74Adam Posted January 4, 2016 Share Posted January 4, 2016 This is a 78 with a 3.0 N/A stroker, 9.7:1 CR and a mild cam. Running MS2, fuel only, with OEM N/A injectors; OEM pump/filter/pressure regulator and the stock throttle body that I modified to be able to use the 240SX TPS. I am also using the OEM AAR for cold start fast idle. So, a pretty simple setup. Anyway, the car runs well, I can drive it on the street and it pulls strong so I feel pretty good about the VE table. I just can't quite nail the cold starting. Once the temperature starts getting below 50 or so it can take a couple of cranks to stay started. If it gets down to 30 it can take three or four times. It will kick to life and almost immediately die. Then after the second, third or fourth time it will catch and the AAR will bring the idle up to 1600 and after a few minutes settle back down to 900, running smooth the whole time. I just wanted to list my basic settings and see what you guys think. required fuel - 18.6 (183 c.i. engine with 180 cc/min injectors) cranking settings: priming pw - 2.0 -40 degree pw - 16.0 160 degree pw - 4.0 flood clear threshold - 70.0 cranking rpm - 300 afterstart enrichment: additive enrichment - 60 ignition cycles - 250 warmup enrichment: (degrees - enrichment) 00.0 - 200 20.0 - 182 40.0 - 165 60.0 - 150 80.0 - 138 110 - 123 130 - 114 155 - 106 165 - 100 I also have a small enrichment for intake air temp. It's about 12% at zero degrees and tapers linearly to nothing at 75 degrees. Anyway, thanks in advance for your help Quote Link to comment Share on other sites More sharing options...
seattlejester Posted January 4, 2016 Share Posted January 4, 2016 Honestly, I just sit there and crank while keeping my foot on the gas maybe about 10%, it catches as you say a couple times, but I just stay on the starter until it really catches and the RPM's climb. I'll go look up my settings to see if they differ from yours. Quote Link to comment Share on other sites More sharing options...
seattlejester Posted January 4, 2016 Share Posted January 4, 2016 (edited) Mine is much less aggressive and starts quite a bit lower. What is your AFR when it catches? I would run a log and see if it is running too lean or rich when it catches and then look at the events afterwards if you really want to solve it. For priming pw: -40 14 ~60 5 170 2 ^That is a bit irrelevant. I was told that the value is basically to purge the injectors of any air, not really an attempt to get fuel into the cylinders. ASE: -40 60 -20 52 0 45 20 40 38.4 45 57.2 28 79.1 21 106.6 15 137.9 8 170 5 ^Yours looks to be about double mine. WUE: -40 190 -20 180 0 160 20 150 40 139 60 133 80 126 100 120 140 109 170 100 ^Seems like yours is also a bit higher here as well. I started my car to move it earlier today, it said it was 1* C in the car and it fired up after about 20 seconds of cranking or so, keep in mind my car is a 3 liter toyota motor with low compression. I think you are putting quite a bit of fuel in there and potentially washing out the cylinders and lowering some compression. Might be helpful to run a compression test and see how it is. A data log of the start will also tell you when the motor catches and why it dies, whether it ran to rich and choked itself out, or the catch was just a detonation from running extremely lean. I would bet it is the former and that when it catches and then subsequently dies it is running quite rich. Edited January 4, 2016 by seattlejester Quote Link to comment Share on other sites More sharing options...
74Adam Posted January 4, 2016 Author Share Posted January 4, 2016 (edited) I'll check tomorrow when I get home from work but it seems like when the O2 sensor comes on line the AFR is at about 12. I realize that is rich but I didn't figure it was out of line since my understanding is that even at operating temperature the AFR is supposed to be a bit on the rich side. I figured with the cold temp enrichments that low 12's was reasonable. My AFR at operating temp is about 13.5, by the way. It sounds like your hunch is that I'm a bit rich and you may be right. I'll try leaning out the cranking and afterstart parameters a bit. Edited January 4, 2016 by 74Adam Quote Link to comment Share on other sites More sharing options...
seattlejester Posted January 4, 2016 Share Posted January 4, 2016 12 isn't all that rich. I was thinking like 10 or something. My car starts and hits about 12-13 then idles around 14 or so. It dips down more when in use, but idle can be on the leaner side generally unless you are boosted or need the extra fuel. I would take a log and examine that before changing anything by too much. Also remember not to change values too drastically, take it slow. Quote Link to comment Share on other sites More sharing options...
dexter72 Posted January 4, 2016 Share Posted January 4, 2016 Turbo280z has a cold start settings video on youtube.. His old turbo 280z setup.. I used his and they worked on my old L28nat setup.. Cygnus1 has his settings on youtube also. i would check those videos out and compare.. Both guys are members on this forum Quote Link to comment Share on other sites More sharing options...
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