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My LT-5 is ported and cammed. 450+rwhp. Idle ~. 925rpm, One particular annoyance is when making slow speed 90* turn, its possible the engine will stall out u less playing w accelerator. Related to that is when you are inching forward in traffic with on/off accel, possible to experience engine stall again when backing off accel. Played w timing for Too Low Idle, and IAC V mph and a few other things. Any other recommends?
All the fueling in that area correct? When it dips down low rpm and higher map before stall sometimes those areas can be too rich and kill motor
timing also is needed. I’d try bumping it up everywhere around idle maybe, lower rpms below idle and higher map areas where it would dip into before stall
All the fueling in that area correct? When it dips down low rpm and higher map before stall sometimes those areas can be too rich and kill motor
timing also is needed. I’d try bumping it up everywhere around idle maybe, lower rpms below idle and higher map areas where it would dip into before stall
Could the too rich condition be coming from too much AE at small MAP changes, ie when initial takeoff?
It may be the stall saver (SS) logic. In SS the ECM opens the EST/BYPASS and reverts to base timing. Here is a thread that describes this logic for $8D and $6E. The '92 LT5 $D0 mask uses the same SS routine.
Note that this thread also describes how to disable it:
We've had this discussion before and I had set those params to 0 some time ago based on ur recommends. DFCO is also disabled. Just recently had motor rebuilt with basically new short block. Did a log yesterday so I will look at SA to see what happens during those times of "crawling" and feathering the clutch.
OK, good to have the SS covered. A new engine is going to be tight. IOW, there is going to be more running friction. After some miles are put on the engine it will loosen up. Can usually tell when it starts to rev more quickly.
OK, good to have the SS covered. A new engine is going to be tight. IOW, there is going to be more running friction. After some miles are put on the engine it will loosen up. Can usually tell when it starts to rev more quickly.
RBob.
Good point RBob. Took a look at the log from yesterday and I did note that as Orr suggested that it goes rich as I make small change to TPS/MAP from takeoff. Then goes lean for a number of frames thereafter.
I had a going rich then lean at light throttle off idle problem. I finally figured out that to much AE was causing the rich and the resulting stumble and misfire was making the o2 sensor see a lean condition. Once I fixed the rich condition and the lean then corrected itself.
I think ur right Larry. However, I took another look at the datalog and I believe attached is an example of what RBob was describing above with Stall Saver. U can also see the Rich/Lean thing happening.
There is a Closed Throttle constant which I have set at 20*. Also the flag is checked to allow Closed Throttle SA. Don’t see a table in the .xdf I have.
I checked and the table I thought was closed throttle is closed secondary ports. The one thing I noticed in the above screen shot is that the low timing is somewhat relative to throttle opening being near 0%.
I checked and the table I thought was closed throttle is closed secondary ports. The one thing I noticed in the above screen shot is that the low timing is somewhat relative to throttle opening being near 0%.
But something is going on, just not sure what.
RBob.
That’s right RBob. That’s the reason I highlighted those areas because it looked like what u had described was happening.
Well, I have scanned the log closer after seeing a pattern emerging. My observations are:
1. An SA of 9.49 initiates at TPS% <= 1.17%
2. But only if MPH <= 15mph
3. Once RPM is <= 1000, timing appears to be restored back from the 9.49 default value.
So my IAC Max MPH for Idle Mode is set at 15mph,
That's 0x7CA in the $D0A .xdf
My IAC Max TPS% for Idle Mode is set at 1.17%. 0x7C7
C/L TPS% Threshold is also set for 1.17% 0x6B2
Finally, there's a SS recovery rate (assume blend rate) of .49%/sec. 0x48
Again, I have the SS params =0 as outlined by RBob. Initial(base) SA is set at 5.98* with Closed Throttle SA = 20.08*
