skirkland1980 Posted October 30, 2013 Share Posted October 30, 2013 I'm trying to tune my L28et with the ms2 and the new cam. I was told by delta cam that it is a 272/.460" lift. My idle is quite rough with some unburned fuel emissions. I had to adjust pulsewidth all the way down to 4ms to keep the plugs from fouling. Calculated pulse with is 7.1ms. How should I tune this engine? It seems to be a basket case at this point. Thanks. Quote Link to comment Share on other sites More sharing options...
rucus01 Posted October 30, 2013 Share Posted October 30, 2013 How much vacuum are you pulling at idle? What is your AFR showing ? Matt Quote Link to comment Share on other sites More sharing options...
skirkland1980 Posted October 30, 2013 Author Share Posted October 30, 2013 Vac at idle is about 10". Afr is unstable but around 14. Quote Link to comment Share on other sites More sharing options...
rucus01 Posted October 30, 2013 Share Posted October 30, 2013 Whats your timing look like. At 10" vac how much timing do you have in ? Matt Quote Link to comment Share on other sites More sharing options...
skirkland1980 Posted October 30, 2013 Author Share Posted October 30, 2013 30 degrees Quote Link to comment Share on other sites More sharing options...
SleeperZ Posted October 30, 2013 Share Posted October 30, 2013 You have 440cc injectors running a 4mS pulsewidth at idle? I'm running a stock cam (which certainly pulls more vacuum) but with the same size injector I am running 1.7mS at idle. No wonder it's so rich. I know you can't run that low of a pulsewidth with the cam, but it seems like you have a lot of room yet to reduce fuel. 30 degrees also sounds like too much timing for idle. My old turbo cam, similar to what you describe, timed just like the stock one. 20 degrees of ignition timing was perfect. Quote Link to comment Share on other sites More sharing options...
rucus01 Posted October 30, 2013 Share Posted October 30, 2013 If he is reading 14 on his AFR it isnt that rich. What is the complete cam card read? What is the LSA etc.. What actual compression ratio are you at? Large cam motors do like a lot of timing at closed throttle conditions. The lower pressure and dirty mixture burns a lot slower and will need to be lit earlier. A hot cam will require a lot more fuel at idle because it simply requires moving more air to keep the engine running. Depending what the exact specs etc are on that cam you may have to just learn to deal with a rough idle and unburned fuel in the exhaust. Quote Link to comment Share on other sites More sharing options...
skirkland1980 Posted October 30, 2013 Author Share Posted October 30, 2013 Logged into tuner studio under basic setup/ engine Constants, the required fuel calculator recommends 7.1ms. I changed it to 4 just to lean it out. What I ended up doing was changing it back to 7.1 and leaning out the fuel map. I actually just now got the car to idle by itself. vacuum at idle in neutral (1200 rpm) is 12 inches. In gear at 1000 rpm is 10 inches. I'm not sure about our differences in pulse widths. Quote Link to comment Share on other sites More sharing options...
SleeperZ Posted October 30, 2013 Share Posted October 30, 2013 (edited) Logged into tuner studio under basic setup/ engine Constants, the required fuel calculator recommends 7.1ms. I changed it to 4 just to lean it out. What I ended up doing was changing it back to 7.1 and leaning out the fuel map. I actually just now got the car to idle by itself. vacuum at idle in neutral (1200 rpm) is 12 inches. In gear at 1000 rpm is 10 inches. I'm not sure about our differences in pulse widths. I was confused. You were talking about changing required fuel, and I thought you had already leaned the map. Yes, 7 is approximately the correct required fuel, and you are now doing the right thing by modifying the map. You should be able to see actual pulse width on your laptop while idling, and I expect you are less than 2mS if you are now idling ok. Edited October 30, 2013 by SleeperZ Quote Link to comment Share on other sites More sharing options...
skirkland1980 Posted October 31, 2013 Author Share Posted October 31, 2013 Oh ok. I didn't know about that feature. Very interesting. Thanks Quote Link to comment Share on other sites More sharing options...
skirkland1980 Posted November 3, 2013 Author Share Posted November 3, 2013 I got the car tuned enough to make a boosted run. Holy CRAP! I was still shaking from the adrenaline rush 10 minutes after I parked the car. This car is sick! I'm going to try to make it to the strip next sunday. Hopefully I'm in the mid 7s. Will keep this updated with results. Thanks. Quote Link to comment Share on other sites More sharing options...
SleeperZ Posted November 4, 2013 Share Posted November 4, 2013 Sounds great! Quote Link to comment Share on other sites More sharing options...
skirkland1980 Posted November 17, 2013 Author Share Posted November 17, 2013 engine idling https://www.youtube.com/watch?v=Yweinr6CzOU Quote Link to comment Share on other sites More sharing options...
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