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Holley Sniper Pro?

turbotim2

____________
Joined
Jun 26, 2003
Messages
1,938
Any Sniper experts in the NE willing to help a brother out? I can not get the IAC to stay consistent. Been trying for a year and a half. Been on the Holley forum trying everything thrown at me.
 

DirtDonk

Contributor
Bronco Guru
Joined
Nov 3, 2003
Messages
44,005
Back to the top for you Tim. Hopefully somebody has some good pointers.
Good luck.
 

chuckji

Full Member
Joined
May 5, 2017
Messages
354
Loc.
SE Michigan
what problem are you having?
are you controlling timing with the Sniper?
what engine?
what‘s your exhaust system?
 

904Bronco

Contributor
Bronco Guru
Joined
Sep 28, 2004
Messages
5,433
Loc.
San Martin, CA
I had a similar problem with the IAC, couldn't get the idle below 11-1200 rpm. Jumped through so many hoops, loong waits on hold with Tech, sending them info as requested and not hearing back from them. Finally, the Tech I talked to on a Saturday (after an hour wait on hold) agreed with me that IAC was bad on their unit. I asked for a replacement IAC and he sent me an entire replacement unit. Finally the thing idled appropriately. Kind of soured me on the Sniper unit.
I hope you find some resolution....
 

Cooter_76

Sr. Member
Joined
May 18, 2004
Messages
858
Do you have a fuel pressure gauge installed? One of the issues I had with the Sniper was related to the internal fuel pressure regulator. The IAC was fighting excessive fuel pressure.
 

chuckji

Full Member
Joined
May 5, 2017
Messages
354
Loc.
SE Michigan
Sorry you’re have such trouble solving this problem.
I think the advice on the Holley forum about checking exhaust leaks and the secondary butterflies is a good starting point. I was actually having IAC troubles at one point and it turned out it was being caused by both of those. The secondary butterflies would stick open very slightly with a hot engine causing higher than set idle speed and 0 IAC. once that was identified and fixed, exhaust leaks (I went through a few sessions to find and fix them) would cause a false lean condition, wreaking havoc with my AFR and IAC. The last exhaust leak to fix was literally a pin sized hole in a weld joint just before the O2 sensor.
I know you’ve been investigating these based on the Holley forum advice.
here are some things I’ve learned from my personal experience.
- don’t trust exhaust band clamps to completely seal. I could never get them to seal and have since switched to either welded pipes or V clamps.
- header ball joint clamps leak, at least mine did. Switch to V clamps for a reliable seal.
- use a shop vac in blower mode and connect it to your tail pipe. Spray soapy water on all joints and exhaust manifold/header connection points. If you’re using headers, don’t forget to check the joint where the 4 pipes come together at the collector and check the O2 bung. You are using a weld in O2 bung, right. that O2 clamp that comes in the kit is not reliable.
- if/when you are experiencing an IAC of 0 at idle (assuming you’ve already accurately set the IAC to between 2%~10% at idle at running temp) it means the engine is taking in air from somewhere - that is why the IAC is at 0. Take notice, is your idle speed above what you’ve set? if you blip the throttle will it return to normal operation (IAC and idle speed)? Or if you pop the hood and manually work the secondary linkage closed, does normal operation resume? If yes to either of these, your secondaries are sticking open. Pull the Sniper off and go through the adjustment procedure. Secondaries sticking open with a hot engine is/was a common issue people were seeing.

sorry if this is obvious stuff for you, I’m not familiar with what you’ve actually done or your troubleshooting methods.
 
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turbotim2

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Joined
Jun 26, 2003
Messages
1,938
Thank you for your suggestions.
- I am running a fuel pressure gauge and get a consistent 60psi.
- I have no exhaust band clamps upstream or near the O2 sensor which is installed in a weld in bung.
- Headers have flat gasketed clamps.
- I have checked the primary and secondary (really, all primary on these) butterfly valves and they are consistently closing correctly.
I could get the IAC set and drive it without issue. Next day I would start it and the IAC would go to zero and idle high. Get it adjusted again, next time I drive, the IAC would hang around 40-50 and really low idle and wouldn't be able to adjust it. Next time, it would set correctly and then would bottom out at 0 after a drive. It has been all over the map making it difficult to pinpoint. I guess the only constant is change related to leaving it for a few days between attempts so it was cold when going back to it.

I have replaced the CTS twice now (the first one was bad when I got it from Holley). The current one is working. I have a new insulated base gasket coming today to see if excessive heat was affecting it.
 

DirtDonk

Contributor
Bronco Guru
Joined
Nov 3, 2003
Messages
44,005
Sounds almost like an ECU issue. The coolant temp sensor debacle was a big deal a couple of years ago for all the manufacturers. Must've been a big batch of bad ones coming in from overseas that everyone was pulling from. Was a big problem with FiTech for sure.
Luckily all the replacements seemed to fix the issues.

Good luck. Sounds like you've been all over it so far.

Paul
 
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turbotim2

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Jun 26, 2003
Messages
1,938
So I finally received and installed the new base gasket (EDL-9266) for dual plane manifolds. I immediately noticed the idle was smoother. I had also installed a fixed orifice PCV. I was able to set the IAC and went for a drive. It ran good and held the IAC setting. Hopefully this will be repeatable on my next few drives!
 

bmc69

Contributor
Bronco Guru
Joined
Jun 11, 2004
Messages
11,505
So I finally received and installed the new base gasket (EDL-9266) for dual plane manifolds. I immediately noticed the idle was smoother. I had also installed a fixed orifice PCV. I was able to set the IAC and went for a drive. It ran good and held the IAC setting. Hopefully this will be repeatable on my next few drives!
Good news. I'm installing the Sniper Pros on a pair of twin-turbo 534 engines and am hoping its going to be a reliable setup compared to the blow-through Holley 4V setup they had before.
 

chuckji

Full Member
Joined
May 5, 2017
Messages
354
Loc.
SE Michigan
So I finally received and installed the new base gasket (EDL-9266) for dual plane manifolds. I immediately noticed the idle was smoother. I had also installed a fixed orifice PCV. I was able to set the IAC and went for a drive. It ran good and held the IAC setting. Hopefully this will be repeatable on my next few drives!
That’s great! Hope that proves to be a fix for you.
 

BradGP

Newbie
Joined
Sep 22, 2020
Messages
48
Good news. I'm installing the Sniper Pros on a pair of twin-turbo 534 engines and am hoping its going to be a reliable setup compared to the blow-through Holley 4V setup they had before.
My uncle is looking at this Bronco with 534 twin-turbo engines. We'll take a look at it soon after we finished bumper and jeep wheels on the Wrangler this week. Looking forward to your updates.
 
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turbotim2

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Jun 26, 2003
Messages
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Unfortunately the good news didn't last long. Drove about 25 miles this morning and noticed that when I was stopped at lights (idling and in drive), the IAC would gradually creep up and continue to do so as long as I was stopped. It got up to 50 or 60% that I noticed. And at the end of the drive, in park the IAC went to zero and the engine idle would hover 50+ rpm higher than the set point.
 
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turbotim2

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Joined
Jun 26, 2003
Messages
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I did find a minor vacuum leak that helped but did not fix the IAC issue. I replaced the IAC motor and that seems to have solved the idle issue. Unfortunately I have a new problem now, the AFR just pegs at 35.6 and won't move plus cutting out at lower RPM's. I suspect this is a bad O2 sensor. A year and a half of fighting this thing has me at the end of the rope. No two drives are the same, replacing parts already, I don't dare drive it far. My experience with the Sniper has been terrible, I would not recommend it.

I just put the Bronco away for the winter so I don't have to think about it for another 7 months!

To be clear - this is the Sniper 4150 model.
 

bmc69

Contributor
Bronco Guru
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Jun 11, 2004
Messages
11,505
ugh. I need to go on that user forum and read up...is Danny Cabral still the "guru" on there? If I'm going to put Snipers on these marine engines like I've planned they've got to be stone-cold reliable. I've seen plenty of "horror" stories about FiTech units too.
 
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turbotim2

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Jun 26, 2003
Messages
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Danny is still there and helps where he can. You will see a number of similar threads on there to mine. The Sniper seemed to get the best reviews so that is why I went that route.
 

toddz69

Sponsor/Vendor
Bronco Guru
Joined
Nov 28, 2001
Messages
9,186
Sorry to hear about your troubles with this unit. The reliablity of these aftermarket throttle body EFI units just doesn't seem to be there yet despite all the advances made over the years.

Todd Z.
 
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