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Thread: Hard Hot Start With Air Cleaner Installed

  1. #11
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    Quote Originally Posted by Sponge View Post
    I know it's an old topic, but 20 lbs/hr Cranking Fuel hot seems like a lot, because I've got only 4.5 on mine.
    4.5 lbs/hr Cranking Fuel (hot) may be enough for smaller engines, but it's not enough on larger engines. My Cranking Fuel is 9 lbs/hr at 180°F & higher. Also, ensure the "Actual System Pressure" parameter is correctly programmed in Engine Parameters. If it's not, the lb/hr values will be inaccurate (throughout the EFI software).
    May God's grace bless you in the Lord Jesus Christ.

    '78 BRONCO: 508" stroker, TFS heads, 11:1 comp ratio, Dominator MPFI & DIS, cold air induction, Spal dual 12" fans/aluminum radiator, dual 3" exhaust/Magnaflow mufflers, Moroso vacuum pump, Accusump, engine oil & trans fluid coolers, 100HP progressive dry direct-port NOS, A/C, LenTech Strip Terminator wide-ratio AOD/2500 RPM converter, 3:1 Atlas II, modified Dana 44/60-lockers-4.10s, hydroboost/4-disc brakes, ram-assist/heim joint steering, Cage long radius arms, traction bars, 4" Skyjacker lift, 35" mud tires

  2. #12

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    20 lbs/hr from -20°F − 80°F
    18 lbs/hr at 100°F
    16 lbs/hr at 120°F
    7.3 lbs/hr at 140°F
    5.7 lbs/hr at 160°F
    4.5 lbs/hr at 180°F − 260°F

    So I'm asking if my "After Start Enrichment" is not too high: 114 from 140°F till 260°F. If I understand those figures well; the Decay Rate is the number of seconds it takes to "spray" the additional percentage in the "After Start Enrichment"? For example, 114% means it takes xx seconds to spray 14% of what? Cranking Fuel?

  3. #13
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    Quote Originally Posted by Sponge View Post
    If I understand those figures well; the Decay Rate is the number of seconds it takes to "spray" the additional percentage in the "After Start Enrichment"?
    EFI Software Help Information/Instructions:
    ‒ On the top Toolbar, click "Help" & "Contents". This opens all Help topics.
    ‒ When navigating the software, click "Help ?", drag it to any parameter and click again.
    ..This automatically opens the definitions for that specific parameter.
    ‒ Tuning information can be read by clicking the F1 key, when you're viewing any screen.
    http://documents.holley.com/techlibr...10555rev17.pdf (Holley EFI Wiring Manual & Diagrams)
    http://documents.holley.com/techlibrary_199r10544.pdf (Holley EFI Help/Instructions Overview)
    http://forums.holley.com/showthread....ents-Read-This! (Initial Checks & Adjustments - Read This!)

    In the "Help" Contents of the EFI software (Step-By-Step Beginner's Tuning), look at the "Idle Fuel vs. Temperature" graphical representation - Figure 8, Section 5.1.
    Under 400 RPM (the "Crank To Run RPM"), the ECU only looks at the Cranking Fuel (lb/hr) Table, the Cranking Timing value, and the IAC Parked Position %.

    Cranking Fuel & After Start Enrichment are not the same thing. Cranking Fuel only happens during cranking. When the engine starts, the After Start Enrichment is injected for a brief period of time (After Start Enrichment Time - Decay Rate). The After Start Enrichment fuel is a modifier (%) of the Base Fuel Table, based on coolant temperature. The After Start Decay Rate (linear decay to zero) is the time duration of the After Start Enrichment in seconds.
    May God's grace bless you in the Lord Jesus Christ.

    '78 BRONCO: 508" stroker, TFS heads, 11:1 comp ratio, Dominator MPFI & DIS, cold air induction, Spal dual 12" fans/aluminum radiator, dual 3" exhaust/Magnaflow mufflers, Moroso vacuum pump, Accusump, engine oil & trans fluid coolers, 100HP progressive dry direct-port NOS, A/C, LenTech Strip Terminator wide-ratio AOD/2500 RPM converter, 3:1 Atlas II, modified Dana 44/60-lockers-4.10s, hydroboost/4-disc brakes, ram-assist/heim joint steering, Cage long radius arms, traction bars, 4" Skyjacker lift, 35" mud tires

  4. #14

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    I'm trying to optimize my hot starting as well. To me, it seems that the engine should fire up very clean & crisp when hot, and mine just doesn't. With respect to Cranking Fuel, wouldn't this number be similar to the fuel flow rate at idle? Andrew

  5. #15
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    Quote Originally Posted by andrewb70 View Post
    With respect to Cranking Fuel, wouldn't this number be similar to the fuel flow rate at idle?
    On some engines, it is a good hot starting point (see post #6). Some engines like more Cranking Fuel. Try it both ways and see which amount your engine likes. Also, some engines don't tolerate a lot of "Fuel Prime Percent" on hot restarts.
    May God's grace bless you in the Lord Jesus Christ.

    '78 BRONCO: 508" stroker, TFS heads, 11:1 comp ratio, Dominator MPFI & DIS, cold air induction, Spal dual 12" fans/aluminum radiator, dual 3" exhaust/Magnaflow mufflers, Moroso vacuum pump, Accusump, engine oil & trans fluid coolers, 100HP progressive dry direct-port NOS, A/C, LenTech Strip Terminator wide-ratio AOD/2500 RPM converter, 3:1 Atlas II, modified Dana 44/60-lockers-4.10s, hydroboost/4-disc brakes, ram-assist/heim joint steering, Cage long radius arms, traction bars, 4" Skyjacker lift, 35" mud tires

  6. #16

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    Thanks Danny. I'll play around with it some, after I get some wiring work redone. Andrew

  7. #17
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    You already know this; it's about tuning air, fuel & timing. We addressed fuel in post #17. Ensure your throttle blades are adjusted far enough open. Try 10° or 15° of Cranking Timing.
    http://forums.holley.com/showthread....7913#post77913 (Related Cranking/Startup Tuning Post)
    May God's grace bless you in the Lord Jesus Christ.

    '78 BRONCO: 508" stroker, TFS heads, 11:1 comp ratio, Dominator MPFI & DIS, cold air induction, Spal dual 12" fans/aluminum radiator, dual 3" exhaust/Magnaflow mufflers, Moroso vacuum pump, Accusump, engine oil & trans fluid coolers, 100HP progressive dry direct-port NOS, A/C, LenTech Strip Terminator wide-ratio AOD/2500 RPM converter, 3:1 Atlas II, modified Dana 44/60-lockers-4.10s, hydroboost/4-disc brakes, ram-assist/heim joint steering, Cage long radius arms, traction bars, 4" Skyjacker lift, 35" mud tires

  8. #18

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    Wanted to close the loop on this. I've had my IAC Parked Position at 38%, and my Cranking Fuel around 3.5 lb/hr, and I had the Fuel Prime set to 100%. I noticed that it seemed to fire up a little faster if I bumped up the IAC Parked Position to 50%. I then upped the Cranking Fuel to 4.5 lb/hr, and changed the Fuel Prime to 150%. Now it fires up almost instantly! Andrew

  9. #19
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    Quote Originally Posted by andrewb70 View Post
    Now it fires up almost instantly!
    Congratulations. That's what tuning is all about. My (hot) IAC Parked Position is also 50%.
    May God's grace bless you in the Lord Jesus Christ.

    '78 BRONCO: 508" stroker, TFS heads, 11:1 comp ratio, Dominator MPFI & DIS, cold air induction, Spal dual 12" fans/aluminum radiator, dual 3" exhaust/Magnaflow mufflers, Moroso vacuum pump, Accusump, engine oil & trans fluid coolers, 100HP progressive dry direct-port NOS, A/C, LenTech Strip Terminator wide-ratio AOD/2500 RPM converter, 3:1 Atlas II, modified Dana 44/60-lockers-4.10s, hydroboost/4-disc brakes, ram-assist/heim joint steering, Cage long radius arms, traction bars, 4" Skyjacker lift, 35" mud tires

  10. #20

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    What's the Fuel Prime Percent a percent of? Currently using 100% for the Fuel Prime, although I'm not sure what it is 100% of. As for starting without an IAC, do you have any recommendations for settings?

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