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Thread: Tuning the 3.4L with TunerCat

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    Default Tuning the 3.4L with TunerCat

    I've been working on a new engine for my 92 S10 for the past year. It had the weak 2.8L @ 125HP. Manual Trans.
    New engine is a 95 Camaro 3.4L with a 2003 Grand Am 3400 top end. 3400 pistons and head gaskets. The calculated compression ration is 9.6. The only mods are a mild street strip cam and 1-3/8" shorty headers. Factory GA injectors for now. I believe these are 22.5#.

    Got it started after sorting out a few bugs a couple of months ago. At this point it runs pretty good. Still have some cold start open loop things to work out. Thought I would share what I have learned. I'm sure there may be better ways to do some of this, there's a lot of experts out there.

    Important note: If you are tuning in a garage, run a tube on your exhaust to the outside so you don't die.


    How to turn your PCM into a brick:

    I was writing new bin to the PCM and had a question about something in the Scan94/95 program. When that program starts the first thing it does is check the USB port for an ALDL cable. Well, TunerCat was using it so the write process got interrupted and we have an instant brick. Lesson #1: When reading or writing to the PCM don't do anything else. I don't browse the internet, edit spreadsheets, play games or anything but wiggle the mouse to keep the program alive. Disable screen savers, make sure the car has a full charge (keep it on a charger) and keep the laptop charged.

    Spare PCM:
    Before you brick your PCM pick up a spare from the wrecking yard or a refurb from Rock Auto. Rock Auto is running out of stock and are $116 w/$90 core.
    ACDELCO Auto Trans #16184737
    ACDELCO Manual Trans #16196397

    Wrecking Yard $65 at the U-Pull-It: These are all 94-95 model years, 3.1L and Auto Trans: Located behind the glove box so most of them are clean and dry.
    Chevy Beretta, Corsica, Lumina, Monte Carlo.
    Olds Acheiva, Cutlass.
    Pontiac Grand Am, Grand Prix.
    Buick Regal, Skylark.

    BEWARE: Picked up a Grand Am PCM yesterday. It has a different part number. And a different wiring diagram. OBD1 connector will be the clue. Has the exact same BIN as the OBD1.5 version.

    I take a small 12v/7.2aH battery, some wire with an inline fuse, the laptop and cable to extract the program first. Saves you the trouble of returning a bad one. You need to locate both PCM fuses and power them with the battery.

    May need to swap Knock Modules. Hopefully someone can verify this.

    File Management:
    Keep your original bin in a separate folder. My is called Original_BIN. There are several in there. Got Camaro, Firebird and Grand AM bins. With TunerCat you should also export the bin to this folder (Print all to file). This will save a non-definition specific copy for reference.
    Save edits into a different folder and a new file name every time there is a change. My latest folder is 3400_H22. H22= Headers and 22# injectors. If I put in different injectors it will be 3400_H28. Save file names with Rev1_A or something. Keep a text file with notes about each change.

    Software:
    TunerCat with the Ver L definition file. It finally (06/2019) has support for setting Fuel Injector flow rate plus some new tables. Idle VE is a handy one.
    DataCat -- Datalogger, analyzer, supposed to be able to edit the BIN from the analyzer. Scalable wideband input. Fuel injector duty cycle analyzer.
    Scan94/95-L32-V6 from GaryDoug for datalogging and scanning.
    Trimalyzer for adjusting the Idle and Main VE tables. It also provides a Knock analyzer for adjusting your timing.


    I'm trying to convince GaryDoug to modify the Scan94/95 datalog column names so that it matches what Trimalyzer is looking for. Should make for an easier tune experience.
    Work around is to copy/paste this into the .csv:

    Date-Time,RPM,AFR,RPM 24x,Target idle,IAC Position,Min IAC Position,Coolant temp(F),Intake air temp(F),Fuel pump voltage,Speed (MPH),Engine run time (s),3x Time Period (ms),Baro pressure (kPa),TPS volts,TPS %,EVAP (CCP) duty cycle,MAP (kPa),MAP (volts),A/C pressure (psi),A/C temp (F),Spark advance degrees,Knock retard degrees,Knock counter,Ignition volts,Left bank 2 O2 sensor (v),Right bank 1 O2 sensor (v),BLM cell#,BLM Bank B,BLM Bank A,INT Bank B,INT Bank A,Base inj p/w (ms),#History DTC's,#Total DTC's*,DTCfail,AC REQ,AC FdBk,FAN ON,AC Clutch ON,EGR Sol1,EGR Sol2,EGR Sol3,ClosedLoop,LeftO2Rdy,RightO2Rdy,Kickdown,InjF ault,FuelTrimEnab,AC Press Hi,AC Temp Lo,Freon Lo,WOT=NoAC,NoCamSignal

    Right click on the filename and click edit.
    Last edited by Sparky; 10-19-2019 at 07:38 PM. Reason: Spare PCM Update

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    Modes of Operation:
    There's many different going on just to get the engine started and warmed up to closed loop operation.
    Crank
    In TunerCat there's a table called Crank PW Multiplier Vs. RPM. It starts at 0 and goes up to 640 RPM. The PCM must assume the engine is running if it gets past that point since the 3.4L does not have a Crank input signal to the PCM.
    The Base Pulse Width is ignored and the PW from Crank Fuel PW Vs. Coolant Temp. is used to set the amount of fuel during crank. The PW Multiplier Vs. RPM reduces that value as the engine speeds up. Pushing the throttle adds fuel up to 75% TPS. After that the Flood Clearing flag is set and fuel should be cut off.
    There is also Crank BPW Correction Vs. Ref. Pulses. Apparently, BPW plays a part based on pulses from 3X Crank, 24X Crank or the cam position sensor.
    The IAC Startup Position, Time Out Spark Decay/Delay and Choke AFR Correction Vs. Startup ECT tables look at the Start Up Coolant Temp to set their initial values.

    Choke:
    Choke kicks in at 400 RPM up to 1600 RPM and uses a base AFR from Closed Throttle Open Loop AFR Vs. Coolant Temp. and picks the start up Choke AFR Correction Vs. Startup ECT value then increases AFR based on RPM or ECT.
    TPS of 1.2% cancels Choke mode. Probably kicks back in below 1.2%.

    Open Loop:
    Warming up the O2 sensors. Lots of stuff going on here. Lots of opinions about this. Not going to add mine.
    Current open loop issues:
    Very rich during 32 deg starts. AFR between 8-9.
    RPM fluctuating between 800-1200 RPM.
    RPM increase during shifts.

    Closed Loop:
    O2's are controlling fuel.

    The Tuning Part:
    Switches:
    Need to disable Lean Cruise Option for a proper tune. You can also disable VATS Select here.

    Constants:
    The all important Injector Flow Rate needs to be correct.
    For starters need to disable DFCO for a proper tune. Set all 4 DFCO entries to zero.
    Initial spark advance -- All of the bins I have found have this set to 4.9 deg. The S10 2.8L uses 10 deg. I have tried various settings all the way up to 20 deg. It has very little effect on idle timing. Left mine at 10 deg.
    I did not disable Launch mode although that is easy to do. Set Launch Mode Disable Speed to zero.
    I shortened the timers for entering Closed loop. You could lengthen them for more open loop tuning.
    Cold Closed Loop Enable Timer 240 Sec.
    Cool Closed Loop Enable Timer 120 Sec.
    Warm Closed Loop Enable Timer 45 Sec.
    Hot Closed Loop Enable Timer 10 Sec.
    BPW: If the BPW is too long the engine will run rich. Scan94/95 will try to trim but you will see the Base inj p/w (ms) locked in at the default setting. I believe that this value is used for DFCO to keep some fuel going into the engine.
    Async Inj. Firing Enable Delta BPW
    Default BPW
    Default BPW Enable BPW
    Make sure that Number of Cylinders is set to 192. Note from TunerPro says this is CO/192=6. ??? Failed emissions test going back to 6.


    Tables:
    Disable PE -- Set all entries in Power Enrich Enable TPS Threshold. Vs. RPM to 100% TPS.
    Crank Fuel PW Vs. Coolant Temp. Even with the Injector Flow Rate correct, I was still having rich starts. My injectors are 30% larger than stock (22.5/17). Highlight the whole table and multiply by .75 should get it closer.

    Save with a new Rev# and write to the PCM. Should be ready for that first start. Close TunerCat.
    Start up Scan94/95 Connect and start scan and select datalog.
    Crank it. Hopefully it starts.
    On the Actuators button select 1200 RPM if it won't idle. Should get better while it warms up.
    If you have a wideband O2 sensor you should be able to verify that the AFR matches the target AFR.

    There are 2 tables that affect the Closed Throttle Open Loop AFR:
    Closed Throttle Open Loop AFR Vs. Coolant Temp. and Choke AFR Correction Vs. ECT. The Choke AFR Correction Disable TPS is set to 1.2 %. So the choke AFR correction only works at closed throttle. I would leave the main table alone and trim with the Choke AFR Correction Vs. ECT table.

    This will take a lot of cold starts to sort out.
    Last edited by Sparky; 10-19-2019 at 11:49 AM. Reason: Change # cylinders

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    Idle VE Tuning:
    Hopefully you got it to run long enough to get into Closed Loop.
    In order to start a new datalog, shut off the engine and close Scan94/95. Restart the scanner and start the engine. Start the datalog when it shows closed loop. This will create a clean new closed loop log. Target AFR should be 14.7. BLM's should be getting closer to 128.
    Click on the Actuators button and select 1200 RPM. Let this run for 2-3 minutes until the BLM's get settled in. Change to 1000 RPM and repeat. 800 RPM and repeat. Click on A/C Relay OFF to release the actuators. Idle should return to normal. Let the data log run until things look pretty stable.
    Turn off the datalog and shut off the engine and close the scanner. The log is located in the Scan94/95 folder. I always change the file name to match the Rev# of my BIN.

    If the BLM's won't trim at idle you may need to manually adjust the Idle VE Vs. RPM Vs. MAP table by the same percentage that you modified the Crank PW. 75% is probably close.

    Trimalyzer:
    Open Trimalyzer. Click the ADD button and find your log. Chances are that only MAP will autofill in the Field Mappings. Click on the gear icon and fill in the rest of the fields. Don't need MAF.
    In the Filters section create a new filter called Closed Loop=1 This will block any open loop readings. Second filter TPS<1 in case you blipped the throttle.
    Click the Process Logs and Open Analyze button.
    Check the Parser Tab to make sure all of your data didn't get filtered. May have to open the .csv log file in whatever program you use and double check how many cells that should fit your filter.

    The default table in Trimalyzer will not match the V6 PCM Idle VE Vs. RPM Vs. MAP table. You will have to create a new one.
    Click on the New VE Layout button. Add a title Camaro_VE_Idle.
    Open TunerCat, open your bin and the Idle VE Vs. RPM Vs. MAP table. Note the column/row numbers for MAP and RPM. These will need to be manually entered into Trimalyzer. These need to match exactly. My layout is not rotated. Click save. From the drop down select your new layout. You should have a layout identical to the TunerCat table and some cells filled in.

    Applying the changes to TunerCat:
    Highlight all of the cells in the TunerCat Idle VE Vs. RPM Vs. MAP table. CTRL+C or right click/copy.
    In Trimalyzer click the Modify Clipboard data. Agree to the 2 dialog boxes. If it fails the layout you created probably has an error. Switch to TunerCat and make sure that all the cells are highlighted and CRTL+V or right click/paste. Save to a new Rev#. Close all programs except for TunerCat, Turn key on engine off and write to the PCM. When it's done start the engine and datalog again using the same method as before. Might take 3-4 times to get real close.

    Should have a good idle.
    Last edited by Sparky; 10-05-2019 at 08:35 PM.

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    Long time lurker first time posting. Sparky I'm almost finished with my build 1995 3.4 with 3400 pistons and 3500 upper 260 cam 23 lbs injectors. I have been looking everywhere for some of the information you posted thank you very much it will help me tons . I am using tunerpro instead of tuner cat but your data will help me get a base line

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    Russ,
    Hope it helps. I tried tunerpro but couldn't get the tables to display properly. Probably missed something. Maybe you can start a tunerpro topic. Nice to have options. I'm editing the above posts almost daily so things may change a little bit as I figure stuff out.

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    Sparky,
    I'm still about a month away from starting it. I will check on your edits. If I get it to work I will start a new topic. Thanks

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    Road Tuning VE:
    This is pretty much the same process as the idle VE tuning except you are moving. Just need a warm engine in closed loop. Not too aggressive to start with. 25% throttle up to 3000 RPM several times. At least 30 minutes of driving.
    Same process to import into Trimalyzer. Add filter "Closed Loop=1", "TPS>1".
    Create a new table layout called Camaro_Main_VE. Make sure it is the same size as the TunerCat Volumetric Efficiency Vs. RPM Vs. MAP table.
    Same process as the idle VE.

    Knock Analyzer:
    Click on the Trimalyzer Visual Analysis tab. At the bottom click on the Knock Count Map. Red dots are the Knock points. Hovering on them will show the RPM and MAP when the knock occurred. Open the Main Spark Advance Vs. RPM Vs. MAP in TunerCat. If there's only a few, probably doesn't need any attention. If there is a cluster, then note the upper and lower RPM and MAP numbers and lower the corresponding cells in TunerCat. There may be several problem areas. Typical advice is to lower by 2 degrees until the knock goes away. I will lower problems areas by 4 deg and then raise the entire table by 2 deg (up to my current RPM threshold).

    Repeat the road logging and knock analysis increasing the throttle and RPM each time.
    Main Spark Advance Vs. RPM Vs. MAP table only goes to 4800 RPM. Anything above that will likely be in PE mode.

    One area that doesn't need advance is 800 RPM idle @ 30-40kPa. Too much advance can cause excessive HC and you may fail emission testing. Comparing spark maps in the BIN's for the 3.4L iron head to a 95 Grand AM aluminum head 3.1L there is a drastic difference in low RPM spark. 25 vs. 35+.

    PM me if you want a copy of the Grand AM BIN. I haven't figured out how to attach files.
    Last edited by Sparky; 10-05-2019 at 08:28 PM.

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    Driveability Issues:

    Cold starts at 32 deg F. -- it's running very rich, the idle is swinging +/- 200 RPM. Target AFR is 8.5. Wideband does not agree.
    I think the extra fuel is from the Choke AFR Correction Vs. ECT table. It was adding 4 to the Closed Throttle Open Loop AFR. Changed it to 2. Waiting for another cold day.

    Open Loop driving -- RPM's increase during shifts.
    Pasted Max Throttle Follower Steps Multiplier Vs. Cool Temp table from Grand Am.

    Failed emissions testing. HC levels were 3X the limit of 220. Suspect too much idle timing. Didn't help that I had to wait in line for 15-20 minutes. When I got back home I see that the O2 sensors were cooling down enough to cause it to go into open loop. Takes less than 90 seconds from stopping. Didn't think it would be a problem with the short tube headers, especially with the ceramic coating.

    Currently converting to heated 3-wire O2's from 93 S10/Astro 4.3L. Have to add a switched +12v and grounds to each.
    ACDELCO 213632 O2 Sensor.
    ACDELCO PT2363 Connector.

    I don't have AC or Cruise so that fuse was available.

    Building a new fuel injector harness. Too many splices in mine and the intake compresses it when torqued down. Crappy factory wire was all melted together.

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    Still failing emissions test. Max HC is 220. I got it down to 275 by raising idle to 850 and lowering the Main Spark table around idle to 10 deg. 600-1000 RPM 25-55 kPA. Can still smell it in the exhaust.

    It's a 30 mile round trip to get tested, so I'm swapping the injectors back to the FJ93 18#. I had a fairly good tune going with stock manifolds but had since installed headers and bumped up to the Grand Am 22# injectors.

    Seems to me that if I can solve this with a smaller injector it shouldn't be that hard to do with the 22#. Once I get through emissions it's 2 years of playing around before it's due again. There is chatter that the emission testing may be ending soon. Fingers crossed.

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    Thats a lot of work for inspection lol.

    I'm glad we never required emissions testing. we recent stopped requiring inspection. Granted now the cops can pull you over for more.

    I hated that stupid sticker that meant nothing. it was 5 dollars every year. and they didn't check anything just recorded mileage and slapped a sticker on lol.

    I feel bad for all you that have to pass emissions. I can imagine places like CA is worse.

    Good luck on ditching the emissions test. hopefully they do.

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