1998 Gen4 V6 Camry Plugs Replace/Change options

[Just Out of Reach]

I see that some people have changed plugs on the rear bank without taking off the plenum and some prefer to take it off.

A)is there anybody that's done it both ways?

B)Is there an advantage to taking of the intake because you can clean out some buildup? IE is it obvious where the gunked up runners are and does anybody agree that this is a problem worth addressing?

C)To do it without removing the plenum, I see this tool list:
10" extention; 6" extention; spark plugs socket; 1 or 2 universal joints or flex
I have a 6" and a 3" extension. Would this work?
[It looks like too long or too short will get in the way]

[BMR]

You're right about it being important to use the correct extension lengths in the correct order. I don't remember for sure how it was for my 3VZ-FE V6, but I think it went, from the spark plug up:

Socket
3" extension
U-joint
6" extension
Ratchet.

All were 3/8" drive; dunno if that's important.

What I do remember for sure is that the extension above the socket must be just long enough to be even with the top of the valve cover.

[BMR]

...forgot to answer your other Q's.

I've done it both ways. On my 3VZ, removing the intake plenum/manifold is a royal PITA. I suspect it's the same on your V6. It's wwaaaaaaayyyy easier to change plugs without removing it.

Is it worth removing so it can be cleaned? Depends. If you've got a lot of miles on it, and you want to eke out every last HP it can deliver, yeah, do it. It builds up gunk from the EGR and PCV gases that pass thru it. Sludgy-gritty-oily film on the walls, can't miss it.

That's my 2 cents anyway.

[Just Out of Reach]

On cleaning it out, is there a specific spray solution or something available that people here like?

[Just Out of Reach]

Tearing into the engine intake looked daunting, after identifying all it would take, so I opted for just changing the plugs.

The trick was in having the extensions in the correct order (and probably having smallish hands).

It was crucial to duct tape all joints together and when I tested my plug socket on a new plug, it was obvious that it wasn't going to be tight enough so I had to pad the inside with some tape.

Only two are hard: the rear bank center and the rear bank driver's side.

For the rear center, getting the wire off is the hardest part. I was able to just fit my hand in there and pop it off but one guy here suggested a BBQ fork and that would have been my next move.

In this picture you can see a PCV hose and a wire attachment that are in the way and will likely need to be moved as well as the plug wire clip (bottom center) and the Diagnosis plug. I have them on in this picture for detail. You can see the wrench in the center plug hole:



The sequence for the 3/8" wrench on the center plug was:
Socket>3">U-joint>3">U-joint>6">Driver
This puts the wrench in this position:


You can reach in and guide it with your hand:


The sequence that worked for the driver's side was:
Socket>6">3">U-joint>Driver
But rather than snake it in, it needed to be assembled at the hole, in two halves, from the driver's side of the vehicle.
You might be able to reach through the hole in the intake with a tool to pop the wire

The passenger-side rear plug is easier to get to as long as plug-wire clips are removed. Socket>3">U-joint>Driver

I doubt I was able to torque the new ones in as hard as they were when coming out. My understanding is that they shouldn't be torqued all that hard anyway. One plug broke coming out (couldn't tell when/how). I used the NGK Iridium that were rec'd here rather than the OEM double-tip platinum.

Since I didn't remove the plenum, I sprayed the throttle body out and brushed it inside with an old toothbrush taped to a stick.

Improvement was noticed.
--------
Can somebody explain the system for me: why do the plugs on the front bank have an additional electric unit but the rears don't?

[BMR]

Originally Posted by Just Out of Reach

Two are hard: the rear bank center and the rear bank driver's side.

Yup. My 3VZ V6 is the same way. The one closest to the passenger side is a lot easier than the two you mentioned.

Can somebody explain the system for me: why do the plugs on the front bank have an additional electric unit but the rears don't?

Those are ignition coils. Your 1MZ V6 has one for each front plug, and each one also supplies high voltage to the rear bank spark plugs. They fire simultaneously. Called a "waste spark" system because one cylinder gets a spark fed to it when it's in its exhaust stroke; "wasted". It's harder on the plugs because they fire twice as often as necessary, so it's recommended to use dual platinum plugs so they'll last longer

[Just Out of Reach]

Originally Posted by BMR

Those are ignition coils. Your 1MZ V6 has one for each front plug, and each one also supplies high voltage to the rear bank spark plugs. They fire simultaneously. Called a "waste spark" system because one cylinder gets a spark fed to it when it's in its exhaust stroke; "wasted".

Cool, thanks. I knew those packs were coil/senders but now that you explain it I can see how they're routed to the rears. Is the "one cylinder" always the same; I.E. they're wired in pairs?

Wouldn't firing during the exhaust stroke waste some of the EGR?

Originally Posted by BMR

It's harder on the plugs because they fire twice as often as necessary, so it's recommended to use dual platinum plugs so they'll last longer

Oops, I opted for the Iridium. Will they not last as long? Should be newer technology.
Was anything gained in the double-electrode technology?

[BMR]

Originally Posted by Just Out of Reach

Cool, thanks. I knew they were coil/senders but didn't see how they would route to the rears. Is the "one cylinder" always the same; I.E. they're wired in pairs?

Yup. If you follow one of the rear plug wires it'll go to one of the front coils. I'm not sure which, but it'll be a pair of cylinders that are both at TDC at the same time, one in its exhaust stroke and one in compression.

Wouldn't firing during the exhaust stroke waste some of the EGR?

I don't think so, but I'm not very knowledgeable about EGR systems.

Oops, I opted for the Iridium. Will they not last as long? Should be newer technology.

I think those are good. Maybe someone else can chime in?

[Just Out of Reach]

Originally Posted by BMR

I don't think so, but I'm not very knowledgeable about EGR systems

I guess it wouldn't because at that point there's no oxygen left in the cylinder. (The EG has to collect oxygen on its way back through).

Originally Posted by BMR

I think those are good. Maybe someone else can chime in?

OK. The reason I ask is because there's a white sticker under the hood that says "Only use double-tip platinum; do not gap".

One person (I think on this site) reasoned that that info is now outdated and you can use NGK Iridium now.

As for gapping, the new plugs came at .039" and the NGK site says to gap at .044" so I widened them. I thought that was strange, that they didn't come pre-gapped; have always heard that narrower gap makes "less work" for the spark to arc. I figured the sticker was referring specifically to the double-tip type, though.

The idea with Iridium is that they would last longer (no other advantage over OEM), but I didn't consider that the double-tip design might have something to with the Wasted-Spark design?

When the quad-tips first came out I fell for the hype and spun them into my Supra engine. They noticeably stunk and I had to take them out. Since then I've went with the standard j-electrode.

EDIT::
I found this and it sounds logical:
"Platinum plugs are designed to last longer and be consistent for smog control, not perform better. You get best performance with copper plugs replaced or reconditioned every 20,000 miles, but it requires owner responsibility thus platinum plugs were developed because people as a rule abuse their cars when it comes to maintenance.

Iridium offers better conductivity than platinum (which is not a good conducting metal) combined with highest possible lifespan."

If that's the case, and given the PIA changing plugs on this model, then Iridium sound like a good trade-off. Some people say, however, that NGK Iridium IX last half as long as OEM Platinum.

[mabmab12345]

Here is a link to some pics I took of my spark plug / manifold removal on a '93 Lexus ES300 (3vz-fe) engine.

http://www.clublexus.com/forums/es30...d-removal.html

[slpr1mz]

i took my plenum off. its' actually really easy and just looks like alot. don't b afraid of doing things the right way. it'll give you a chance to clean the plenum, egr and even behind the throttle body. the biggest pain was removing the mounting bolts on the passenger side of the plenum. its just a tight squeeze. i also recommend buying some copper metal gasket spray.

and also i had a problem w/ the single pronged iridium which didn't happen at fisrt but slowing started to become a problem. i think the plugs where too hot and burning the plugs out. so i switch back to the NGK platinum dual pronged. so much better response and fuel economy.

[slpr1mz]

Originally Posted by BMR

I don't think so, but I'm not very knowledgeable about EGR systems.

the EGR system AKA exhaust gas re-circulation was designed as a smog control device. When the engine temperature in the combustion cylinder reaches a vital point the gasses from the molecule NOx. when N bond w/ an O ion. this combination it a great pollutant and under normal condition a Catalytic converter slows the Exhaust down enough to re-heat the gasses so platinum can bond w/ the Nx. but when the heated O2 sensor along w/ the ECU indicates there is an over abundance of NOx the valve in the EGR opens to re-burn the exhaust gasses slightly increasing combustion chamber temperatures so the Cat can effectively finish the combustion cycle.

[JohnGD]

The NGK plugs should have come pre-gapped. You might have purchased the "generic" ones ("BKR6EIX"). Did you get the following? The "-11" at the end means 1.1mm or ~.044" pre-gapped plugs.

NGK Part # 3764 BKR6EIX-11 Iridium IX Spark Plug .044

NGK Iridium-IX will work fine in the engine and should last the full 60K interval if not more. You may notice very little wear at the end of 60K and most of the wear would be on the ground electrode. So if you gap it then you may be able to run it longer, but I'd just change them out after 60K-75K miles.

The thin center electrode means the plugs require less voltage to fire and can ignite leaner mixtures. As NGK puts it, these plugs offer "extreme ignitability, improved throttle response and superior anti fouling". The plugs should be torqued to spec when installing (13 lb/ft with a dab of antiseize three threads away from the tip, or 18 lb/ft dry). You can also use Denso iridiums, but the even thinner center electrode (0.4mm vs 0.7mm) means they need to be swapped out at 30K miles. I personally prefer NGK ignition products.

Harbor Freight has torque wrenches that used to be around $12-15 on sale, but looks like the prices have been going up. I thought you should be able to wiggle a plug socket on a 6" extension for the rear bank? No?

Originally Posted by Just Out of Reach

OK. The reason I ask is because there's a white sticker under the hood that says "Only use double-tip platinum; do not gap".

One person (I think on this site) reasoned that that info is now outdated and you can use NGK Iridium now.

As for gapping, the new plugs came at .039" and the NGK site says to gap at .044" so I widened them. I thought that was strange, that they didn't come pre-gapped; have always heard that narrower gap makes "less work" for the spark to arc. I figured the sticker was referring specifically to the double-tip type, though.