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Thread: Idle Very Rich

  1. #1

    Default Idle Very Rich

    Hi everyone. I'm pretty new to this forum and learning how to tune my Sniper unit, but I do know my way around it a little.
    I'm currently having a problem where my truck will only idle at around 12.5 or richer, any leaner and it will shake pretty bad. I know that every engine is different of course, but I just have a very mild 383 (~360 HP) and not a crazy cam. Seems too rich too me. Any suggestions? Sorry if this has already been answered before, I searched around and couldn't find much. Thank you again.

  2. #2
    Join Date
    Dec 2009
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    Originally Posted by Danny Cabral
    The Target Air/Fuel Ratio Table & Base Fuel/Timing Table (and MAP kPa & RPM axes/scales) should be configured using the Sniper EFI software:
    In the Sniper EFI software (LINK), Target Air/Fuel Ratio Table (Fuel ICF) & Base Timing Table (Spark ICF), select "2D Table" Type (not "Simple").
    The Target Air/Fuel Ratio Table & Base Timing Table can then be properly configured & tuned for any engine.
    https://www.holley.com/support/resou...Fuel_Injection (Sniper EFI Software & Holley 558-443 CAN/USB Dongle)
    https://forums.holley.com/showthread...679#post100679 (Sniper EFI Optional Comm/Data Cable Accessories)
    Originally Posted by Danny Cabral
    Is the Sniper EFI Learning? Is the ignition timing synchronized? Is the fuel pressure 58-60 psi (LINK)? IAC Position
    of about 5% at hot idle? Check for ignition misfires/RPM signal problems, exhaust leak upstream of WBO2 sensor,
    or if the WBO2 sensor (or other sensor) has failed and corrupted the Learn Table. Look at the Data Monitor/Gauges.
    Also, the Holley Sniper EFI will intermittently inhibit Closed Loop at idle, if the AE vs TPS/MAP RoC Blanking values are set too low.
    http://documents.holley.com/techlibrary_199r11259.pdf (Holley Sniper EFI Help Manual)
    http://documents.holley.com/199r11369.pdf (Holley Sniper EFI Troubleshooting Guide)
    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" SBF, Dart SHP 8.2 block, TFS TW 11R 205 heads, 11.8:1 comp, TFS R-Series intake, Dominator MPFI & DIS, 36-1 crank trigger/1x cam sync, 160A 3G alternator, Optima Red battery, A/C, 100HP progressive dry direct-port NOS, Spal dual 12" fans/3-core Frostbite aluminum radiator, Pypes dual 2.5" exhaust/off-road X-pipe/shorty headers, S&W subframe connectors, LenTech Strip Terminator wide-ratio AOD/2800 RPM converter, M4602G aluminum driveshaft, FRPP 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 tires.

  3. #3

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    Have done all that. I bumped up the timing quite a bit and it seemed to help. Thank you Danny.

  4. #4

    Default

    How old is the tune? If you're just starting out the base calibrations are very rich and may even foul the plugs. Check your plugs and see if they need replacing. Also, look down the throttle bores with it running to make sure there is fuel in all four.
    69 Camaro
    400 SBC, ProCharger D1SC

  5. #5

    Default

    Quote Originally Posted by cniss7 View Post
    Hi everyone. I'm pretty new to this forum and learning how to tune my Sniper unit, but I do know my way around it a little.
    I'm currently having a problem where my truck will only idle at around 12.5 or richer, any leaner and it will shake pretty bad. I know that every engine is different of course, but I just have a very mild 383 (~360 HP) and not a crazy cam. Seems too rich too me. Any suggestions? Sorry if this has already been answered before, I searched around and couldn't find much. Thank you again.
    How do you know what the actual AFR is? Are you reading that off the handheld or are you going by what you programmed? You might want to look at other things such as actual fuel used and then watch to see what's going on with the compensations. What's the engine temp when you're looking at the AFR? You've left out a lot of information, so it's hard to help.

  6. #6

    Default

    Quote Originally Posted by gregs69rs View Post
    How old is the tune? If you're just starting out the base calibrations are very rich and may even foul the plugs. Check your plugs and see if they need replacing. Also, look down the throttle bores with it running to make sure there is fuel in all four.
    I've been tuning for a few months now. Runs great everywhere, just idle doesn’t seem to run correctly.

    Quote Originally Posted by andyf View Post
    How do you know what the actual AFR is? Are you reading that off the handheld or are you going by what you programmed? You might want to look at other things such as actual fuel used and then watch to see what's going on with the compensations. What's the engine temp when you're looking at the AFR? You've left out a lot of information, so it's hard to help.
    Engine is warmed up, >160°F. Looking at actual AFR off of handheld. Injector Pulse Width is around 4, which I believe is high.

  7. #7
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    Quote Originally Posted by cniss7 View Post
    I've been tuning for a few months now. Runs great everywhere, just idle doesn’t seem to run correctly.
    http://forums.holley.com/showthread....e-Tuning-Notes (EFI Idle Tuning Notes)
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: 385" SBF, Dart SHP 8.2 block, TFS TW 11R 205 heads, 11.8:1 comp, TFS R-Series intake, Dominator MPFI & DIS, 36-1 crank trigger/1x cam sync, 160A 3G alternator, Optima Red battery, A/C, 100HP progressive dry direct-port NOS, Spal dual 12" fans/3-core Frostbite aluminum radiator, Pypes dual 2.5" exhaust/off-road X-pipe/shorty headers, S&W subframe connectors, LenTech Strip Terminator wide-ratio AOD/2800 RPM converter, M4602G aluminum driveshaft, FRPP 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 tires.

  8. #8

    Default

    Have you tuned the AFR at idle in Open Loop? Typically you need to tune idle in Open Loop so you know what the engine wants. Once you know what the engine wants then you lock it into the Target AFR table.

    The Holley Sniper approach is to guess at the correct AFR and force the engine to operate per that guess. That kind of sometimes works, but it isn't the correct way to do it. Get the engine warm and then put it in Open Loop and adjust the AFR up & down until you find the point with the maximum intake vacuum. Just like tuning a carb. Once you know the AFR that the engine likes then you can program the Target AFR table and set the IAC and the idle speed and you should be good to go.

  9. #9

    Default

    That sounds pretty simple. Thanks so much!

  10. #10

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    Quote Originally Posted by andyf View Post
    The Holley Sniper approach is to guess at the correct AFR and force the engine to operate per that guess. That kind of sometimes works, but it isn't the correct way to do it.
    The "Sniper Approach" worked well for me, letting it idle in Closed Loop, changing the Target AFRs in the idle area cells, and watching for the lowest kPa (highest vacuum) and steadiest RPM. Didn't take long at all to find how lean-rich it liked.

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