Jump to content

vectorsprint

New Members
  • Content Count

    23
  • Joined

  • Last visited

Community Reputation

3 Neutral

About vectorsprint

  • Rank
    Newbie

Profile Information

  • Location
    Beaverton, OR
  1. vectorsprint

    ZX Turbo and the AFM of secrets

  2. vectorsprint

    ZX Turbo and the AFM of secrets

    This one I put in my last thread: It doesn't demonstrate the popping. That's new. After I plugged all of my vacuum leaks, replaced the CHTS with the correct size unit from Nissan, made sure all of my injector harness clips were secured, replaced the belts and timed it, it still runs like garbage while cold, and will pop out the intake under boost. I put the timing at 24 BTDC ad indicated in the manual, but I'm willing to take my skills as suspect. Right now, it feels and sounds like its running lean, and given that it sat for a while, I'm kind of leaning towards the injectors being varnished and not giving me good flow.
  3. vectorsprint

    ZX Turbo and the AFM of secrets

    Hard Data Get! Well, it's more firm, than hard. AFR eludes me. I have no good way to measure it. AFM, I looked in the 83 manual. I might be blind, but I wasn't able to find an AFM test procedure in the 83 ZX FSM. Is that in the FI bible instead? Anyway, plug color. All plugs look.. A little lean. Not scarily so, but I've also jumped off of it every time it pops. Cyl's 1 and 2 had kinda rich-looking crusty plugs. I hope the head gasket is not eroded between cyls 1 and 2. From what I understand though, that's rare on these cars, and a blow to an oil gallery or coolant gallery is much more likely. But, I also grabbed fuel pressure and vacuum data Fuel pressure jumps a bit, seems to coincide with a slight lifter tick I have (P90A head). But it's bouncing between 36-38 PSI with the FPR unplugged. And since I had the FPR unplugged, I have a manifold vacuum of 17-17.5 Inches of mercury./ I have no idea what an ideal vacuum is, though thats in the green on my gauge. I do know that a ZX turbo wants at least 36 PSI at the fuel rail stock. I may try loosening the spring tension in thew AFM to richen it a bit, but seeing these numbers, and the disparity in plug reads, I'm kind of leaning towards my issue being injectors. Guess it's time to build an injector tester and get a noid light.
  4. vectorsprint

    ZX Turbo and the AFM of secrets

    1983 280ZX Turbo. Stock setup. My other topic was a bit old and named for a distributor question that you guys helped solve months ago. Now, I have a whole new and interesting set of issues. So as was seen in the video I posted, the car idled low, and was near stalling. I have the digital dash, so have no idea what my actual RPM is, and don't know how to measure it. But I bypassed the VCM, as I had replaced the vacuum lines on it, and when I applied vacuum to the AAC with a pump, the car wanted to die. SO the AAC is on the car but not connected to anything, the EGR is not being actuated. Car runs much better at low speed. Doesn't pop and buck at low and part throttle anymore. Now my bucking and popping is in boost near the top of the boost gauge. I have yet to put a fuel pressure gauge on it, but the popping is coming from the intake. Wisdom I've seen on other Z boards indicates an intake pop is a lean condition. So that leads me to the next question I have, and it regards the AFM. I spoke to the person who owned the car before I did. As we talked, it came out that he'd had the AFM open. And now I have a suspicion that the screw in the afm was turned, and the spring sproinged. Now the flap is not at the proper tension. I know running down this path is probably a red herring, but the fuel pump, FRP, and injectors are all pretty straightforward. And since I can't find a Z31 turbo computer around me, I'm left using the 1983 ECCS, so that means using the afm. Reading about afm tuning, it looks like if the flap has the wrong tension, it can cause rich and lean conditions. Any suggestions on how to recover the afm? Or am I better off trying to find a known good used one?
  5. vectorsprint

    Distributor questions- 280zx Turbo

    Oh. I hadn't even considered the coil might be the issue. I'm a dum. I'd been so focused on vacuum and fuel delivery. Plugs and wires are both new, so should be okay. I'll see to inspecting the coil and maybe dropping on a replacement unit. I've got some spare parts from my old '80 ZX and a coil is among them, never been out of the box. I might toss it on and see if anything improves. As far as valve lash, the 83 FSM has all valve adjustment procedures listed as "Model without turbocharger". I presume that's because my head, a P90A, has hydraulic lifters. And yes, I do know it's a P90A as that's the casting number on the side of the head. I have no reason to suspect that it's been modified with solid lifters, given how stock everything else is. I know from my days with aircooled VW, VW liked to say the hydraulic lifters never needed adjustment, but they could be adjusted, and there were unpublished specs. Are the Nissan hydro lifters truly maintenance free,or is there actually a ash adjustment that can be done on them which is not documented in the fsm?
  6. vectorsprint

    Distributor questions- 280zx Turbo

    So after a long drive, a couple of hours, I found new and interesting problems. Car doesn't quite idle smoothly, and sometimes under power, it'll start to run rough, and backfire a few times, before it smooths back out. As near as I can tell, I'll probably want to replace the tired old fuel pump (It's a factory original unit) and get my injectors flow tested; 34 years and it's been sitting a lot of them, I'm sure I have fuel delivery issues. I also think I still have a vacuum leak, which I may have isolated; The rubber boot that comes from the back of the AFM, to the turbo intake. Other sources have mentioned it can get hairline cracks from years of the small flexes it has, and can be a source of unmetered air. So I did some shopping, and nobody makes an aftermarket one, near as I can tell. All that's out there is used, or NOS. No problem though, a silicone tube as found on every turbo car ever would do, except one engineering problem I can't suss out. The valve cover breather tube. It vents via a hose to the post afm intake boot. Stock car has a rubber nipple that a steel coupling pipe goes into. But I can't figure out now to do something similar with a silicone boot, and make it airtight. But I bet someone else has done that, because I can't be the only stock ZXT left in the world. Anyone found a solution to this? Or has the go-to solution been to put something like a PCV check valve in the breather and put a filter on the end of that? That seems to me like a vacuum leak waiting to happen, but I wanted to put a feeler out and see if anyone else had tried this sort of thing.
  7. vectorsprint

    Distributor questions- 280zx Turbo

    Well, it's done. Vacuum lines replaced, plugs and wires replaced, the engine timed, O2 sensor and cylinder head temp sensor replaced. Now it runs smoothly, and has plenty of power! And now I have more movies! I'd like to thank everyone who replied in this thread and helped me get the car running over the last 5 months or so!
  8. vectorsprint

    Distributor questions- 280zx Turbo

    I have it timed! It idles much better now. It also doesn't have an oxygen sensor. The sensor body broke off, and the bolt head is rounding off. I'm going to try to weld a nut to the top of the remains of the sensor, but I strongly suspect the lack of the oxygen sensor is the cause of the last issue I have, which is a general coughing and backfiring when under load while I'm not in boost. Once the engine starts making boost, it's fine, and has loads of power. Other than that, I think I can say I've successfully rescued this Z from a kid who had delusions of a drift missile Z.
  9. vectorsprint

    Distributor questions- 280zx Turbo

    Cool. I almost got it. I just need to clean up my timing mark; I smeared the paint like a nub. If you face the car from the front, turning the dizzy right is advance and left is retard, yes? Or is that reverse? I plan on timing it as soon as it's dark enough in oregon to see my garbage timing light.
  10. vectorsprint

    Distributor questions- 280zx Turbo

    Well, everything's in order, now I just need to time it. I know this question has been done to death, but I have no idea how to use my timing light. It's an old craftsman model that I inherited. It has a dial on the back. I presume I set the dial to 24 btdc on the light, then mark 24btdc on my timing tab, mark the timing chip in the crank pulley in white, start the car, let it warm up, then turn the dizzy/CPS until the mark on the pulley and tab seem to not move relative to one another, then tighten down the dizzy/CPS bolts and the computer will handle advance and retard as I go, right?
  11. vectorsprint

    Distributor questions- 280zx Turbo

    Nevermind on the pinout; I've been a blind fool, and there's a comprehensive pinout on EL-42 of the 83 FSM. I'd just overlooked it.
  12. vectorsprint

    Distributor questions- 280zx Turbo

    I should probably make a new thread for this, since my distributor questions were all answered. But the Turbo Z moves now. I have 24 pretty pictures per second on this: I'm having digital gauge issues. It flickers, wants to shut off. I disassembled the cluster, and I traced issues down to the black multipin connector on the back. It supplies power and RPM/Fuel Data. When I play with that connector, the cluster goes in and out, despite it being plugged in securely. I'd like to avoid tearing the dash out to replace the cluster for now, so does anyone have a pinout of that connector, or any experience on how to secure it and make it less apt to screw up?
  13. This is probably going to sound real dumb, but so far, I've not been able to find any information about steering wheel spline sizes for various nissan/datsun cars. My 83 ZXT's wheel is pretty rotten, having been wrapped in some 80s vinyl sport wrap and left to mold. Where I am, for some reason, S130s tend to be pretty scarce. At least in any quality. So I've been trying to find if something from an S30, an S13, or a Z31 or D21 will fit my spline, as I'm not too into fancy aftermarket wheels. Is there a source for spline count and shaft size among Nissan/Datuns, or anyone have them committed to memory? I don't hold out much hope for interchange; I know Datsun shared parts among cars for years, but I don't hold out a hope of them being like GM and using basically the same steering column over a huge range of models and years.
  14. vectorsprint

    280ZX Stereo Modification

    The idea was going to be attach a phone, an MP3 player, or anything else using a 3.5mm miniplug. But your solution sounds like a winner. Keeps the factory stereo intact, and might also let me keep using the tone knob and such.
  15. vectorsprint

    280ZX Stereo Modification

    Yah, the tape deck adapter had crossed my mind. But I've had bad experience with them and decks that feature auto reverse. I'll have to grab the number next time I'm at the car, but it's the one with the dolby codec and stuff. I'll give the tape adapter a try; It's so cheap I have nothing to lose. And the switching port is a good idea.
×

Important Information

By using this site, you agree to our Terms of Use.