knock sensor

[kondo]

what dealership quoted you that price? Also the mechanic at Folsom Toyota told me that the knock senors only work above 4k, he said that they pick up vibrations from the engine and then tell the ecu to correct them by letting the ecu know the oscilllation of the knock. The reason the light comes on is because the ecu is not getting a signal from the sensor. My light has been going on and off for the last week. Last night I hit the gas ans redlined my car and the light turned off and has not come back on yet but I'm sure at some point when I least expect it I will look down and see that evil orange light looking back at me.

Nick

[cdssolara]

How much money did toyota tell you it was going to be?
The toyota in my town quoted me$650 out the door.
but today I took it in and they said that it was working fine, because it was reading bank 1 and bank 2,
My CEL only comes on when i hit 4-5 thousand rpms. And when I drive it nice for a coulple of days it turns off. But as soon as I hit high RPM's it comes back on.
So I am going to redyno-tune, check my fuel pressure, check my low-throttle( S-AFC) with a OBII scaner, Make sure my timing is at the right degrees. And then I'll probley change out my knock sense. Last resort!
OH, and my car only idles at like 500rpm.
One day this will all be fixed

I have a 5.5 psi pulley, and I have had the exact same experiences that you are talking about. My CE light comes on if I get my rpm up, usually over 5000. I don't notice any problems with performance after this happens, and the light goes off in a few days. I asked around about this, and the best explanation I could get was that the ECU senses a "soft fault", probably some type of knock but not enough to blow the sensor completely. If the sensor was blown, the CE light would not shut off on it's own.

I have been thinking about getting new cylinder heads from Jim@Foreign Affairs to reduce compression. I would be interested to hear what results you get from the things that you are planning to do. Keep us posted.

[chef solara]

I will keep you posted. but the problem I'm having right now is that my dyno shop is closed untill the 28th. Unless I drive down south to Fort Lauderdale. which is like more than an hour drive.
So I will just wait till the shop reopens.

You were saying that you couldn't feel a difference after the CEL came on right. Same here, but flip sayed that you should feel some sort of slugish performance.
You know I really cant tell either, I have a auto, maybe that's why. There just slugish anyway.

[cdssolara]

Sorry about the double post.
You were saying that you couldn't feel a difference after the CEL came on right. Same here, but flip sayed that you should feel some sort of slugish performance.
You know I really cant tell either, I have a auto, maybe that's why. There just slugish anyway.

He's probably referring to what will happen if your knock sensor is actually blown. From what I understand, your ECU will retard timing, resulting in engine sluggishness. If the sensor is not actually blown, as in our cases, I don't think the timing will be affected. It seems that this is more of a warning. In the long run, it might be a good idea to get a new knock sensor, anyway.

By the way you can delete double posts using the Edit feature.

[Yanks0114]

By the way you can delete double posts using the Edit feature.

Guests can't delete posts but I took care of it

[chef solara]

Well my CEL went off tonight. It makes me alot happier to see it go off.
And now I know that I didn't blow the sensor. Which gives me the oppertunity to enrichen my mixture back up.
I have a benifit, I installed a upgraged fuel pump from EL. prototypes. Which made my car run really rich. So when dyno-tuning my car I just had to lean it out some. But the problem came when the tuner guy, leaned it out to much. So now i just slowly keep adding fuel to the mix, with my S-AFC, but evertime the CEL comes on I have to wait untill it goes off, which takes usally 2 days.
So maybe I can figure out the problem on my own.

[JoeB]

My understanding is when the check engine light comes on, the computer goes into a fall-back mode that offers limited performance but helps protect the engine. That is why you get more sluggish performance.

About a week or 2 after I had my S/C installed (stock pulley) at Toyota my CEL came on. It wasn't my knock sensors though. They replaced:
90910-12174 Valve, Duty Vac.
25620-20020 Valve Assy, EGR W
89412-33050 Sensor, E.G.R Gas
and the O2 sensor on exhaust (don't have that paper in front of me -filed).
They covered all but exhaust O2 sensor under warranty as part of S/C install. Another benefit of going to the dealer. Plus, there was no way I could tackle a project like that myself. -Joe

[AT]

I have 99 Solara 5spd w/ 2.8 (6lb) pulley. Check engine light- knock sensor bank 2 error. Has anyone corrected this yet? I don't want to replace knock sensor unless I know how to fix it.

Any help would be appreciated.

Thanks

[chef solara]

Well the only way I know how to fix this problem is by replacing the sensor. Toyota quoted me 650. out the door. So that's my last resort, I need to get on a dyno so I can see where my air/fuel is at. But in the end I will probley have them replaced.

[AT]

Replacing the knock sensors is not a problem. How do I prevent it from happening again?

Thanks guys

[Guest]

I'm not positive this is the way to eliminate or at least reduce the problem but if I understand what I've read from all the knowledgeable folks here, you need an S-AFCii or better yet a Split-Second calibrator to maintain the proper air-fuel ratio. The problem is the knock sensors blow because the car runs too lean. Sounds like it's not much of a problem at 4psi but when you get up to 6psi it is almost required. -Joe

[JoeB]

Sorry, the previous post (Guest) was mine. I keep forgetting that even when I am logged in, if I respond to an email after clicking the notification thread in an email, I have to log in again in that window. -Joe

[Flipside909]

Replacing the knock sensors is not a problem. How do I prevent it from happening again?

Thanks guys

You cannot. The only way to help prevent it is to keep using premium unleaded fuels...and keeping your engine properly tuned.

[cdssolara]

I have 99 Solara 5spd w/ 2.8 (6lb) pulley. Check engine light- knock sensor bank 2 error. Has anyone corrected this yet? I don't want to replace knock sensor unless I know how to fix it.

Any help would be appreciated.

Thanks

Flipside's response above is correct. The 1MZFE engine has a 10.5:1 compression ratio, which is fairly high. When boost gets as high as 6 psi, detonation is a lot more likely to occur, which is why your knock sensor is indicating a problem. The prevailing wisdom is that 6 psi is the maximum safe boost, but the problem is that your boost can spike to 7 or 8 psi. This is especially true if you have a restrictive exhaust, like the stock unit. You didn't mention whether you have an aftermarket exhaust. If you don't, then installing one might be helpful in minimizing the knock problem. IN addition, use premium gas; 93 octane if it is available. As other posts have said, get an S-AFC to control the air/fuel ratio, and get a dynotune. The only other alternative, which is a lot more expensive, is to reduce the compression of your engine.

[chef solara]

Yep, to get Jim's heads. Which are anywhere from 1,500. to 2,000. w/ a core charge. They are a good idea, Eric sol Just got his from Jim, Let see what kind of increase they have.
I really wish that jim would get on a dyno, to get some numbers, of my understanding he has a base run, but he's done so many upgrades to his engine, I would love to see what his auto dyno's at.
Eric said that the heads bring the compression down to like 9:3:1 or something close to that. I can't remember, I talked to him on Wednesday.

I'll be ordering the header from JP in July, can't wait!!
Although eric said that Jim may be making header also, and I have to see if that Xerd company is for real.