454 tbi loping/surge

Here is the pic inside cap. The center coil terminal is charred black also forgot to mention there was a piece of black plastic laying inside top of rotor like it broke off from somewhere

Ok, good luck with rebuild , let us know how it's going

Sadly might not happen for awhile. Leaving for vacation Friday night. Sucks I hate leaving stuff like this not fixed in the garage

docstoy said:

What you can do to ck specific cylinder is to cut some vacuum hose 1 to 1 1/2 inches long, pull plug wire at distributor cap install hose reinstall plug wire. Using a test light to ground you can short each cylinder that may help you isolate or find which cylinder miss is on. Think it's 1/8 inch rubber vacuum line should fit snug in plug wire boot.

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Or blunt the sharp points of 8 small nails, SLIDE the nails between the plug wire and plug boot until you feel the metal terminal of the plug wire. DO NOT PUNCTURE THE INSULATION.

Then you can short-out individual cylinders by grounding one end of a jumper wire; or grounding an incandescent test-light, then touching the other end to each nail in turn.

Well I would like to post a bit of a vindication post to say- I am not a complete idiot! I am finally fixed the truck.

my brand new DUI distributor was junk. I posted how it was burnt. I was going to rebuild my old one, but advance had a new one for $130 on sale, with a lifetime warranty. Dropped it in before I left for vaca and all my problems went away. Truck idles great, no miss.

That's great, glad you found it

Tiger joe said:

my brand new DUI distributor was junk. I posted how it was burnt.

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A failed distributor cap does not mean the distributor was junk.

Update.

Can’t believe I’m typing this, but I got 2 bad distributors. Brand new out of the box.

First I already mentioned- summit DUI dizzy. More than cap was bad. Cap/rotor were cooked. Not sure about ICM. I talked with a mechanic buddy he said pickup coil was probably bad taking out rest of the dizzy. Not good for new out of the box.

Second- day before I left for vacation I bought a “100% new” distributor from advance. The advance auto distributor ran better, much better, but I had a bouncy tach. For the hell of it I swapped ICMs and the problem went away. So a bad ICM right out of the box. ICM is at least easy to swap, but still this junk is brand new off the shelf and not working properly.

By chance, while I was gone, I bought an nos AC delco dizzy off eBay. Thought I would keep it as a spare but when the ICM was bad I said screw it dropped in the ACDelco. This one has no issues worked just like it should.

Now I just need to put some miles on the truck make sure it’s all good.

Ignition modules have always been knocked-off by junk manufacturers. I remember trade magazines from the '70s talking about bottom-feeder HEI modules.

Nearly all "new" distributors are sourced from China...so you can expect the module to be from the lower-end of the quality tier.

This applies to "new" starters, "new" alternators, and so much more.

Yes the advance auto one seemed good after the new ICM. The cap and rotor looked like quality pieces, but I would always be questioning the pickup coil.