random high idle

[JJK]

I have a BPE 347 with Holley Sniper EFI, all settings as came from BPE. Three times now I have come to a stop but the idle ramps up to 2000-2500 rpm, without my foot on the accelerator. Never had an idle at start or during a drive, only when decelerating to stop. I have read this is not uncommon and adding an extra wind to the secondary return spring should fix things.

Question is, do I need to do anything with the IAC settings for the sniper after adding the wind, or is that independent?

[Blitzboy54]

I am your one stop shop for this issue and finally think I have it resolved but who knows. This has been a 2 year battle for me. I have a thread about it but here are the highlights. I had my original Sniper that was replaced on warranty for an injector. The unit I was given was a refurb. It had the hanging idle issue and I could not resolve it. I replaced the IAC and throttle position sensor. I put RF caps on everything and did all sorts of driving condition experiments and checked the vacuum for leaks like 10 times.

After lots of back and forth with Holley he at one point asked for data logs and noticed my firmware was way out of date. I updated it per their procedure. This made the issue completely disappear, for 500 miles, then it came back. The last data log I sent them he said my IAC was getting strange inputs and I should disable the idle spark to see if the problem went away. If so we could change my IAC settings to fix it or just leave it off.

This was at the end of last years driving season so my car sat until spring. I can say now I have close to 500 miles with the Idle Spark disabled and the issue has not returned. I see no difference in performance or gas mileage so I have opted to leave it off. If I go another 1000 miles and this doesn't come back I might be willing to call it root cause.

Go ahead and disable your idle spark and see if that helps. It's pretty easy and only takes a few seconds with the hand held.

[weendoggy]

I have a BPE 347 with Holley Sniper EFI, all settings as came from BPE. Three times now I have come to a stop but the idle ramps up to 2000-2500 rpm, without my foot on the accelerator. Never had an idle at start or during a drive, only when decelerating to stop. I have read this is not uncommon and adding an extra wind to the secondary return spring should fix things.

Question is, do I need to do anything with the IAC settings for the sniper after adding the wind, or is that independent?

The "hanging idle" is usually due to IAC Ramp Down settings. Idle Spark has little to do with hanging idle and unless you're running a Dual Sync or Hyperspark setup, is useless. Even then, not the usual culprit. I'm not suggesting you just arbitrarily start adjusting those settings, because the base settings need to be correct first. i.e.: idle speed, idle IAC setting etc., all done at normal operating temperature. If you're not sure on what direction to take, someone taking a look at a datalog and current tune could help. The usual cause is when the Ramp Down settings aren't setup for the engine and/or driving style of the operator and then get caught in "limbo" for what you expect it to do.

[BradCraig]

Few things:

1. Make sure your IAC is at 3-10% (varies based on who you ask) at idle at normal operating temp.
2. When the high idle condition occurs, if you can, open your hood and check to see if the secondaries are hung slightly open by manually pushing on the secondary linkage. This is a common issue causing high idle and can usually be remedied by putting an extra wind on that shaft spring
3. Sometime, but not incredible common, the butterflies get misaligned from the factory. You'd need to loosen and reset.

That's where i'd start. Google search on all the above will get you a LOT of info. Good luck!

[Blitzboy54]

I have reset my secondary’s a dozen times. I adjusted my ramps downs settings to the point of them being absurd and I over wound the spring. None of it worked more than a couple of rides. It always returned. I am running a dual sync but adapted to hyperspark because of the steel gear. You can tell me the idle spark has nothing to do with it until your blue in the face. Holley disagrees and it’s what (to this point) seems to be the only thing that solved it.

If you connect your hand held and have it available when you’re driving you can see what the IAC is doing in relation to the TPS. This will also be collected when you data log.

[BradCraig]

I have reset my secondary’s a dozen times. I adjusted my ramps downs settings to the point of them being absurd and I over wound the spring. None of it worked more than a couple of rides. It always returned. I am running a dual sync but adapted to hyperspark because of the steel gear. You can tell me the idle spark has nothing to do with it until your blue in the face. Holley disagrees and it’s what (to this point) seems to be the only thing that solved it.

If you connect your hand held and have it available when you’re driving you can see what the IAC is doing in relation to the TPS. This will also be collected when you data log.

Yep...there are a LOT of variables so you have to hit all the obvious and common things first. Then go from there to see what moves the needle. The Sniper is NOT a plug and play device for certain.

[weendoggy]

I have reset my secondary’s a dozen times. I adjusted my ramps downs settings to the point of them being absurd and I over wound the spring. None of it worked more than a couple of rides. It always returned. I am running a dual sync but adapted to hyperspark because of the steel gear. You can tell me the idle spark has nothing to do with it until your blue in the face. Holley disagrees and it’s what (to this point) seems to be the only thing that solved it.

If you connect your hand held and have it available when you’re driving you can see what the IAC is doing in relation to the TPS. This will also be collected when you data log.

Every engine is different and should be adjusted to its liking. You didn't read my post either. I said "unless you're running a Dual Sync or Hyperspark", so in your case, maybe it works for you. I can say for all the ones I've done, none require that to be disabled. So much is not given in the OP's post, so basic beginner things are what to look for, and not arbitrarily saying "this will fix your problem". Without detailed tune and datalog (current to the drive), it's a crap shoot.

[JJK]

For additional clarification, I have a standard distributor controlling the timing, not the Sniper. Given this setup, does turning the idle spark on/off have any impact on things? Happy to try next time I fire it up, but was under the impression this would only affect things if the Sniper controlled the timing through a dual spark or hyperspark distributor system.

[Blitzboy54]

That's right, it probably shouldn't matter then.

[CaptB]

Ok so I had the same issue and found a random video that showed if you took another turn on the secondary spring it tightened up the pedal resistance. That fixed it, that simple.



Also, I switched from a dual plane to single plan and the fuel flow was signficantly better.

One other note, take the Sniper off and make sure your secondaries are closing all the way, there are a couple of screws to adjust it so they close properly.

Good luck.

[weendoggy]

For additional clarification, I have a standard distributor controlling the timing, not the Sniper. Given this setup, does turning the idle spark on/off have any impact on things? Happy to try next time I fire it up, but was under the impression this would only affect things if the Sniper controlled the timing through a dual spark or hyperspark distributor system.

No.

[JJK]

Thanks for the clarification on the Idle Spark, no need to play with that.

CaptB,
That was the video I watched and it sounds like it is what I need. Is this independent from the IAC controls or do I need to recalibrate the Sniper after adding the wind? If this simply adjusts the tension on the pedal then I assume it is independent.

I have never taken the Sniper off, so not sure if BPE used a single or dual plane intake. But, since I have only had idle problems a few times under similar circumstances after a deceleration to stop, I assume the secondaries are closing properly the majority of the time.

[RJD]

In addition to the extra wind on the return spring, I put together these steps to troubleshoot my high idle issue. I just went down the list steps 1 thru 5. In the end, I think steps 3 & 4 solved the problem - lowered the IAC hold and raised the RPM Ramp Start. I had no RFI/EMI issue, and it's been a year now without high idle issues. Good luck.

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[CaptB]

Thanks for the clarification on the Idle Spark, no need to play with that.

CaptB,
That was the video I watched and it sounds like it is what I need. Is this independent from the IAC controls or do I need to recalibrate the Sniper after adding the wind? If this simply adjusts the tension on the pedal then I assume it is independent.

I have never taken the Sniper off, so not sure if BPE used a single or dual plane intake. But, since I have only had idle problems a few times under similar circumstances after a deceleration to stop, I assume the secondaries are closing properly the majority of the time.

My problem with the fuel distrobution may be a one off but I had 6 plugs that looks like they were working and 2 that always stayed new. I saw significantly less heat on the headers for those cylinders too, so I think they were firing occationally. But the switch to the single plane was certainly a game changer. I (like you) got tired of it sticking and then you had to rev it to get it back to idle. Very frustrating.

[JJK]

RJD and CaptB, thank you both. I will spend some time this weekend adding a wind to the secondary spring and confirming the IAC and ramp start parameters. Hopefully this gets things smoothed out.
Best
JJ

[Randy's]

I have a BPE 347 with a Sniper and had the same issue. My research resulted in a lot of suggestions, just like this thread. That tells me that it can be caused by various things. Ultimately, my issue was with the spark plug wires. I had done some cosmetic upgrades to my engine, Ford Racing valve covers, spark plug wire separators/organizers, etc. With that, I routed the spark plug wires differently and used zip ties to hold them in place. My fix for the high idle was simply to remove the zip ties so that the wires fell further away from the Sniper. Needless to say, I am surprised that the proximity of the spark plug wires near the Sniper could cause this, but in my case it did.

[Avalanche325]

If your distributer's mechanical advance is sticking, it will cause a high idle. It acts very much like a sticking throttle. It may stay high. It might go high and very slowly come back down, etc.

Take the "football" fly weights off, clean and lightly lubricate.

[FFinisher]

The one I had with this issue was much more simple. The throttle plates were not centered in the bore and were not allowing the throttle to return.

I am not as confident that is the fix as "Mr One stop shop" But that's what I would look at .:-)

[JJK]

As an update, I added a wind to the secondary return spring. I have only driven about 45 minutes since, but so far, no hung idle. I will give it a few weeks and post back my experience once I have driven it more.
From my research, it appears this is a common "fix", but the root problem could be misaligned throttle plates or insufficient vacuum.

[RJD]

As an update, I added a wind to the secondary return spring. I have only driven about 45 minutes since, but so far, no hung idle. I will give it a few weeks and post back my experience once I have driven it more.
From my research, it appears this is a common "fix", but the root problem could be misaligned throttle plates or insufficient vacuum.

Keeping my fingers crossed for you, but if it comes back after the added wind, like mine did, lowering the IAC hold and raising the RPM ramp start is pretty simple by adjusting the settings via the touchscreen LCD.

[Blitzboy54]

The one I had with this issue was much more simple. The throttle plates were not centered in the bore and were not allowing the throttle to return.

I am not as confident that is the fix as "Mr One stop shop" But that's what I would look at .:-)

Sure, I should have used a different phrase. The point is I went through it with this issue for years not weeks or months. Hours of data logging, waiting on hold and having my sniper at Holley. Every single solution offered in this thread had been tried multiple times.

I apologize for jumping to the conclusion that worked for me but the frustration with this was enough to ensure the next engine I build will likely have a carb.

Fixed now so all is well that ends well but it left scars.

[BradCraig]

As an update, I added a wind to the secondary return spring. I have only driven about 45 minutes since, but so far, no hung idle. I will give it a few weeks and post back my experience once I have driven it more.
From my research, it appears this is a common "fix", but the root problem could be misaligned throttle plates or insufficient vacuum.

Glad that worked. Often the simplest solution is the best solution so start there. I will say though, that there are some combos that the Sniper simply doesn't like and folks try for years to get them dialed in. Things are not "auto-tuning" whatsoever.

[Mike.Bray]

ensure the next engine I build will likely have a carb.

FWIW, I really hate that a budget, entry level EFI system like the Sniper gives so much frustration and EFI a bad name in general. You truly get what you pay for, a port injection system with a more sophisticated ECU like a Fast Sportsman or Holley Terminator is literally a world of difference. A proper EFI system simply cannot be beat, think about your daily driver (for the past 40 years or so) and virtually every racing series including NASCAR taxicabs and NHRA Pro Stock.

Okay, I'm biased as I hate carbs. And I've worked on all of them from Q-Jets to Holley to Webers to Delortos on my racing karts. And I'm lazy, I like my cars to start, idle, and go without dealing with chokes, stuck floats, etc. To me carbs are a 150 year old Rube Goldberg mechanical metering device that are more art than science to tune. And with today's ethanol-blended fuel there's the problem of gasoline evaporating leaving behind an ethanol residue to clog the precision passages that make a carburetor work. Even using ethanol-free gas every spring it's a battle to get my leaf blower started.

I've been running EFI systems since the early 90's and never had a problem with them. But I never did a low end system like the Sniper.

End of FWIW

[BradCraig]

FWIW, I really hate that a budget, entry level EFI system like the Sniper gives so much frustration and EFI a bad name in general. You truly get what you pay for, a port injection system with a more sophisticated ECU like a Fast Sportsman or Holley Terminator is literally a world of difference. A proper EFI system simply cannot be beat, think about your daily driver (for the past 40 years or so) and virtually every racing series including NASCAR taxicabs and NHRA Pro Stock.

Okay, I'm biased as I hate carbs. And I've worked on all of them from Q-Jets to Holley to Webers to Delortos on my racing karts. And I'm lazy, I like my cars to start, idle, and go without dealing with chokes, stuck floats, etc. To me carbs are a 150 year old Rube Goldberg mechanical metering device that are more art than science to tune. And with today's ethanol-blended fuel there's the problem of gasoline evaporating leaving behind an ethanol residue to clog the precision passages that make a carburetor work. Even using ethanol-free gas every spring it's a battle to get my leaf blower started.

I've been running EFI systems since the early 90's and never had a problem with them. But I never did a low end system like the Sniper.

End of FWIW

I agree with you, but I will say I have a Sniper on my Camaro and it's been flawless outside of self-induced issues. It's a mild SBC so none of the hot cam issues, etc.

[Rockman]

I have a BPE 347 with Sniper. I developed the intermittent high idle issue after one year of driving. I would get the high idle when the ambient temperature was cold and the engine was not fully hot. I would have to tap the throttle to get the idle to reset. I did the magic extra wind on the spring and have never experienced the issue again. Other than that one issue, the sniper has been flawless.

[john42]

I have the Bluetooth dongle and use my iPhone to see the settings, etc etc. Today when I went out for a drive I got a Holley firmware update. Immediately after a forced "reboot" my idle is surging and won't settle and was pretty much stuck at 2200rpm. After looking around for a few minutes I turned Idle Spark back on. For clarification I have a Holley Hyperspark distributer. Instantly all is well again. After a several hour cruise she's running great! Initially I had tons of issues with return to idle and problems with surging and stuck idle. Turning off Idle Spark fixed it. Seems now Holley had some sort of fix? Well, my single data point of a test of 1 seems good to me.

[CDXXVII]

As an update, I added a wind to the secondary return spring. I have only driven about 45 minutes since, but so far, no hung idle. I will give it a few weeks and post back my experience once I have driven it more.
From my research, it appears this is a common "fix", but the root problem could be misaligned throttle plates or insufficient vacuum.

I have the Holley Terminator X Stealth

The exact same high idle issue. After chasing every last possible condition I came across a thread describing the secondary spring and throttle plate alignment issue.

I spent a good hour aligning the plates and added one turn to the spring. Reset the tune and started the process again.

Problem is gone and the engine is running better than ever. Silly issue from Holley and I am really surprised the techs are not up to speed on this.