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#1 |
Senior Member
![]() Join Date: Mar 2014
Location: Toano, VA
Posts: 874
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Sniper EFI + Dual Sync - No Spark (was a driving truck)
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.
__________________
"Sometimes I do serve as a good bad example. Glad to be of service." My Build Thread (1967 C10, lowered, EFI, daily truck): http://67-72chevytrucks.com/vboard/s...d.php?t=830809 |
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#2 |
Registered User
Join Date: Dec 2014
Location: Tucson, AZ
Posts: 672
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Re: Sniper EFI + Dual Sync - No Spark (was a driving truck)
Being a low-tech guy, I'd make sure of the battery's voltage.
Is there a ballast resistor/resistor wire?
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1987 V20 farm-hand rescue 1998 C2500 lot-rot rescue |
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#3 | |
Senior Member
![]() Join Date: Mar 2014
Location: Toano, VA
Posts: 874
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Re: Sniper EFI + Dual Sync - No Spark (was a driving truck)
Quote:
I have been charging the battery, so once I get home today I will see how it cranks with the battery 100% charged.
__________________
"Sometimes I do serve as a good bad example. Glad to be of service." My Build Thread (1967 C10, lowered, EFI, daily truck): http://67-72chevytrucks.com/vboard/s...d.php?t=830809 |
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#4 |
Senior Member
![]() Join Date: Mar 2014
Location: Toano, VA
Posts: 874
|
Re: Sniper EFI + Dual Sync - No Spark (was a driving truck)
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.
__________________
"Sometimes I do serve as a good bad example. Glad to be of service." My Build Thread (1967 C10, lowered, EFI, daily truck): http://67-72chevytrucks.com/vboard/s...d.php?t=830809 |
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#5 |
Registered User
Join Date: Dec 2014
Location: Tucson, AZ
Posts: 672
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Re: Sniper EFI + Dual Sync - No Spark (was a driving truck)
![]() Did they mention potential reasons for the failure?
__________________
1987 V20 farm-hand rescue 1998 C2500 lot-rot rescue |
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#6 |
Registered User
Join Date: Dec 2017
Location: Elkhart, Texas
Posts: 1,699
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Re: Sniper EFI + Dual Sync - No Spark (was a driving truck)
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?? |
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#7 | |
Senior Member
![]() Join Date: Mar 2014
Location: Toano, VA
Posts: 874
|
Re: Sniper EFI + Dual Sync - No Spark (was a driving truck)
Quote:
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.
__________________
"Sometimes I do serve as a good bad example. Glad to be of service." My Build Thread (1967 C10, lowered, EFI, daily truck): http://67-72chevytrucks.com/vboard/s...d.php?t=830809 |
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#8 |
Registered User
Join Date: Dec 2014
Location: Tucson, AZ
Posts: 672
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Re: Sniper EFI + Dual Sync - No Spark (was a driving truck)
Your Sniper I wasn't that olde, was it?
__________________
1987 V20 farm-hand rescue 1998 C2500 lot-rot rescue |
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#9 |
Senior Member
![]() Join Date: Mar 2014
Location: Toano, VA
Posts: 874
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Re: Sniper EFI + Dual Sync - No Spark (was a driving truck)
As far as being used, no, about a month of consistent run time. As far as purchase, I bought it in 2022. I really should have waited so I could have had a warranty while it was running but at that point I wasnt sure of my road with the truck, so I got it to get the expense out of the way. All I did was incur another cost at a later date
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__________________
"Sometimes I do serve as a good bad example. Glad to be of service." My Build Thread (1967 C10, lowered, EFI, daily truck): http://67-72chevytrucks.com/vboard/s...d.php?t=830809 |
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#10 |
Senior Member
![]() Join Date: Mar 2014
Location: Toano, VA
Posts: 874
|
Re: Sniper EFI + Dual Sync - No Spark (was a driving truck)
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.
__________________
"Sometimes I do serve as a good bad example. Glad to be of service." My Build Thread (1967 C10, lowered, EFI, daily truck): http://67-72chevytrucks.com/vboard/s...d.php?t=830809 |
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#11 |
Registered User
Join Date: Dec 2014
Location: Tucson, AZ
Posts: 672
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Re: Sniper EFI + Dual Sync - No Spark (was a driving truck)
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.
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1987 V20 farm-hand rescue 1998 C2500 lot-rot rescue |
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#12 |
Senior Member
![]() Join Date: Jul 2015
Location: Warrenton VA
Posts: 1,052
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Re: Sniper EFI + Dual Sync - No Spark (was a driving truck)
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.
__________________
71 c-10 Long Bed, under the knife for a No Limit Engineering Wide Ride Chassis Pack and coil over static drop. 07 Silverado Classic 2wd 95 Camaro 427SBC/TH350 |
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#13 | ||
Senior Member
![]() Join Date: Mar 2014
Location: Toano, VA
Posts: 874
|
Re: Sniper EFI + Dual Sync - No Spark (was a driving truck)
Quote:
Quote:
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.
__________________
"Sometimes I do serve as a good bad example. Glad to be of service." My Build Thread (1967 C10, lowered, EFI, daily truck): http://67-72chevytrucks.com/vboard/s...d.php?t=830809 |
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#14 | |
Senior Member
![]() Join Date: Jul 2015
Location: Warrenton VA
Posts: 1,052
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Re: Sniper EFI + Dual Sync - No Spark (was a driving truck)
Quote:
__________________
71 c-10 Long Bed, under the knife for a No Limit Engineering Wide Ride Chassis Pack and coil over static drop. 07 Silverado Classic 2wd 95 Camaro 427SBC/TH350 |
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efi, holley, no spark, sniper |
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