1999 5.7 350 vortec P0304 cylinder 4 misfire

[Orpedcrow]

1998 CHEVROLET K1500 Davis Unified Ignition 36100BL Davis Unified Ignition Cap and Rotor Kits | Summit Racing

Free Shipping - Davis Unified Ignition Cap and Rotor Kits with qualifying orders of $109. Shop Distributor Cap and Rotor Kits at Summit Racing.

www.summitracing.com

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[Schurkey]

The Achilles heel of these systems (original coil in cap HEI) is the rotor... ...Standard/Blue Streak finally came out with a DR318X rotor that is made of stouter plastic with higher dielectric strength, and these will last longer under heavy use.

The original GM HEI rotors were made from black plastic. They developed a reputation for what we called "Punch-Through", where the insulation value was low enough that the spark grounded directly through the plastic.

GM issued at least one bulletin denying the problem.

Later, they "improved" the rotor and made it out of white plastic to be immediately identifiable.

Naturally, the bottom-feeder aftermarket suppliers began making white rotors out of thin, cheap plastic. The proper aftermarket suppliers made quality parts out of white plastic, and Blue Streak sold even-better rotors (and caps) made from blue plastic. I used to love Blue Streak parts.

The most-recent Blue Streak item I bought was a "Ford" solenoid for starter and ignition. Same shade of blue-colored plastic...made in Communist China. I sent it back.

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Wild guess--Every brand of Vortec cap with a vent in it, is made in the same factory to the same specs. Buy the one that costs less.

DUI gets lots of attention, but far as I can tell, they MAKE nothing. They buy in bulk from the usual suppliers, perhaps do some in-country QA, assemble and repackage it, and potentially tune the distributor advance curves.

 

[socal k1500]

Im going to go with the rock auto one. Your right they all look the same but this one is cheapest. If the summit one had a good warranty id go with that.
In this adventure of mine with this recent repair i broke pretty much every spark plug wire holder / separator. How important are these? My wire routing isnt great they are criss crossing over the top of each other

 

[HotWheelsBurban]

Im going to go with the rock auto one. Your right they all look the same but this one is cheapest. If the summit one had a good warranty id go with that.
In this adventure of mine with this recent repair i broke pretty much every spark plug wire holder / separator. How important are these? My wire routing isnt great they are criss crossing over the top of each other

Wire routing is very important! Particularly on the #5 and #7 (back two on driver's side bank) because they are next to each other in the firing order.

 

[socal k1500]

Wire routing is very important! Particularly on the #5 and #7 (back two on driver's side bank) because they are next to each other in the firing order.

if the wires are insulated how does the routing affect them? is it because they are such high voltage they can interfere with each other?

 

[HotWheelsBurban]

if the wires are insulated how does the routing affect them? is it because they are such high voltage they can interfere with each other?

Yup! Especially if the wires are old. The insulation breaks down over time.

 

[Orpedcrow]

if the wires are insulated how does the routing affect them? is it because they are such high voltage they can interfere with each other?

Eddy currents

 

[socal k1500]

changed oil ran truck for about 20 minutes, temps good. Oil psi good, cmp retard was 3.8 degrees at 2krpm

Truck still misfires at idle cylinder 4 shows misfires. The misfire at idle isn’t enough to set a code the count is very little and if you give it gas it doesn’t misfire.

 

[socal k1500]

Seems like it runs exactly like before. So I’m wondering if it is my valves

 

[socal k1500]

My plan of action for right now is to put the new cap and rotor on the blue one and then also get the cam retard as close to zero as i can. I ordered a new dizzy hold down clamp thats like the OEM one and allows for minor adjustment. the one that came with my dizzy locks it into place and its obviously not within spec.


from there if nothing changes I guess next step is to just save up money for new heads.


the truck doesnt throw any codes and drives fine 90% of the time. It idles slightly rough its probably safe to drive right as long as i keep an eye on my coolant and oil levels and temps?