Spark Plugs / Knock Sensor

[JD797]

So a few days ago, my car was VERY shaky on startup, even when I started driving, so to play it safe, I had AAA tow it to the shop. Though they said that after running for 5-10 minutes the shaking stopped, they said it needed new spark plugs, which made sense to me, and a new knock sensor, which I have no clue about. Can anyone suggest a good place to get these parts at a good price? Also, he said I should get laser spark plugs, and quoted me $19 each from the dealer, and $90 for the knock sensor from the dealer... he said the spark plugs would last 80k miles

[bigern45]

you dont want laser's in your high boost car.. go with coppers. and gap them lower.. otherwise you will have misfires at high boost.

[NOTORIOUS VR]

Do you have a check engine light on? Knock sensors usually aren't something that just breaks.

[fas4tt]

(spark plugs) I would go with the side fires, JHM sells them.

[JD797]

Do you have a check engine light on? Knock sensors usually aren't something that just breaks.

Well, I've had it on since I replaced the downpipes lol, the mechanic said it was throwing some sort of code... should I just leave it alone for now? Cuz I'm sure it was the spark plugs causing the main issue

[mholme]

Did this mechanic pull codes?

[JD797]

yeah. btw is there another name for knock sensors or no?

[mholme]

yeah. btw is there another name for knock sensors or no?

If he pulled codes, it's possible that one was there for the sensor detecting engine knock, without the sensor itself being faulty. You should get the codes. Audi mechanic?

[NOTORIOUS VR]

The OP needs to buy VAG-COM... Everyone that owns a VW/Audi product needs to own one. Buy the $10 cable from ebay, download the free software from Ross-Techs site and tell us the codes.

Yes you will have a CEL from not having cats. A misfire could cause a knock sensor code I guess if it was bad enough... Anything is possible. It could also be that once of your knock sensors actually went bad.

Problem is we don't know because you don't have enough info.

Shaking motor = misfire.... check/replace spark plugs, check coils & boots and go from there. Clear codes and drive.

[GarbatyA4]

It was probably just a coil pack or bad plugs.

I'm sure the Knock sensor was fine.

How many knock sensors on the 2.7 block are there? 2?

[bigern45]

a major misfire will not cause a knock code. knock codes are set due to an electrical malfunction with the knock sensor. if there is a mis and the knock sensor picks it up and it registers then it is doing its job. OP, follow the advice and get VAGcom.. its your best bet.. then you can relay the codes yourself here, to us..

[JD797]

yeah i think im just gonna go with spark plugs for now and take it from there. I actually bought the cable a long time ago, problem was whenever I hooked it up to my laptop it gave me the blue screen of death. I have windows 7 on there now, so maybe it'll make a difference? who knows, probably worth checking now though seeing how I'm having a few issues.

[NOTORIOUS VR]

a major misfire will not cause a knock code. knock codes are set due to an electrical malfunction with the knock sensor.

That's what I figured, but I dont' know every single code the ME7 has so I figured it was a possibilty there was a knock code that didn't point to a faulty sensor, etc.

[mholme]

a major misfire will not cause a knock code. knock codes are set due to an electrical malfunction with the knock sensor. if there is a mis and the knock sensor picks it up and it registers then it is doing its job.

You're kind of contradicting yourself a bit? When I lost a cylinder due to a failed ICM, I also had a code there for signal too high from the knock sensor on that same bank that the cylinder was not firing. This was a direct result of the dead cylinder. Replaced the ICM, cleared the codes and it hasn't come back. That's why I want to know the OP's exact codes he's getting.

[bigern45]

You're kind of contradicting yourself a bit? When I lost a cylinder due to a failed ICM, I also had a code there for signal too high from the knock sensor on that same bank that the cylinder was not firing. This was a direct result of the dead cylinder. Replaced the ICM, cleared the codes and it hasn't come back. That's why I want to know the OP's exact codes he's getting.

you apparently have no idea what your talking about. registering knock means that the sensor is doing its job, where it be pre det, misfire or any other type of pinging. hell, you could be banging the engine with a hammer and if you look at the knock voltage and it changes, then the sensor is REGISTERING KNOCK and working properly. most knock codes show knock sensor open, short or malfunciton. ive NEVER seen a misfire show up as a knock sensor code.... yours would be the first...

[mholme]

you apparently have no idea what your talking about. registering knock means that the sensor is doing its job, where it be pre det, misfire or any other type of pinging. hell, you could be banging the engine with a hammer and if you look at the knock voltage and it changes, then the sensor is REGISTERING KNOCK and working properly. most knock codes show knock sensor open, short or malfunciton. ive NEVER seen a misfire show up as a knock sensor code.... yours would be the first...

Woh guy..why so aggressive? I wasn't coming after your statement as false, I was just saying it seemed a little contradictory(maybe the way it was worded or the way it reads to me). The reason my car registered the knock was exactly why you said, the dead cylinder caused the engine to vibrate so badly that it assumed knock, as in, the sensor was working. I never said a misfire showed as knock detection, I just wanted to know what the OP's other codes were as to why his mechanic said he needed spark plugs(probaby had misfire codes), and the specific knock code he has. He may be dealing with a dead cylinder that would possibly be interpereted by the engine as knocking. They are quite sensitive and have a very specific operating range.

I don't know why people are so quick to go on the offensive on this forum these days...

[bigern45]

Woh guy..why so aggressive? I wasn't coming after your statement as false, I was just saying it seemed a little contradictory(maybe the way it was worded or the way it reads to me). The reason my car registered the knock was exactly why you said, the dead cylinder caused the engine to vibrate so badly that it assumed knock, as in, the sensor was working. I never said a misfire showed as knock detection, I just wanted to know what the OP's other codes were as to why his mechanic said he needed spark plugs(probaby had misfire codes), and the specific knock code he has. He may be dealing with a dead cylinder that would possibly be interpereted by the engine as knocking. They are quite sensitive and have a very specific operating range.

I don't know why people are so quick to go on the offensive on this forum these days...

no sweat.. calling me contradictory set me off.. and i havent been laid in like 3 days.. sry..

[maniac33]

no sweat.. calling me contradictory set me off.. and i havent been laid in like 3 days.. sry..

Efff that...
I feel your pain.. try 3 months. GF broke up with me...

[JD797]

lol i love how this went from "misfires, spark plugs and knock code issues" to "its been a while" haha. I'll try and get the exact codes from the guy in the morning

[mholme]

I'll try and get the exact codes from the guy in the morning

Better yet, see if anyone in your area(regional forum) can scan your car and give you a saved file of it and post it here. Maybe they even have time to do a thorough diagnostic to see if you possibly have a coil pack or ICM issue.

Then buy a VAG-COM.

[2BblkAudis]

I had Denso Iridiums in my car and just replaced them with the Bosch Sidefire F5DPOR and all my misfires at the top end are gone. I've been getting a check engine light for the past several months when I would do some spirited Driving. When scanned I was getting the random misfire code (P0300?).

Just put the bosch in and did some aggressive pulls from all gears and it's finally running like it should.

Good luck with the bug. Not sure exactly what the gap on the Denso is right now but it looks like a fairly large gap.