Figured out my low rpm chug/misfiring

[L31MaxExpress]

It was the plug wires spacing on the OEM plug wires. Now makes me wonder if that is why it has always ran somewhat rough. I set up a set of aftermarket plug wire looms that seperated the plug wires roughly 2x the distance of the stock wires. I think the ignition wires have been getting random crossfiring for years. 5 & 7 had the most misfire counts and the factory routing has them side by side for most of the length of the wires. I modified the routing on those 2 cylinders to keep them seperate from each other for more of the run. Makes me wonder if crossfiring was some of the weird random knock retard I was seeing even with the stock 350 on the stock tune even.

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[0xDEADBEEF]

Engine masters did a thing on the crossfire theory and debunked it with wires in good condition. Could have just been a bad wire. It does look very nice and neat!

I've got mine all tied together on my coil relocation and no issues so far.

 

[HotWheelsBurban]

They're probably right about old wires, I can definitely see that on a truck as old as ours are, especially if they have lotsa miles on them. I'm sure the wires are original on Rawhide, maybe on the Burb too for that matter. I bought wires for it in November 2018 but only ever got the coil wire changed. Was going to check spacing and crossover and that takes time I never seemed to have....
Maybe I'll get another coil wire and put these on the crew cab..... when it cools off a little. This is detail work and doesn't need to be rushed or F'd up because I'm sweating like I'm running a race. I found out, moving parts to one set of shelves, that I have some extra separators. Won't all be the same color, but I'm not that OCD.....

 

[L31MaxExpress]

Engine masters did a thing on the crossfire theory and debunked it with wires in good condition. Could have just been a bad wire. It does look very nice and neat!

I've got mine all tied together on my coil relocation and no issues so far.

May very well be the problem. This van eats wires as well as a cap and rotor every year or two and always has. The heat causes the ignition components to break down more quickly insulation wise. When it is cooler outside you can barely drive it a block or two with the engine cover off before you get a blast furnace of heat coming out of the engine bay.

 

[L31MaxExpress]

They're probably right about old wires, I can definitely see that on a truck as old as ours are, especially if they have lotsa miles on them. I'm sure the wires are original on Rawhide, maybe on the Burb too for that matter. I bought wires for it in November 2018 but only ever got the coil wire changed. Was going to check spacing and crossover and that takes time I never seemed to have....
Maybe I'll get another coil wire and put these on the crew cab..... when it cools off a little. This is detail work and doesn't need to be rushed or F'd up because I'm sweating like I'm running a race. I found out, moving parts to one set of shelves, that I have some extra separators. Won't all be the same color, but I'm not that OCD.....

I am not too OCD on it either. A couple of those are old, couple are new and they are different brands. The rails were a cheap amazon buy. My only requirements for them was they were solid, not brittle and held the correct size wires.

 

[Supercharged111]

Ever nerd out and ohm the wires? I was thinking the other day when my cap took a dump I should probably at least try that.

 

[HotWheelsBurban]

May very well be the problem. This van eats wires as well as a cap and rotor every year or two and always has. The heat causes the ignition components to break down more quickly insulation wise. When it is cooler outside you can barely drive it a block or two with the engine cover off before you get a blast furnace of heat coming out of the engine bay.

Yes I believe these trucks don't really have enough airflow under the hood in warm climates anyway. And vans never have! Just a trip to the store and back which is less than 5 miles, and I can feel the heat coming out from the grille for a bit after we park. Fan clutch seems to be working, it's a severe duty one. The crew cab has a metal fan on it instead of the plastic 11 blade fan that the Burb has. Seems like the Burb was breathing hot in the warmer weather too though, and neither one runs hot(according to the gauge). Eventually they'll probably both get the auxiliary fan up front like the big block 2500/3500s have.

 

[L31MaxExpress]

Yes I believe these trucks don't really have enough airflow under the hood in warm climates anyway. And vans never have! Just a trip to the store and back which is less than 5 miles, and I can feel the heat coming out from the grille for a bit after we park. Fan clutch seems to be working, it's a severe duty one. The crew cab has a metal fan on it instead of the plastic 11 blade fan that the Burb has. Seems like the Burb was breathing hot in the warmer weather too though, and neither one runs hot(according to the gauge). Eventually they'll probably both get the auxiliary fan up front like the big block 2500/3500s have.

My Tahoe came with that pusher, I set it to run for 3 minutes after shut down if the engine is 195F or hotter to help cool the engine compartment. I need to get the Tahoe back up and running.

I have the heads back from the machine shop after a long period of time waiting, just have not had time to re-assemble the 8.1 and put it back in.

 

[alpinecrick]

L31,
I like your wire looms. Where did you find them?

I think there is a lot more arcing across wires then we realize. Plug wires should probably be replaced more often then we think.

On these 1st gen Vortecs the coil wire naturally lays on the coil bracket, and I have seen arcing there often when checking the plug wires in the dark.
It's fun watching the fireworks show under the hood.......

 

[L31MaxExpress]

L31,
I like your wire looms. Where did you find them?

I think there is a lot more arcing across wires then we realize. Plug wires should probably be replaced more often then we think.

On these 1st gen Vortecs the coil wire naturally lays on the coil bracket, and I have seen arcing there often when checking the plug wires in the dark.
It's fun watching the fireworks show under the hood.......

They are a little thinner than I would have liked, but these are a tight fit as they are. I screwed those L shaped brackets into the stock wire loom bolt holes with 1/2" long steel sleeve tube stock spacers to clear the header flanges.

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