AtlantaZ

I've considered some of those options... Maybe if I ever want to buy it back, I'll go to the trouble. Right now it's mostly idle curiosity.

Here was my for-sale thread: http://forums.hybridz.org/topic/101908-1976-280z-turbo-in-atlanta/

Probably a long shot, but I'd love to find out what happened to one of my favorite cars. I sold my red 1976 Datsun 280Z, VIN HLS30297337, to a young man near Memphis, Tennessee sometime in 2011. Before I sold it, I had done a turbo conversion and swapped in a 5-speed, along with some projector headlights. If you've seen this car around, please let me know!

Unfortunately it was my daily driver, and I couldn't afford to keep it as a project AND have a separate DD. It hurt to sell it, especially because it was in such great shape... The moral of the story is to never turn your daily driver into a project car! Sold her for $6k.

Well, she's officially sold. I hope someone benefits from my notes, and I definitely hope that my Z's new owner treats her well!

Well, shame on me. Things improved a lot when I fixed the EDIS trigger offset numbers! I had tested the car to see if I had the toothed wheel offset by 180*. When I reset the EDIS trigger offset (-6*) to where it should be, things got a lot better! I also conducted my cylinder power balance test. I let the car idle and warm to 180F to set a baseline RPM, then I started logging in Tunerstudio. I disconnected a single injector, waited 5-7 seconds, then reconnected the injector. Rinse and repeat for all six injectors. Then I took samples of the logged RPM values at one-second intervals during the disconnected period and took an average. Here are my results (values are RPMs): BASELINE - 1039.1 Injector 1 - 975.6 Injector 2 - 983.6 Injector 3 - 959.5 Injector 4 - 984.0 Injector 5 - 989.3 Injector 6 - 986.6 (Example: during the test, the engine ran at an average of 975RPM when injector #1 was disconnected) So it's apparent that injector #3 causes a slightly larger drop in power. As I understand it, a "healthy" engine will show values for each cylinder that are within 5% of each other. My greatest variation was between cylinders #3 (959.5) and #5 (989.3). The difference is 29.7, or a variation of about 3%. So... pass! Think I just need to keep working on the tune. Have ruled out pretty much everything else.

Took the car for a quick test drive this morning. Same symptoms as before - spluttering and intake manifold backfiring at medium-high load. Still investigating wiring. Feels like a timing issue to me.

Got the damaged wires repaired. I will be installing heat shielding under the intake manifold this week. Once I have everything in place, I will conduct a "cylinder power balance" test on the engine. The procedure involves starting the engine and, while datalogging, temporarily disabling one injector at a time by unplugging its connector. As a cylinder temporarily stops producing power, the engine RPMs will drop. I can compare the data plots in MegalogViewer and clearly see exactly how much the RPMs were affected at each cylinder. If disabling one injector (and that cylinder) causes comparatively little RPM loss, then clearly that cylinder is not producing as much power as it should, and I know where to start looking. Some procedures suggest disconnecting spark plug wires as part of the cylinder power balance test. I prefer to disconnect injectors as the voltages are much lower and less likely to arc. The injectors are on a fused circuit thanks to the relay board, so there's little chance of harming myself or the other components in the system when I pull the injector.

Good tips! My laptop was dead so I couldn't run a log, but I definitely will as soon as the car is back up and running. Right now I'm repairing some damaged wire that touched the hot intake manifold and partially melted. Got the cam timed to factory, so I think I'm good there...

Still feeling flat. And last night I had a couple of rich "hits" - driving at about 13.5:1, then a clunk and 10:1 for 1/2 second, then back to 13.5:1. It felt like a misfiring plug. I'm going to double check connections to EDIS and the coil pack, and I definitely spotted some exposed solder in my injector wiring. I also am considering cutting out the resistors that I used to convert my injectors to high-resistance. Back then I thought the fuel pressure issue was injector related but have since solved it by having the fuel tank refinished. So I will probably be messing with wiring this weekend. Also need to replace my rear main seal, which is slowly leaking oil on my garage floor. My oil pressure is healthy but I'm tired of the mess (and don't want oil on my nice clutch & flywheel!). Finally, cygnusx1 was kind enough to point out a couple of issues with my tune file, which I will be addressing this weekend. Such as turning off warmup enrichment past 160*F.

Ok, going to quit stinking up this thread with my comments. Moving discussion to my build thread, please feel free to read/chime in over there: http://forums.hybridz.org/index.php/topic/95992-another-s30-turbo-project/

Ignore anything past 150kPa or 4500RPM - untuned areas. Plugged in raw numbers from a borrowed map.

Will do a continuity check on the EDIS-to-coilpack wires tonight. I'm also going to inspect the injector wiring, as I think I saw some exposed solder that may be grounding out on the aluminum heat shielding. I think coil voltage is good... otherwise I would expect to see darker/wet spark plugs. But I'll be checking all of the wiring in the fuel and ignition system over the next few days.

What's the best way to check voltage to the coils during running, besides cutting a hole in the plug boot and poking it with a coat hanger?

I just noticed the warmup issue myself! I was double checking my startup and warmup curves, and somehow I have a warmup curve that is enriching even at normal operating temperatures. Not sure how that happened, but I will definitely pull that down to zero enrichment at CLT>=160*F. And yes, I have AE turned off so I can focus on the base VE table. So far the transitional throttle response hasn't been a problem - I've just kept my throttle pedal movements gentle.