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One problem fixed, but now rough running 383 stroker.

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  • One problem fixed, but now rough running 383 stroker.

    1967 Chevelle SS
    Blueprint 383 Stroker
    Holley Sniper EFI
    HyperSpark ignition

    Coming into today, the car had one major issue: When pushing the clutch in to shift, the engine RPM would not drop, instead it would slowly run up to 3500 or 4500. Sometimes a throttle blip would correct it back down, but in a couple instances it required the ignition key to be shut off.

    Today we did some troubleshooting to try and fix this. We assumed it was something in the EFI system. Turned out, it was a sticky secondary throttle linkage. Rubbed down a rough spot, greased it up and put an extra turn on the spring. That problem now appears to be solved.

    While troubleshooting, however, we went into the Sniper handheld and noticed that the ignition cutoff was set to 20,000 RPM (?!). We changed that to 3500 initially to see if it was actually pushing to the ECU, then eventually stepped it to 6,000 to avoid blowing the engine if it ran away too much.

    At some point during our test runs, the engine started running very rough. It was idling much lower than the EFI software setting of 800, and almost to the point of stalling.

    We then adjusted a second parameter on the handheld, changing the idle RPM from 800 to 850. That seemed to help bring it up a little bit, but still not quite right.

    The AFR was running mostly around 15.0. The Target AFRs are 13.5 Idle, 14 Cruise and 12.5 WOT.

    We're new to this EFI stuff and just looking for some advice. I have the Config File and some datalogs if anybody would like to take a look and see if it might be something obvious. Thank you!
    Last edited by 67ChevelleSS; 09-19-2022, 09:31 PM.

  • #2
    Zip the files and then upload them to the forum. We can open them and look for anything obvious. With the throttle issues, have you readjusted your idle screw on the front shaft? It may have been closed too far when dealing with the flaky rear throttle shaft. Check your fuel pressure at the inlet to the Sniper to confirm that you have a steady 60 psi. Low or high pressure can create odd system behavior. 20.000 RPM is the default rev limiter when creating a tune with the Wizard. You were correct in dropping it down to a safe level for your engine. Avoid any type of tuning changes until you can get it to idle with 60 psi of fuel pressure and an IAC Position value of 2 to 5% at hot idle. Note that if you have to turn the idle screw in it will change the TPS value and if the TPS goes to 2% it will open up the IAC and the idle will jump. If it does this, turn off the ignition and restart the engine. The Sniper will reset the TPS to zero and you can continue setting the idle. Post the datalog and Config File and then we can make other suggestions.

    Comment


    • #3
      Don't have a fuel pressure gauge or know how to use one, but I suppose we can pick one up.

      We didn't adjust the idle screw, no. Will try that tomorrow.

      I'll attach the Config File that I pulled off the SD card today. It may be just the original settings. I didn't download it from the ECU. I don't see any "Learned" data in it. Maybe that's normal, I don't know. I can download the most current from the ECU tomorrow.
      Attached Files

      Comment


      • #4
        When you download it use the Save As function and change the name. It should end up in the Saved GCF folder. The Config File you posted is the original Config File created by the Wizard.

        Comment


        • #5
          Here's the latest from the ECU.

          Do you know why the RPM isn't showing in the datalogs? Everything else appears to be there.
          Attached Files

          Comment


          • #6
            Look in the throttle body while it's idling. I suspect one of your injectors is not operating. Search loose injector connector in this forum.

            Zero out your Learn Table after you fix the injector and before you start it again.
            Last edited by a b c; 09-20-2022, 01:35 PM.

            Comment


            • #7
              Most of your Learn Table table is maxed out at 50%. You may want to zero out the Learn Table, but often when the Learn Table is maxed out with positive numbers the system will have a fuel delivery problem, low flow due to filters, regulators, etc. When it can't get enough fuel the Closed Loop Compensation will attempt to add more fuel. The street/strip cam you selected is usually too rich for most engines, so when we see such high Learn values in nearly all cases, it's a lack of fuel. A pressure gauge installed at the inlet is required. If you had a fuel delivery issue that has been solved, you do need to Clear the Learn Table as it's corrupted. If you're not comfortable using the EFI software to do this you may want to run a new Wizard. You can do this because you have a backup of your current Config File. The Wizard will create a new blank Learn Table. If it fills up again with high values, you know that there is a fuel problem. If it starts to run better, you know that the old has a bad Learn Table that needs to be cleared.

              RPM will not display if you're trying to look at datalogs with the latest EFI software. You likely have a build 23 in your Sniper and the new version of the EFI software is build 50. This is important because you won't be able to edit Config Files with the EFI software and upload them to the Sniper because there will be a version mismatch. If you can, determine the ECU firmware version in the Sniper and use the Help function in the EFI software to determine what version you have on the computer.

              Comment


              • #8
                https://forums.holley.com/showthread...tor-Connectors (Holley Sniper EFI Loose Fuel Injector Connector Fix)​
                May God's grace bless you in the Lord Jesus Christ.
                '92 Ford Mustang GT: 385"/6.3L SBF, Dart SHP 8.2 block, forged steel crank & rods, forged pistons, Trick Flow T/W 11R 205 CNC comp ported heads, 12:1 comp ratio, 232-244 duration/.623" lift/114 LSA camshaft, TFS R-Series FTI comp ported intake, BBK 80mm T/B, Holley Dominator MPFI & DIS, Holley 36-1 crank trigger, MSD 1x cam sync, PA PMGR starter, PA 200A 3G alternator, Optima Red battery, 100HP progressive dry direct-port NOS, R134a A/C, Spal dual 12" fans, Frostbite 3-core aluminum radiator, Pypes dual 2.5" exhaust, off-road X-pipe, shorty headers, Earl's -6AN fuel system plumbing, Walbro 255 LPH in-tank pump & Pro-M -6AN hanger, S&W subframe connectors, BMR upper & lower torque box reinforcements, LenTech Strip Terminator wide-ratio AOD, 3000 RPM C6 converter, B&M Hammer shifter, Stifflers transmission crossmember & driveshaft safety loop, FPP aluminum driveshaft, FPP 3.31 gears, Cobra Trac-Lok differential, Moser 31 spline axles, '04 Cobra 4-disc brakes, '93 Cobra booster & M/C, 5-lug Bullitt wheels & 245/45R17 M/T Street Comp tires.

                Comment


                • #9
                  New Config File and a couple datalogs from today. Changed idle back to 800 RPM. Adjusted idle screw so IAC Position was ~3%, per the Holley video.
                  We datalogged a ride. Afterwards, the IAC Position was a little higher, around 8-10%. Car ran great during the ride, so didn't re-adjust the idle screw again.
                  It hesitated for a couple seconds to shutdown when the ignition key was turned off.
                  Attached Files

                  Comment


                  • #10
                    GPatrick: I agree, I think we should run a new Wizard. I only hesitate because the engine was running so nice today. It's not perfect though, like I said above it didn't shut off immediately with the key. It also stalled a couple times at idle. Would idle fine for five minutes or so, then get a bit rough and stall. Hopefully those datalogs help, I don't really know what I'm looking at there.

                    ECU firmware is 1.1.6. (also stated as 1010060 in another location).
                    Handheld firmware is 1.1.20 (Device type 10 - Rev D).
                    I don't see a 'build' listed anywhere on the handheld.
                    Last edited by 67ChevelleSS; 09-20-2022, 04:33 PM.

                    Comment


                    • #11
                      Now the datalog shows big negative Learn Table value numbers. I'll have to look in more detail as your symptoms vary so much. Danny may be on to one potential issue that could cause symptoms to change. If you have a loose injector connector it will cause a lean condition and the Sniper will try to compensate. If you go over a bump in the road the right way, the connector could begin to make contact again. The next time it's really acting up, remove the air cleaner and see if all four injectors are supplying the same amount of fuel.

                      Comment


                      • #12
                        We had the air cleaner off to adjust the idle screw. They all appeared to have the same amount of fuel.

                        I'm not sure why the learn table would be so different. We didn't zero it out or do anything with it. EDIT: I did go into one of the menus: Tuning/Advanced/Adv Learn/Transfer Table(?) - clicked on RUN, then hit CANCEL. Would that have reset the table somehow?

                        One thing I thought might have been contributing to it running rough yesterday was the weather. It was cold and very humid, raining off & on. The car had never been driven in those conditions. Only really on warm, dry days.
                        Last edited by 67ChevelleSS; 09-20-2022, 05:31 PM.

                        Comment


                        • #13
                          Check the injectors when it is running bad. When all four are firing it will run fine. But erratic/inconsistent fuel flow can do the same.

                          Comment


                          • #14
                            Didn’t bother with a fuel pressure gauge today because the fuel line is metal and I don’t have the skills to mess with that. We will have one installed. Do you recommend an under hood gauge or one that goes through the firewall and we can have inside?

                            Comment


                            • #15
                              https://forums.holley.com/showthread...8356#post88356 (Holley Sniper EFI Fuel Pressure Tester/Gauge)​
                              May God's grace bless you in the Lord Jesus Christ.
                              '92 Ford Mustang GT: 385"/6.3L SBF, Dart SHP 8.2 block, forged steel crank & rods, forged pistons, Trick Flow T/W 11R 205 CNC comp ported heads, 12:1 comp ratio, 232-244 duration/.623" lift/114 LSA camshaft, TFS R-Series FTI comp ported intake, BBK 80mm T/B, Holley Dominator MPFI & DIS, Holley 36-1 crank trigger, MSD 1x cam sync, PA PMGR starter, PA 200A 3G alternator, Optima Red battery, 100HP progressive dry direct-port NOS, R134a A/C, Spal dual 12" fans, Frostbite 3-core aluminum radiator, Pypes dual 2.5" exhaust, off-road X-pipe, shorty headers, Earl's -6AN fuel system plumbing, Walbro 255 LPH in-tank pump & Pro-M -6AN hanger, S&W subframe connectors, BMR upper & lower torque box reinforcements, LenTech Strip Terminator wide-ratio AOD, 3000 RPM C6 converter, B&M Hammer shifter, Stifflers transmission crossmember & driveshaft safety loop, FPP aluminum driveshaft, FPP 3.31 gears, Cobra Trac-Lok differential, Moser 31 spline axles, '04 Cobra 4-disc brakes, '93 Cobra booster & M/C, 5-lug Bullitt wheels & 245/45R17 M/T Street Comp tires.

                              Comment

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