2000 2.7L Knock Sensor

[Brock31]

Anybody know where this is located? Also, how to test if the sensor is bad? I'm getting moderate knock between 2K and 3K rpm's. Plugs are in good shape. Just replaced rear O2 sensor. Problem was occurring before this replacement though. One Seafoam treatment did not help.
Any advice would be great!

Thanks,
Brock

[MTL_4runner]

This should help you out....(in 2000 the 2.7L is the 3RZ–FE engine)

Location:
http://www.tankota.net/repair/Repair_Manual/03tacoma/sf2rzfe3/knosen/insp.pdf

Testing:
http://www.tankota.net/repair/Repair_Manual/03tacoma/di/eg2rzfe3/cip0325.pdf

[Brock31]

Thanks for the info. Do you know if a bad know sensor would throw a CEL?
I am getting audible knock and can't figure out why its not being compensated for by the ECU. I normally use 87 oct. but right now am running a tank of 93 oct. which is helping.

[MTL_4runner]

A bad sensor can throw a CEL, yes.
If in doubt, check the sensor per the FSM I linked you to (it's not likely to be bad without a CEL).

What plugs do you have in the motor and when were they changed? Also what other tuneup items (plugs, fuel filter, MAF cleaning, TB cleaning, etc) have you changed or done recently and did you use OEM parts on those too?

[Brock31]

NGK Iridium plugs, can't remember heat range, but they were factory spec. I put them in about 25K miles ago. I looked at them a couple of weeks ago in an attempt to diagnose my knock problem and they all looked OK. I also cleaned the MAF sensor at about the same time. Fuel filter was replaced the same time as the plugs, ~ 25K mile ago. I have done one treatment of seafoam through the brake booster intake line, but have never cleaned the actual thrttle body. Oil is changed regularly using either 10w30 or 5w30 synthetic and pure-one gold oil filter.

I'm kind of wondering if it isn't the plugs? Whats the best way to tell? ( I know buy some new ones and see if that helps :screwy:]

[MTL_4runner]

Yes, I would buy another set of OEM plugs and replace just to be sure. Look at the spark plug boots when you change them to see if any might be arcing at all. I assume you cleaned the MAF with brake cleaner (if not do that). Another item to check for a misfire is the TPS. I would also do an in-the-tank Seafoam treatment too (run the gas down to 1/4 tank, add 2-3 cans of Seafoam and drive it normally until it's on empty).

[Brock31]

I ran about a half a can of seafoam through the tank with 1/4 tank of gas left. I've got another full can of seafoam so I'll put that in the tank when I get down to about a 1/4 tank.
TPS [is that "throttle position sensor"]? I'm not familiar with that acronym?
What would I look for on the plug boots for arcing?

[MTL_4runner]

I ran about a half a can of seafoam through the tank with 1/4 tank of gas left. I've got another full can of seafoam so I'll put that in the tank when I get down to about a 1/4 tank.
TPS [is that "throttle position sensor"]? I'm not familiar with that acronym?
What would I look for on the plug boots for arcing?


1/2 can of Seafoam in the gas tank isn't much and they're cheap compared to other high end fuel injection cleaners (like BG) so it pays to be liberal about it if you want it to really do a good job (and seeing as you have a knocking problem this is a pretty critical step). Use 2-3 (the more concentrated the better) whole cans in the last 1/3-1/4 tank of gas and drive it normally until you see the empty light.

Yes, TPS = throttle position sensor
Fairly easy to check with a cheap digital multimeter.

On the plug boots you'd look for burn marks or carbon trails on the boot.
You can also buy a little dielectric grease and put it on the boots for added insulation.

[MTL_4runner]

Brock, does this sound like what you're experiencing with yours?
Has the knock been there since you've owned it?

http://www.automotiveforums.com/vbulletin/t31554.html

[Brock31]

Brock, does this sound like what you're experiencing with yours?
Has the knock been there since you've owned it?

http://www.automotiveforums.com/vbulletin/t31554.html


That doesn't sound like what I'm experiencing. Here in the winter, occasionally on the coldest days, if I don't let the truck warm up I'll get a little bit of piston slap. This doesn't happen when its warm. The knocking I'm experiencing now is definitely detonation. When I filled up with 93 octane last week, the truck desn't knock. The issue there is that premium fuel shouldn't be required for this engine. I'm really beginning to lean toward the plugs and plan to replace them this week. While I'm at the store I'll probably pick up another couple of cans of seafoam.
The truck has not knocked for a really long time. I bought it with 25K on it and it now has 95K. [knock on wood- no pun intended] the truck has been very good to me

[MTL_4runner]

Ok, that's a very good sign.....I agree, loads of Seafoam in the tank and change the plugs.
I'd do 3 cans of Seafoam in just under 1/3 of a tank of gas left and see how that does for you.

[Brock31]

will do.
I really appreciate your insight and will post back with any results I get

[Brock31]

Well, I ran a whole tank of 93 oct. through and did 3 more seafoam treatments through the intake and one more full can with less than a 1/4 tank. I ran all that through then changed out the plugs for a set of new OEM's. Filled back up with 87 and it still knocks a little bit. Not as bad as before but still knocking none the less. I guess I'll just have to use at least 89 oct. gas from now on.