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Old 03-03-2021, 12:12 PM   #26
crsgmc
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Re: Dead

I used to go with AC Delco, Now, not so much. I will buy ACDelco if the price is not double, and if it seems like a good part. The ICM and coil that I replaced not long ago were AC Delco. Seems they are dropping the China stuff in an AC Delco boxe and selling it for twice as much. I did not buy the AC Delco cap and rotor because the terminals are now made of aluminum. The one that I purchased had good ratings and brass terminals. The reviews are not much good because they don't tell you if the part failed after 10 to 20 thousand miles. Over that period of time people don't provide much feedback. I don't know what failed at this point, but the lack of power out of the distributor narrows it down. I am guessing that it is not a little corrosion or arcing. It totally shutdown going down the road so I am guessing something broke.
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Old 03-03-2021, 03:24 PM   #27
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Re: Dead

Here's a good read:
https://www.acdelco.com/counterfeit-auto-parts
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Old 03-03-2021, 07:00 PM   #28
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Re: Dead

I decided since the weather is nice I would remove the cap and rotor. I did try to attach the pictures I took but the size is still to big even resizing to the minimum on my phone. Looking at the cap and rotor it looks very clean some metal build up on the terminals. The thing that I don't get is if you take the cap and turn it upside down and then visually center the rotor upside down the contact points are not even close. You can feel that you are on the spring and centered visually, the contact is about an 1/8 of an inch from touching the terminals. I thought that they should be really close? At this point I guess I will install the new cap and rotor when it arrives. I have a bad feeling that it is not going to fix the problem. I should get the inline spark tester a couple of days after I get the cap and rotor. If it does not work with new cap and rotor I will check again for spark out of the distributor.
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Old 03-03-2021, 07:21 PM   #29
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Re: Dead

What other components inside the distributor could cause a total shutdown on a 1996 and produce a no spark condition?
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Old 03-03-2021, 07:30 PM   #30
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Re: Dead

One more quick question. It appears that the metal buildup is not centered on the cap terminal. All the buildup is on the right side of the terminal on all the terminals. It is like it is firing after the rotor terminal has passed the center of the terminal on the cap. Hopefully this makes sense.

x cap terminal the metal buildup is on the right side of this x
x

x center of cap
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Old 03-03-2021, 07:45 PM   #31
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Re: Dead

You might have to upload the pictures one at a time. If the coil is firing then the cap and rotor should be the problem.
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Old 03-03-2021, 09:24 PM   #32
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Re: Dead

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Originally Posted by crsgmc View Post
What other components inside the distributor could cause a total shutdown on a 1996 and produce a no spark condition?
The circuits in the cap actually will break. Usually they start running rough first.
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Old 03-04-2021, 10:51 AM   #33
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Re: Dead

You were correct, I tried to upload all of them at once.
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Old 03-04-2021, 10:54 AM   #34
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Re: Dead

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Old 03-04-2021, 10:55 AM   #35
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Re: Dead

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Old 03-04-2021, 11:00 AM   #36
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Re: Dead

You can see from the top view what I was trying to say. If you look carefully the burn area is off the right side of the terminal not in the center.

I made a little diagram in the post above but when it posted it took out the spaces making it useless.
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Old 03-04-2021, 11:04 AM   #37
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Re: Dead

I don't think the cap looks that bad for it to completely shutdown driving down the road. Maybe someone with more experience will think the cap looks really bad. As stated above it could also have an internal break.

Thanks to all that have responded.
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Old 03-04-2021, 12:09 PM   #38
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Re: Dead

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Originally Posted by crsgmc View Post
I don't think the cap looks that bad for it to completely shutdown driving down the road. Maybe someone with more experience will think the cap looks really bad. As stated above it could also have an internal break.

Thanks to all that have responded.
Yeah, generally a bad cap will just make it run really rough. I had an experience (different model year - 1971) where we were camping on the beach and the salt air got to it. I put in a spare set of points and got it started but it still ran awful. About 10 miles down the road it smoothed right out, when the engine heat dried it out. Finally got to a store and bought a new cap/rotor but didn't put it on right away. Same thing: ran rough for a couple miles until it warmed/dried out. Later installed the cap/rotor at a campground and it was fine after that.

When my 89 just shut down going down the road, it was the ignition module in the distributor.
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Old 03-04-2021, 12:12 PM   #39
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Re: Dead

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Originally Posted by crsgmc View Post
You can see from the top view what I was trying to say. If you look carefully the burn area is off the right side of the terminal not in the center.

I made a little diagram in the post above but when it posted it took out the spaces making it useless.
That's normal. Where the burn is is about timing, and if you drive a lot where timing is advanced then the burn marks will be further over.

Those caps fail internally usually. Since you have it off, test continuity between the contact post and the corresponding spark plug wire port. That's where the faliures usually are in the caps. The port is not above the contact on these distributors like the TBI and older, so you'll need to see where they run to or get a diagram.
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Old 03-04-2021, 12:51 PM   #40
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Re: Dead

I tested the cap and got continuity at all connections. Had to scratch the probe on most of the inside terminals to get volt meter to go to zero. Thanks for the tip. I guess I will find out if this is really the problem when I install the new cap and rotor.
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Old 03-04-2021, 02:34 PM   #41
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Re: Dead

One other thing I thought of, although not likely, is the ECM has an issue. Not a common occurrence but it does happen. Did you test the ignition coil yet? You should be able to just test it with a multimeter
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Old 03-04-2021, 03:30 PM   #42
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Re: Dead

He said the coil is firing, the spark isn't making it to the plugs. You can put up to five pictures in a post, you just have to upload them one at a time.

How springy is the center button in the cap? I had a spring break on one and lost spark to the plugs.
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Old 03-04-2021, 05:08 PM   #43
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Re: Dead

This is what I thought happened. That would explain total shutdown. It is not broken and has good spring. Hopefully the ECM is not having problems.
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Old 03-04-2021, 06:57 PM   #44
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Re: Dead

UPS just delivered my cap, rotor, and fuel pressure kit. I noticed that although a different brand, cap looked exactly like the old one from MSD. Exactly alike even the letter on the top of the cap. Installed the cap and rotor and the truck fired right up.

Questions:

What the heck, 14000 miles on a distributor? Not crazy about replacing it every 10000 miles. Do you think that I just got a bad one or am I going to have this again. Is there anything that is causing this problem. More than half the miles were put on the truck with the old coil and ICM. These parts did not fail when I replaced them. Could an old coil or ICM cause this?

I drove a couple of miles and immediately could tell it was different. I know this is going to sound crazy...........but. In the past when I would let up on the gas it tended to engine brake. This happened even if I was low in the gear range. Now when I let off the gas it just tends to glide down the road.

Lessons Learned:

I cannot look at the cap and rotor and tell if it was bad enough to be the problem. Some of you with more experience may see it but not me. I was sure that it was not going to fix the problem. It just did not look that bad. I was obviously wrong.

Thanks everyone for the help. I learned a few things along the way.
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Old 03-04-2021, 07:17 PM   #45
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Re: Dead

Quote:
I learned a few things along the way.
Me too. I really would not have expected a cap to just fail completely like that.
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Old 03-04-2021, 08:58 PM   #46
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Re: Dead

This has been covered before. Those caps are notorious for failing. http://67-72chevytrucks.com/vboard/s....php?p=8437273
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Old 03-05-2021, 10:13 AM   #47
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Re: Dead

You must not have read the link you posted or did not look at the pictures in this post. The posted thread talks about the problems using aluminum for the terminals. My distributor that failed has brass terminals. Don't bring up AC Delco caps and rotors because they now have aluminum terminals. The link had a lot of good information but little in the way of solutions. I was interested in his use of AC Delco cap and rotor and having the same problems. My solution maybe to buy another cap and rotor and keep it in the truck with the necessary tools.

Last edited by crsgmc; 03-05-2021 at 10:58 AM.
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Old 03-05-2021, 12:40 PM   #48
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Re: Dead

Quote:
Originally Posted by crsgmc View Post
You must not have read the link you posted or did not look at the pictures in this post. The posted thread talks about the problems using aluminum for the terminals. My distributor that failed has brass terminals. Don't bring up AC Delco caps and rotors because they now have aluminum terminals. The link had a lot of good information but little in the way of solutions. I was interested in his use of AC Delco cap and rotor and having the same problems. My solution maybe to buy another cap and rotor and keep it in the truck with the necessary tools.
I've read that post multiple times, I even posted in it. Anyway, my point is that those caps are notorious for failing for a variety of reasons. Keep a spare that you tested around just in case.
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Old 03-05-2021, 01:12 PM   #49
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Re: Dead

Unless your cap and rotor look like this, it should run. This was in my truck a year or more ago and the truck died on the highway and would not start. I have been in cap and rotor hell since.

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Old 03-06-2021, 11:16 AM   #50
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Re: Dead

61_FL_Apache, thanks for posting that picture. To my eye that cap looks really bad. I am not surprised that the truck would not run. I had almost no dust and corrosion. I live in SE Wyoming, that humidity is low most of the year, even in the summer when the winter wheat fields are growing it is usually less than 30 percent. I did have some erosion of the terminals and in other areas almost a buildup of metal. When testing continuity I had to scratch the metal to make contact. Maybe that was a sign. I hope I am not headed for cap and rotor hell in the future.
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