensor came on within about a minute or so, but it was s till a ways down the street and a couple of stops later that the air regulator was finally closed and my idle went down and vacuum went to normal.

I'd like to get ahold of that, the only problem I see is well it's setup for a blowoff valve, there's no port to run a line from the J-pipe to the air regulator. I guess you'd have to T-off the spot on the pipe for the blow-off?

I was thinking that at first, but yesterday being about 75 degrees out. I took the car for a nice long drive to make sure everything was warmed up all the way. Vacuum remained around 17-18inHG, but like clockwork at night it was lower. I'm thinking it may be definitely related to the alternator. I need to run a check on my alternator to make sure it's working properly as I still have issues with my idiot lights staying on every so often. I measured the battery voltage across the terminals one day to find barely even 12 volts while holding the car steady at 2k rpm, no lights, stereo, etc turned on. I've also heard a bad battery can cause this, but the battery is fairly new and not even a year old, plus I generally don't have problems on startup. It seems to turn over everytime. Although every now and again I will need to jump it, but that seems to be when I turn the car off before turning the headlights, stereo, etc back off and then the car off.

Whether it was actually offered or not I'm not sure, but I believe the 280ZX book I have from 1978 or so. The one that Nissan gave out, mentions a 5-Speed, a 4-speed, and a 3-speed auto. If there was ever a 4-speed put on the 280ZX it probably was the very base model, and was probably extremely limited. What's the point of offering a 4-speed when you already have a 5-speed that people would probably want over the 4.

Doesn't the power steering pump bracket or something cover up that fuel pump hole on 280ZXs?

I've been going through my engine bay and fixing vacuum leaks, blocking off anything that might leak. From what I can tell the EGR may be leaking just a small amount, and I know my oil dipstick doesn't seal too well. Anyway I've noticed something odd. Yesterday around 6pm or so I took a drive, my vacuum hovered right around 17-18inHG at idle. The car is on auto so my vacuum is a little lower at idle in Drive. Anyway then at night coming home from work I noticed my gauge was reading around 15-16inHG at idle. This morning I saw there was a little vacuum line that I must have disconnected by accident. I plugged it back in, went to the auto parts store. There and back vacuum at idle was 17-18inHG again. On my way to work and on my way back idle vacuum was down 15-16inHG again. This isn't really a big problem or anything, but I'm just curious what would cause this. The only thing I can come up with would be at night with the lights on and such, that would increase the load on the alternator and the engine, which would cause engine speed to drop a little and vacuum to drop? Does this sound right? I'll have to take the car for another drive in the morning and see if vacuum is back up again.

For 1981 280ZXs Nissan began using 2 different heads. The P90 for the Turbo applications and the P79 for the non-turbos. For 83' model year Turbos, they started using the P90a with hydraulic lifters. Originally I thought all the P90a heads were all hydraulic, but I keep hearing that there are quite a few P90a heads that are not hydraulic.

What color red did you do that supra in? I'm wanting to do my ZX in that color. Thanks for the info. I realize it's a lot of time, but I do like that it's cheap. Plus it's a good way to get good with body work, wet sanding etc. Neveremind I saw you used Safety Red. I'm not sure if I want to go with Safety Red or Sunrise Red.

I've actually seen this on another Z. I believe it was a 71' a guy here in Ohio has a 240 he restored and the sill plate shows GVWR 2400. I couldn't believe that. Like you said that would indicate a ridiculously low weight. I almost wouldn't be surprised if they started calculating it differently a year or so later. The 73' I looked at had a weight of around 2700 or 2800 lbs. I always try to figure these weights out by assuming 2 people at 150lbs each, so about 300 lbs, maybe 50 lbs for cargo, 20-30 for spare tire, and at least 50lbs for gas. Although I have no idea how they determine, but I see what you're saying as this would indicate a curb weight of less than 2000 lbs.

I'd like to get a hold of a connector and some wiring fro the Z31 O2 sensor. Anyway I removed the 3-wire, put the 1-wire back in. Car still ran like crap, but at least now it was drivable. I also found that my cheapo blow-off valve had decided to fail open at idle. It was drawing in mass amounts of air, so this was the biggest part of my problem, but oddly enough the O2 sensor was bad and just adding to the problem. I was thinking what I'd do, is I connect the black signal wire to the existing shielded signal wire for the 1-wire O2 sensor. I also ran the heater power through the fuel pump relay circuit so it would only be receiving the heater current when running. I think I may just add another pin and run the other heater wire into pin 115 on the ECU as that seems to be made for the O2 as pin 16 seems to be solely for the Air Regulator. From what I've looked up the 300ZX did use 3-wire titania, but that was the 86+ turbo cars. All the others used the 3-wire Zirconia which fit into the existing threading on my downpipe.

Would it be possible for the O2 sensor to be messed up to the point that it can really cause me to run really poorly? Is it possible that tapping the heater wire into the ECU ground could screw something up?

280ZXT with 84 ZXT ECCS. I installed a 3-wire O2 to help with warmup period. Ordered a universal bosch 3-wire for an 84' ZXT. Spliced one heater wire into green wire that feeds power to air regulator from Fuel Pump Relay. I spliced the other heater wire into the ECU ground wires. Now I have a bunch of problems. I'm wondering if I just screwed up the wiring. I checked the power wire and with ignition on I was receiving battery voltage, the other wire was like .14 volts or something of the sort. I don't know if that indicates a funky O2 or just a wiring issue. Could the fact that the O2 sensor heater doesn't have polarity cause an issue with the ECU grounds?

You can remove EGR, AAC, VCV, even the air regulator if you like. I have not put on my egrless N42 yet, but I'm going to eventually, but I have removed the EGR, AAC, and the VCV. Immediately after doing that my car would idle super low, around 500. It would get shaky and want to die. I needed to up the idle which helped solve the issue. If the car runs fine when cold and you still have an air regulator that would probably be your answer. Air Regulator open while cold, car has extra air to keep idle up and not have problems. Once warmed up air regulator closes your idle is extremely low and will barely keep the car going. You will need to adjust your idle via the throttle stop screw on the side of the throttle body. There is an 8mm nut that holds the screw in place. I found by working with the nut I was just able to get the screw to turn enough that I was able to raise my idle. Car currently idles right around 700-750ish.

You can use the injectors and ECU, but to do that it will require extra wiring, swapping the rotor plate from the 300ZX distributor to your 280ZXT distributor, as well as wiring up the MAF from the 300ZX in place of the AFM. To use the injectors you would need to wire up dropping resistors into your ECUs harness. So yes it can be done, but no it won't just swap over without some work.

I went ahead and ordered the colortune as a cheap alternative to getting my mixture correct. So that should be cool to have once I get it. Then I'll hook my air regulator back up, and install my heated 3-wire O2 sensor. Everything by that point should be good. I've been refraining from doing any mods or anything until I've got this running just right. Then I plan to up boost, and add in my mallory ignition. Something interesting I found out, was that using the ball valve in place of the air regulator, the ball valve is capable of passing much more air through it. So even though I kept turning the screw on the MAF more and more rich eventually from a cold start I was running really good, I think at that point I had the mixture correct, but it was matching the amount of air. By Turning the screw lean some, and closing off the ball valve more it would still act the same and run really good.

Actually I really don't get many bubbles, I have the paint thinned to about a little thicker than water. If not just about water., it could be because I'm putting some pressure on the roller when I lay, then like I said I go back over with just the weight of it. I may have to clear off a part of the trunk lid and start redoing it to see. Is it better to load the roller up, then work the paint out of it, before I start applying it to the panel? Or load the roller up and then start applying it and working it all around the panel?

Alright, I've been doing alot of searching and alot of reading. I've been wanting to paint my 280ZXT using the roller/Rustoleum method. I'm beginning to think I should just go a spray gun route with the rustoleum/mineral spirits. Anyway after reading alot of threads I don't think I've ever seen anyone post a good technique for rolling the paint on. Anyway I've been practicing on a trunk lid from a honda civic that my brother had lying around before I actually started painting on my Z. My ZXT is a daily so I'm not super worried if the paint comes out perfect or not. My main questions are: What's a good technique to use? I've been doing where I get the roller really covered in paint, then I roll it over the bumps on the paint tray with some force about 8 times to get alot of the paint out, then I do about two strips kind of overlapping that are about 12" long. Then I dip the roller back into the paint get the paint mostly out, and overlap a little into the last strip, and repeat until it's covered. Then I try to get as much paint out of the roller as I can then using the weight of the roller I go over the whole thing to try and smooth it out, it doesn't look bad, but it seems like you still see alot of marks from the roller. Do these finally come out with the final 1500-2000 wetsand? I've been wetsanding with 600 grit after every 2 coats and get it really smooth, but you can still see the marks. Any advice on this would be appreciated.

I know what you mean how you feel if it's the right buy or not. If you feel the next day you want it more then usually it's going to be hard pressed to change your mind.

Armand if the Z looked like that, hell I'd have been ready to pay $6k for it I keep on looking, I'm in search of a 70-73 240Z or I wouldn't mind a 74' 260Z. I think it was on Zhome.com where I read, don't be worried about spending more for an old Z, because even if it means more upfront, it's better than all the amounts of work you may put into a cheap car. I'm primarily looking at the body on these, but for a really super clean body, that needs paint, interior work, some engine work, suspension work, and has collision damage, I'd guess $5000 is a bit too much, but at the same time out here in Ohio it does go up a bit since I'd be spending at least $500 extra on an out of state car just to get it back. I'd probably have it brought back via car carrier which would cost even more.