Changing Spark Plugs/Removing Wiring Connector

[MidwestT4R]

I finally changed the spark plugs on my 2004 V8 and used some of the threads that document how to do so. You can easily find them. The basic steps are as follows:

1. Remove the ignition coil wiring clip
2. Use 10mm socket to remove ignition coil bolt
3. Remove ignition coil and rubber gasket
4. Remove spark plug
5. Install new spark plug and torque to 12 or so ft lbs
6. Clean ignition coil gasket and lube with silicone spray
7. Install ignition coil and bolt
8. Re-attach wiring clip to ignition coil.

I'll comment that it was pretty easy once I got the wiring clip off each ignition coil. That was the real pain in the ass on my car. The car is a 2004 with 185K miles on it. I would press on the tab on the face of the clip to release the catch and then try and pull the clip off. I don't know whether the clip tab is weak or mine are just old, but pressing the tab with my finger and even a screwdriver would not release it far enough to be able to remove the wiring clip. After about 20 minutes or so of screwing around I remembered some auto hose tools I had. I found one of the smaller ones, pushed on the release tab with my finger and gently inserted the tool under the bottom of the clip. The clip then came right off. I had them all off in two minutes. Then I did all the other steps to complete the job. See pics below:


Here is a picture of the tool


This is what I mean by inserting it under the retaining tab. I had to use my right hand to take the pic otherwise it would be in the picture pushing down on the top part of the tab, inserting the tool with my left hand, and then pulling the clip off while my left hand holds the tool in place.

So just use one hand to push on the tab and then gently insert the tool under the bottom of the tab just enough to raise it a bit more. The clip should come right off. BE CAREFUL: Don't jam it in too far and snap off the clip. You only want it in far enough to hold the tab open. It doesn't take much to do this.

Just a few other things I noticed while doing the job.

• There may be a lot of dust and grime on the engine heads. Blow or dust it off before removing anything. You don't want grime getting in the way of the rubber gasket at the bottom of the ignition coil
• Some people put some dielectic grease in the ignition coil to get a good connection with the spark plug. Your call. I did it using a small paint brush. Just a small dab.
• Use a torque wrench or not. One of the other threads said to seat the new spark plug and then go another 1/2 turn. If you don't use a torque wrench, just be careful and make sure it actually seated.
• Tape your spark plug socket to the extension. That way it won't come loose when you pull it out. Nice tip from another thread.
• On my V8 I used a 9 inch extension on all spark plug except the rear drivers side of the engine. That one I had to cobble together some shorter one (maybe 6 inch total extension) because the brake booster got in the way.
• Some people may have to remove the air filter assembly. I didn't because I have a Volant CAI on my truck. It wasn't in the way.

Anyway, that's it. Total time was about 1 1/2 hours. But if I had figured out the hose tool trick right away I think it would have run about an hour. Maybe a bit more. Good luck.

 

[chompster4runner]

I finally changed the spark plugs on my 2004 V8 and used some of the threads that document how to do so. You can easily find them. The basic steps are as follows:

1. Remove the ignition coil wiring clip
2. Use 10mm socket to remove ignition coil bolt
3. Remove ignition coil and rubber gasket
4. Remove spark plug
5. Install new spark plug and torque to 12 or so ft lbs
6. Clean ignition coil gasket and lube with silicone spray
7. Install ignition coil and bolt
8. Re-attach wiring clip to ignition coil.

I'll comment that it was pretty easy once I got the wiring clip off each ignition coil. That was the real pain in the ass on my car. The car is a 2004 with 185K miles on it. I would press on the tab on the face of the clip to release the catch and then try and pull the clip off. I don't know whether the clip tab is weak or mine are just old, but pressing the tab with my finger and even a screwdriver would not release it far enough to be able to remove the wiring clip. After about 20 minutes or so of screwing around I remembered some auto hose tools I had. I found one of the smaller ones, pushed on the release tab with my finger and gently inserted the tool under the bottom of the clip. The clip then came right off. I had them all off in two minutes. Then I did all the other steps to complete the job. See pics below:

View attachment 254446
Here is a picture of the tool

View attachment 254445
This is what I mean by inserting it under the retaining tab. I had to use my right hand to take the pic otherwise it would be in the picture pushing down on the top part of the tab, inserting the tool with my left hand, and then pulling the clip off while my left hand holds the tool in place.

So just use one hand to push on the tab and then gently insert the tool under the bottom of the tab just enough to raise it a bit more. The clip should come right off. BE CAREFUL: Don't jam it in too far and snap off the clip. You only want it in far enough to hold the tab open. It doesn't take much to do this.

Just a few other things I noticed while doing the job.

• There may be a lot of dust and grime on the engine heads. Blow or dust it off before removing anything. You don't want grime getting in the way of the rubber gasket at the bottom of the ignition coil
• Some people put some dielectic grease in the ignition coil to get a good connection with the spark plug. Your call. I did it using a small paint brush. Just a small dab.
• Use a torque wrench or not. One of the other threads said to seat the new spark plug and then go another 1/2 turn. If you don't use a torque wrench, just be careful and make sure it actually seated.
• Tape your spark plug socket to the extension. That way it won't come loose when you pull it out. Nice tip from another thread.
• On my V8 I used a 9 inch extension on all spark plug except the rear drivers side of the engine. That one I had to cobble together some shorter one (maybe 6 inch total extension) because the brake booster got in the way.
• Some people may have to remove the air filter assembly. I didn't because I have a Volant CAI on my truck. It wasn't in the way.

Anyway, that's it. Total time was about 1 1/2 hours. But if I had figured out the hose tool trick right away I think it would have run about an hour. Maybe a bit more. Good luck.

I just did that last weekend using the pick and flat head to pry the clip off. My first time switching on the Runner.

 

[Utah_4runner]

05 V8 4runner

Thanks for the write up. I just did this last week and noticed that the hardest part was getting those connectors off of the coils. Good idea on using a small brush to get dielectric grease on the backs of the plugs.

 

[BlackWorksInc]

There's definitely a "feel" for doing this. It's how I take connectors off of spark plugs because they're notorious for breaking. I use a pocket screwdriver to push the connector off the coil after using a pick to gently lift it up.

 

[MidwestT4R]

Ok, this is purely anecdotal. My spark plugs were long overdue for the change. Now that I have changed them and driven the truck around for a few days I noticed a bit of a difference.

I can't really say I notice a difference in power, but the truck seems to keep to lower RPM's when driving around town. For example, when I am cruising around 45-50 miles per hour the truck is in fifth gear. But when I encounter a hill or some other stress on the engine it doesn't seem to be in any rush to downshift. It just pulls along in fifth at 1200-1300 RPM and goes right up the hill. And that is not solely because I am taking it easy on the throttle.

Yes, I know this is purely seat of the pants stuff. I could be imagining the whole thing. But I wonder if there is actually a bit better combustion going on and that small increase in power has the computer hanging on a bit longer at low RPM's when stressed with a hill or something like that.

The real test will come this weekend when I go on a road trip with a full truck. I will be able to check mileage a bit better to see if there is a meaningful improvement.

 

[Gasmanxj]

Funny I changed plugs a few weeks ago and used the same tool, agreed it makes removal of the connector easy. I also recommend using a torque wrench on the plugs. I found 4 of 8 plugs were loose, 3 of which loose enough to let combustion blow by as evidenced by the discoloration on the plugs/coil boots. I also had ticking noises under the hood which I thought were a manifold but turns out it was the loose plugs, after changed and properly tightened ticking is gone (yea, no cracked mainifolds!). Not sure if they were original, they were correct NGK's and looked like they were older but hard to tell. The previous owner said he never changed them (he got it with 92k on the clock and I just bought it at 104k) but the timing belt and water pump had been changed at the dealership before he bought it so maybe they changed plugs too. Anyway, I'm going to check them periodically now to make sure they are tight!