My check engine light is on and I checked the codes. One of the codes is the knock sensor. I've been using 87 octane gas for over a year. I've read both that 87 octane will and will not ruin my knock sensor. If the sensor is not ruined then will the 87 octane gas trigger the code/light? I'm hoping to resolve this issue without changing my knock sensor.

 

premium is recommended...therefore i would say try using premium for a while to see if it goes away but i doubt it. you'll probably have to change it anyways

 

Clear the code, Fill up with 91 or higher, and check the fluid forums to see what the best fuel system cleaner is and use it. If this doesn't work you'll have to changed the KS. Not that hard, I had limited tools and managed, took about 15-20 min to change.

 

damn, ive been putting 85 in once in awhile, and 91 in when i can afford it, but i guess i better just start using 91, or at least 88. does it really ruin the knock sensor if u use lower than 91?

 

What was the other code?

The KS comes as a ghost code with quite a few other engine codes.
The KS cannot tell what type of fuel your using (87 or 91).
The type of fuel you use may, or may not cause knock and ping. My car runs perfectly fine on 87, actually my best MPG was obtained using 87 grade. My buddies 98 I30 has over 180,000 miles of regular fuel (87) clocked on his engine. To this date, he's never had a check engine light come on.

The KS is the most over rated, discussed and replaced sensor on this forum.

 

Running regular gas is fine

What codes are you getting (all of them...)? Ignore the KS for now

 

I bet the other code is an o2 sensor code.

 

The other sensor is the MAP sensor. I've ignored the knock sensor for months but its inspection time and they check codes in Mass. I get passed every day on the highway by 100 people driving Escalades and other SUVs pushing out twice the emissions as my car and I get rejected for a knock and a MAP sensor.

 

actually the emission on the SUVs isnt as bad as you'd think. plus they have a v8 to pass you, more weight. . but more power.

 

lower octane gas will pre-detonate during compression in our engines and other higher compression engines.

the KS is a dumb devise that more-or-less senses vibration in the block. pre-det rattle the block and produce the typical "knock" sound.

run the 91 stuff...

 

im running race gas...is that ok? haha jk..93 for me...

 

wow we dont have 93 octane here.....just 91

 

Same here in AZ 91 is premium.

 

93! Imagine people thinking that 93 is the good stuff.
Can't get it any more, but in England I ran my sports cars off 100 or 101 octane. When i left 11 years ago you could still buy 97.

 

i been puting 87 for the last 6 yrs, still runs great never had any codes

 

ok... knock sensor detects ping.

then it will retard the timings on the ECU.

if your using low quality gas (not low octane) it may ping. hell it may ping from using low octane too. but do yourself a favor and find out how ping is detected.

one thing that could happen is something caused a great vibration and the knock sensor detected it.

my knock sensor was cracked, yes cracked!

you can use a multimeter to test the knock sensor or you can just change it out. its not manditory to use 91 octane but it wouldnt hurt, only your pocketbook.

its hard to get at the knock sensor but its easy if you have small hands and arms, so a young kid or a girlfriend/wife could do it easy (they might get scraped up alittle bit but you would likly get scraped up much much more.
use a long wrench with a gear end on it to get right in there and pop it loose, then unscrew it by hand or use a magnet to help ya. this stuff will likly drop.

i bought myne from ebay for about 70 something with shipping. highly recomend because thats alot cheaper than say autozone or rockauto etc.

 

I put 93 octane in and reset the codes. The knock sensor code came back later that day. I also got the MAP sensor code again and the oxygen sensor code. I'm convinced the knock sensor is bad because I didn't get any pinging or engine vibration after resetting the codes that would have set it off. I'm buying a knock sensor on ebay for $79 plus shipping. Advance Auto wants $168.

Thanks for the help.

 

Your problem is the MAP and O2 sensor.

You only cleared codes you never fixed the root cause of your engine trouble.

You can't hear what the KS hears and the KS ALWAYS comes as a ghost code when other emission related codes pop up.

Your wasting your $$$ and time replacing the KS. Get the other two codes cleared first by replacing the MAP and O2 sensor. Check for the KS in a few weeks time, I guarantee it's gone after your car is running correctly.

 

Quick question guys...as our engines age, doesn't the compression go down due to worn out seals and valve guides? If that's the case, I'd imagine after like 150K miles you can use lower octane gas and not get knocking.

 

No, your compression should be just fine at 150,000 miles.

Excessive carbon build up in poorly maintained engines can cause hot spots as well as an increase in compression causing excessive ping.

 

Running lower octane gas will not cause the knock sensor to go bad nor will it cause a CEL.

 

If you use regular and it detects knock, will it set off the knock sensor code even with a healthy knock sensor?

 

no... the knock sensor code comes up only when it dies.

 

Gay KS's. i think i might need one. theres a writeup to check what, volts.... resistance for the KS??? hmmmmmm. could it be one of those things you didnt know was holding you back until you changed it???

 

Have you done the first step and checked for the KS code?

 

bumping 2 1/2 year old thread for this

 

I was running 89 octane for a while and I kept getting a cel which gave me KS and O2 sensor codes. I changed to using 91 octane and the cel went away. Been using 91 ever since.