Sniper EFI + Dual Sync - No Spark (was a driving truck)

[KyleSeal]

On Tuesday, I went out to start my '67 and it would not start at all. Cranks over, seemingly strong, but no spark - not even a slight kick off.

So I will lay out all the information I have:

ISSUE: no spark at all when cranking

Base info; 1967 C10, 350 V8 / 700R4. Sniper 1, Dual Sync distributor. Boyd Fuel Tank with in-tank fuel pump. New American Autowire full harness. Optima red top battery (dual post as Holley suggests).

Handheld data (when cranking):
-Fan 1 & 2 - OFF
-AC Shutdown - OFF
-CTS, *F - 98
-IAC POS% - 58
-AFR, A/F - ranging from ~15.2 - 14
-Battery Volts - ranges from 10 volts (millisecond at 9.8) but seems to show consistently 11.2 volts (when cranking) - WHEN THE KEY IS IN THE 'ON' POSITION, NOT CRANKING, BATTERY IS 12.3V
-RPM - 140-148
-CL Status - OpenLP
-Learn Status - NoLearn

Testing done:
-Inline tester on coil wire to cap - no spark when cranking.
-Pulled white wire as per diagnostic tree provided on the dual sync, grounded white wire, inline spark tester shows (seemingly strong) spark.
-Checked fuses - nothing blown.
-Checked connections, pins, crimps, no issues, burns, loose connections or melted connectors noted or seen at this time.
-Checked inside distributor - no burning or damage noted
-Replaced with good ignition coil - no change
-Tested for power at the positive wire to ignition coil on a test light - tests good

Background information:
-This was a running truck the day prior, ran good and quite solid I might add.
-I did have an issue on the way home the last time I drove it, the truck randomly died without event, and I coasted to the side of the road. Smelled fuel. Inspected under/around truck, no leak, truck restarted and ran fine. The key was left on during the coasting I did, and AFR went super lean (I suspect the Sniper thought it was still running so it was still recording). Never lost electronics (radio, headlights, dash)
- I was still in learning mode, as the truck just got to running in June, and this is a Sniper kit that had never been run, I bought it back in '21 with hopes the truck would be on the road earlier than now.
- I replaced the oxygen sensor the weekend prior due to AFR going rich when in overdrive and throttle applied.
-I had noticed for a few weeks, when the truck is at operating temperature, the IAC will sometimes surge up to 50-60% randomly and try to 'push me through a stop sign' when stopped. It would almost sound like a camshaft surge, to liken it to something.

Tasks I performed when installing the Sniper + Dual Sync combination:
-Sized alternator through American Autowire with my given accessories.
-OHM'd each plug wire after building
-Referenced all wiring diagrams
- NEVER guessed at wire placement, always consulted tech or a known good shop
-Power & ground directly to battery
-Kept all wiring from RFI potential areas
-12v crank wire to a 12v crank source (as confirmed by American Autowire tech)
-Shielded all wiring subject to head with either Earls heat shielding or other heat resistant sleeving
-Visually checked for fuel at throttle body
-Can hear fuel pump prime/run when key is actuated, sounds normal as it did

My suspicions I am trying to either disprove or confirm:
-Either a bad ECU and I am lucky I made it home with hot dinner, so far I do not see any at home tests for the ECU
-A battery with low cranking voltage.

At this time, this is all the information I have. Keep in mind, this truck cranked, ran and drove for multiple weeks before this issue occurred.

[Shifty One]

Being a low-tech guy, I'd make sure of the battery's voltage.

Is there a ballast resistor/resistor wire?

[KyleSeal]

Originally Posted by Shifty One

Being a low-tech guy, I'd make sure of the battery's voltage.

Is there a ballast resistor/resistor wire?

No ballast resistor here - to my knowledge the CD box delivers all spark commanded by the Sniper.

I have been charging the battery, so once I get home today I will see how it cranks with the battery 100% charged.

[KyleSeal]

Well, after 3/4 of my lunch on hold, I was able to reach a Holley tech. He was very pleasant, and it was a great conversation. We reached the conclusion that there is most likely a failure in the ECU. He stated a rough idea of 6-8 weeks, potentially more. For me, that is far too long to be without, especially since this would put me past the Triple Crown, which I want to take it to. So I believe a Sniper 2 is in my near future.

[Shifty One]

Did they mention potential reasons for the failure?

[RustyPile]

Originally Posted by Shifty One

Did they mention potential reasons for the failure?

X2.. That question screams to be answered.. I hear/read this complaint about Holley not offering a flow chart or diagnostic procedure for their Sniper systems. "well, it sounds like the XXX is broken"... Every experienced mechanic knows that guesswork is not a diagnostic procedure..

KyleSeal, did the Holley Rep offer any steps that will verify his guess prior to buying another ECM??

[KyleSeal]

Originally Posted by Shifty One

Did they mention potential reasons for the failure?

Originally Posted by RustyPile

X2.. That question screams to be answered.. I hear/read this complaint about Holley not offering a flow chart or diagnostic procedure for their Sniper systems. "well, it sounds like the XXX is broken"... Every experienced mechanic knows that guesswork is not a diagnostic procedure..

KyleSeal, did the Holley Rep offer any steps that will verify his guess prior to buying another ECM??

The rep himself did not really offer any extra means to diagnose - but as you can see I did do quite a bit myself before calling.
I think the warning signs for me were an erratic IAC, and killed an O2 very early on.
The main 'diagnosis' that lead me to believe the ECU failed is that the white wire, when grounded, will create a strong spark at the distributor. Since the Sniper controls spark when using a dual sync distributor, this would indicate either a dual sync dist issue, or a Sniper issue, and since the handheld shows RPM when cranking, indicates the Sniper is at fault.

But - come saturday, I will have the Sniper 2, and will update if it runs at that point.

[Shifty One]

Your Sniper I wasn't that olde, was it?

[KyleSeal]

The truck runs!

The Sniper 2 was truly a quick swap. Would have taken way less time if I had a TH350, but setting up the TV cable was a difficulty, which would be with any carb/EFI TBI setup swap.

The throttle is way smoother, far more 'foot tunable'. And honestly I will miss the gold (they no longer offer it) but I do really like the polished look. This also looks far closer to a Holley double pumper, which to me is a bit more retro.

[Shifty One]

I'm glad you're rollin', but it kind of irks me that the Sniper 1 dumped so early (in it's using-life)....premium names (and premium-priced) should not have this kind of crap happen.

[biketopia]

The sniper 1 was a problem chile from the instant it came to market. The sniper 2 seems to improved on many of the common failures & shortcomings of the original.

[KyleSeal]

Originally Posted by Shifty One

I'm glad you're rollin', but it kind of irks me that the Sniper 1 dumped so early (in it's using-life)....premium names (and premium-priced) should not have this kind of crap happen.

Originally Posted by biketopia

The sniper 1 was a problem chile from the instant it came to market. The sniper 2 seems to improved on many of the common failures & shortcomings of the original.

Oh yeah, I definitely wasn't happy with the Sniper 1 failing. Super annoying - especially after doing all of my due diligence and making my full system as problem free as possible. But unfortunately sometimes that is the game we play with this stuff. Stinks but I am just glad to be back on the road.

The Sniper 2 really does fit the bill of the needed improvements and honestly, though I was sad to lose my gold unit, the polished one is a nice addition. Kinda actually makes me want to throw a bigger cam and some headers on it now that it looks like a double pumper.

[biketopia]

Originally Posted by KyleSeal

The Sniper 2 really does fit the bill of the needed improvements and honestly, though I was sad to lose my gold unit, the polished one is a nice addition. Kinda actually makes me want to throw a bigger cam and some headers on it now that it looks like a double pumper.

Do it!! I have a terminator stealth system that I ran on my camaro and will run on the truck. It looks like a double pumper but charcole. It ran like a top, but it also uses the Dominator ECU and has every bell and whistle as far as tuning ability. I'm thinking of a cam change before it goes into the truck, although over 500hp was fine.