AtlantaZ Posted August 29, 2011 Author Share Posted August 29, 2011 That's the plan, amigo! You in the market? Quote Link to comment Share on other sites More sharing options...
AtlantaZ Posted September 7, 2011 Author Share Posted September 7, 2011 (edited) I'm continuing to work on the car's tune. I am very happy with the idle - reading 45kPa manifold pressure at idle, with AFRs in the mid-high 13's, and turning about 1100rpm. The driving timing feels flat - a little retarded - but I'm hesitant to mess with the timing too much. I will focus on VEs for now, then carefully raise the timing in specific areas. I am also looking to set up knock detection to prevent damage. If you're reading this and know of a good knock sensor that can be readily adapted to the F54 block and works with Megasquirt, please let me know. Edited September 7, 2011 by AtlantaZ Quote Link to comment Share on other sites More sharing options...
AtlantaZ Posted September 9, 2011 Author Share Posted September 9, 2011 On the advice of the local Z expert, I pulled the valve cover and double checked the cam timing. I pulled the cam sprocket, aligned the chain, and reinstalled the gear. I think it may have moved one link. I took it for a test drive immediately after and it definitely felt faster - a lot faster. Obviously I need to tune the maps again, but this shows a lot of promise. Quote Link to comment Share on other sites More sharing options...
AtlantaZ Posted September 9, 2011 Author Share Posted September 9, 2011 BTW - for those of you in the Atlanta area who are looking to do the swap and/or run Megasquirt, drop me a line and I'll gladly show the car. Quote Link to comment Share on other sites More sharing options...
AtlantaZ Posted September 11, 2011 Author Share Posted September 11, 2011 (edited) After the test drive, I still thought the car felt weak. So I rechecked the compression, calibrated the LC-1, and checked the spark plugs. I noticed something interesting with the plugs - it looks like 5 out of 6 plugs looked whitish (lean), and cylinder #4's spark plug looked very dark (rich!). I think that injector #4 may be sticking open, leading to overfueling in that cylinder. But the net exhaust output looks stoichometric to the LC-1, so I wasn't seeing anything in the logs. I will have the injectors cleaned and tested this week, reinstall, and see what happens. Getting closer! Edited September 12, 2011 by AtlantaZ Quote Link to comment Share on other sites More sharing options...
AtlantaZ Posted September 15, 2011 Author Share Posted September 15, 2011 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. Quote Link to comment Share on other sites More sharing options...
mario_82_ZXT Posted September 16, 2011 Share Posted September 16, 2011 Misfires show up as lean (usually). I've never had an issue with injector resistors. Try running a laptop to datalog, those hiccups that you feel could be resets. On your cam timing, I would set the engine to TDC and go to Atlanticz.ca, and look at their tech tips on mechanical timing, and set it to factory. Quote Link to comment Share on other sites More sharing options...
AtlantaZ Posted September 16, 2011 Author Share Posted September 16, 2011 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... Quote Link to comment Share on other sites More sharing options...
AtlantaZ Posted September 19, 2011 Author Share Posted September 19, 2011 (edited) 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. Edited September 19, 2011 by AtlantaZ Quote Link to comment Share on other sites More sharing options...
AtlantaZ Posted September 22, 2011 Author Share Posted September 22, 2011 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. Quote Link to comment Share on other sites More sharing options...
AtlantaZ Posted September 28, 2011 Author Share Posted September 28, 2011 (edited) 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. Edited September 28, 2011 by AtlantaZ Quote Link to comment Share on other sites More sharing options...
AtlantaZ Posted October 18, 2011 Author Share Posted October 18, 2011 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! Quote Link to comment Share on other sites More sharing options...
akeboshi Posted December 2, 2011 Share Posted December 2, 2011 why did you sell it? It was gonna be a badass car! sorry for the rude question but how much did it sell for? marcus Quote Link to comment Share on other sites More sharing options...
AtlantaZ Posted December 12, 2011 Author Share Posted December 12, 2011 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. Quote Link to comment Share on other sites More sharing options...
zentech Posted December 13, 2011 Share Posted December 13, 2011 Ok, I got the retaining springs (the "mousetrap springs" from above) and clips from Capitol City Nissan ($38.00, free shipping). I got the clips on after some effort, but the retaining springs are very, very loose. Is it possible that I got the wrong springs, or did the P90A head not use retaining springs on the rocker arms? Anyone? Still have the P-90 new springs, new rockers and locks. Let me know.. thanks. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.