Engine Sniper EFI, no start

[furnsworth]

I have a Sniper EFI in my '84 CJ8 . I bought it post install and it's ran fine since buying it 7-8 months ago. All of a sudden, I am really struggling to get it to start. You click it into position, the electric fuel p

 

[Manic Mechanic]

Is the pump coming on? Is it external or internal pump? Also is there gas in the tank? Not what the gauge says but actually have gas?

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[furnsworth]

I can hear the pump coming on, yes. You turn the key and it primes I guess. I was told to allow it to do that when I bought it. You can hear it whine for 5-10 seconds. It's an external pump. There is gas in the tank, gauge shows half a tank when it started, then I put another 5 gallons in so it's nearly full, no change.

 

[Manic Mechanic]

Second question is there spark? You can check the gas by unhooking the fuel line and turning it on (put the hose into a bottle) it should fill it. If you have fuel pressure reattach the line and check spark

Easiest way to check spark is with a random spark plug plugged into #1 wire and lay it on the valve cover where you can see it while you turn it over

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[furnsworth]

Yes, there is spark from the plugs. Same with fuel, if I crank, it shoots out gas.

 

[Manic Mechanic]

Let me ponder this one for a few moments

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[Manic Mechanic]

Does it try to start or not?

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[furnsworth]

Ok! So since I posted I've replaced spark plugs, wires, rotor, batteries, alternator, starter.

The problem is so random I think it would be tough to take to a shop.

I tested the pump and it's working, shoots fuel every time into the system before you try to crank it.

I tested spark, after replacing everything it's a nice blue arc.

For instance today, fired right up, runs perfect. Drive for 10 minutes, dies, then it will not restart. I probably cranked it, let it sit, cranked it, 15 times and finally it fires up. Then I drive it, shut it off, fires up again, I drive it a bit more, shut it off, then again it won't fire up.

It's getting spark, it's getting fuel, it's getting air and when it runs it feels like a brand new engine.

 

[Manic Mechanic]

Call Holley tech support. I'm thinking if all that is working as it should it could be an ECU issue but you need some data logs to verify or if it's a sniper 2 they should be able to remote into the unit

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[Dakardad]

I have a Sniper EFI also. At one time had a similar issue. After a week of profuse profanity it was fixed. Turned out the EFI unit is sensitive to low voltage. I changed my old battery put new cables on and cleaned EFI connections. Fixed. I now run dual batteries and wired so l can switch electrical power between the two. If l loose voltage in one battery I can switch to the other.
I don’t recommend trying to clean cables etc. just start fresh.

 

[1badcj8]

I fixed my Sniper 1 (after the Computer on it fried) by upgrading to the Sniper 2... It's awesome, just flat out works like it's supposed to. From the jump.

 

[007]

Cold starts good or bad? Have you tried turning off learning / closed loop to rule out O2 sensor issues? Stock ones seem to have a short shelf life, Bosch branded ones seem to be WAY better. Holley will tell you the stock ones are Bosch, but something is different. Gone through too many in a Holley box and only1 in a Bosch box. Lastly you ARE getting spark when it won't fire? Coil / ignition related issues come to mind as well.

 

[Belizean]

My original Holley Sniper O2 sensor is a Bosch one. You know a little about mine and the problems, or at least a couple of mine. Someone in the middle of that suggested I get a new one because of the richness of my engine. So i did and found an exact replacement Bosch in a box. What I didn’t know is the replacement Bosch is giving me bad AF readings on the Sniper Screen. Either too rich or all over the place. So that screwed me up. To many variables at that point.

 

[007]

As I recall, I think we determined you might have cooked your Bosch where it was positioned, and later O2 sensors were placed further down the exhaust weren't they? With a new sensor, fluctuating AFR is most often an exhaust leak where clean air is getting pulled into the exhaust.

 

[Belizean]

Nope. Original O2 is working well further down stream now, where Holley recommends it. The new O2 is causing the fluctuations and showing its burning rich. I also checked exhaust and intake manifolds all around and where the Sniper is bolted to the manifold and around both O2 sensor openings with flammable spray and found no leaks.

 

[007]

Nope. Original O2 is working well further down stream now, where Holley recommends it. The new O2 is causing the fluctuations and showing its burning rich. I also checked exhaust and intake manifolds all around and where the Sniper is bolted to the manifold and around both O2 sensor openings with flammable spray and found no leaks.

So you’re running the original sensor further downstream or the new sensor which is causing you problems? I’m confused.

 

[Belizean]

So you’re running the original sensor further downstream or the new sensor which is causing you problems? I’m confused.

Original further down stream now. New sensor in that location is causing fluctuations of rich and lean sometimes, and the rest of the time rich. Just depends on which it goes to when started up .