Sniper EFI bad injector

This season has been [censored]. I'm starting to think this car is trying to bankrupt me.

I've was making timing adjustments and the damn car was running very inconstantly. Sometimes it would idle and start right up. Others it wouldn't start at all or run rough. Entire time I thought I screwed something up with my timing adjustments and was beating my head against the dash. Finally got it running and took it around the block. Got on it a little and it flat out died right in front of my house. Wouldn't even give any indication of starting and was stinking of gas. Check the pressure gauge and it read zero. Should read 50 pounds after the system primes. Tried it again while watching under the hood this time and a geyser of fuel erupts out of the throat of the TBI. Had to get neighbor and his son to help push my car up the drive and into the garage (I live on a hill).

Here is a video of it in action:



I'm assuming the injector is shot. Yes? Anyone familiar with how hard it is to replace it or even where to get one?

I know I'm out the $50 worth of fresh oil in the pan too. Might have the car on the road in time for August at this rate.

fitech has got its share of problems too. should be able to get another injector from holley. any of these cheap efi kits are bound to fail a few times until you get the bugs worked out

Injectors are easy enough to change, you may try the forums or facebook sniper owners group for the part number. I think holley just started selling them al-la-carte.

I had way too many troubles with my Sniper setup.

Define cheap.... my Sniper kit was over $1500. That's not cheap

Go with an MPI setup, that'll define the sniper as being cheap

I've got about $1500 tied up into mine between the pump, unit and fittings. It's been on the car for three years now, so well outside warranty. What little I've been able to find it looks like the injectors are proprietary and Holley won't sell them separate. I really don't want to send this back to them for service. Car has been down long enough.

I was gonna post that, but someone who lives in America that owns/knows how to weld aluminum would say how you "only" need to buy the ECU and everything else can be found for free

Yeah that looks like one injector is sticking open or something. Could be a wiring issue. Take the sides of the Sniper off and carefully check the connectors. Sometimes the connectors come undone or partially undone so that could be the problem. If it is just the connector then you can snap it back together and be good to go.

You can pop the injectors out and take them to a local injector cleaning service. Around here we have Doctor Injector, not sure what you have back there. I don't remember what the injectors come out of, but they aren't a Holley unique part. They are some sort of production injector.

I have spare injectors on hand so if you determine that you have a bad injector just shoot me a PM and I'll swap it out for one of my spares.

$1,500 is cheap compared to what you'd have to pay for each part of a factory set up, plus all the engineering.

Did you call Holley? They have always sold single injectors for past systems. Would be good to know if they will not sell them as I would go another direction.

Not yet. This just happened late Saturday. I'll give them a call tomorrow afternoon and report back.

I really appreciate that Andy. I'm going to call Holley first and see if they sell them without having to send the unit in.

Took the injector out tonight and it doesn't look bad. Plug was still fully seated in the injector too.

I'll post back after I hear from Holley tech support tomorrow.

You cant visually look at an injector and tell if its bad. You probably have some trash in it and its stuck open.
Are you running a proper fuel filter(s) for fuel injection? My bet is dirty fuel caused your problem, not a failed injector.

Could you just do a test with a gravity fed push of fuel (or something safer) and activation current applied to the injector? I cannot imagine that wiring one up would be all that difficult...just need the proper harness?

My thinking is: if the injector delivers fuel once activated than it must be something else that's causing the problem.

Yeah, I got the Sniper master kit that included the pump and the pre/post filters. At time of install I also ran all new hardline and made my own pickup with a new sock.

I made a homemade injector cleaner years ago. I used one of those pump up garden sprayers, cut the spray nozzle off and hose clamped the hose to the injector input. A couple of jumpers with alligator clips and a battery to cycle the injector. Filled the prayer with cleaner, in this case MEK, pumped it up, opened the injector and let it flow.

Something is making the injector flow. Usually injectors are wired with a constant switched 12v and the ECU cycles the ground. If that ground is shorted then the injector is always on.

Since you got that far then just swap the suspected bad injector with the one next to it and try it. The problem will either follow the injector or it will stay with the throttle bore. If the problem stays with the throttle bore then you have a wiring or circuit board problem. If the problem follows the injector then you have a bad injector. If the problem goes away then you have something else going on. Once you do the swap test you'll have a much better idea of what the actual problem is.

Swapped from front to back and it seems to be behaving itself. This is damn weird. I'm going to button it up and start it after I change the oil.

I'd be double, triple, quadruple checking that wiring.
Also depending on how it's plumbed and where the filters are, a miniscule piece of anything inside the line or hose beyond the filters could have hung it open. I typically hard plumb everything, deburr the ends and blow compressed air through both lines and hose just before install. This one would make me nervous for a while unless I found the reason for it happening

Alright, spoke too soon I guess. That hole wasn't spewing gas because the injector wasn't firing. The first time I put it back together one of the pins didn't line up properly. The plug itself is just a couple of pins free floating - no molded plastic to keep them centered. After assembling it a second time it started spewing gas out the barrel that had the original problem. This is after swapping the injectors front to back. Has to be electrical, but I couldn't find anything glaringly wrong with it. Back to Holley it goes. Already have a return label. Thank you everyone for your help.

By doing that test you proved that it was a problem with the injector driver circuit so Holley tech support should have been willing to do an ECU swap. If you hadn't done that test then they would've played 20 questions with you. Once you are able to prove that it isn't an injector problem then it gets easier to get a swap. Bummer on the whole thing since it chews up time but that kind of stuff happens. Parts fail sometimes.

So I'm a bit confused ( not unusual LOL)

Is that with another injector or the same one? I assuming a different Injector as you're now suspecting an electrical issue.

SNIPER earlier mentioned he believes they are fired off a ground signal. If so, just out of curiosity, I might try to disconnect the signal wire at the ECU to see if the injector shuts off. That would confirm 2 things. It is the ECU, and that you do not have a pinched wire or other erroneous problem.

Was this the first time firing up in the 3 years you have had it?

No, it was running in the fall. Originally took it apart to swap valve springs as the builder had the wrong ones in place. Sniper unit sat on the top of the car over the winter.

Had the original problem of the rear passenger barrel blowing fuel all over the place. Swapped injectors front to back on Andy's suggestion and observed it wasn't doing that anymore. Upon further inspection though I noticed the passenger rear injector wasn't firing at all. Turned out I didn't plug it in correctly (pins float and aren't held in place in a molded plug). After I corrected that mistake the original problem came back with the passenger rear barrel blowing fuel again. This was with the injectors being swapped, so I can only conclude now it's an electrical fault since the issue didn't follow the injector.

Look for short to ground on the trigger wire for that injector. Typically all the injectors share a common power feed (+). The injectors are turned-on (activated) by supplying a ground to the individual injector. Each injector has it's own driver in the control module (typically). This is the case for your set-up. Simply unplug the the offending injector and back-probe each wire in the terminal. You can front probe if you're careful to not damage the female terminal in the connector. It's really easy to permanently spread the terminal with a probe from the DVOM lead so it's best to back probe the connector. You can use a small t-pin to slip past the weather seal.

First measure for voltage at each wire at the injector connector KOEO using battery ground terminal for DVOM common. One should read source (battery) voltage, the other should read zero, or may fluctuate in mV. Probe the terminal that reads source voltage. Next, move the DVOM common lead from the battery negative to the other terminal in the injector plug. If you read anything other than zero or a floating mV then the trigger wire/terminal/driver in shorted to ground. Unplug the harness from the PCM/controller to help isolate the location of the fault and use the resistance function on the DVOM. With the harness unplugged from from the controller both leads should read OL (over limit or out of limit) when measured to battery negative. Turn the key off before you unplug the harness. You may also want to wiggle the harness to see if the problem is intermittently grounding and to help locate the location of the short.

If you don't have a dvom you can use a 12v test light or a small 12v bulb in a bulb-socket with a couple of leads. If the bulb lights-up when connected to the injector terminals then you've got a shorted trigger wire.

Chances are the wire is pinched or has melted somewhere in the harness.

but I beat you to it LOL

I believe I beat both of you.

Just an update. Holley called yesterday and repaired the unit. Faulty injector driver. Cost me $250 seeing as how it was out of warranty. I'm happy though. Only took them a week to turn it around and they covered shipping there and back.

Glad you got it fixed.
Price seems a little high? How old is the system, and what does a new complete Sniper cost?

New unit is $1k. Mine is three years old. The tech said they replaced the logic board too.