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Okay, so I'm pretty much happy with my part throttle cruise, WOT tune. Idle in gear is good. Idle out of gear is good. What I can't seem to solve is the park to drive (or reverse) transition. I have searched this forum till I'm half-blind and cannot seem to solve this puzzle. I can make it worse but can't seem to get it where it should be. Out of gear, idle at 800 rpm (I increased the park addition to 200 in hopes of helping the transition) IAC counts of 5 to 8. Drop it into gear and rpm drops right past 600 rpm (commanded) to 475 rpm, then finally climbs back up to 600 and stabilizes. SA jumps to 20 degrees, where it hits the limiter (15 base plus 5 idle speed error), but rpm continues to fall until the IAC finally increases and "saves" it from stalling. Since I have the Bosch III injectors, the low pulse width offsets are all zero'd out. Also, I noticed that the IAC counts don't seem to be much different in gear or out. Seems like I should be getting more IAC counts in gear (than out) with increased load. BTW, new ACDelco IAC installed a few months ago, throttle body cleaned prior to TPI conversion.
I've tried increasing AE delta map mulitplier vs TPS and also increasing low rpm SA (which made it worse, if anything). Is this a fueling problem made worse by increasing SA, or is this a SA problem not getting enough fuel?
IAC step count is too low. Get it into the 20 - 25 step range by adjusting the idle stop screw. This is on a warm engine and no other loads.
Note that the $8D code on a stall saver sets the SA back to the base setting. It does this by opening the EST/BYPASS line to the ICM. Can disable this 'feature:'
IAC step count is too low. Get it into the 20 - 25 step range by adjusting the idle stop screw. This is on a warm engine and no other loads.
Note that the $8D code on a stall saver sets the SA back to the base setting. It does this by opening the EST/BYPASS line to the ICM. Can disable this 'feature:'
No wideband, injector pulse is at 2.46 when the idle speed bottoms out at 475 rpm. Injector pulse doesn't really start coming up until IAC counts increase. Injector is at 1.68 in park; eventually rises to 2.69 before leveling off at 2.32.
If i look at that right it appears pulse stays roughly same at normal idle and when rpms drop its still the same meaning its too rich. This certainly would drop rpms abit imo. Pulse width should drop if rpm drops, it simply doesnt need the fuel. Whats your ve table look like at idle rpm then down to the 400 rpm range?
If i look at that right it appears pulse stays roughly same at normal idle and when rpms drop its still the same meaning its too rich. This certainly would drop rpms abit imo. Pulse width should drop if rpm drops, it simply doesnt need the fuel. Whats your ve table look like at idle rpm then down to the 400 rpm range?
I've been working off the assumption that it's too lean. When I add advance, it gets worse, not better. Here's the current VE table...
Maybe try taking some fuel out and see? I ran into a similar issue on my car before and it was too much fuel. Do it in the map areas where it idles and higher, as rpms drop kpa level should increase some if it starts dropping rpm that low. Just my thoughts
whats the 3d graph look like. I see a dip already at 900 rpm 40 kpa and at 1200 rpm 40 kpa
Maybe try taking some fuel out and see? I ran into a similar issue on my car before and it was too much fuel. Do it in the map areas where it idles and higher, as rpms drop kpa level should increase some if it starts dropping rpm that low. Just my thoughts
whats the 3d graph look like. I see a dip already at 900 rpm 40 kpa and at 1200 rpm 40 kpa
Thanks, I'll need to look into that for sure. As I said, I've been thinking all along that it's going lean. Here's the VE graph...
It very well could be going lean. For one, i would smooth out those valleys between peaks and vice versa. Lines from low rpm to high should rise smoothly to peak torque rpm and then taper off some to peak hp, depending how far peak trq is from peak hp rpm lol but in general things should smoothly transition. Yours is abit rough
The idle area and lower rpms to 400, that ve area is a fairly steep slope down so it could be goin somewhat lean and dying off a bit
you can try either way, increase the ve in the 400 and 600 rows to get it abit closer to your 800 values, so the slope isnt as steep there and see if that helps. If not maybe try less fuel but looking at the table it very well could be too lean
fast acting wideband may show some hints there, but the pulsewidth not changing seemed suspect to me as rpm dipped. That was implying rich imo
Why do the IAC steps decrease first as the RPM is dropping?
RBob.
I think that's the $10,000 question. Makes no sense. Also notice the SA drops immediately before RPM drops from 15 base to 10 degrees, then jumps to 20 degrees (where it hits the SA Idle advance adder limit); it seems to happen as the shifter is moving out of park, but isn't into gear just yet. I know there's a signal to the ECM for "Park"; so when it "sees" the out-of-park signal, it cuts SA. Why?
I bumped up VE in low rpm/low kPa table and closed the throttle blades a bit more to try and increase IAC steps. Seemed to help. Should I try giving the Idle Spark Advance Vs. Idle Speed Error a little more headroom? Latest data log attached.
Eh i honestly would make everything in the 400-800 rpm rows 15 deg. Going into gear will increase load aka higher map which will use less timing in the table which lowers torque against the converter which will slow rpm
unless that table is not used and a closed throttle spark table is used?
Basically find a stock 305 tpi bin spark and try that in those lower rpm cells
Eh i honestly would make everything in the 400-800 rpm rows 15 deg. Going into gear will increase load aka higher map which will use less timing in the table which lowers torque against the converter which will slow rpm
unless that table is not used and a closed throttle spark table is used?
Basically find a stock 305 tpi bin spark and try that in those lower rpm cells
Yeah, the Closed TPS SA table is stock AXXB, so it's 15.47 from 0 to 800 rpm.
Just an update and some conjecture. By careful (and time consuming) tweaking of my VE and SA, I've got the P-D transition a bit better, but I had a thought after reading some more threads here. It seems the Bosch III injectors are a variable that could have some unforeseen consequences. This occurred to me after reading RBob replies referencing "SCALAR FOR MAX PW." In my BIN, the injector flow rate is set at 17, even though they are "19 lb" injectors. This seems to be a pretty typical recommendation when the Bosch III injector is replacing the stock injectors in a TPI engine. But is the rest of the tune using that 17 flow rate (instead of 19) to determine all the other applicable variables? If so, seems to me it could effect several things. As a test, I bumped up the Crank Fuel Pulse Width Vs Coolant Temp by 10% (19/17=1.118) and, sure enough, my cold start improved significantly. I see no way to alter the SCALAR FOR MAX PW in TunerPro $8D.xdf, but would really appreciate some input here.
OK, so I'll apologize in advance for my lack of ability to grasp this (I've read dozens of threads trying to do this without begging for help and failed) but I'm assuming I should increase both gain and duration (10%?) on the low end to help my P to D transition? Idle is great once it's there, only the transition needs help.
Thanks, my BIN is based on AXXB (SD 305 TPI Auto). Having trouble figuring out how to access airflow data. Checked several adx files and none have this parameter (???).
07-10-2019, 09:30 AM
