How to Change the Spark Plugs and Wires in a Corvette

Learn how to change the spark plugs and wires in a C4 Corvette with an LT1 or LT4 from 1992 through 1996. This is a job the every day person can do and save yourself some money! This also applies to the LT1 and LT4 Camaro, Impala, Caprice, etc.
How to Gap the Spark Plug: • How to Gap a Spark Plug
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Disclaimer:
Due to factors beyond the control of ChrisFix, I cannot guarantee against improper use or unauthorized modifications of this information. ChrisFix assumes no liability for property damage or injury incurred as a result of any of the information contained in this video. Use this information at your own risk. ChrisFix recommends safe practices when working on vehicles and or with tools seen or implied in this video. Due to factors beyond the control of ChrisFix, no information contained in this video shall create any expressed or implied warranty or guarantee of any particular result. Any injury, damage, or loss that may result from improper use of these tools, equipment, or from the information contained in this video is the sole responsibility of the user and not ChrisFix.

[@kevincamacho5350]

It’s absolutely insane that you made this video when I was 8 years old and now it’s helping me with my corvette. Thanks a million for getting me into cars and for all your great videos that have helped me.

[@moodberry]

This is hands down the best video on YT explaining how to replace wires and plugs on a C4. I really liked how you anticipated questions and showed the "hard parts" without wasting time showing everything. Yes, this video is 10 years old and you have likely moved on. Oh, and at the end showing the graphic was another great bonus.

[@chrisfix]

I'm glad the video is still helpful all these years later! Thanks!

[@moodberry]

Yes! And one other thing. Do you have a video series only on the C4? If so, can you link me to them? Thanks.

[@getoffmydick777]

​@@moodberryfr @crisfix could you make a playlist wit all ur old c4 videos? Theyre so helpful!

[@chrisfix]

Sweet! That was the whole idea of the video! To allow fellow Vette owners to see what they need to do to get the job done!

[@marks146]

I owe you a beer. Thanks. All your Corvette videos are priceless.

[@CoderSal-XIII]

I purchased a Snap-On magnetic spark plug socket set (PN 206SPKPLGMAG) a while back and it proved invaluable for changing the plugs on my '94 C4. It made the job so quick and easy. Make sure to first blow out the area with compressed air BEFORE removing any spark plugs. If you do not own an air compressor at home, at least a leaf blower will suffice. Anything to blow out any foreign material that could potentially fall into your cylinders.

[@24GarrettFPS]

Thanks so much. 10 years later still a great video. Couldn't find anything this detailed on this engine, and just picked up a '95 z28 camaro. thank you once again.

[@assetallocationshow8629]

Just did a 93 Vette with the help of this video. You rock Chrisfix. Always good informative videos.

[@vetteboy-5324]

That #8 plug was like wrestling a bear,, Thanks for all the C4 videos.

[@chrisfix]

+Vetteboy- 53 Haha, yea it is tight in there. No problem!

[@TheMickhowes]

Really helpful, thanks for these vids. Just got my 92 on Saturday after 15 years with a C3. Awesome car. UK Vette owner!

[@martydonovan777]

Really Hoe much did u pay for yours

[@zachdoster1206]

I change the spark plugs in my grandpa’s 1941 Studebaker once. I’ve learned a lot about fixing cars from you keep it up Chris.

[@dolnick7]

I'm in the middle of doing this job at the moment. Just finished the passenger side. The plugs I took out were burned down to the electrodes; I guess the PO didn't relish tackling this job. Tough but doable. Can't wait to drive my car with fresh plugs! (My other car is a 1980 MGB. Changing the plugs on that is a joy.)

[@marioacosta-ps5qp]

I took my time today. I finished the passenger side. Tomorrow I’ll tackle the driver side. Thanks a bunch for great suggestions that do work.

[@marioacosta-ps5qp]

What helped me was to remove the tensioner and a pulley. Both in fact needed to be replaced. With them out of the way I could easily see the driver side Optispark plug wire connections. Thanks again for your encouragement.

[@chrisfix]

hahaha, thanks man! Put them to good use! That's why I made them, to help others!!! Glad it worked for ya!

[@geneyus6411]

Probably the best video on KZbin about this topic. Maybe why the guy has almost 9 million subscribers😯 A lot of the other videos are a joke compared to this!👍

[@Honeycombs91]

I successfully changed the spark plugs in my '94 this weekend. This video was invaluable help!

[@chrisfix]

AWESOME!!!! I am glad the video was helpful and you change your plugs!!!

[@akyelarda]

You improved the quality drastically! I watch every seconds you share.

[@jamescarson4087]

Update, I figured a simple hack to get all the Driver's Side boots on the Optispark. Just unbolt the Tensioner Pulley and remove it, (16 mm bolt) this gives you much more room and leverage to get the boots on #1, #7, #3 and #5. I found that a 16 mm box wrench works best to get the Tensioner bolt off, as I didn't have enough clearance between the frame member and the bolt to get a ratchet on it. Also, another hack for installing the #8 plug: Slip the plug into a magnetic 5/8" socket, face forward, lean over the right front tire and with your left hand, reach back with the socket and plug with your wrist turned outwards. This worked the first time I tried it after numerous failed attempts. (and choice swear words.)

[@zabalarick]

Dude...Your the man! Thanks so much. I have a 96 Vette and was having the hardest time with the wires on the driver's side.

[@chrisfix]

Thanks man! Exactly, it's so rewarding fixing your own car!

[@larrysmith5581]

Nice video. A little helpful idea is to use a fine point Sharpie to mark the boots or wire with the correct number as well. If you want to get fancy, there are marking bands, rings, and labels available from MSD, Accel, and many other sources.

[@chrisfix]

Glad to help man! That is why I make these how to videos!!! It is such an easy job, but also such a frustrating one!

[@lorenhyung2296]

I just did this job myself. Removing the belt tensioner pulley itself was a huge help as it gave much more room to get your hand at the optispark on the driver's side.

[@ethanwatters8704]

Thanks Chris. Good content and the diagram at the end is very useful. Firing order is a bit important.

[@davedavis775]

I loved doing plugs on my 96 LT1. I purchased a 3/8s , 90 degree ratchet from Mid America made to help with changing the plugs. It sits in my tool box and I haven't used it since 2006. My 91 ZR1 is easier to change the wires and super easy to do just plugs. Being that the LT5 is a hemi the plugs sit right on top of each cylinder. It's not that hard to pull the plenum to change out coils and wires.

[@josephgibbons1631]

Chris Fix.....best how to car vids out there. I have a 94 C4 and your Corvette segments have been a great help. Can you do a video on replacing weatherstripping on the doors? The inner door panel needs good weatherstrip to seat right.

[@JP.7605]

I was 7 when this video came out now it’s helping me with my vette😂

[@hasbeengood]

Well done. Thanks. The fun in the hobby is all about finding creative solutions. Not once are you affraid of the next challenge. Keep it up.

[@mytruckinlifeace4047]

This was before you had a good tool collection. You’ve come along way.

[@StartupStudcom]

You're awesome man. Third time you've saved my butt with a C4 guide.

[@ChrisScratch]

Great video, I never would have guessed that panel pops out on the driver side wheel well.

[@steffydog]

Wow, what a mission, well done Chris, thanks for the excellent video.

[@matt911112]

Thx replaced all this yesterday and now my engine is running new. Just a word of advice. My 92 LT1 looks a little different in the ASR area. When I removed it I broke a small vacuumed line under it so might wanna warn them of that. It was a real easy fix though.

[@corvettecoupe3731]

Can't imagine a header swap on an LT1 Vette because it's so damn tight! I've owned a lot of performance vehicles in my 50 year span on this planet and my 95' Vette tops it...

[@chrisfix]

Corvette Coupe Yea, it is a little tight. Not too bad, but not as open and easy as it should be! The C4 is a great car!

[@geneyus6411]

I realize this was one of your first videos but when applying anything on spark plugs, you don't need to gunk it on. A few small dabs of whatever product you want to use, then roll your finger or Qtip around the threads. To much of that anti seize globbed on can make it's way to the plug electrode and ground out the plug. To much of that silicone globs up the connections, causes mis fires.

[@ragalMX]

I am training a snake to help me to reach those tight place

[@chrisfix]

lol

[@squiggle2054]

cool to see chris reply to comments on his 6 year old vid

[@2025944]

I'd almost say it'd be faster to pull the fucking motor

[@rushtk2112]

Will you rent him out 🙏 plz

[@chrisfix]

It's not too bad. Especially since it wears out only once every 15yrs. Worth the coolness of hide-a-ways!

[@marioacosta-ps5qp]

Where do the two wires go that have straight ends? The six others have angled boots for the spark plugs. Thanks for great videos

[@TheMickhowes]

Thanks for the quick reply, it is only the main display (speedo, fuel into etc) nothing else is affected. I am hoping it is something simple like earthing or poor connection, tapping the screen as I say sometimes clears it, as does hitting a bump in the road, will have a go on the forum as you suggest.

[@transam8607]

Just a little tip for number 8 spark plug I used a vacuum hose at the tip of the spark plug lined it up in the hole and I started twisting the vacuum hose to get it started or till it Bottomed out then I use the ratchet to tighten it down it can save a whole lot of time you're welcome just give me a thumbs up

[@danielmckenzie6858]

Chris you are awesome, I need to pull out spark plug 1 to get to TDC to put the harmonic dampner back on, you turn a nightmare into a a scary thought. I had to replace the new distributor i put in 8 months ago and put the old one back in, which only needed a cap n roptopr rep[lace

[@hondamancl450]

Chris i have been watching your videos for years now enjoying all of them 📹 that opti spark location bad design by GM 💧 water pump right over it

[@chrisfix]

No prob! Glad they are helpful! I make more as I fix things lol.

[@chrisfix]

No problem! Hope it helped out!

[@chrisfix]

Well the Corvette team from Chevy did an awesome job. LOL

[@gabou1370]

a v12 would be so much fun :o

[@icanjuggle]

great video.. very clear. Haven't started yet but doing my Power Steering pump and water pump at the same time so I should have even more room. Still haven't actually seen my Opti yet...must be under there somewhere. Bad place to put it for such routine maintenance.

[@chrisfix]

Ty Tojo Juggling Thanks man! The opti is hiding under and below the water pump.

[@chrisfix]

No prob! Glad to help!

[@ohmanbretbmods1059]

tackled this today... Thanks for the video ChrisFIx!.. Not sure if mentiond yet but if you go ahead and remove the tensioner 1( 14 mm bolt) makes things nearly as easy as passenger side;)

[@chrisfix]

+Ohman Bret bmods Awesome! Glad the video was helpful and thanks for the tip!

[@sanford1471]

very helpful, I have a 94 also that i will be doing come spring, your tips will make the job go alot smoother for sure

[@hossamali8536]

Chris you are the man hop all the best for you

[@mendels1536]

Chris why do you sound like it's a burden in these old videos in the new ones you sound extremely enthusiastic

[@DIYLukie]

$$$

[@positronicreflex.]

Helped me alot on my 96, thanks.

[@getoffmydick777]

was just bouta run this for my LT4 96, so its still all tha same?

[@positronicreflex.]

@getoffmydick777 Yeah, pretty sure

[@anthonydalessio3435]

Outstanding vid sir..

[@chrisfix]

Thanks and no problem... This was the hardest video I ever made... so hard to explain what to do and to get into the tight spaces with the camera!

[@orenkrief]

woooow good job man the best .its the first time i see how to do the driver side

[@sgwhite4]

Helped a bunch, thanks for sharing Chris.....

[@chrisfix]

Great! Glad the video was helpful!

[@WildRose_Weaponry]

Awesome video need to more of the corvette!😃

[@markarcher5730]

Such a big help mate. Thank you

[@lindyp38]

Where did you order the plugs from? I’m interested because you mentioned they are individually numbered. Thank you

[@JDPINTERNATIONAL]

Please Chris! make a video on how to change the Optispark on the LT1. They eventually all go bad on every LT1. I have a 1994 Camaro Z/28 and I’m thinking of changing it in case one day it just ceases to work.

[@huskybrushape]

JDPINTERNATIONAL That would be a mistake, if your optispark is working don’t change it, you could install a new one and have it go bad, chances are new could go bad sooner than the one you have now that’s working ,very common. As far as an opti goes if it ain’t broke don’t fix it

[@delhenry9837]

@@huskybrushape Before thinking the optispark is the issue with your car problem, check the Ignition Control Module (ICM) and the Ignition Coil located on the upper right front of the motor. I went through this nightmare of being told by 3 different professional dealers that the optispark needed replacing on my '95? GM dealers did not want to do the job because no GM part was available anymore and the record of after-market optisparks had very high failure rates. There was nothing wrong with my optispark, the ICM was the issue. If replacing the ICM, make sure to find a GM part, as I went through two after-market parts from O'Reilys that failed. NOW, if replacing an optispark, go to Petris Enterprises, Scottsboro, Alabama. They make a great optispark that I installed thru all of this nonsense of not checking the ICM first. If you have to replace the optispark, call Petris...

[@Ottonic6]

Nice thing about using a spark plug socket. Not only does the rubber protect the ceramic, it also aids in gripping the spark plug for easy removal.

[@Ottonic6]

to be correct i meant to say "aides" in gripping the spark plug.

[@garryhall2828]

Dano C. II

[@BATMETALOCALYPSE]

ChrisFix, your C4 is the only other one online I can find that only has 3 cables going to the ASR box instead of 4 that have a Transmission Throttle Cable as well. Why do ours only have 3 and how do I adjust the slider on the throttle cable to the ASR box to it's proper position as in calibrate it.

[@pantera1973]

Excellent job. :-) Thank you for taking the time & trouble to video this.

[@mickaellequint3075]

Merci du français ! Thanks for this vidéo thatt helps me alot. Mickael from France

[@chrisfix]

I am glad the video was helpful!

[@PatrickACoico]

Chris, Great video. I have a '94 Corvette and I am getting all the parts together to do the wires and plugs along with the Optispark and the waterpump, coil and ICM. My question is as an update to this older video.... What are your thoughts on using anti-sieze on spark plug threads now that they are applying special platings to the threads. I know most plug manufacturers are now saying DO NOT use anti-sieze on the plated plugs. I plan on using NGK TR55-IX plugs in my Vette. NGK has a tech bulletin out advising NOT to use anti-sieze. Thanks again. Great videos on the Vette and all your others. BTW, do you still own that Red '96 Vette that was in your waterpump replace video ?

[@alirahman4762]

What is the correct opinion on cleaning spark plugs that were running on rich mixture? should it be done or would it ruin anything?

[@chrisfix]

Great! Glad the video helped!

[@sdcoinshooter]

Chris, I wish you lived next door to me, my 95 Vette and I would have a sense of inner peace knowing you were there to help. Ever think about moving to San Diego? Ol buddy ol pal? 😁

[@Nobr8ks305]

Hey man! Great video. Truly helpful. It was able to concur the driver side with ease by accessing the option spark from underneath the car. After all, I’m experiencing some issues. The engine stalls & stops after starting & going into gear. Trying to diagnose it myself before handing it over to pros. I came across a 9th spark plug wire below the throttle body. I was curious why there were ten wires but only eight plugs. But now I see there is a 9th to replace but not a 10th. Do you have an idea or is that in fact an “extra?”

[@chrisfix]

Thanks a lot! I believe the 2 extra wires are connected to the coil terminal and electrical harness, but it might be different depending on the exact configuration!

[@Nobr8ks305]

Hey. So I replaced the 9th wire which connected to the 9th port on the optispark looked around but can’t find where the 10th wire would go. Can you recall for sure that it in fact takes 10 wires? My car was stalling immediately after going into gear but now that I’ve changed that 9th wire, it hasn’t stalled or given me any issues since. Lol I’d really like to be done with this task

[@jonrandall5490]

Thanks for this video, Chris. You are always clear and precise. You might freshen up on the correct names of some of the tools you are using so you don't end up calling a socket a ratchet, etc... but great video !

[@chrisfix]

This is an old video (one of my first) so things are a little different with the new ones ;)

[@johnreece8102]

Very helpful, thanks

[@moodiblues2]

Chris you and I have similar tastes in cars as I have a 94 vette and a 2002 Tbird and Mustang. Do you know anywhere to get new parts for the vette? I’m losing capabilities in mine such as ABS, antislip, cruise control, ac controls, and tire pressure sensors due to lack of parts. My mechanic, the most knowledgeable in my area won’t put used parts on my car.

[@chrisfix]

This is tricky. Does anything else go crazy (Climate control, information center above the climate control, radio, etc)? Might want to ask the people on the corvetteforum. They are helpful for specific stuff like this.

[@JoseFuentes-th9ut]

Hey Chris I wanted to know if you can post something (vid or just text) on how to test or rule out a problem with the optispark on a C4 LT1. Thanks!

[@chrisfix]

What are your symptoms? Misfiring is the most common issue.

[@marioacosta-ps5qp]

Thanks. I need help with the frame rail Ground strap attaching point. It is supposed to go somewhere on the engine. Mine appears to be held on with a self tapping screw attached to the catalytic converter bracket. Where is the correct attaching point ?

[@everydayinterviews615]

I could swear I have this exact corvette by those hashmarks down the side of the driver fender is this an automatic? Mine is in Tennessee

[@Skaarjy]

On my 92 there was a second metal pipe leading from somewheres. It was preventing me from pulling the wires across the pulleys like you did. However, completely removing the belt tensioner was the answer. Once it was out of the way you had a clear shot of the optispark and could pull the wires straight through. Also the heat protection looks very pathetic, thin plastic that tightly wraps around the cord. I will be replacing that with something more effective.

[@chrisfix]

Interesting, thanks for sharing!

[@geneyus6411]

That plastic on the wires isn't really a heat protection, more likely to prevent chafing. I'm surprised Chris didn't mention that to you.

[@RobPrice-x9o]

Taking off the belt tensioner gives plenty of access to the opti wires on drivers side !

[@chrisfix]

Yea, it is the first time you do it. The second time it isnt as bad!

[@chrisfix]

Not really. They sell the larger diameter ones, but they wont fit very easily. Plus, the resistance of the wire is different, and since the Vette has a fiberglass firewall, you could get interference with your radio. Stock wires are the way to go. Corvette did an awesome job designing this car so...

[@jamescarson4087]

Chris: Great video, very helpful But....how did you get the Driver's Side plug boots on the Optispark? I managed to get #1, #7 and #3 on without too much cursing, but #5 (Top receptacle) is a bear. I cant figure out how to get it on. Any advice?

[@Wormaldmichael]

Hey Chris, what size wires did you use on your Vette? My car has 7mm. I was thinking about getting 8mm. But they might not fit on the wire holder.

[@corvettecoupe3731]

Getting ready to go in, god help me...🙄

[@DominickNicolai]

Love it

[@cleanprobuildingmaintenanc7155]

Hey Chris, I had my clutch replaced and my 92 base model vette now keeps throwing ASR & ABS messages. In first gear at start up, it pulls back with humming behind me. Can you give any advice? Thanks!

[@tomasgliderpuigjane]

Chrisfix I did all the plugs and the passenger wires. But for the life of me I can't get the wires to come out of the opti spark from the driver side. Do you know of a way to get them unstuck? Thanks Great video helped me a lot. It's a 1996 corvette

[@chrisfix]

tomas puigjane If you can get a thin crow bar or something similar to pry the plugs off, that might help.

[@6capthowdy9]

great vid thanks

[@oscardelaserna9788]

Is that grease the same as the one used in polyurethane suspension bushings?

[@chrisfix]

+Oscar De la Serna yes, silicone grease.

[@chrisfix]

Nice, maybe it just got vibrated off the connection to the dash and you just need to push the connection back in...

[@derickpouliot5548]

Whats the difference in the Corvette LT1 and the Camaro LT1? I have a 96 Camaro Z28.

[@Lucky_106]

Hello new friend here, give me more friends here. Nice to meet you here as a friend. I am watching from Phulippines. God bless

[@glen-ozzstarscars8474]

To install the plug wires on the drivers side would it make sense to remove the idler pulley to gain easier access to the Opti? thanks

[@chrisfix]

I didnt do that, but it might help. If it helps you get your hand in there, then go for it. Its easy enough!

[@brandonherrera2891]

I changed the plugs and wires on my car like 3 months ago. I didn't route them correctly and two of them rub on metal pieces. Saw them arcing last night. Also don't have the wire heat shields. Chris, do you think I should buy the wire heat shields?

[@brandonherrera2891]

Meant to say didn't route them correctly on the wire looms

[@chrisfix]

Brandon Herrera If you route them correctly you dont need heat shields. Even with the heat shields, if they are constantly touching a hot engine piece, they will eventually burn.

[@marioacosta-ps5qp]

I paused the video and noticed that 6&8 are the ones that use the straight plug wire.

[@Cutthroatflame]

Chris I have a 94 Corvette LT1 and every time their is dew or rain it will turn over but not start...it makes a rump noise and shakes like it is flooded. Raise the hood and let it get sun for 10-15 minutes and it starts right up ...Driving me nuts trying to find the problem..Tried LPS water dispersment on all electrical plugs and wires..still does same thing...

[@melonas22]

Colt Brinlee It is the optispark probably getting moisture in it if I had to guess. It could be something else but if I had to guess I would say OPTI because your 94 did not have the vented and more water proof one unfortunately.

[@Sonnywitdamoney]

is it throwing a code and/or check engine light on

[@22putts]

+Colt Brinlee --Its the optispark for sure. had the same thing. Its 12 bolts in total to get to it and get it off buts its a mother. You can save money buying it on line instead of the auto parts store.

[@anubisgodofgods]

GM no longer makes a factory replacement optispark, they have been gone from dealer and parts store shelves for years. Aftermarket opti's are poor quality and they can fail in a very short time. Some have been put in and found to be bad from the get go. Replacing an opti and having it go bad in a week or a month is not uncommon.

[@crazyjkz]

The pre-1995 Optispark distributor had this problem where moisture could gather inside the distributor and cause starting issues during high humidity or rain. For the 1995 model year GM upgraded the distributor with vacuum vents to solve this problem. Many of the OEM and aftermarket replacement distributors will have these vents, so if you replace the distributor with one of those updated versions it should solve the problem.

[@Ottonic6]

What size are those meats (tires)?

[@johnsmithth3318]

Good video but, it is a pia job. I've broken a few plugs taking them out (by using the universal attachment )

[@victorsandoval4154]

Hi Chris I have a 96 and it's all original parts. I want to do a full service on it. Any other recommendations other then plugs and filter's Or anyone else out there can help me out?

[@thomasknight7734]

Personally I’d just disconnect the battery to keep it from dying And shorting

[@GunHoInc]

First thing I did when I bought my Vette several years ago was replace the plugs and wires. Took me two days and a lot of swearing. I dropped the socket numerous times on number eight, and getting to the opti on the drivers side was unbearable. Last month I replaced my water pump, and I could clearly see the drivers side of the opti. It might be a little more work removing the water pump to do the plug wires, but there would be a lot less swearing envolved going this rout in my opinion. Besides, the Lt1 can always use a fresh water pump ever now and then.....😉