Bringing TBI and Multi Port Fuel Injection to a New Level.     EFI Conversions and Tuning! Seattle to Portland! E-mail Tuning Consultant!
Page 9 of 11 FirstFirst ... 4567891011 LastLast
Results 121 to 135 of 164

Thread: 95 LT-1 Idle Cell Comparison - Humidity?

  1. #121
    Fuel Injected! spfautsch's Avatar
    Join Date
    Apr 2015
    Posts
    481
    So back to tuning the prime pulse tables - last night I decided to go ahead and cook my closed throttle BLM split into my individual cylinder trims, which amounted to adding approximately 10% to the right side.

    Code:
    1    82    130
    8    7D    125    increased to >    129    81
    4    84    132    increased to >    141    8D
    3    80    128
    6    83    131    increased to >    140    8C
    5    80    128
    7    7E    126
    2    83    131    increased to >    140    8C
    No other changes were made save fiddling with some IAC adders relative to A/C.

    To my surprise all startup fueling went out the window. Cold, hot, and everything else required cranking until the run flag was set. I just reverted the individual trim changes and startup went back to how it's been for the past several days - not quite perfect but very good. Just a note to anyone tuning on their startup fueling tables - individual cylinder trims seem to apply to the prime pulse and cranking afr tables.

    Another thing I noticed when looking at the individual trims - what I gather from the disassembly it appears to my untrained eye that the 0x126db "low" limit might be ignored for transitioning to the off-idle trim table.

    Code:
    688A    18 CE 26 E5     @290    ldY    #$26E5                            ; bt8_CylBal(AtIdle)
    688E    12 26 08 04         brset    L0026, #%00001000, @291           ; at idle (or closed throttle) status bit
    6892    18 CE 26 DD         ldY    #$26DD                            ; bt8_CylBal(OffIdle)
    I don't see where bit 4 of L0026 is set - so maybe I'm just missing something obvious.

  2. #122
    Fuel Injected!
    Join Date
    Mar 2013
    Posts
    650
    Great experimental finds. Even though I still insist that trims are not used until the engine run flag is not set. In your case @32*C that will be engine spining above 300 rpm for 4 low res pulses. I guess that can be reached pretty quick and after that there is a flood from the trims.

    Actually the conditions are pretty starightforward. Not in PE or cat protect mode, engine on flag and tps thresholds. I also added a map threshold but that needs some patching.
    L0026, #%00001000 is the ZERO tps flag.

    To do more experiments on starting I strongly recommend playing with the beta I send you. You can preset the trims before starting with ign on, and change crank ve upto 5%.

    NOw on my case.

    I messed with so many things at once that didn`t make sense and the results are good so far.
    First I fixed the startup fuel flow constant in the patch, Now there is separate fuel flow settings at start up. Next loaded some modified crank ve based on lt4
    Code:
    14
    14
    14
    14
    11
    11
    9
    8
    6
    4
    2
    0
    0
    0
    0
    0
    0
    Loaded stock lt4 settings for the prime pulse tables and the multiplier. Also lower the trims by 1 on 3 cylinders.

    ON the first cold try it started much better than before{I have to notice that the engine was air flowed and there was no residual fuel left over, cranking with inj fuse off to check the cranking fuel pressure}. Hot restarts upto 60*C were also right on.

    Now when it starts the rpm goes upto 1500rpm, indicating there is much more fuel left over during cranking. Some of the older logs shows barely 1000-1200rpm rise immediately after starting.

    I guess now it dumps much more at prime time and leans after that.

    About the blms, it could be inbuilt limitation for some splits possibilities, based on headers and exhaust pipe configuration. I have seen numerous bins with differen swing voltages set on the left and right side. Maybe GM tried to cure the split by changing the per side swing voltage.

  3. #123
    Fuel Injected! spfautsch's Avatar
    Join Date
    Apr 2015
    Posts
    481
    Quote Originally Posted by kur4o View Post
    Great experimental finds. Even though I still insist that trims are not used until the engine run flag is not set.
    Is the run flag logged directly by eehack? I only see engine runtime, and just assumed the AIR output was enabled in conjunction with the run flag. Unfortunately I didn't log any of my hard starts with the "fat" cylinder trims.

    Quote Originally Posted by kur4o View Post
    L0026, #%00001000 is the ZERO tps flag.
    I was hoping I could set the 0x126db value to use the closed throttle trims until about 7% tps, but it doesn't appear to work that way. ???

    Quote Originally Posted by kur4o View Post
    First I fixed the startup fuel flow constant in the patch,
    Are you talking about the 0x12680 multiplier???

    Quote Originally Posted by kur4o View Post
    About the blms, it could be inbuilt limitation for some splits possibilities, based on headers and exhaust pipe configuration.
    I think I'm going to swap injectors bank to bank because it's possible my BLM split might have appeared after going to the modified injectors. Yesterday I found a couple logs made before I replaced the stock multecs where the left side was 2 points lean of right, but that was almost 3 years ago. I've taken the modded injectors out of the fuel rails several times since first installing them and I never paid any attention to which one was where. If there's one injector that's flowing a lot more than the others at low pulsewidths that would seem rational. If it's more than one it's somewhat unlikely I've put those two (or three) on the left side in two or three different builds, but entirely possible. I was really hoping these cheap modded injectors would suffice, but if they're the cause for my BLM split I'm probably looking at a set of m-9593-lu80 or some LS7 injectors.

    Edit: Swapping injectors was a bust - right side still leans out when it gets to temp. Took the intake off. I was shocked to find oil wetting the bottom of the throttle body and in all the intake ports in the heads. The pcv hose wasn't wet on the inside, nor was the right side valve cover breather tube. But the breather inlet in the throttle body (the hole that opens into the top cover) was slightly wet. Anyway, I'm finding nothing to indicate that the idle passages are clogged but I'm going to clean it thoroughly while I have it disassembled.

    Looking at the miniscule size of the #1 feed hole I'm seriously debating enlarging it some. Seeing the size difference next to the #3 feed hole from the bottom really emphasized how big a difference there is here. This alone seems like it could account for at least 50% of my split.

    Another interesting thing I noticed were traces of the crud getting sucked out of the idle feeds, being deposited on the inboard side of the intake runners. I'll try to post a picture or two tomorrow, but this reinforces the notion that adjacent cylinders are robbing charge from across the plenum.

  4. #124
    Fuel Injected! spfautsch's Avatar
    Join Date
    Apr 2015
    Posts
    481
    I've had some time to disassemble and clean things, and I think my oil issue was caused by the intake gaskets being positioned too far down on the front ports. When it goes back together I'm going to remove the plastic locating pegs and glue the gaskets to the heads with RTV overnight before final installation to make sure they're where they're supposed to be. The oil infiltration problem was primarily on the 1 & 3 ports where the gasket misalignment was most evident, and the rest could have just been normal PCV function.

    Quote Originally Posted by LeMarky Dissod View Post
    So far, I have not seen a single LT1 inlet manifold that has had its idlespider properly cleaned during a socalled cleaning. This will definitely have an impact on your idle, as it does for us all.
    My intake is the 5 plug design identical to the one posted back on page 5 by kur4o [link]. I blew some compressed air through the idle air plenum and was able to feel some coming out of all four of the tapped plug holes (the center hole connects to the EGR passage). There is a bit of crud in these passages (far more in the EGR passage) so I decided to soak the manifold in some diesel fuel before taking a pressure washer to it tomorrow. I wasn't able to find a disposable pan big enough to submerge the portions I wanted to clean so I flipped it over and started pouring diesel into the idle plenum. Immediately I noticed this was connected directly to the PCV inlet, so I capped it off. I then poured what I felt was an alarming amount of fuel into this plenum. Eventually fuel started to trickle out of the IAC inlet hole below (actually above) the primary throttlebody inlets. I was shocked at how much fuel this passage holds, and that the level of liquid while stabilizing only 1/8" below the port orifice holes was barely trickling out of the IAC inlet that by my estimation is at least 0.8" lower (intake inverted). I suppose it would take a couple x-rays to figure out what's going on here but it seems this plenum has a complex internal layout.

    I'm seriously contemplating enlarging the #1 idle feed hole. All the others are 15/64" / 6mm, but this one is 5/32" / 4mm. I'm thinking I'm going to go to 13/64" / 5mm. Anyone have any thoughts on this?

  5. #125
    Fuel Injected! Terminal_Crazy's Avatar
    Join Date
    Oct 2015
    Location
    Lancashire England
    Posts
    334
    Quote Originally Posted by spfautsch View Post
    I'm seriously contemplating enlarging the #1 idle feed hole. All the others are 15/64" / 6mm, but this one is 5/32" / 4mm. I'm thinking I'm going to go to 13/64" / 5mm. Anyone have any thoughts on this?
    I did & can't say whether it did or didn't make any noticeable difference.
    Idle ports are all the same size now.
    I'm using the Edelbrtock LT4 manifold to match the head ports.
    Machining is not very good.
    Flash left in idle ports and ports exit the runners in different places.

    Notes are:

    On Edelbrok 7109 Air Gap Manifold LT4
    Idle air ports are drilled badly into the sides of the port wall near the head
    No 1 drilled at 4.5mm
    2-8 Drilled at 6.mm but only allow a 5.5 drill through into the port

    Stock GM Manifold idle ports are
    No 1 measures 4mm - smaller than the Edelbrock
    2-8 measure 6mm but are drilled all the way at 6mm
    All ports are drilled at an angle half way into the port runner floor


    HTH
    Mitch
    '95 Z28 M6 -Just the odd mod.
    '80 350 A3 C3 Corvette - recent addition.

  6. #126
    Fuel Injected!
    Join Date
    Mar 2013
    Posts
    650
    When I made the ports equal diameter, I got all kind of surging problems with stock individual cyl trim settings. I had to rework the trims it all the way and now #1 gets much more air and needs more fuel. You get to the point where balancing cylinders with more fuel at #1 is not possible. The reason GM restrict the air flow at #1, and some fancy drilling sizes on the other ports. I also remember that not all ports were equal at 6mm.

  7. #127
    Fuel Injected! spfautsch's Avatar
    Join Date
    Apr 2015
    Posts
    481
    Odd. All others in mine are 6mm exactly.

    I went up two drill sizes on #1 to 3/16". Hopefully it wont wreck the tune. I didn't see any other reason the left side would be getting less air than the right.

  8. #128
    Fuel Injected!
    Join Date
    Mar 2013
    Posts
    650
    Prepare to start all over with cyl trims.

    I made some progress on the first cold start. Still needs some fine tunning. While experimenting it turns out that running around 20-35*C coolant at startup it idles best at 14* advance and a liitle fatter mixture.[Tuned by sound and feel.]
    I will let you know the best setting I came up when it gets fine tuned.

    You can monitor the rpm rise after startup to tell if it needs more or less fuel. If the rpm rise alot like upto 1500rpm it has more unburned fuel left on the walls from prime pulses.

  9. #129
    Fuel Injected!
    Join Date
    Mar 2013
    Posts
    650
    Another vote for the adjustent cylinder fuel robbing.
    The lt4 settings are

    Cylinder Multiplier
    1 1.05 3 0.96
    2 1.05 4 0.97
    5 1.01 7 0.98
    6 1.02 8 0.96

    Somehow my trims closely resembles this pattern with the exclusion of #2 1.039 and #4 1.024.
    Next on the list is to test it on running engine and starts to cut #4 to around 0.98 and see what happens.

    The fuel robbing feature seems to be more pronounced on cammed car than to be related with ports size and headers lenght and style. Interesting to know the stock size idle air feed holes on a GM production lt4 manifold.

    Can you source some pics on the vette air induction system like filter box, passages, maf mount and so on. Are you running some form of CAI kit. I suspect that the air induction system is the reason there are different scaling in MAF tables across platforms.
    Last edited by kur4o; 3 Weeks Ago at 11:33 AM.

  10. #130
    Fuel Injected! spfautsch's Avatar
    Join Date
    Apr 2015
    Posts
    481
    Quote Originally Posted by kur4o View Post
    I suspect that the air induction system is the reason there are different scaling in MAF tables across platforms.
    I also suspect it, times ten. In fact it's widely published that OEMs generally mock up the entire front of the car on a flow bench to develop their MAF transfer curves. Google: "helmholtz resonator". OEMs have been using them for > 10 years to smooth airflow in the intake ductwork for this specific reason (more accurate MAF transfer curves).

    Here's the stock y-body intake. I believe all MAF equipped LT-1s got this intake setup. I'm also fairly sure the ZR-1/LT-5 (read: 450 hp off the showroom floor) also got an identical airbox and MAF but with a slightly different shaped throttlebody bellows.





    This might be closest to a ram air Pontiacs. The only anomaly in this tract is that the Y-body engine is slightly offset towards the passenger side of the car. Anything that came with an elbow in the air ducting will likely have vastly different MAF curves.

  11. #131
    Fuel Injected!
    Join Date
    Mar 2013
    Posts
    650
    The recommendation from GM is at least 4 inch of straight pipe before the maf sensor, to get reasonable air flow readings. That is for the newer style slot type of mafs but I guess it can be applied to older setups too.

    Thanks for the pictures. It looks like a funnel, before and aftre the maf and is vastly different from the f-bodies. The vette maf curve reads lower from 2-3% at low airflow to 5-6% at mid airflow upto 10-11% at high airflows, compared to stock f-body settings.

    I am running the slp version of CAI and there is some problem with lower map readings at high rpm, high load at WOT, especially on third and forth gear I am wondering if it is airflow restriction of some kind. Have you measured the map drop at wot pulls under high rpm and load. What are the max AFGS you have reached with the new setup.
    Attached Images Attached Images

  12. #132
    Fuel Injected! spfautsch's Avatar
    Join Date
    Apr 2015
    Posts
    481
    I haven't been doing much logging or tuning at WOT with this setup so unfortunately not much to report. I will try to pick through what logs I have but as I recall the few times I've gotten into it hard while logging were mainly corner exits or two lane highway stops / takeoffs where I didn't have much WOT time due to traffic. The majority of the hard throttle passes I've made thus far were a few un-logged joy rides I owed a couple guys that borrowed me tools and such where it broke the tires loose around 5500 rpm in 2nd and immediately bounced off the rev limit.

    What I've read on the subject of MAF tuning (primarily Banish's stuff) has me thinking it will be something I touch as a very last resort if the wideband is still showing lean during WOT passes after I've removed as much as I'm comfortable with from the injector constant. The accuracy of the instrumentation I have to work with is inferior to what GM was using in the 90s by orders of magnitude, and I have a lot of unknowns like the modded 42lb mystery injectors.

  13. #133
    Fuel Injected! spfautsch's Avatar
    Join Date
    Apr 2015
    Posts
    481
    Initial start + warmup after cleaning intake and enlarging #1 idle feed orifice didn't show any considerable improvement. But after an initial warmup I started working with individual trims and unlike before was able to see responses in closed loop BLMs after moderate trim changes. This is what I'm running currently for individual trims.

    Code:
    1	131	83
    8	127	7f
    4	134	86
    3	126	7e
    6	136	88
    5	127	7f
    7	125	7d
    2	135	87
    The last log I made (attached) had left trims at 131 and right at 135 albeit for a short time, and at higher air density / lower IAT numbers than previous logs. This is the best cell 16 split I recall logging with the current build. Idle felt and sounded good. Unlike 2 weeks ago I feel like there's potential for improvement simply from continuing to fine tune individual trims. I also removed a small amount from the prime pulsewidth multiplier to account for the trim changes and had good results.

    I think there's a lot of knowledge to be had from putting an oxygen sensor in all 8 header tubes. There is definitely charge scavenging happening and I feel like we're just scratching the surface of learning the airflow dynamics happening here.
    Attached Files Attached Files

  14. #134
    Fuel Injected! spfautsch's Avatar
    Join Date
    Apr 2015
    Posts
    481
    Here's a log with a WOT pull starting at timestamp 1120.0. [link]

    As you've noticed it seems like it's making a small amount of vacuum at 100% TPS, but this was going downhill in 2nd so very low realized load. MAF peaked just under 320g/s @ 5900rpm. I could have pushed it another 1000 RPM but my second cup of coffee hadn't quite taken effect yet and I figured it best not to. Notice my wideband must have gotten too cold and jumped back to it's warm-up routine.

    Results from logging today was promising. The idle split was back as bad as ever this morning, but BLM splits in the main driving cells were much better then before pulling the intake. I have no idea if enlarging the #1 feed hole or eliminating the oil getting sucked into 1 & 3 were both factors or only one. Whatever the case, this seems to be improvement in pretty much all the driving BLM cells.



    I have one disassembly question that I would fault no-one for ignoring. I've been tinkering with the IAC adders and multipliers trying to eliminate the surge when the a/c clutch engages and disengages. It seems like it's improved in all areas except idle, where the IAC adder seems too much and the RPMs will flash up slightly before the clutch locks completely. I'm trying to figure out what the row labels should be for the table at 0x26A3. The cell values seem to be multiplied by 0x2691 and I believe the lookup is comparing to VSS but not 100% positive. Here's what I've done with the disassembly.

    Code:
    855A    15 89 08        @32    bclr    l_0089_, #%00001000
    855D    B6 01 56        @33    ldaA    l_0156_NTRPMX_25/bit    ; rpm scaled in 25 rpm/bit
    8560    13 87 20 21         brclr    L0087, #%00100000, @35  ; a/c request?
    8564    B1 26 71            cmpA    L2671            ; d8 in OE cal (5400rpm?) 
    8567    24 48               bcc    @39
    8569    F6 01 9C            ldaB    L019C            ; one MPH/bit road speed variable
    856C    C1 30               cmpB    #$30            ; 48mph?
    856E    23 02               bls    @34
    8570    C6 30               ldaB    #$30            ; if vss below 48mph load 48mph into B
    8572    54              @34    lsrB                ; else shift register B right
    8573    54                  lsrB    
    8574    54                  lsrB    
    8575    CE 26 A3            ldX    #$26A3            ; load pointer to 7 byte table to X
    8578    3A                  aBX                ; add registers b & x ???
    8579    A6 00               ldaA    0, X            ; load something into register a ???
    857B    B1 02 4C            cmpA    L024C
    857E    23 26               bls    @38
    8580    7C 02 4C            inc    L024C
    8583    20 56               jr    @44
    Disassembly isn't my cup of tea - if anyone has any pointers it would be greatly appreciated.

    Edit: I see a major mistake I made around the bls jump at 0x856E - I'm thinking this means this tables rows top out at 48mph?

  15. #135
    Fuel Injected! spfautsch's Avatar
    Join Date
    Apr 2015
    Posts
    481
    From post #108

    Quote Originally Posted by kur4o View Post
    Otherwise I am sure you will like the new controller interface. It is also resizable and can hide the less used stuff.
    I finally took the time to download and build this. Nice work on the controller window! I was able to utilize it thoroughly today. I did make some modifications to get the overall build to my liking - if you're interested in incorporating them I can send you the sources I changed. First off I made the fields and fonts for the dashboard data I like to be able to see bigger. Next I added the log timestamp to the knock events. This may or may not be useful if you have a car with knock - it doesn't tell you which log the knock happened in so it can be a bit of an adventure if you're analyzing multiple logs. Lastly I added a setFocus() call to each of the individual trim button's toggled event i.e.

    Code:
    void controller::on_cylcutcorr_1_toggled(bool checked) {
        if (checked == false) {
            parameter_indicator_display(ui->lcd_cyl1,false);
            return;
        } else {
            ui->slider_cylcorr->setFocus(); // <<< ADDED
            drop_cyl_corr(1);
            // int lcd_cyl1 = ui->lcd_cyl1();
            int trim1_int = ui->lcd_cyl1->value() ;
            ui->slider_cylcorr->setValue(trim1_int);
            control->m4_cyl_corr (trim1_int);
            update_m4_raw_display();
            parameter_indicator_display(ui->lcd_cyl1,true);
       }
    }
    This lets you jump directly to using the keyboard to adjust the trim slider with the left / right arrow keys after clicking one of the cylinder trim buttons. Keyboard = efficiency of motion!

    The only thing that would be better is the ability to set the prime pulsewidth multiplier in a similar way. It's the only thing I feel I'm going to spend time fine tuning on since every time I touch individual cylinder trims startup goes to crap.

    Spent about an hour today working on cylinder trims. Idle BLMs are still split by 4% but idle feels and sounds good open or closed loop. I was having a bit of part-throttle surging that improved immensely with a couple trial and error sessions with the new off-idle trim controls. I'm holding off on calling it a victory though because a weather system has moved in dropping air temps and bringing a bunch of moist air with it so BLMs are taking fuel out almost everywhere but idle. I hate winter! :-\

    I'm thinking the off-idle trims may take even more time & effort than closed tps trims because even though my surge seems much improved, I'm feeling a good bit of NVH when opening the throttle slightly without load.

    Whatever the outcome I feel like what's left are minor tweaks and fine tuning. And I'm pretty sure there are no other bolt-ons I can try that I don't already own except forced induction. Hmm... :-)

    Anyway, thanks to everyone who chimed in to help. kur4o in particular - I still have a diy-ltcc board with your name on it if you'd like. I'm sure it will drive the capacitive discharge coils I have and by my butt-dyno estimation they seem to be just as beefy as the truck coils everybody wants (and they're cheaper).

Similar Threads

  1. E-Cell Program Modifier
    By NeilBreakwell in forum GM EFI Systems
    Replies: 7
    Last Post: 02-08-2019, 05:33 AM
  2. LT1 knock module comparison?
    By babywag in forum GM EFI Systems
    Replies: 4
    Last Post: 10-20-2016, 10:44 AM
  3. Replies: 1
    Last Post: 08-19-2015, 06:25 PM
  4. BLM CELL 16 (special cell)
    By frankied in forum GM EFI Systems
    Replies: 1
    Last Post: 11-19-2013, 12:14 PM
  5. Cross Counts, IAC, Duty Cycle - relevant comparison?
    By Scrib in forum GM EFI Systems
    Replies: 5
    Last Post: 03-19-2013, 07:08 PM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •