68 cuda 383. that is driving me nuts. just built the motor got it back in and while it was out replaced the voltage reg, and complete new harness from firewall out. it has elec. ignition. try to crank it and no spark. changed coil, pick up, ignition box, ran continuity on wire from ecu to coil and dis. checked all connections. cleaned them and used dialectic grease on every thing. have hooked hot wire from battery to coil +. ran ground from battery to ecu. i am out of ideas. when it does crank it runs great, no issues. and after it cranks it will crank for the next 3 or 4 hours. let it sit over night and it will not start. what am i missing
another no spark sometimes
- Thread starter wesleydax
- Start date
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Intermittents can be TOUGH
Next time this happens, get out your meter or at least your test lamp.
Clip your meter on the coil+ to ground, and insure you have "same as battery" when cranking, USING THE KEY. Do not make this test by jumpering the starter relay
If that is OK, put your lamp (or meter) on coil NEG and crank, and see if you can determine if it's "pulsing" on/ off there
Inspect all connectors, pull them apart, push them in/ out to scrub them, and "feel" for tight connections.
If you can get it to run, do a "wiggle" test on the ECU, distributor, and ballast connectors, and wiggle the harness in general. Wiggle the bulkhead connector.
Make SURE the rear of the ECU and firewall are clean, and use star washers under the bolts. It is a good idea to make up a no12 or larger jumper from the block to one of the ECU bolts, and to one of the regulator bolts.
How does the distributor look? Shaft play? You know how to set the reluctor gap?
Next time this happens, get out your meter or at least your test lamp.
Clip your meter on the coil+ to ground, and insure you have "same as battery" when cranking, USING THE KEY. Do not make this test by jumpering the starter relay
If that is OK, put your lamp (or meter) on coil NEG and crank, and see if you can determine if it's "pulsing" on/ off there
Inspect all connectors, pull them apart, push them in/ out to scrub them, and "feel" for tight connections.
If you can get it to run, do a "wiggle" test on the ECU, distributor, and ballast connectors, and wiggle the harness in general. Wiggle the bulkhead connector.
Make SURE the rear of the ECU and firewall are clean, and use star washers under the bolts. It is a good idea to make up a no12 or larger jumper from the block to one of the ECU bolts, and to one of the regulator bolts.
How does the distributor look? Shaft play? You know how to set the reluctor gap?
Inertia
Well-Known Member
Is it possible your accelerator pump/choke aren't working, and that you're not getting fuel cold ?
Sorry, had to ask..
Sorry, had to ask..
checked coil voltage on + side with meter and comparing to battery voltage im dropping about a tenth. by reluctor im guessing thats the pick up? if so i set it at .010 but reading here i see .008 is recommended. havent checked for pulse. i will do that and break out the jumper wires and ground everything
i have visually checked for fuel by working the accel. linkage by hand. it floods easy. one thing i forgot to add. i replaced the switch because the motor would kick. go from start position and not crank, back to run and then when you went to off the engine would kick like it tryed to fire.
The wiring comming to and going out from your 68 ignition switch is suspect. There is a blue wire with white tracer that originally went from the igh' switch to a weld splice in the harness. One branch goes to the instrument panels gauge voltage limiter. Another branch went to the orignal voltage regulator. We add the ign controller and more to that wire expecting it to supply enough current to everything.
Look into a later model wiring harness and you'll find all of this is a larger gauge wire, including to and from the ign switch. We can accomplish the same with a relay and better power source.
Th original dark blue w/white would still power the inst panel and only signal a realy outside the firewall.
Am I sure this is the problem and the cure ? Heck no, I'm just guessing.
Look into a later model wiring harness and you'll find all of this is a larger gauge wire, including to and from the ign switch. We can accomplish the same with a relay and better power source.
Th original dark blue w/white would still power the inst panel and only signal a realy outside the firewall.
Am I sure this is the problem and the cure ? Heck no, I'm just guessing.
With a brass feeler gauge I hope, if not you can damage the pickup coil.
yes brass, thats why i set it to .010 its the only brass one in the bunch.
you might check out the thread I had on something similar Mopar ECU Orange Box Strange Issues , 73ABodEE put in a 4 pin ECUwiring schmatic and I had a wire hooked up wrong, there's also a 5 pin wire schmatic in there, good luck
BillGrissom
Well-Known Member
To close the loop, explain a bit more. In the single ballast setup, there are 2 connectors (not wires) going to the ballast. I see no way that reversing them would make any difference. Do you have a dual ballast? If so, one is 0.5 ohm and the other 5 ohm, so if you swapped the resistors used it would matter. However, the connectors are keyed to prevent that. Kind of silly to upgrade points to the old dual ballast setup today. Indeed, simpler, cheaper, and better to install an HEI module and forget ballasts.
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