mikeatrpi Posted April 26, 2009 Share Posted April 26, 2009 I humbly solicit help with this data log and MSQ. This is an 82 280zx NA engine with a turbo and manifold from a ZX bolted on. Eclipse BOV, 2.5" downpipe, AEM wideband (linear), ZXT injectors, NA fuel pump, locked VR distributor, MS1 v3.0 running MSnSe code. I see some tach flutters. This is probably noise, yes? When I start the car (beginning of the data log) it stumbles until I open the throttle slightly, then the idle smooths out. The rest of the log is me driving very slowly around my neighborhood. I see the O2 readings go up and down. How do I interpret what causes these fluctuations, and what should I do to correct them? Many thanks!!!!! drive2.zip Quote Link to comment Share on other sites More sharing options...
mobythevan Posted April 27, 2009 Share Posted April 27, 2009 When the car is warmed up will it idle on its own? If not you may need to adjust the butterfly so it is opened more for idle. What AFR do you adjust to at idle? To rough in a tune I have someone drive the car around while I look at the laptop. In Megatune I watch the AFR and adjust the VE table on the fly. Once the tune is roughed in I have been using megalogviewer to take a 30 minute log and the do the VE analyze. I don't take the changes from VE analyze completey, I then look at them to see if the make since and smooth the table out accordingly. Quote Link to comment Share on other sites More sharing options...
mikeatrpi Posted April 27, 2009 Author Share Posted April 27, 2009 Yes, the car will idle on its own, I'm trying for an AFR in the high 12's to low 13's. Do you see anything interesting in my data log or MSQ file? With the tach spikes, and roughness of the tune, I don't feel confident driving it very far yet. I have the acceleration enrichment and O2 correction shut off, which also probably makes it harder to drive. I'll do the VE Analyze thing soon - and I see I have to choose target AFRs for that too. Quote Link to comment Share on other sites More sharing options...
mobythevan Posted April 27, 2009 Share Posted April 27, 2009 The only thing I see in the msq is the injector staging set to simultaneous. That always made my engine idle bad. I used alternating. In the log I can see the spikes on rpm, you should try to clean that up if you can. Are you running the VR pair from the dizzy all the way in to the megasquirt box? Quote Link to comment Share on other sites More sharing options...
mikeatrpi Posted April 27, 2009 Author Share Posted April 27, 2009 Here's a super fast reply... When I try Alternating, it won't run. I assume I need to re-tune the VE table up or down? Changing to alternating felt like a step in the wrong direction this weekend, but if that's the "correct" setting I'll work at it some more. Yes, for the VR I run a pair of 18 ga wires twisted together to the MS box. I am going to visit the "home products division" supply cabinet for some spare 75 ohm shielded wire soon. Thanks Moby, I really appreciate that you loaded up my files to take a look. Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted April 27, 2009 Share Posted April 27, 2009 Mike, run multi strand alarm wire with an aluminum shield. Ground the shield to the MS connector body. I might be able to spend some time late one evening helping you out. Typically, I am available only late at night after the kid goes to bed. 9pm or later. This Friday, I am available from 1pm to about 4pm. If I get laid off this week (rumors) I will be available anytime! What firmware are you running? Quote Link to comment Share on other sites More sharing options...
mikeatrpi Posted April 28, 2009 Author Share Posted April 28, 2009 Here is another log and MSQ, this time with "Alternating" squirts. It seemed to idle slightly smoother once I played with the VE table a little bit. drive4.zip Quote Link to comment Share on other sites More sharing options...
mobythevan Posted April 28, 2009 Share Posted April 28, 2009 The spikes are still there and they seem to be causing some trouble. Try the shielded wire to get rid of them and if that doesn't work look at what the EDIS guys do to run from their VR sensor into megasquirt. Quote Link to comment Share on other sites More sharing options...
mikeatrpi Posted May 3, 2009 Author Share Posted May 3, 2009 OK - I got some time yesterday to replace the VR wiring with some 50 ohm coax, grounded at the MS unit. The VR+ and VR- are transmitted on separate coaxial cables. As far as I can tell, the tach spikes are gone! Here's a new data log. I still don't know how to interpret the causes (and fixes) when the WB goes rich or lean. I know it takes a while for you to load it up and take a peek, and I really appreciate that. This was a drive around the neighborhood, then a few miles on near-by back roads. drive6.zip Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted May 3, 2009 Share Posted May 3, 2009 Mike, most of your AFR spikes are centered around throttle position moves. This is going to get better as you fine tune your AE settings. I do see a tach spike at 1302, 1324, and 1339sec. Start inching in AE enrichments, based on TPS, MAP, or mixed. I run mixed, 80/20 with MAP dominant. Get into the tuning screen for AE and move your pedal around and watch the AE bar, to get a feel for TPS threshold. Then set your AE pulswitdhs low for now. Bring them in slowly. I will post mine if you want a reference. BTW Now is a great time to start bringing your log files and msq files into MegaLogViewer and running VEanalyzer. After three iterations of VEanalyzer, the car should be running MUCH better providing you have a good AFR table. I included mine here. Quote Link to comment Share on other sites More sharing options...
mikeatrpi Posted May 3, 2009 Author Share Posted May 3, 2009 Aw, you're right on the tach spikes. I am still running copper plugs, but I bought some NGK's. I'll put those in soon and maybe get some new wires to cut down on the noise. At least these spikes aren't bad enough to feel it when driving. I have the Accel Enrichment settings disabled. I think you're telling me its time / ok to enable them. I'll do that and also start using VEanalyzer, basing my settings off yours. Will keep you posted... thanks for the advice Dave! Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted May 4, 2009 Share Posted May 4, 2009 Some people recommend tuning with the AE off. I did it with the AE on. It's just another variable to juggle. You can get the VE table real close with AE off or on, using VEanalyzer. Your call. I got the car driveable "by ear" then adjusted the AE "by ear". I got it driving well while watching my AFR's and manually tuning after the drive. When I thought it was running well enough, I began VEanalyzer. That's when things really got better. I went back and forth for a long time...as a matter of fact I am still tuning. It never ends. I recently went closed loop with Autotune (MSII) and the car is self-correcting, as I drive, to match the actual AFR's to my AFR table! Right now it drives better than my factory WRX, as far as response, smoothness, power delivery, and I am getting 22mpg in mixed driving. Quote Link to comment Share on other sites More sharing options...
mobythevan Posted May 4, 2009 Share Posted May 4, 2009 Using Ve analyze you can have the AE turned on and closed loop correction turned on so that makes it nice to drive around while working on the tune. I recommend driving for 15 minutes at least if you are using VE analyze so you log files is large enough to have a lot of samples. Quote Link to comment Share on other sites More sharing options...
mikeatrpi Posted May 12, 2009 Author Share Posted May 12, 2009 OK, here's an update. First, some good news. I have been doing "real" driving now. We took a ride this weekend probably 30-40 miles to a nice bakery in a pretty part of Connecticut. So I'm getting my confidence, but its still not quite "good" yet. I put in some NGK BPR6ES-11 plus, gapped at .028". Stock is 044, but I hoped that a smaller gap would help reduce some of the pinging I'm getting. I think it worked, but its hard to tell. I also shifted my entire spark advance map down by 2 degrees. I do still have the tach spikes. I'm going to order some Magnecor wires. Ugh, another $100. I have a miss now; its been there with the old and new plugs. It seems worst when I'm lugging the motor - coasting then getting back on the throttle. You can feel the car jerk, and watch the tach dip for a split second. I tried to put some markers in the data log when this happened. I'm thinking that I have a hole in the VE map. And, I need to adjust my timing a little bit under boost. Maybe pull it back another degree. drive13.zip Quote Link to comment Share on other sites More sharing options...
mikeatrpi Posted May 12, 2009 Author Share Posted May 12, 2009 I forgot to mention, I have been using VE Analyze. It doesn't seem to zero in on the AFR's that precisely, but I can definitely feel an improvement in the drivability of the car! Quote Link to comment Share on other sites More sharing options...
mobythevan Posted May 12, 2009 Share Posted May 12, 2009 Yeah, I look at ve analyze's output and see if it makes since to use all the changes it suggests, most of the time I just use a few that seem to smooth the table out. I think my friends car had the same jerking problem getting back on the gas during cruise and it was because he needed more tuning in that area with the AE turned off. Quote Link to comment Share on other sites More sharing options...
mobythevan Posted May 12, 2009 Share Posted May 12, 2009 I just remembered another thing with my friends car. It did not idle smooth and would miss a bit and surge a little bit. A small adjustment to the injector opening time fixed it. Something else to think about. Quote Link to comment Share on other sites More sharing options...
mikeatrpi Posted May 21, 2009 Author Share Posted May 21, 2009 I changed the gap to 032, based on some reading in the archives. I also installed Magnecor wires, a new cap, and rotor. I have been playing with the timing a lot, and I think I'm messed up. The car doesn't have the oomph it used to at the bottom end. Mind you, its still the NA compression ratio. I think I'm too conservative on the timing out of boost. When I get in the boost, it goes rich and I definitely feel the added power - but I do have some pinging. I did change the injector settings per Z-ya's thread with the measured opening times. It definitely helped. Here is a log, if anyone is bored, of my morning commute. Today was my first day driving to work. Don't tell the boss, I'm spending more time doing Show and Tell than work...... towork.zip Quote Link to comment Share on other sites More sharing options...
mikeatrpi Posted May 21, 2009 Author Share Posted May 21, 2009 UGH! I think I blew the head gasket. I took a buddy out for a ride, and I might have been horsing around a little bit... the car goes "PSSH PSSH PSSH", and it sounds loudest around cylinder #1. I have a 45 minute commute home, I'm planning to leave before rush hour and limp home. If its a BAD idea to drive it like this, somebody should let me know... Quote Link to comment Share on other sites More sharing options...
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