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6K views 33 replies 16 participants last post by  powerglide 
#1 ·
I was looking for a set of AC Delco spark plug wire set but for some reason non of the shops I visited had them in stock, so I went to Autozone and picked up some "double silicone" wire set but I ended up returning it cause the guy gave me the wrong K&N air filter:hmm: . Just today I went to NAPA and picked up their "Belden Max" wires and the lady said they're about the same if not better, and it did cost me about 100 dollars. My car is misfiring right now and I want them changed asap, so should I be concerned about using NAPA parts instead of AC Delco like everyone else here say?
 
#3 ·
I was going to get new wires for mine this spring because my seville STS is nearing the 200,000 mile mark. It is running a bit rough and im sure by now new wires and plugs would make a huge improvement. Are AC delco plugs the OEM the best to run in the northstar as well? I wanna buy all the supplies soon and be ready to get my tune up done. Thanks Ranger for the advice on the plug wires.
 
#6 ·
And, if you get a "boxed set" of ACDelco wires, they are "lifetime warranty" just keep your box and receipt:D I keep a folder forevery car in the file cabinet just for this sort of thing.
 
#8 ·
Ranger said:
General concensus is that OEM wires work the best. Best price I found was $122 (shipped) from http://www.rockauto.com. Had them in two days.
Here's a pic of them;) on the box it says it gives better protection than OEM and has a limited lifetime warranty that should it failed before the engine does I can get one free. The jacket is pretty slick like those expensive car/pro audio RCA cables, and the features looks pretty promising...the only difference is these are 7mm cable and the AC Delco is 8mm, not sure what does it mean. it's really cold out today so I'm still trying to decide if I should go with these...
 
#10 ·
7 to 8mm will not change resistance...that measurment only tells the thickness of the insulation, not the core. I have those same napa brand wires on my 94 STS and after 10,000 miles, I'm getting a constant miss at cruising speed...not sure if its the wires, but I have a strong suspicion that they are what is causing my annoying problem. Go with the Delcos!!!
 
#11 ·
Spyder said:
7 to 8mm will not change resistance...that measurment only tells the thickness of the insulation, not the core. I have those same napa brand wires on my 94 STS and after 10,000 miles, I'm getting a constant miss at cruising speed...not sure if its the wires, but I have a strong suspicion that they are what is causing my annoying problem. Go with the Delcos!!!
Well did u changed the spark plugs while at it? I changed my spark plugs with AC Delco and guess what, one of them was defective and went out in less than 30 miles:annoyed: Costed me 140 dollars for the mechanic to figure that out...after this my car never idled the same...but I think it's the wires so thus the topic post:p

I guess what I'm trying to say is are these wires going to rob my power or reliability? I mean they do have a lifetime warranty so I don't think they will just say it for the hell of it, and I always thought OEM parts are unheard of in the high-performance racing scheme.
 
#12 ·
freefaller07 said:
I was going to get new wires for mine this spring because my seville STS is nearing the 200,000 mile mark. It is running a bit rough and im sure by now new wires and plugs would make a huge improvement. Are AC delco plugs the OEM the best to run in the northstar as well? I wanna buy all the supplies soon and be ready to get my tune up done. Thanks Ranger for the advice on the plug wires.
Yes, stick with A/C Delco 41-950 plugs.
 
#17 ·
weister42 said:
Well today I decided to put them in...and yes cured my misfiring problem and it seems to work pretty well(did I mention these wires smell good)! I'll keep an update tho if this wire set fails
So, how's the performance and missfire? I recently did the same, plugs and wires, for the a slight trip at cruising speed and the improvement was great. Smooth at cruising speed and better accelleration.
 
#18 ·
M&N said:
So, how's the performance and missfire? I recently did the same, plugs and wires, for the a slight trip at cruising speed and the improvement was great. Smooth at cruising speed and better accelleration.
So far it's great, my car starts a lot better and no more misfiring, the engine runs STRONG and I just took a cruise on the highway and everything feels smooth...let's just see how long this can last;)
 
#19 ·
I did a plug change a while back...runs great but I have a question as to the plugs: I used the AC 41- 950 @ 0.050 but the book that came with the car and my GM Cadillac service manual for the '98 deville say AC 41-900 @ 0.060.
The Haynes states AC 41-950 @ 0.050 and the only one I can find a 0.060 gap for is the 4.9.
So is the service manual a typo?:hmm:
 
#23 ·
Thanks for the infromation. I had no doubt that I put the right plugs in with correct gap...was just curious as to the difference in the manuals. I bought the caddy used and could not find a emmission lable on it.
Thanks again for the responses.:bouncy:
 
#26 ·
The usual problem with aftermarket wires of any sort is the RFI and EMI....Radio Frequency Interference and ElectroMagnetic Interference...the plug wires carry high voltage and radiate electromagnetic "noise" that can raise havoc with the other electronic systems on the car...including the ignition system itself. The OEM wires are suppressed to avoid any interference with other systems on the car but it is hard to say about aftermarket wires. With all the electronic content on the Cadillacs it is easy to have an EMI problem with the wrong spark plug wires. Common problems are misfiring due to the low voltage crank and cam sensor circuits picking up the radiated noise and causing stray signals to the ignition module and stray MPH readings from the vehicle speed sensor picking up EMI on the low voltage wires. The OEM wires are the only guarantee against problems like this so that is one reason they are recommended. People have often reported problems with different aftermarket wire sets as mentioned above and ended up going back to the OEM wires to fix the disturbance.
 
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