well, I damaged a wire changing plugs (they were pretty stuck, 5 years since last plug change).

So........wanted to get it done, so I grabbed a set of Premium
Bosch wires. Bosch makes the plugs for AC Delco, and I use all their stuff for the old Mercedes, so I figured there was even a good chance they actually made the AC Delco wires for them too.

WRONG. They looked fine, but when I did a quick resistance check, I found one wire with 320 ohm, and the other 7 wires read from 4000 to 6000!!!

I'm sure the car would run and not miss and probably be fine with that much wire resistance; but the 2000 FSM called for 700 ohm max; and there's gotta be something going on with Bosch's quality if there is that kind of resistance spread among a wire set.

So, ordered the GM red performance wires, and they came pretty quick,
they all ohm'd 730-740, very tight spread.

Now, about the 700 ohm max in the manual. The original wires on the early C5's had 320 ohms; but when they changed to the 0.040 gap and the iridium plugs, the wires went to 730 or so.

 

Good thing you checked them before installing them. That is one heck of a spread on the resistance.

 

x2, good job checking them out not many people are aware of even doing that... msd has had a bad reputation for this as well, I experienced it on my own car with a brand new set... I had 1 wire at like 2k ohms right out of the box... msd makes good stuff and a friend of mine told me that their problem is in the way the wire is crimped, this could be the case with the bosch's you had... when I relocated my coils I built my own wires using bulk msd wire along with their boots and terminals and I crimped them the way my friend suggested and they all came out great

 

I've also seen this with multiple sets of MSD wires.

 

Checked a new set I just bought, reading 6 were reading 2k ohm 2 were 400 ohms , they are going back to Rockauto

 

Thanks much.
This post brought good news to me, not that I am happy about the problems with your wires, I was glad I stumbled into a good buying decision when I bought the GM red wires.
PLus I now know to check the resistance against specs when replacing wires.

I didn't have the guidance of deep knowledge, I never even thought to check resistance, and don't have a repair manual .

I have considered getting the manual at times, but was concerned it might be too technical to be of much use for me. I am more of a Chiltons manual level of understanding. I know the dealerships have their top guy with factory training working out of these books. Do you have any advice about the usefulness of these books for a low skill guy ?

My buying decision was influenced , in part, by an old jag that was particular about plugs, something I had never seen before. Without the internal air gap in the factory stock Champion plugs, the ignition didn't work as well. Weird but true. I do know that electrical systems need balance, and I guess the old Lucas design was sensitive to any change. Ngk, my usual brand, was a strike out. Ever since then , I leave the ignition as it left the factory.
I had a few other learning experiences trying to modernize a system that wasn't broken.

The other influences on my buying decision were more direct. Posters here said the GM red wires fit the best, and a couple of hired gun restorers out of Texas, brought in for a museum event, spelled it out very clearly for me. Always buy factory parts unless cost is an objection. Made things simple, although my goal is maintenance, not restoration.

I know this post in needlessly long, and all about me. Just trying to offer something in return. I mean , some guys, me, dig reading about old spark plug problems. I even saw a display of antique plugs that had a fascinating variety of design.

 

The books are, IMHO, extremely useful in that they answer many of the kinds of questions people post here. In fact many times, I have read a post and thought, Go read the manual! They are a bit off-putting at first, purely due to the size and the format, which is a follow-this-procedure approach, meant for reliable trouble shooting. They do tell you how to remove and replace things, which is very useful.

Personally, I could not imagine owning a box of rolling electronics like the C5, without having them to hand.

 

I guess you are right, one of the first things I realized was the simple need to understand how to remove the various fasteners. Guess how I learned, error, the less popular branch of DIY. I will work on my price objection.