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Tip in throttle, lean spike.


cygnusx1

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Are there any tuners out there that can help me with this little issue. If I am cruising along off throttle, when I open the throttle slow or fast I get a real fast swing on the O2 mixture gauge. If I snap throttle quickly open, the mixture gauge snaps max rich and then max lean within a half a second. I also feel a flat spot in the engine response until it recovers and pulls smoothly into proper mixture. If I snap throttle open slowly, the O2 just spikes very lean and then stabilizes. The same flat spot is felt in the motor for a second then it goes fine. I tried messing with accel parameters but nothing seems to make it much better. When I use full MAP for accel, it seems better. I checked the TPS calibration and functionality. It seems fine and reads correctly in Megatune. Could this be a function of the large 440cc injectors taking time to respond in 2-Squirts-Alternating mode?

 

If I let it idle really rich (12.5:1) and keep the map rich for a few load points off idle, the throttle response is better, but it blows whiteish smoke if I rev it in idle and it's smelly.

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I forgot to mention I am using MS-II. What is EAE? I actually got it running better. I spent some more time at the keyboard and driving and was able to tune most of the flat spot out. At this point, I will just wait until I get up to the Dyno for a real tune.

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That is for the MS-II Extra code. I am still learning to tie my shoes with the MS-II code. EAE sounds interesting but it should be used after you have a well tuned VE table. I am still dialing in my VE table and probably won't get into a solid dyno tune until this Fall. Until then I am playing with my butt dyno. MS-II Extra looks interesting but it omits Automatic Mixture Control which is a bit dissapointing since I like being able to Autotune with the wideband O2. On the other hand, I suppose once it's dyno tuned I wont need Autotune anymore.

 

I drove it to a car show tonight and it ran pretty good. Not as good as it ran with the stock 83 EFI but it's driveable.

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  • 4 weeks later...

It really annoys me when I find a thread that dead ends...so I try to come back to my posts and post a solution.

 

After a couple of days of tuning with the LC-1 WB O2 sensor, datalogging, and running the automatic analysis on the datalogs and VE tables, the car is running MUCH MUCH better. I set my AFR table to range from 14:1 to 12:1 in different load conditions and the datalogging and LC-1 made it happen. The tip in throttle issues are gone. Once the VE map was tuned well, I was able to run AE in full MAP mode, with a good low threshold of 25kpa/s and very very low AE pulswidths were needed to make the engine respond nicely to throttle inputs. Look for my .msq files in the sticky.

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umm yessir I can as soon as I get home. The lowest setting was like 0.5ms the top was 6ms I think

 

40--100--200--300 kpa/s---MAP speed.

0.5--1.0--3.0--6.0 ms---PW Accel

 

Something like that....I will screenshot it later to get the exacts. I will put them in the sticky for msq's and maps.

 

http://forums.hybridz.org/showthread.php?p=774480#post774480

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  • 2 months later...

ok I have been playing with my MSII for a while now and am satisfied with my tuning capabilities with it on my NA setup.

 

bolt on the t3/t4 60 trim Garrett, tial wastegate and bov, extra large intercooler, and a Greddy profec b, lc-1.

 

my question is how do I figure what kpa values to use?

I am assuming they are related to the amount of boost I am running but what is that formula?

thanks for any input.

and yes I searched before posting but was inconclusive.

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ok thanks for the converter.

so I want to tune for 10lbs first. I converter 10psi to kilopascal and got 68.9475728 kilopascal.

not sure how to use this number tho. Did I use the correct conversioln? please enlighten me.

 

also. once I figure it out for say 10lbs boost. and my boost control ler will store high and low settings and I want 15lbs on high. will I have to have a completely different map settings to run 15lbs.

If so then it makes that little hi lo setting not as easy to use as I wanted.

 

thanks again.

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