Holley Sniper wont idle (1 Viewer)

[american outlaw]

Hey, I bought a sniper kit from Mosley Motors a while ago.

Of course it came with a dead fuel pump that didnt work. So i replaced that with the same make and model.

It worked well for the first few times i fired it up and its just progressively gotten worse to the point that it cant idle for more that a minute or two before it starts backfiring and dies.

The AFR is stable around 13.5 or so, then it just looses control of the AFR and it flickers between 13 and 14, then 12 and 15 then 11 and 16 until the car dies. If the fuel prime is on, it just blasts fuel all over the barrel the whole time the car is on.

My friends and I have reset the snipper back to the factory calibration with the wizards, played with the AFR, played with the idle speeds, adjusted the coolant enrichment curve, turned off the closed loop, turned it back on....

I just cant make heads or tails of what to possibly do to fix the damn thing. It was nice and happy and just has s*** the bed real hard. I plan on pulling the sniper off and giving it a good blast to get all the soot from the back firing off everything and pray that helps.

Kinda thinking about ditching the hunk of junk and dropping a carb onto it

 

[KennyBob]

Two thoughts come to mind... Your o2 sensor is bad or the sniper isn't getting enough fuel pressure/flow. I have read that the o2 sensors are notorious for dying when they get too hot. My issues have always been fuel filter related (mostly my fault).

 

[charliemeyer007]

I love the concept of fuel injection. However I can actually work on a carb and a points distribution, yes not as efficient but that's fine with me.

 

[JackA]

I heard that Holley has a hot line for tech support. Have you tried working with them to solve your issue?

 

[Wasatch Jay]

One of my very best friends installed a Holley Sniper system on his Bronco project. He is a super-meticulous guy, and he said he followed the directions to the letter. Then he had a miserable time trying to get the engine to run.

Holley's so-called "Technical Support" department was terrible. My friend thinks they have a lot of turnover of personnel, and most have minimal knowledge. Eventually, after many, many wasted calls he spoke with someone who was knowledgeable, and the problem turned out to be a defective (brand new) Holley supplied distributor.

He is done with Sniper, and will never use them again.

A buddy and I decided to install aftermarket fuel injection on a Tucker Sno-Cat project. It had a Chrysler 360 Industrial engine and we used Edelbrock's ProFlo 4 system. There was some ass-pain with the installation, but once complete the engine ran MUCH better than it ever did when it was carbureted. Engine starting was significantly improved, as well. In term of "bang-for-the-buck", it was an excellent upgrade. We never needed to call Edelbrock's tech support folks.

I was so impressed I bought another ProFlo 4 system for a project with a Ford 460 engine.

 

[american outlaw]

Two thoughts come to mind... Your o2 sensor is bad or the sniper isn't getting enough fuel pressure/flow. I have read that the o2 sensors are notorious for dying when they get too hot. My issues have always been fuel filter related (mostly my fault).

So the open/closed loop system in the sniper allows me to bypass the o2 sensor and run off the "preprogrammed algorithm vs a feedback loop... and that setting doesnt change anything.

I think I might just try to sell the thing and recoop my losses

 

[sogncab]

I'd just send it in to Holley to have then test it. Should be their problem yet

 

[KennyBob]

Have you verified you're getting 55-60 psi to the sniper with the new pump?

 

[77mustard40]

I love the concept of fuel injection. However I can actually work on a carb and a points distribution, yes not as efficient but that's fine with me.

Old school here too but with a rebuilt, recurved FJ60 electronic dizzy and its been rock solid for years.

 

[KennyBob]

It’s all cool in my opinion. I’m too much of a tinkerer to leave well enough alone though and play with the new fangled stuff.

 

[jhsmith]

Sounds like a fuel issue with yours, but the most common problem I have heard of with Sniper installs are vacuum leaks. Vacuum leak messes with the MAP sensor which causes incorrect mixture. In particular, the intake manifold seal to the engine and the phenolic spacer block between Sniper and intake manifold. Can you easily check phenolic spacer (top and bottom) with a straight edge?

 

[franklin40]

check to see you have. fuel from each injector. just look in the bore while it’s running and look for fuel. i had a bad injector (twice now) which caused those symptoms. bad O2 sensor can also cause it.

 

[Skreddy]

This sounds similar to an issue I had with my sniper in the beginning. May not be your problem but an easy check is look at the passenger side of the sniper, there’s a port with a plug in it. If your sniper is used in a boosted application, this plug is removed so a nipple can be installed to send a vacuum signal. Mine came out of the box with no nipple installed. AFR looked good but the more it ran it got worse. Basically way overcompensating for that big vacuum leak.

 

[american outlaw]

Finally ripped of the snipper installed a good carb... only to realize the few low pressure fuel pumps i had laying around were laying around for a reason

Gonna have to dig out the old mechanical fuel pump and see what it does with that plumbed in.... but the Sniper was GROSS from all the back firing. Pray for me boys

 

[raymond2335]

I used a Howell TBFI system.... ran horrible for a week while I pulled out my remaining hair. No codes to help. Eventually found a vacuum port on the Tbfi that was unplugged. It was for air conditioning idle up which I was not using. Anyways, Runs perfect now. I'd do it again in a heartbeat....

 

[american outlaw]

So I got a carb installed reset the timing out of sheer anger... and discovered that all 6 of my spark plugs were fouled beyond recognition. Like they WERE BLACKER THAN COAL.

So after sanding those down to get the soot off of them the land cruiser runs good and strong off a carb... absolutely 0 idea why my sniper lost control and wound up fouling my spark plugs so bad... Imma just rock the carb for a while... Cant do the frustration of the sniper for the time being.

If someone else is feeling good about their electronic trouble shooting would be willing to sell the sniper and all the other mosley motor thingies it came with for a REAL fair price. Local pickup to alabama only tho. Really dont care to ship things

 

[Grayscale]

Valve stem seals? Worn rings?

 

[charliemeyer007]

Spark plugs are cheap. Making a deep scraper hook out of broken hack saw blade allows you to clean out the gap outside the electrode. Second make use the center electrode has a square edge. Having spend a good deal of time with a spark plug break down tester was good training and very illuminating - some new plugs the fire would blow out at 60 psi, while a properly adjusted would still be firing at 175 psi the compressor limit.

 

[american outlaw]

Valve stem seals? Worn rings?

I think it was just a completely s*** air fuel ratio mixture from the EFI sniper. It wasnt oily or anything it was just a heavy layering of carbon build up on everything. Which is impressive given that they were new spark plugs that never got driven on. Only idle and toying with the EFI. All 6 had an equal coating of thick carbon. Which says it was from fuel air, more so than internal leaking. hard pressed to beleive all 6 would go out at the same time

ill keep an eye on the system with the carb in it. If it builds up again, ill probably look into overhauling the engine. But the engine should of been rebuilt by the previous owner and then never driven cause he couldnt figure out the smog stuff

 

[WildernessRimFab]

I think it was just a completely s*** air fuel ratio mixture from the EFI sniper. It wasnt oily or anything it was just a heavy layering of carbon build up on everything. Which is impressive given that they were new spark plugs that never got driven on. Only idle and toying with the EFI. All 6 had an equal coating of thick carbon. Which says it was from fuel air, more so than internal leaking. hard pressed to beleive all 6 would go out at the same time

ill keep an eye on the system with the carb in it. If it builds up again, ill probably look into overhauling the engine. But the engine should of been rebuilt by the previous owner and then never driven cause he couldnt figure out the smog stuff

Are all of the sniper sensors reading reasonable values? My sniper arrived with a dead coolant temp sensor, it was reading a low error. New sensor was 11 bucks. The black plugs suggest that it was running really rich either from a vac leak or bad sensor. Where is your 02 sensor located? Those sensors can also get nuked pretty easily if you are doing multiple rounds of fuel pump priming and short runs of the engine without getting everything up to temp.