Has no spark, have changed the rotor, coil and distributor
Mar 20, 2006 at 10:40 AM
1986 GMC Truck
1986 GMC
MISU3266
- MEMBER
- 2 POSTS
Advertisement
Check for input power at the coil-no power backtrack it to the ignition switch. Power there check out the ignition control module
Mar 20, 2006 at 10:52 AM
If no spark occurs, check for the presence of normal battery voltage at the battery (BAT) terminal in the distributor cap. The ignition switch must be in the ON position for this test. Either a voltmeter or a test light may be used for this test. Connect the test light wire to ground and the probe end to the BAT terminal at the distributor. If the light comes on, you have voltage to the distributor. If the light fails to come on, this indicates an open circuit in the ignition primary wiring leading to the distributor. In this case, you will have to check wiring continuity back to the ignition switch using a test light. If there is battery voltage at the BAT terminal, but no spark at the plugs, then the problem lies within the distributor assembly. Pick up coil, module, and/or coil should be tested.
Good luck and let us know. :)
Good luck and let us know. :)
Mar 20, 2006 at 10:59 AM
Try this stick a Tach/Dwell meter to the Tach terminal on the distributor, if the needle fluctuates it means the ICM is okay, its closing and opening the primary circuit.Check the coil and cap contact button.
BTW do you have power to the coil.
Note: The ICM is like the Ignition Point Contact it opens and closes the Primary Circuit. The Magnetic P/U and Reluctor is the one that tells the ICM when to do its job.
BTW do you have power to the coil.
Note: The ICM is like the Ignition Point Contact it opens and closes the Primary Circuit. The Magnetic P/U and Reluctor is the one that tells the ICM when to do its job.
Mar 20, 2006 at 9:54 PM
🔧 Tools & Auto Repair Parts
Find automotive tools, diagnostic equipment, and replacement
parts for your next repair.
Shop on Amazon →
Paid affiliate link. As an Amazon Associate, we earn from qualifying purchases.
Suggested Repair
With the ignition ON, check for battery voltage at the coil and the distributor BAT terminal. If there is no power, trace the primary ignition wiring back to the ignition switch. If power is present but there is still no spark, test the ignition control module, magnetic pickup, coil, and distributor cap contact button; a tach/dwell meter on the tach terminal can show whether the module is switching the primary circuit.
Conversation Summary
A 1986 GMC truck has no spark after the rotor, coil, and distributor were replaced. Experts recommend checking power at the coil and distributor BAT terminal with the ignition on, then tracing an open circuit back to the ignition switch if voltage is missing. If voltage is present, they advise testing the ignition control module, pickup coil, coil, and cap contact button.