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Thread: '87 350 TBI, custom application, looking to go bare-bones

  1. #31
    Fuel Injected! Mrgto68's Avatar
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    Quote Originally Posted by S.O.B.B. View Post
    The 3 wire egr plug is for evrv.2 wire egr plug is egr solenoid.
    Pin A4 says egr.grey wire.
    The 3 wire for evrv is the same 2 wires as in the 2 wire egr solenoid plug.the 3rd wire is a ground.hth
    Thanks again for this info S.O.B.B! The attachment really helped!

    Today I installed the 3 wire O2 Sensor & Switched the 2 wires from the 2-wire EGR Plug on the new wire harness to the old 3-wire plug. I also realized that we didn't connect the Grey wire coming from the new Fuel Relay to the Tan / White wire from the old Fuel Relay, so the 3 - 4 crank start was from the Oil Pressure switch supplying power to the fuel pump.

    Dave W, it looks like she's running open loop at idle but quickly goes close loop once I get to about 750rpm. Does that sound right?

    It's humbling for sure, You guys Schooled this ol wrench turner.

    Here's the current data log file from a cold start to operating temps at Idle and tach up to about 2,800rpms.

    I'm still waiting on the Speed Sensor from JTR and will then take the rig out for a test drive.
    Attached Files Attached Files

  2. #32
    Fuel Injected! Mrgto68's Avatar
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    Is there a way to increase the idle speed?
    I'm running two high output Alternators and need to be about 850rpm to get maximum output.

  3. #33
    Fuel Injected! Mrgto68's Avatar
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    I was also curious what this Relay was for. It looks like at one time it was mounted either on the passenger side firewall or fender.

    Relay.jpg

  4. #34
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    That's the heater fan relay.

    In an application with OEM installed THM400, the TCC wire connects to a relay used to downshift the THM400. Probably not needed unless your low speed application regularly sees high load and WOT.

    Increasing throttle speed can be accomplished with an old fashioned idle speed "kicker," a simple device that electrically opens the throttle when needed. Or, if your chip supports factory A/C you can try tricking the ecm into thinking you have the A/C on which usually increases idle speed slightly. A custom chip could be burned to increase the idle considerably if the A/C is on.

    One of the functions of the P/N switch is to indicate to the ECM that throttle steps (IAC Opening) should be increased slightly to account for additional load created by the trans.

    Why not adjust pulley size to increase alternator speed?

  5. #35
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    Quote Originally Posted by Mrgto68 View Post
    I was also curious what this Relay was for. It looks like at one time it was mounted either on the passenger side firewall or fender.

    Relay.jpg
    Bam! Thank you sir

  6. #36
    Fuel Injected! S.O.B.B.'s Avatar
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    20190216_220208.jpgsorry about the blury pic but there are those settings and under iac there are settings for how many counts the opening is.that's how much air it's letting in to idle at desired rpm.there are many articles on the gm iac function and set up for minimum idle speed.if u look at the top line the xdf and adx are from this site courtesy of Eaglemark.they are defined and have tips and patches etc.the magnifying glass is your parameters search tool.20190217_122735.jpg20190217_122712.jpg click the pic and zoom.if it's still too blury I guess it's no help.sorry.
    Last edited by S.O.B.B.; 02-17-2019 at 08:40 PM.
    Jeeper
    87 sjimmy powered by a 92 cadillac 4.9L pfi on 7427pcm /700r4/ 8.8 3.55 rear/disc brakes.

  7. #37
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    Thinking about a system like this for some of our parking lot bound shuttle buses:
    https://www.fallbrooktech.com/access...ves/alternator

  8. #38
    Fuel Injected! PlayingWithTBI's Avatar
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    You can raise the idle with the torx screw on the bottom right of the TB behind the plug (pry or drill it out).
    Attached Images Attached Images

  9. #39
    Fuel Injected! Mrgto68's Avatar
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    Quote Originally Posted by 1project2many View Post
    That's the heater fan relay.

    In an application with OEM installed THM400, the TCC wire connects to a relay used to downshift the THM400. Probably not needed unless your low speed application regularly sees high load and WOT.

    Increasing throttle speed can be accomplished with an old fashioned idle speed "kicker," a simple device that electrically opens the throttle when needed. Or, if your chip supports factory A/C you can try tricking the ecm into thinking you have the A/C on which usually increases idle speed slightly. A custom chip could be burned to increase the idle considerably if the A/C is on.

    One of the functions of the P/N switch is to indicate to the ECM that throttle steps (IAC Opening) should be increased slightly to account for additional load created by the trans.

    Why not adjust pulley size to increase alternator speed?
    Thank you for the additional info!! Is it safe to assume that the relay on the firewall to the right of the Fuel Pump relay is the THM400 relay? If so, then which wires on the TCC would connect or spliced into which wire on the relay?

    firewall.jpg

    I could try and find a smaller pulley for the alternator, but would rather bump the idle up to at least 850 rpm which would allow the alternators to charge at 14v and peak output.

    Are you able to read the data file I attached to my post earlier today? would that show if the chip supported AC? I know there's an AC wire on the new harness.
    Last edited by Mrgto68; 02-17-2019 at 07:49 AM.

  10. #40
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    Quote Originally Posted by PlayingWithTBI View Post
    You can raise the idle with the torx screw on the bottom right of the TB behind the plug (pry or drill it out).
    Wouldn't this cause the computer to continue making adjustments? I thought raising the idle would need to be made via programming ?

  11. #41
    Fuel Injected! Mrgto68's Avatar
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    This is interesting for sure, but it appears that the company is still in the development stage.

  12. #42
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    I'm not at the programming stage of my TBI education lol. I'm still trying to figure that all out. the blurry photo had me squinting to see what you have posted. ;-)

  13. #43
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    Quote Originally Posted by Mrgto68 View Post
    Wouldn't this cause the computer to continue making adjustments? I thought raising the idle would need to be made via programming ?
    Your IAC will rise up too. Eventually O2 and closed loop will change too. If you don`t want idle setting over programming, why don`t you mount a manual choke to the gas pedal?

    I looked to your xdl and imported it to excel. I fear if you want to reach your goal, you have to programm the memcal.At the moment the border line for switching to closed loop seems to be at 800 rpm.You may detect that if you hold your idle speed at constantly 825, your desired rpm) for a while.Have a look to column BD (closed loop) and column BR (rpm).
    Engine was not fully warmed up when you stopped your logging.No fault codes at the moment.But have a look to excel yourself. Rename xuza.txt XUZA.xls.
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    Last edited by mecanicus; 02-17-2019 at 10:46 AM.

  14. #44
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    Is it safe to assume that the relay on the firewall to the right of the Fuel Pump relay is the THM400 relay?
    I'm sorry, but I seem to be having trouble seeing the relay or any of the wires attached to it. Maybe you have a wiring diagram and can match up wire colors?

    I could try and find a smaller pulley for the alternator, but would rather bump the idle up to at least 850 rpm which would allow the alternators to charge at 14v and peak output.
    In industries such as transit and utility we usually opt to increase alternator rpm without increasing engine speed when possible. There are some tradeoffs to increasing idle speed above converter stall speed. With custom programming, which is easier to do than some of the work around solutions you're thinking about, you could set conditions so the idle speed is only increased when necessary. If you're not interested in programming then a mechanical solution to alter throttle position when needed is the best.

    Are you able to read the data file I attached to my post earlier today?
    I'm not at the programming stage of my TBI education lol. I'm still trying to figure that all out.
    There are new terms and procedures to programming along with a few new tools. But once you get the hang of it making changes can be easier and less time consuming than a tune-up on your R30. We can even help. It may be possible to locate a copy of your chip on the 'net which would allow viewing of the contents without actually disturbing the chip. There's a three or four letter code on the chip called a BCC. If you find that we can look for a file that is similar.

    In the meantime this calibration is from an '87 3500 truck with 350 and THM400. It is likely to be close to yours in many ways. I've also included an xdf file for Tunerpro. This way you have the tools to begin looking at what's under the hood, so to speak, of your computer. There are a *lot* of variables when you first look through. Most don't need to be changed so you won't need to worry about them. But as you learn about what they do and think about how you want your vehicle set up, you may decide it is appropriate to change some. For example, it may be appropriate to disable the EGR. Setting the EGR CTS Enable to max temp and EGR On TPS to max would effectively disable EGR.
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  15. #45
    Fuel Injected! Mrgto68's Avatar
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    Quote Originally Posted by mecanicus View Post
    Your IAC will rise up too. Eventually O2 and closed loop will change too. If you don`t want idle setting over programming, why don`t you mount a manual choke to the gas pedal?

    I looked to your xdl and imported it to excel. I fear if you want to reach your goal, you have to programm the memcal.At the moment the border line for switching to closed loop seems to be at 800 rpm.You may detect that if you hold your idle speed at constantly 825, your desired rpm) for a while.Have a look to column BD (closed loop) and column BR (rpm).
    Engine was not fully warmed up when you stopped your logging.No fault codes at the moment.But have a look to excel yourself. Rename xuza.txt XUZA.xls.

    Thanks for looking this over for me. I'll run a log again, I must have somehow stopped the logging sooner then I thought.

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