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jamunm90

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About jamunm90

  • Birthday 08/01/1967

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  1. I should probably have said a 280zx instead of the L28....thought the ones used on this engine were all the same. I need one for a 82 280zx turbo if that helps any....
  2. Hello All I need a good 3 pulley harmonic balancer for a L28. Anyone have one they don't need?
  3. I need 1 snowflake center cap...Any available?
  4. I'm not sure if this has been asked, but what oil are you using? Synthetic? If so, I would drain and swap to a regular oil for the next 500 to 1K miles. It will eventually break in with the synthetic, but will just take longer. It "may" fix the problem, but even a fresh stock rebuilt engine should not smoke like that unless you have blueprinted it and are running a racing spec rebuild with extra piston/ring clearance? I assume you measured your ring end gaps when you assembled it? It's possible that you simply have a bad oil ring in there someplace. I came across new main/rod bearings that were out of spec right out of the sealed package from a national brand. I sent them back and got another set...I think they were either mis-labled or mis-boxed but this kind of stuff does happen. I would put some more miles on it before you tear into the engine...it could seal up with some additional wear...Regular "dinosaur squeezings" oil will help speed up this process a bit.... Good Luck!! MB
  5. I need a 82 or 83 280zx turbo EFI box for troubleshooting some issues....Any one have a spare laying around they don't need? Would prefer one from a manual car... Thanks!!
  6. Hello I hope someone out there has had a similar experience that might be able to give me some advice. The first question probably should be, do these engines have a vibration common to all L6 series at low rpm? Here's the background...I have a 1980 280ZX. At about 90K miles, the N/A engine developed a small but noticeable vibration at 1200 to 1500 rpm...I can describe it almost as a lope, similar to an engine with a mild cam. Never could figure out what it was, it was a little irritating but it wasn't bad enough to pull the engine....It was small but noticeable at idle, but disappeared above 1700 rpm or so. At 400K miles, I rebuild another L28 engine, this time a turbo motor from another car. Rebuilt the entire engine and put it together, dropped it into the car, and the same vibration is present...This happens in neutral so I know the drive train is not part of the problem. Now there are NO parts that were shared between these two engines. I then pulled the flywheel and clutch, had it re-surfaced and re-balanced since it was from another donor car that I was not familiar with. It was within spec but had it done anyway...I understand these engine parts almost never need to be rebalanced. Also, I know all valves are straight and seal well, cam lobes, cylinder pressure, crank runout and connecting rods are all within spec and straight as I rebuilt the engine, and I checked all of these again during reassembly. Motor mounts looked OK so I didn't bother replace them, as well as the harmonic balancer. Valve timing and clearances are in spec. Fuel injector spray pattern was checked and looked ok...This is a stock engine using the stock ECCS FI. Could this be something common to L series engines or should I be looking at something else? I've run out of ideas but I'm probably overlooking something simple… Thanks all!!
  7. You've got an electrical problem somewhere, likely a short or grounding issue. No, the spark signal comes from the distributor. The fuel pump shouldn't run without the key in the "on" position. Until you find this out and fix it, there is no telling what the issue is. Shorts and grounds can cause back-circuits and all kinds of wierd things begin to happen. This likely caused your EFI relay issue. Replacing it with a new one will likely result in a new burned up relay. Time to pull out your voltameter and trace the battery drain to the source
  8. Thanks for the input everyone. I was suprised it was this off, and the shop told me the clutch cover actually helped it a little, which didn't make me feel much better. Anyway, as my luck goes, they're backed up and won't get around to it for about another week. I'll also eye that harmonic damper...I ASSumed it was ok...damn it, I did that again! Thanks Tony for the advice to check for cracks. I actually have a Ardrox Penetrant Dye kit that I need some more practice on, so I'll check it with that too. Drool...I'd love to have a forged chrome-moly flywheel, lightened of course! Now I'll think about that everytime I see a VW bug putter by on 45 bhp, and smile.
  9. Quick question. Is a stock flywheel/pressure plate assy. that is 33 grams off considered significantly out of balance? Just finished my n/a to turbo conversion on my 80 zx after 400,000 miles, so that engine was tired!! (No cylinder bore cross hatches visible on this engine!!) Anyway, after rebuilding a turbo motor and putting everything together, the engine and car vibrates at 1500 to 2K rpm, engine loaded and unloaded, clutch in or out, moving or stationary, it doesn't change this vibration. All plugs are even colored, and compression is equal within 5 psi. Also valve train is adjusted to specs. The 5 SP non-T5 gearbox was swapped over from the old car, so I know it's fine. Bought a used 240mm flywheel on ebay and a new turbo clutch and pressure plate assy. After pulling out what little hair I have left, I decided to pull off the clutch and flywheel and check the balance. The machine shop stated it was off by 33 grams. Is this significant and could this be the source? A co-worked stated that compared to the weight of the flywheel, it wasn't much and likely wasn't the culprit, at least not entirely by itself. Do any of you have experience with a flywheel off by this much? Did it cause an issue? Thanks!! BTW...The pulley/harmonic balancer is the same one that came on the turbo engine, so I've eliminated that.
  10. Remember that when you did your test, you were only checking that it sends a spark signal to the ECU. That we already know. Unfortunately at this point, you're getting to the point of finding the issue by elimination. I'd swap out the CAS with a known good unit. If it still does not time correctly, then you've eliminated one major component and you move on to the ECU. Since this is a likely suspect, you can't move on in your troubleshooting until you've eliminated it. Start with the CAS, then do the ECU, then check all of the values of your sensors, etc. This is easily done with a volt meter and is best done at the ECU connector to also identify shorts and grounds. Also, and it's a big also, I've been going on the assumption that all of your wiring is correct, all of your other sensors are hooked up and they are functioning normally. It's possible you have a wiring issue or possibly a ground someplace. If both the ECU and CAS check out, check all of the other sensors. If they check out, then you likely have a sensor or sensor wire that’s grounded or shorted somewhere in the ECU wiring. Grounds and shorts will create back circuits and do all kinds of weird things. I know, this is a lot of time consuming grunt work and it sucks, but once you're eliminated the above, that's what you're left with.
  11. Simply put, all the AFM tells the ECU is the amount of air being used by the engine. This is a simple system, and the computer doesn't actually know the system is under boost, but only knows it's using a given qty of air, and so it adjusts the fuel mixture accordingly. Now, the spark curve is part of the same map, and is mapped against other parameters such as Airflow (AFM), Engine RPM, Cylinder Head Temp, Intake Air Temp, Crank Angle Sensor, etc, and then adjusted down a percentage based on the knock sensor. If it senses detonation, it drops the spark curve to a lower curve on the map. So it’s not quite as simple as saying the AFM adjusts the spark. By itself, it doesn’t, but it is an input into the ECU map and is used to calculate the spark/fuel curve. So, a bad AFM won’t cause the spark advance problem you are seeing. If the AFM is bad or going bad, it also affects the fuel flow, and that will be very noticeable. The engine will hesitate and actually cut out when driving down the road. Or if it’s completely gone, the car won’t start. It’s a simple device with a air flap and a electric meter/sliding contact, and when that begins to fail, it starts to cut off the fuel completely during normal driving.. The Crank angle sensor is used by the same map to tell the computer exactly where the crank is, and uses this info to determine when to fire the spark. My thinking is that it is not functioning, and you are getting the idle spark advance all of the time, so the spark timing is not moving as the RPM's increase.
  12. It isn't...The vacuum and mechanical advance is only used on the NA cars. The ECU controls the advance on the turbo. No idea why it wouldn't be working....makes me think it's a crank angle sensor issue, or maybe a bad ECU, but you've checked that. BTW...the air flow meter doesn't control the spark at all. Even at idle, it just gets the mixture close, and the oxy sensor/idle air bypass fine adjusts the idle mixture. After thinking about it more, I'm pretty sure you have a crank angle sensor. Anyone correct me if I'm wrong, but the increase in injector speed as the engine increases is controlled by the tach/ingition pulse, not the crank angle sensor.
  13. Hello All I'm finishing up my original N/A 280zx to zxt install, and had a question before I drop the motor back into this and make this fix, if needed, much harder. First, for the background info, I'm installing a 280zxt into an n/a zx car and will be using the stock 280zxt Nissan FI. Also, being in Texas, it WILL have A/C... The question is...On the N/A car, the A/C idle is bumped up at idle by a vacuum valve on the intake manifold which allows metered air to bypass the TB and increases the idle. This is controlled by a vacuum valve switch on the vacuum canister, and the N/A ECU doesn't care (no signal wire to the ECU for this) After sorting through an 1882 ZXT factory manual, I found, to my surprise, a wire in the turbo ECU that does reference the A/C, but this system still seems to bump up the idle speed in the same method as the N/A car? Does anyone know what effect this wire has on the ECU or have experience using/not using this signal wire? I didn't include it in my wiring harness and I don't want to spend a weekend pulling all of that apart again to add a wire that doesn't do anything significant. Any advice on this is appreciated!!
  14. Anyone ever tried using this as a turbo cooler? Having it come on and blow cool air over the turbo for 15 min doesn't sound like a bad idea to reduce the incredible heat soak on the turbo.
  15. You don't have to take it down to change the color. The trick to changing the color is painting ALL of the car. including all of the door jams, hatch jams, underside of the hood and engine bay, and anywhere else paint is visible, but you shouldn't strip it to the metal. Just spray a self etching primer and then a sealer over the old paint and you're ready to go. Only strip the old paint if you have underlying issues, such as rust or the current paint isn't adhearing to the body and could peel off. I learned this a long time ago, as I used to think removing all of the old paint was the "right" was to do it. Actually, it's better to leave it on.
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