99 GMC Sierra Classic (old body style)---What distributor do you suggest?

OldBlueDually

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Gent's, I certainly HOPE this is the right spot to post something like this! Chances are many of you have a truck like this, or have had the same damned issues I have with this era 5.7 Vortec!!

My problem for many years now: Cap & rotor get moisture, causes horrible misfire problem (stuttering & shaking truck), can barely start. When cap & rotor are new, or cleaned up she runs like a champ!!!

I purchased the truck with 60k mileage on it (2nd owner, I know the guy that bought it new). Around 200k (give or take some) it got a horrible stuttering misfire problem. Cleaned up cap & rotor, problem gone! It came back....so I bought new cap & rotor and the problem was gone! It happened again, so I cleaned cap & rotor, problem gone!! It happened again, and again, and again, and again, and again........you get the idea.

So, 2 months back I bought a nice used junkyard distributor/cap/rotor....it has worked fine! Today, we had blizzard warnings, high winds, snow...etc. Drove it to work today and part way there I heard a "pop" occasionally on I-35....then over my lunch hour I had to run an errand with it, and here we are again with stuttering & misfires! Barely made it back to work, could not hardly start the damned thing to come home tonight.

I have searched, and searched and everything I read about new distributors people have issues with them.

This one had way better reviews than the MSD brand;

This one has the best reviews I have seen;

What would you guys suggest for a new distributor??


Here she is back in the day (2003 I believe) with Boyd Coddington wheels, steel cowl hood, stainless trim, nerf bars, dual exhaust, NO RUST, and these pics prior to my windows being tinted. She was the sharpest looking rig in town! Man I spent a crap-ton of money on this baby back then!! Unfortunately the MN rust has taken over now on rockers, cab corners....

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yevgenievich

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I seen someone on gmt400 finding a good billet distributor that was claimed to be decent. I need to try and dig up which exactly was used.
Or 24x and coil on plug conversion
 

Turbo4whl

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A couple questions:

Did you try a new coil?

Is the spark pretty blue or orange/yellow?

Last, is there an AC compressor hose running over top of or near the distributor on your truck? (Factory recall for this issue)
 

yevgenievich

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bucket

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With the later Vortec engines, you really need a quality cap and rotor to avoid the issues you describe. AC Delco or Napa Echlin works well.

When I worked at the shop, it was quite often that a Vortec vehicle got towed in for a no start condition when it was cold and rainy. They often just needed the s hit cap and rotor replaced with good stuff.
 

yevgenievich

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I had a no start issue in any weather due to a bad cap on my 97 before. Was really at a bad time as well. Keep a spare in the glove box now. And working on getting that coil on plug set up
 

OldBlueDually

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A couple questions:

Did you try a new coil?

Is the spark pretty blue or orange/yellow?

Last, is there an AC compressor hose running over top of or near the distributor on your truck? (Factory recall for this issue)

I have a used coil on there now. Changed that a few weeks back after no spark at all.

Spark color, I did not check that.

There is not any hoses running near the distributor right now, nor over the top of it.
 

OldBlueDually

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This is the one I think was mentioned before:


Wow, that is a very nice looking, and looks to be a very well built distributor, I like that it is not all plastic! This one may be worth the investment.
 

OldBlueDually

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With the later Vortec engines, you really need a quality cap and rotor to avoid the issues you describe. AC Delco or Napa Echlin works well.

When I worked at the shop, it was quite often that a Vortec vehicle got towed in for a no start condition when it was cold and rainy. They often just needed the s hit cap and rotor replaced with good stuff.

I have used both of those brands. Eventually the same problem would occur with moisture, then buildup on the electrodes of the cap, then misfires/stuttering.....same old story.
 

yevgenievich

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Recently I tried an upgraded vented cap that seem to be decent so far
 

OldBlueDually

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I did a little reading, and saw a statement that due to the plastic distributor from GM, they eventually get old and just start wearing out. Maybe this is what happened with mine, and with the used junkyard one I put in it??

Either way, what a pain this has been now for years and I am just sick of it. Other than this issue, this has to be one of the best damned vehicles I have ever owned! I now have over $230k on this thing and it is going strong...well, when it runs good!
 

OldBlueDually

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Recently I tried an upgraded vented cap that seem to be decent so far

Speaking of venting, the distributor does have that little screen in the bottom of it, and every time I look at that the screen is clean and no buildup on it. Wonder if moisture is coming up through that??
 

OldBlueDually

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So an update on this guys. Since the last time I drove it when it was having issues I have not touched it. I wanted to work on it today so I was going to move it. It fired up and ran just fine.....hmmmm....

So today I took off the cap to check it out, no arcing, not dirty, no cracks, and electrodes (aluminum) had minor buildup on them. So, I cleaned off electrodes (proper term??) anyhow, cleaned rotor and put it back together.

I also pulled off PCV valve to check that out, it was fine but I cleaned it anyhow.

I then took it out for a spin and beat on it a bit for about 20 minutes so it was good and hot. It ran like a top, ran awesome as it should! However, I park it for an hour so I can clear out the driveway from snow (cold & windy as heck here). I then need to move it so I can clear the other part of the driveway so I fire it up and move it, the damned thing starts missing!!!

I took it down the road and it was doing the same damned thing again!!

Spark plugs are maybe a year old. Plug wires (good ones from Napa, blue ones, lifetime warranty) are also about a year or so old.

I still think it is the cap & rotor on it....I'm wondering if the distributor shaft/housing is just wore out and letting moisture come up into the cap & rotor from the engine....I don't know. Wonder if I should just get a new one, and also get a brand new coil for it too so that I know both are good.
 

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I had similar problems with my K20. Sometimes would lose spark altogether. I found that power wire that plugs into the dizzy was worn out and loose. I cleaned it up and there was improvement... for a while. I didn't have another plug... which is strange because I have several old dizzys ... so I took the plug apart, cleaned of the oxidized metal and 'stretched' the tang to make a better connection. I ended up jamming a little tiny piece of felt to go under the 'tang' inside the plug. Now I had a tight fit! Zoom truck has been running without this issue for a few years since I did that.
So if the power connection to the dizzy is even slightly compromised there will be intermittent issues I am sure.
 

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