Replaced Knock Sensor still tons of Knock??

[LKWTSI]

Ok guys, I'm getting a little "P'd" at this knock situation. I posted my log and everyone thought I had too much boost, so I turned it down and still pulled a ton of knock. I replaced the Knock sensor, the old one was definitely shot, and the car feels like it's pulling harder than ever, but my log shows otherwise. I'm running 93 octane at 11psi boost and checked the gap on the plugs and it's got new wires and all the mods are pretty tame, nothing wild.

SO what could be causing my knock now

 

[Jdog]

Hardcore lifter tick or some other insane noise? The knock sensor is just a microphone so anything can falsely set it off.......

 

[LKWTSI]

Hardcore lifter tick or some other insane noise? The knock sensor is just a microphone so anything can falsely set it off.......

At idle I get one every now and then. Could you get that much tick at high RPM, to cause this?? Also what other kind of noise in the high RPM range could you get?

 

[DSMRook]

Well according to your profile it's showing that you're running the stock fuel system. Have you rewired the pump or anything? Might be a good to start there. I know that you're only running 10 psi but that's still a lot more airflow than the stock turbo.

 

[LKWTSI]

Well according to your profile it's showing that you're running the stock fuel system. Have you rewired the pump or anything? Might be a good to start there. I know that you're only running 10 psi but that's still a lot more airflow than the stock turbo.

I have the re-wire kit in the garage, haven't installed it yet. Was waiting on a Walboro pump that I'm going to get from a guy.

Thanks, will be trying it next. Does the re-wire kit make that big a difference? I know from info' out there that the pump drops something like 5-6psi without the rewire, but with my mods, would that cause it to lean out that much and create detonation at high RPM.?

 

[the_mork]

It seems like your boost/fuel are fine. I would be chasing phantom knock and I'd start with revised lifters. Also grab yourself a bottle of seafoam and use it. It isn't a cure-all but it can help any number of problems. Also do a quick boost leak check, if you're running especially lean because of a fueling mismatch that might explain something.

Edit: Taking a closer look at your logs it looks like this could be liftoff/shift knock. It appears to happen after you let off the throttle, this could be caused by a couple of things so I have some questions, is your bov vented? If it isn't vented did you cut the diverter tube (that might be a 2g only thing) do you have a stock intake tube and filter?

 

[allthrottle]

I'm having a similar problem as yours with not nearly as many mods. I do have a rewired pump though, which doesn't seem to be making a difference either way. My maf has the lower honeycomb and I'm starting to lean towards the thought that it may be a problem. I get a ridiculous amount of knock out of nowhere, for seemingly no reason.

Is your maf modified? Have you done a boost leak test recently?

 

[habitatguy187]

Remember that PK usually only happens during part throttle driving. This knock might actually be real.

Like stated seafoam it and see what happens, took care of my PK completely.

 

[Colt4G63 also]

I looked over your car and log. Here's your problem circled in yellow:

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If you look at your log, you'll see the airflow go flat very early on in your RPM range. Your 1G MAF is getting all pissy at 1608Hz and staying flat, but in reality it should be climbing (with RPM) up to 2400Hz or so by redline.

You're welcome.

Ps. It's real knock, so cross your fingers, and upgrade your MAF. I went through this whole process with mine.

 

[allthrottle]

I don't have a lot of experience with maf's, but I just assumed when I saw the logs and the flat/topped out airflow reading that it was because of the following quote:

Airflow:

Range: 0 to 1600hz
Frequency of the signal put out by the MAF sensor. The MAF measures the volume of air entering the engine and the ECU uses the signal along with intake air temperature and barometric pressure to determine how much fuel to inject. The signal as displayed on the logger will not exceed 1606hz even though the MAF can output frequencies well above 2000 hz. This is a limitation in the way the airflow value is sent to the logger from the ECU.

Habitatguy, thanks for posting that. It may help me diagnose my issue. That's exactly what I'm experiencing. Tons of knock and timing retard at part throttle/lower rpm, very little knock otherwise.

 

[Colt4G63 also]

I don't have a lot of experience with maf's, but I just assumed when I saw the logs and the flat/topped out airflow reading that it was because of the following quote:

Oh. I didn't know that about the pocketlogger. How the hell is that usefull? My 1g MAF used to go all kindsa crazy above 1750Hz. Thank god for DSMlink, or I would've never been able to see my problem.

Sorry

Wait, are you sure that log is part throttle? If the gray line is throttle, then that's WOT. And if you can't log anything above 1606Hz, then how do you know it isn't MAF over run. I'm sticking to my previous statement.

That isn't part throttle low RPM. It spikes up to 34 counts of knock up by 5800 RPM.

 

[Colt4G63 also]

Here's what my log looked like with MAF over run:

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Look familiar?

I told link to extrapolate a reading anytime above 1800Hz, and it made a world of difference.

You can see "MAF raw" drop right off while the extrapolated "airflow" reading steadily climbs.

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If you log your wideband, you'll probably see it go lean as your knock really starts to spike.

 

[LKWTSI]

Edit: Taking a closer look at your logs it looks like this could be liftoff/shift knock. It appears to happen after you let off the throttle, this could be caused by a couple of things so I have some questions, is your bov vented? If it isn't vented did you cut the diverter tube (that might be a 2g only thing) do you have a stock intake tube and filter?[/QUOTE]

No, BOV is recirculated like it's supposed to be. Also the Intake is a Dejon, with stock MAF and K&N cone on it. I have to do some research into the whole MAF upgrade thing or make sure my MAF is mod'ed correctly.

 

[LKWTSI]

I'm having a similar problem as yours with not nearly as many mods. I do have a rewired pump though, which doesn't seem to be making a difference either way. My maf has the lower honeycomb and I'm starting to lean towards the thought that it may be a problem. I get a ridiculous amount of knock out of nowhere, for seemingly no reason.

Is your maf modified? Have you done a boost leak test recently?

See my reply to "The Mork", it's my next trouble shoot.

 

[the_mork]

Okay, see if you can get the recirculation pointed well into the intake tube, it may be that your airflow goes crazy when your bov goes off (mine does).

 

[LKWTSI]

Okay, see if you can get the recirculation pointed well into the intake tube, it may be that your airflow goes crazy when your bov goes off (mine does).

Did a boost leak test yesterday and all held really well. Took it up to about 15psi and it bled down to 10 psi in about 30 sec's then to 5psi in about another 30 sec's and the only tiny leak I could find was in the BOV. So I took the BOV off and I did the crush. Don't know if this will help, but at the moment it's all I can do. I'm putting a 255 Walboro and re-wire kit on next week.

As far as the recirc' pipe, I can't make it go at any different angles. It's a Dejon intake pipe and the recirc' pipe goes straight into the intake at a fixed angle. Next step may be to look into a blow through MAF-T. My only concern is that I've followed the tuning upgrades that are on VFAQ and this site and per "stage 1" upgrades and I have exactly what was prescribed beyond Free Mods and the intake and other upgrades shouldn't be giving me this much hassle. SO I'm left with what the heck is causing my knock

I appreciate the input, but I think I may need to tear the engine down and do a rebuild with new rings and lifters on the top of the list.

 

[LKWTSI]

I've done some more reading in the forums and something else on "knock" that I found interesting is the heat issue from wrong plugs and air charge temps. Anyone want to add to this point and tell me if the cold plugs and a heat shield around the intake make that much difference I looked at my plugs and they look fine, although, they are Champion plugs can colder plugs make that much difference. I also looked at my intake temps on the logger and it was about 92* F ambient and the intake was running about 130*F would this make a difference

Sorry if this is classified as bumping

 

[EagleTalon1993]

I had a similar problem with my bone stock 2.0l NT. normal driving was fine but on hard acceleration knock city. turned out to be a combination of two things 1. plugs gapped incorrectly (Couple of wires burnt too) 2. ignition timing was off by 4 degrees Yes it was enough to cause horrible knocking on acceleration especially uphill.

hope something here is useful

 

[LKWTSI]

I had a similar problem with my bone stock 2.0l NT. normal driving was fine but on hard acceleration knock city. turned out to be a combination of two things 1. plugs gapped incorrectly (Couple of wires burnt too) 2. ignition timing was off by 4 degrees Yes it was enough to cause horrible knocking on acceleration especially uphill.

hope something here is useful

I think I'm going to definitely get new plugs tomorrow, but my timing was bang on. I set it with the ECU bypassed and with it not and both readings were exactly 5* and 8*. I wonder if my add-ons and increased airflow, I wonder if I should adjust the timing away from stock??

 

[Colt4G63 also]

Yes your mods increased airflow. That's what they're for. I have no idea what temp range Champions give you, but as my mods progressed I had to switch from BPR6ES to BPR7ES. More specifically: When I changed from a 1g MAF to a 2g MAF and shaved a full half second off my 1/4 mile, I started to need cooler plugs. I was getting knock in fourth gear on 1/4 mile passes because the plugs were retaining too much heat. It didn't look like your knock though, it ramped right up from zero to 16 counts, right after the shift, and pretty much stayed flat, because all the timing retard in the world doesn't cool the plugs.

You really need some way to accurately measure MAF and log your wideband. I'm confident you'll see what's killing your motor.

 

[LKWTSI]

You really need some way to accurately measure MAF and log your wideband. I'm confident you'll see what's killing your motor.[/QUOTE]

I have on my pocketlogger a reading called WB O2, I'll have to research what that is telling me, but so that I'm walking down the same path you're talking about, what would the readings I'm looking for be approx'. I might not have the same capabilities you have with DSMlink, but I'd at least like a base idea of what wideband real constitutes.

 

[Colt4G63 also]

If you are leaning out due to MAF over run, your wideband would show your AFR go lean. (a primary cause for knock). Normally your AFR (with stock fuel map) would run around 9:1 or 9.5:1 under boost. The wideband line shoud flatten out as you reach full boost, and stay flat for the duration of the pull.

Ps. You have a wideband right?

 

[bluegs03]

I have no idea what Champion Spark plugs are but i would stick with the normal ngk copper's in with the code listed down below, these cars have all sorts of issues with the wrong spark plugs and its like a 4$ fix.

I have no idea what temp range Champions give you, but as my mods progressed I had to switch from BPR6ES to BPR7ES. More specifically: When I changed from a 1g MAF to a 2g MAF and shaved a full half second off my 1/4 mile, I started to need cooler plugs. I was getting knock in fourth gear on 1/4 mile passes because the plugs were retaining too much heat. It didn't look like your knock though, it ramped right up from zero to 16 counts, right after the shift, and pretty much stayed flat, because all the timing retard in the world doesn't cool the plugs.

You really need some way to accurately measure MAF and log your wideband. I'm confident you'll see what's killing your motor.

 

[JayRolla]

I dont think he has a wbo2. He said he has a wbo2 feature on his logger which does nothing unless you have a wbo2 to log.

Have we ruled out Phantom Knock?? I dont see why he would be overrunnin the 1g maf at 10psi on his 16g (at 10psi the 16g pushes no more air than a 14b). Unless there is a huge boost leak that he said he doesnt have. 300whp has been made on an safc and stock 1g maf.

Do you get part throttle knock when cruising around? Do you get knock when free reving in neutral? If so than its most likely PK. PK will start at low rpms and will stay untill redline. But if you do a run from 5500rpms up you should not get the PK as often.

Here is a good test of PK. Start doing a log WOT at 2000rpms. If you see knock release the gas and get back on it real fast. If its still under 4000rpms and the knock comes back, release and do it again. PK will clear up and usually not come back at higher rpms and give you a clean run. If its real knock it should come back everytime and if it does clear up and come back over 5000rpms that is most likely the actual knock.

Here is a log of a perfect PK issue that I have and still fight. I believe its due to lifter tick. The red line is RPM and the green is Knock. That a low rpm around 3k when it comes in strong. I release the gas which you can barely see on the rpm line and its clean for the rest of the run.

 

[LKWTSI]

I dont think he has a wbo2. He said he has a wbo2 feature on his logger which does nothing unless you have a wbo2 to log.

Have we ruled out Phantom Knock?? I dont see why he would be overrunnin the 1g maf at 10psi on his 16g (at 10psi the 16g pushes no more air than a 14b). Unless there is a huge boost leak that he said he doesnt have. 300whp has been made on an safc and stock 1g maf.

Do you get part throttle knock when cruising around? Do you get knock when free reving in neutral? If so than its most likely PK. PK will start at low rpms and will stay untill redline. But if you do a run from 5500rpms up you should not get the PK as often.

Here is a good test of PK. Start doing a log WOT at 2000rpms. If you see knock release the gas and get back on it real fast. If its still under 4000rpms and the knock comes back, release and do it again. PK will clear up and usually not come back at higher rpms and give you a clean run. If its real knock it should come back everytime and if it does clear up and come back over 5000rpms that is most likely the actual knock.

Here is a log of a perfect PK issue that I have and still fight. I believe its due to lifter tick. The red line is RPM and the green is Knock. That a low rpm around 3k when it comes in strong. I release the gas which you can barely see on the rpm line and its clean for the rest of the run.

I'll have to try it out.

To answer the previous questions NO I don't at this time have any means of measuring "wideband". My concern was that I have a reading called WB O2 and it's reading about 18.94 every log and there's no literature with the software explaining what this reading is. So I guess I'm in the dark until I figure that out. BUT I know from other posts I'm not running anything other than my stock O2 sensor so, to run wideband do I need a different sensor or another one downstream or what??