LS1 plug wires
Thread Starter
Staging Lane
Joined: Feb 2016
Posts: 70
Likes: 6
LS1 plug wires Hello all. LS newbie here....formerly Ford guy. Recently purchased a 2002 Z28 1SC with 44k on the clock from a friend. Been chasing knock sensor codes for awhile, even after he installed new GM ones with harness before I bought it. SES light sometimes goes out by itself after running its internal knock sensor test routine. Noticed the original owner (my friend was the 2nd owner) installed MSD wires. Took it to the car wash today and all hell broke loose. Idle got rough, SES light came on blinking, threw codes for random misfire and #2 knock sensor. Misfire went away after driving for awhile. So my question is this........should I just go with a new set of Delco wires for this thing? I've heard of a few different reasons for intermittent knock sensor codes (including loose exhaust flanges, which I am not ruling out but believe I have)....wondering if my ignition problem is adding to my issue. What say you all?
TECH Senior Member
Joined: Jun 2016
Posts: 22,291
Likes: 3,616
From: Central Cal.
I say check EVERYTHING you can think of even REMOTELY related to any of this. Check ALL grounds. Check as much of the wiring as you can for cracked or missing insulation. What affects cars like yours is not the low miles, but TIME, which deteriorates materials that might normally get replaced before now when more miles pile up.
Thread Starter
Staging Lane
Joined: Feb 2016
Posts: 70
Likes: 6
I shall do so. Just how picky are these engines when it comes to aftermarket parts? Other than the SLP lid, it's bone stock. I have no problem with going all GM......20 years experience with Fords and Mazdas have taught me that some items are better off being left OEM.....
TECH Senior Member
Joined: Jun 2016
Posts: 22,291
Likes: 3,616
From: Central Cal.
You are gonna find these engines don't need much to really get going! Being a 2002, it already has the LS6 manifold. But before I go further, what are your goals for this car? Daily driver? Stock "plus a little bit"? Or a 500HP stormer? You tell me.
Thread Starter
Staging Lane
Joined: Feb 2016
Posts: 70
Likes: 6
Its a daily driver. Being a M6 1SC it has the 3.42 posi, and the original owner added some SLP bits (air lid, exhaust, skip shift eliminator) and an LS7 clutch. I don't see me doing anymore to this thing....its fun enough 
And I'll probably take the advice on the Delco LS2 wires.
And I'll probably take the advice on the Delco LS2 wires. TECH Senior Member
Joined: Jun 2016
Posts: 22,291
Likes: 3,616
From: Central Cal.
Your best bet is 1) just get it TOTALLY sorted out, then 2) make minor tweaks to the whole thing to let it "be all it can be"! A GOOD alignment job, possibly a good tune, as it does have some aftermarket stuff that should have the engine "tuned to". Enjoy! You have a very fun car!
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I've never had problems with the MSD wires and personally I love them because you can bend the boots off of the headers and they will hold in place. I wash engines often at the shop as part of oil leak repairs and some get water in the boots some don't. Having it run bad after washing it is part of washing engines. Pull each wire off and check for water. While there inspect them close for any damages, replace as necessary.
The knock sensors, they usually have issues due to water build up around them. I would pull the intake and inspect them again even though they are supposed to be new. If either of them is rusted then water has gotten in there.
The last time I washed my truck motor I got water in the plug wires and on the knock sensors. The problems stopped once it dried out.
In the future, don't high pressure spray the motor, just rinse it with low pressure and stay away from under the intake.
If you pull the intake and check and or replace the knock sensors, put silicone around the rubber plug and around the wire for the knock sensor to keep water out.
The knock sensors, they usually have issues due to water build up around them. I would pull the intake and inspect them again even though they are supposed to be new. If either of them is rusted then water has gotten in there.
The last time I washed my truck motor I got water in the plug wires and on the knock sensors. The problems stopped once it dried out.
In the future, don't high pressure spray the motor, just rinse it with low pressure and stay away from under the intake.
If you pull the intake and check and or replace the knock sensors, put silicone around the rubber plug and around the wire for the knock sensor to keep water out.
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If you end up replacing the knock sensors put a horse shoe beed of silicone around the fronts of each boot. That way if water gets in there it goes around and fall off the back of the valley cover.
Just do it all the way around. Moisture can still work it's way in there. And a full circle of silicone is gonna divert water just as much as a half circle, but it'll seal out all instead of most.
I’m only suggesting what a gm mechanic friend told me per a TSB. And he said not to seal them completely. There are other write ups on the subject.
Launching!
Joined: Nov 2010
Posts: 250
Likes: 0
From: Houston, Texas
-KP
+1 If you seal them completely, it will be almost impossible to get them off again, and you'll ruin the plug in the process.
If they're partially sealed they will be hard to pry off also. A scraper blade or razor ran around the silicone takes care of that no problem anyway.
I can see the logic in it, it diverts water but doesn't completely seal it off to allow moisture to escape.. I assume that's the thing with the recommendation anyway. But a cheap *** new harness would be the best thing honestly.
Thread Starter
Staging Lane
Joined: Feb 2016
Posts: 70
Likes: 6
I've never had problems with the MSD wires and personally I love them because you can bend the boots off of the headers and they will hold in place. I wash engines often at the shop as part of oil leak repairs and some get water in the boots some don't. Having it run bad after washing it is part of washing engines. Pull each wire off and check for water. While there inspect them close for any damages, replace as necessary.
The knock sensors, they usually have issues due to water build up around them. I would pull the intake and inspect them again even though they are supposed to be new. If either of them is rusted then water has gotten in there.
The last time I washed my truck motor I got water in the plug wires and on the knock sensors. The problems stopped once it dried out.
In the future, don't high pressure spray the motor, just rinse it with low pressure and stay away from under the intake.
If you pull the intake and check and or replace the knock sensors, put silicone around the rubber plug and around the wire for the knock sensor to keep water out.
The knock sensors, they usually have issues due to water build up around them. I would pull the intake and inspect them again even though they are supposed to be new. If either of them is rusted then water has gotten in there.
The last time I washed my truck motor I got water in the plug wires and on the knock sensors. The problems stopped once it dried out.
In the future, don't high pressure spray the motor, just rinse it with low pressure and stay away from under the intake.
If you pull the intake and check and or replace the knock sensors, put silicone around the rubber plug and around the wire for the knock sensor to keep water out.
I say check the plug that they go into on the back side of the intake. I'd start there and run that wire back to see if there are any nicks or pinches from previous work.. being the sensors and harness were changes once and the problem didn't change I would start there.. plug wires are most likely very far from being the cause. Almost all wires are the same in my opinion when it comes to aftermarket. I like the MSD and have never had a problem with them.. ohm any of them out with a meter and you will get .2 ohm which is perfect resistance and continuity.. doesn't get any better than that.. never seen a wire not ohm the same.
Just noticed the misfire happened after plug wires were changed.. thought it was the same issue as before.. in that case id check the wires to make sure they are seated and clicked on all the way.. then for the knock sensor issue I'd check what I mentioned above.