The 1947 - Present Chevrolet & GMC Truck Message Board Network







Register or Log In To remove these advertisements.

Go Back   The 1947 - Present Chevrolet & GMC Truck Message Board Network > General Truck Forums > Electrical

Web 67-72chevytrucks.com


 
 
Thread Tools Display Modes
Prev Previous Post   Next Post Next
Old 07-19-2024, 09:48 AM   #1
KyleSeal
Senior Member
 
KyleSeal's Avatar
 
Join Date: Mar 2014
Location: Toano, VA
Posts: 884
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
KyleSeal is offline   Reply With Quote
 

Bookmarks

Tags
efi, holley, no spark, sniper


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 06:37 PM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright 1997-2022 67-72chevytrucks.com