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Thread: Sniper idle a little high between shifts and AFR question.

  1. #1

    Default Sniper idle a little high between shifts and AFR question.

    I think I have all of my vacuum issues resolved, and I just recently did a reset of the computer, and started driving the car. I drove my car about 20-30 miles today and did everything from around town to highway driving.

    My biggest problem at the moment is that my car is still idling a little high between shifts and at stop signs. I have the idle in the touchscreen set to 770 RPM, but once I start to drive the car it will go to about 1,050. If I then wick the throttle it will go down, but it will still be at about 900 RPM. If I stop & start the car, the idle is around 825 until I start to drive it. The throttle stays at that 1,025 RPM between shifts. I did notice that my IAC is still at 0% when coming to a stop once I start driving it.

    My other question has to do with AFR. My AFR is staying around 13.5 at idle and while driving around. If I go WOT it will go to about 12.5, which I think is normal. Based on what I've read, the AFR should be around the 14.7 range. How can I lean out the car a little to get the AFR where it should be?

  2. #2
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    Quote Originally Posted by caverman View Post
    My biggest problem at the moment is that my car is still idling a little high between shifts and at stop signs. I have the idle in the touchscreen set to 770 RPM, but once I start to drive the car it will go to about 1,050. If I then wick the throttle it will go down, but it will still be at about 900 RPM. If I stop & start the car, the idle is around 825 until I start to drive it. The throttle stays at that 1,025 RPM between shifts. I did notice that my IAC is still at 0% when coming to a stop once I start driving it.
    Make absolutely sure that your throttle blades are closing fully and not getting hung on the linkage. In particular, have a look at the secondary throttle plates (the ones not affected by the idle speed screw). The spring on that pair of throttle plates is not terribly strong, and the secondaries sometimes want to stick a bit. That should go away with a bit more use, or apply a tiny bit of engine oil if you find that to be the case. I've also had a customer who put an extra turn on the secondary spring to give it more force, but I'm not sure that I would recommend that route for most.

    My other question has to do with AFR. My AFR is staying around 13.5 at idle and while driving around. If I go WOT it will go to about 12.5, which I think is normal. Based on what I've read, the AFR should be around the 14.7 range. How can I lean out the car a little to get the AFR where it should be?
    You can change your Target AFR for idle, cruise & WOT, but I don't recommend doing that unless you have much more time on the system and a very specific reason. Holley did go a bit conservatively rich on this number, but that wasn't without reason, nor should it be a problem. When you've put a thousand miles on the system and everything is working perfectly, if you want to bump the idle target up a tenth of an AFR or two, and then run it another 1000 miles, that would be okay. Enjoy the journey to tuning perfection, don't make it a race. :-D
    Chris Myer
    800-880-0960 x654
    chris@EFISystemPro.com

    Check our website for live stock status on all Holley items!
    www.EFISystemPro.com

  3. #3

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    Quote Originally Posted by cmyer View Post
    The spring on that pair of throttle plates is not terribly strong, and the secondaries sometimes want to stick a bit. That should go away with a bit more use, or apply a tiny bit of engine oil if you find that to be the case.
    Where would I apply the engine oil? I'm assuming you mean apply it to the spring? Does is need to be engine oil or can it be something similar to WD-40?

    I'll try to get out to the shop in the next day or so, and take a look & see if I an tell anything about the throttle blades. I guess I'll have to take the air cleaner off, drive it down the street, and then see if it still looks like they are still open. I've been double checking to make sure there is nothing that would cause the throttle linkage to get caught, and I'm 99% sure it wouldn't get caught on anything. Again this is really only happening when I'm driving around.

    I'll wait on the AFR tuning. I just read in the Holley document where the AFR should be at 14.7, so I thought it might need some tuning, but if I just need to put more miles on the car before fine tuning it then I'm okay with that. Other than the idling issue, it seems to be running well enough. I just need to get the idle issue figured out. It makes it not enjoyable to drive the car and that's the last thing I want to happen.

  4. #4
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    Quote Originally Posted by cmyer View Post
    I've also had a customer who put an extra turn on the secondary spring to give it more force, but I'm not sure that I would recommend that route for most.
    I've done this on the last two Holley EFI throttle bodies I've used. No problems at all. Remember, the main throttle return spring (user supplied) only pulls on the primary throttle shaft.
    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

  5. #5

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    Quote Originally Posted by Danny Cabral View Post
    I've done this on the last two Holley EFI throttle bodies I've used. No problems at all. Remember, the main throttle return spring (user supplied) only pulls on the primary throttle shaft.
    I don't have a throttle return spring on mine. I did initially but took it off thinking that was a possible issue. Should I use a return spring on the throttle arm?

    Also, if I were to put an extra turn on the secondary spring, how would I do that? I don't have the throttle body in front of me to look at, and I haven't found a good picture to show me what the spring looks like, but is there a screw I would turn or would I have to do something physically with the spring.

  6. #6
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    Quote Originally Posted by Danny Cabral View Post
    I've done this on the last two Holley EFI throttle bodies I've used. No problems at all. Remember, the main throttle return spring (user supplied) only pulls on the primary throttle shaft.
    Thanks for the validation on that, Danny. I'll be more confident about suggesting that in the future. Interestingly, another customer stopped by today and was telling me about troubleshooting the same, exact issue on an installation he just completed (secondaries hanging slightly open.)

    @Caverman, the problem with WD40 is that is pretty quickly evaporates and is more of a penetrant & cleaner, than a lubricant. Try just putting a drop of motor oil on the end of your finger and sort of work it into that friction point where the crossbar connects the primary to the secondary. That should help. Less is more, as it could also attract dirt and create a problem if you goop too much on there.
    Chris Myer
    800-880-0960 x654
    chris@EFISystemPro.com

    Check our website for live stock status on all Holley items!
    www.EFISystemPro.com

  7. #7
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    Quote Originally Posted by caverman View Post
    I don't have a throttle return spring on mine. I did initially, but took it off thinking that was a possible issue. Should I use a return spring on the throttle arm?
    Yes, of course you should use a throttle return spring! Just like you would on a carburetor (LINK).
    The factory coiled springs around the throttle shafts, don't count as a throttle return spring.
    You must add a good strong throttle return spring. Carburetor return spring kits are compatible.

    (This is a safety hazard that could cause personal injury or death to you or other motorists.
    Please consider having someone with qualified experience help you with this EFI installation.)

    Also, if I were to put an extra turn on the secondary spring, how would I do that?
    You simply unhook the end of the coiled spring (from V-notch) and loop it around one more turn tighter. It takes 20 seconds and no tools. Don't waste your time looking for a picture of it, it will make sense when you see it.
    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. #8

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    What should my IAC be while driving? It's staying 27%.

  9. #9
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    While you're on the throttle (above 2% TPS), it should be at the IAC Hold Position.
    http://documents.holley.com/techlibrary_199r11259.pdf (Holley Sniper EFI Help File)
    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

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