View Full Version : Holley Sniper question?
ggunter
02-15-2022, 12:52 PM
I have the Holley Sniper set up on my car and for the most part I like it and it works great. But there are two things that bother me with it. 1. setting at a stop light for 30 seconds or so and you go to blip the throttle to go, it will give one stumble then go. Not a big stumble but its there and it aggravates me. 2. When the engine is cold only and backing out of the garage or taking off slowly and the rpm goes down because you let the clutch out the IAC seems to think the engine is going to stall and then it takes off to 2000 rpm for 3-4- seconds. That aggravates me too. Does anyone have any solutions for these issues?
ggunter
02-15-2022, 12:55 PM
By the way the TPS is set at zero and the IAC is set between 6-8
Todd Baumann
02-15-2022, 01:45 PM
Try these adjustments first if you haven't yet. May help.
https://www.youtube.com/watch?v=j5Wz_RoXVSI
D Stand
02-15-2022, 11:03 PM
Those initial numbers for IAC and TPS look right. Have you check fuel pressure yet?
ggunter
02-16-2022, 08:17 AM
Fuel pressure is 58 psi.
Fuel pressure is 58 psi.
Where did you measure the pressure, and are you running a return line? Are you using the internal fuel pressure regulator or did you install an external regulator?
Other trouble shooting:
Check plug wires for any burns
Check for exhaust leaks
Check for electrical interference
Check timing
All vacuum ports capped or used and no leaks
weendoggy
02-16-2022, 12:51 PM
I have the Holley Sniper set up on my car and for the most part I like it and it works great. But there are two things that bother me with it. 1. setting at a stop light for 30 seconds or so and you go to blip the throttle to go, it will give one stumble then go. Not a big stumble but its there and it aggravates me. 2. When the engine is cold only and backing out of the garage or taking off slowly and the rpm goes down because you let the clutch out the IAC seems to think the engine is going to stall and then it takes off to 2000 rpm for 3-4- seconds. That aggravates me too. Does anyone have any solutions for these issues?
Start with a datalog to see what's going on. Guessing is just that, guessing. Is #1 happening when up to temperature? You tune at operating temperature and your IAC is o.k. You can get it lower, but that's good for now. You need to see what the system is doing by the datalog at the time it happens, and if you can replicate it all the time, it'll show. #2 can only be addressed when cold, so that means once a day. Do a datalog there as well. If you know the engine is sound, this is where you want to start.
rich grsc
02-16-2022, 01:41 PM
Sounds lean on tip-in. You may need to add a bit more fuel enrichment at throttle opening. Sorta like adjusting the fuel enrichment pump on a carb, same on cold start, more fuel till the engine starts showing temp
Norm B
02-16-2022, 03:13 PM
If you haven't done it yet, go to Holley.com and download the complete manual for the Sniper. The quick start manual included with the unit is very basic. In addition to Rich's recommendations you should set a cold idle curve. Basically it is like the high cold idle with an electric choke on a carb. Here is a couple of screenshots from my manual giving you an idea of the settings available.
HTH
Norm
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