Looking for some help from the Holley sniper community, can’t get consistent idle and I’ve got a whine coming from the Holley (see attached video). Is this whine normal? If not, thoughts on where it’s coming from? Intake leak perhaps?
2F HOLLY SNIPER EFI
- Thread starter EndlessAloha
- Start date
This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.
I'd suspect an intake leak with that whistle.
What is the IAC % showing at idle? That should give you some better info as well.
Chungas Revenge
SILVER Star
Skreddy
SILVER Star
The whine: sounds just like mine was and it comes from (what I can tell) too tight of a bend at the feed line right to the throttle body. May have too many bends/tight bends that cause it and reverberations/harmonics through the hard line. Try removing or loosening some of your line separating clamps and see if it improves. If it does, you’re on the right track. My solution was 45 degree fitting off the throttle body inlet then my hard line to that.
For the searching idle, add a video of the “vitals” screen. The one that shows map, iac %, afr, idle rpm and coolant temp.
For the searching idle, add a video of the “vitals” screen. The one that shows map, iac %, afr, idle rpm and coolant temp.
All right guys, finally got out to the garage after putting the dodo to sleep. Skreddy, you’re spot on, the harmonic from small vibrations in the first video, the second and third video are of the IAC cold then IAC hot. Thoughts?
Harmonic
IAC cold
IAC warm April 17, 2023 - https://youtu.be/1LCpxEYHDq4
Harmonic
IAC cold
IAC warm April 17, 2023 - https://youtu.be/1LCpxEYHDq4
I also tapped the voltage regulator for starter/crank signal. I’m not happy with it but can’t see that being the cause. Any reccommendations for a better source under hood? I have stock alternator so T’d it off voltage regulator.
thanks, picked up some carb cleaner to test for vacuum leaks tonight, I’ll give it a shot tomorrow
Skreddy
SILVER Star
What is your target idle?
How long has this sniper been going? I.e.: is it a fresh install?
That iac moving is odd for sure. Mine doesn’t hunt like that and definitely not that high of a percentage at idle.
What exactly did you tap to the voltage regulator?
What ignition are you running? If points, are they fresh and gap/dwell set correctly? Vacuum advance or retard and what vacuum source, ported or manifold? PCV operational and correct?
If you have a thread going with a link, post it up here too.
How long has this sniper been going? I.e.: is it a fresh install?
That iac moving is odd for sure. Mine doesn’t hunt like that and definitely not that high of a percentage at idle.
What exactly did you tap to the voltage regulator?
What ignition are you running? If points, are they fresh and gap/dwell set correctly? Vacuum advance or retard and what vacuum source, ported or manifold? PCV operational and correct?
If you have a thread going with a link, post it up here too.
Fresh build, idle set at 700. Adjusted after reaching 160F as per manual.
Tapped voltage regulator for constant crank/start signal to sniper.
Running an HEI dizzy, just required tach signal Only and selected coil (-) in start up sequence
PCV was good two months ago when I removed carb. I’ll check againq
Tapped voltage regulator for constant crank/start signal to sniper.
Running an HEI dizzy, just required tach signal Only and selected coil (-) in start up sequence
PCV was good two months ago when I removed carb. I’ll check againq
Skreddy
SILVER Star
Not that this is your issue, but I don’t think the crank/start signal is used in most applications. What color is the wire from the sniper harness? Not sure if it’s something the HEI needs?
On my setup (with points distributor using pertronix), the only connections are blue for fuel pump, pink to coil +, yellow to coil - (tach signal I think), then constant 12v red (right to battery) and black ground (right to battery).
On my setup (with points distributor using pertronix), the only connections are blue for fuel pump, pink to coil +, yellow to coil - (tach signal I think), then constant 12v red (right to battery) and black ground (right to battery).
Skreddy
SILVER Star
Could try unhooking that red wire from the tap to the voltage regulator and see if it changes anything?
That level of IAC/RPM wandering is definitely not normal. Check for vac leaks and try an alternate connection for the constant crank/run 12V.
I have mine hooked up to one of the fuses (3rd one down maybe) with a glass fuse tap.
I have mine hooked up to one of the fuses (3rd one down maybe) with a glass fuse tap.
Agreed. If you get a chance, go in the menu on the screen and enable logging. Run it for a bit, then upload the results from the SD card here, they give good info.
I'd suspect a leak, but could also be a bad MAP sensor, etc...logs would help rule stuff out though.
I'd suspect a leak, but could also be a bad MAP sensor, etc...logs would help rule stuff out though.
Skreddy
SILVER Star
For constant crank/run 12v, are you guys referencing the pink wire? There is also a purple wire labeled as the crank sensor. Just making sure these terms aren’t getting crossed (I thought you are meaning it’s the purple crank signal wire). Holley references the pink wire as “switched ignition 12v”. If the red wire attached to your voltage regulator is the pink wire from the harness, try moving it to a different spot as noted. If it’s the purple wire, disconnect it.
I was referencing the pink wire (Holley 7 pin terminal F). I didn't use the purple wire but I'm just using a regular Fj40 non us electronic disty.
Disconnecting pink wire from tapped voltage regulator and as suspected, killed the engine. Looked for a stuck injector, does this sound right (see video)? I’ll test for vacuum leaks tomorrow. Also could be EMI as I found several issues with tach/pink wire getting spurious noise from spark plug wires etc. Any other good sources for tapping into crank/start under hood or at fuse box?
Got two of these OTW…thanks!
I don't know the exact fuse setup of your 78, but its pretty easy to figure out a fuse that is hot during crank/run.
Check with a voltmeter. On my 72, the side of the glass fuse towards the rear of the truck is the "hot" side, so if you attach the glass fuse tap to the other end on the front of the truck is is fuse protected. Keep in mind that the pink sniper wire doesnt pull much amps it is just used to signal the relay.
The weird sucking noises that you have are the IAC jumping around. Seems like a vac leak.
What intake manifold adapter are you using? Redline?
That what I am using and I noticed that if you didn't install the correct arrangement of bolts/washers then it wont snug down 100%.
The bolts/washers in the kit aren't labeled and there are no instructions so it could be easy to use the wrong bolts in the wrong places.
Check with a voltmeter. On my 72, the side of the glass fuse towards the rear of the truck is the "hot" side, so if you attach the glass fuse tap to the other end on the front of the truck is is fuse protected. Keep in mind that the pink sniper wire doesnt pull much amps it is just used to signal the relay.
The weird sucking noises that you have are the IAC jumping around. Seems like a vac leak.
What intake manifold adapter are you using? Redline?
That what I am using and I noticed that if you didn't install the correct arrangement of bolts/washers then it wont snug down 100%.
The bolts/washers in the kit aren't labeled and there are no instructions so it could be easy to use the wrong bolts in the wrong places.
Skreddy
SILVER Star
I agree with vac leak. When mine was missing the map sensor plug I was getting a huge vacuum leak and the system was trying to compensate by over fueling at idle (what yours looks like in video).
When looking for a source for your switched 12v (pink wire), you want something that has no other draw or a constant draw. Tapping into the distributor power source should work because when running, it will see a constant voltage. But, tapping something like radio or turn signals can create issues because those are selectable circuits. Meaning, the sniper will be fine but once you turn your blinker on it starts seeing momentary voltage drops and spikes. I’m not thinking that being tapped into the voltage regulator is necessarily causing you issues, but I’d look for a “cleaner” tap.
When looking for a source for your switched 12v (pink wire), you want something that has no other draw or a constant draw. Tapping into the distributor power source should work because when running, it will see a constant voltage. But, tapping something like radio or turn signals can create issues because those are selectable circuits. Meaning, the sniper will be fine but once you turn your blinker on it starts seeing momentary voltage drops and spikes. I’m not thinking that being tapped into the voltage regulator is necessarily causing you issues, but I’d look for a “cleaner” tap.
