Phantom knock or ????

[CrawlinZX14]

Ok, so I have been having a ton of issues with my talon and knocking. My mechanical timing is correct, my belt isnt in bad shape and within spec, and everything runs ok at idle. While logging with my MMcD I keep experiencing knock, and its never the same twice. Meaning the conditions like throttle position, load, duty cycle, AF are always different. So it is being a complete pain in my ass to hunt down the problem. I replaced the knock sensor, put in a wide band, and am logging with the m515 and MMCd. I will try and upload some logs a bit later, the hot sync is taking forever to change everything over to a spread sheet.

My AFR is holding nicely at approx 11.1 across the board and will come to about 8.5 ish at idle. Im boosting about 12psi, and I will get 1-2 instances of knock just free revving the engine in park.

My newest log shows 10 counts of knock at 4812rpm, 11.0 AFR on the wb, duty cycle of 56.2% Timing advance of 13* and tps of 61.3%. FTRL 90.6% FTRM 100% FTRH 100% had 10 counts knock for .023ms. Later on in the same log run it knocked again. This time I had the following conditions.

4281rpm, 10.9afr, 53.9% duty, 10* tima, 16 knock, 73.4 tps, same fuel trims.

Any idea's of what is causing this issue? im running premium fuel and 12lbs boost on a pte 50trim. and 680 injectors. I have 950's ready to go into the car, but it doesnt seem that im over running the injectors yet, however I likely will once i add boost and solve this knock issue.

Is this just a case of phantom knock, or is there likely a major issue here? I have been checking everything I can think of, but no such luck so far. Anyone have any input on this one? Its driving me nuts, and I would like to be able to boost without my car pulling time due to knock. Its being tuned with an eprom chip. Just looking for some idea's as to what the problem could be with this knock.

 

[MY1GDSM]

My AFR is holding nicely at approx 11.1 across the board and will come to about 8.5 ish at idle.

Say what WTF

What exactly do you mean I'm gonna assume that is a miss type ??? being you say your low trim is at 90.6?

The rest of your trims sound like they have not adjusted yet as the chance of them staying at 100% even with a great tune are slim... .

Get the log loaded up even a CVS file iis going to get you more help then the description of what is happening

 

[CrawlinZX14]

I am working on uploading all the logs right now. Its being difficult. But no it was not a mistype. the logger after driving around the block the other day showed 8.5 afr at an idle, but as soon as I would give it a little fuel, it would go back to 11.1- 11.0 I am working on getting some logs up tho.

It is sync'ing now, and once I have em all uploaded, I will do what I can to post em. Only 1 log has the WB reading on it so far however, as I just recently installed the WB. Its an LC-1 that has been calibrated and is running off the stock WB input as well as pin 15 i believe to log the WB reading since I currently dont have a gauge for it. I am using the logger to read it for the time being until my gauge comes in.

 

[CrawlinZX14]

I have been trying to figure out how to get the files changed to the csv, or excel files, but my computer is not cooperating. I do have the pdf files, but they keep saying invalid files when I try to upload in advanced. any advice on how to fix this so i can post. A few local people seem to think this is phantom knock, but I would like some outside opinions too.

Today I readjusted the plug gap from .030 to .028 and got less knock, but still pulled up to 12 counts of knock on stock boost and 680 injectors. I have to install my 950's this weekend.

My knock seems to show up the most when I let out of the throttle, between gears. However it still pulls some knock under load.

 

[mattasi]

It suppose to be 14.7 at idle and around 11.5 WOT.

 

[CrawlinZX14]

well I only see what the logger shows me. Completely off the throttle coming to a stop it will go to about 8.4-8.7 afr. I know thats not ideal to say the least. but its only when im off throttle and my injectors are off. when duty is 0. Say when coming to a stop.

Take for instance a hard pull up to 5843rpm. My AFR was 10.8 at max RPM, with 89.8 duty and 18* adv timing. with 84.3% tps. then off throttle after the shift, and 10.1 tps signal, and 8.4 afr on the wideband with 26* advanced timing and 0.0% duty.

This is the only time my AFR is not in the 10.8-11.2 afr range.

Everything on my logs looks good to me, and I pulled the VC to replace the gasket and all the valves looked in place and good and tight as they should be. So i cant figure out where this knock is coming from. I know I have a minor exhaust leak at my mani due to a stripped stud, but would that cause the problem?

Previous owner over torqued a couple studs on the mani and one is beyond repair. I was able to heli coil the other holes. So without replacing the head or opening up the mani and putting in a larger diameter bolt there is a slight leak.

I guess my question is, what could be causing this knock? Its not going lean under load, and when it knocks all the data looks to be right on. Any insight? compression looks good, and everything looks tight. I know there is a bolt missing in the triangle bracket from the intake to the block that the O2 wire feeds thru, but would that cause a knock to be detected?

 

[96 420a-t]

That leak is before your wb. It will cause an issue. Fix that and report back

 

[MY1GDSM]

I have been trying to figure out how to get the files changed to the csv, or excel files,

See here MMCd Tools

 

[Jason023]

I had a ton of phatom knock would go away one week and come back the next.. i kept checking my link reading the logs things read ok everywhere except i had stock side mount so boosting to much had my temps up to high. i let it go and about a month later engine blew... spun crank bearing. this post is not ment to help or scare just something to keep in mind.

 

[MY1GDSM]

So are you saying you "thought" you had phantom knock and didn't or that you shouldn't make assumptions? Or both?


I think the biggest problem here is the label "Phantom knock" So many people don't know how to address issues that are not knock(other noise) let alone be able to tell when it is real or real cause for concern if it is knock.(whether it is realy or not)

A large portion of the time people try to address things the wrong way making assumptions of how to address them to begin with and only make things worse... FYI You can have Zero "Real" knock and still be beating on your motor... .

It suppose to be 14.7 at idle and around 11.5 WOT.

Yes around 14.7 or targeting there... . But to say it is supposed to be 11.5? Nobody but whoever wrote the code for their Eprom knows this(or the op) and on pump gas I would say the range that they are getting is good(even if that's not what the AFR really is) 10.8:1 - 11:1 is a good afr target for pump gas at higher load.

 

[CrawlinZX14]

The target afr is 11.0. So that's on target. Its not a heat soaked side mount either. I. Have a fmic with 2.5in pipes that is doing a pretty good job of cooling my intake charge. The exhaust leak isn't something I can simply just fix at this point. A repair on it is going to require a new head basically. The previous owner did a job on the one that's on there. I guess its the risk you take when you buy a car off a teen. I'm trying to find a head, but I really don't want to go that deep into the car yet, as I'm trying to see what I can do with an oem motor. And when I find the head, its getting a race prep on it. Oversized valves, min 3 angle valve job, port/polish and cc'ing the head. With all new hardware and cams. So obviously it will no longer be stock. And I don't believe the leak is enough to disrupt my O2 readings very much or if at all.

So with all that said, what could cause a phantom knock issue?

I do have the mmcd tool already, it just doesn't seem to want to save the files in another format. It only uses the pdf format and is driving me insane.

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[CrawlinZX14]

Its also not a bottom end issue. The entire motor has been gone thru. Everything is tight and within spec. Oil pressure is good, and bearings are in pretty decent condition. I have been told is more likely something loose on the block. Like a bracket that isn't tight or the exhaust leak, but we even question the exhaust leak as we can't visually see or hear it, only notice a small soot spot near the ps pump where it is leaking. Anyone know if the stay bracket on the back of the intake is needed to be there. Its a triangle shape and the knock sensor wire runs thru an opening in the middle of it. Can I remove that without risk to damaging my intake under boost? The bottom bolt by the ac compressor is missing on it and I think that may be the culprit.

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[MY1GDSM]

with all that said, what could cause a phantom knock issue?

Nobody will ever be able to tell you whether it is or isn't PK or give you very much insight with out some sort of log...

If You want send me the Pdb file from your palm or upload it some where that you can link to... .

 

[CrawlinZX14]

Ok I will try and send it to you today when I get home from work.

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looks like I finally got it to load.

For some reason the wideband is showing up as a EGRt and in deg on here, but on the logger its WBO2. Its ran thru pin 15 for egr for logging.

961 is where the knock showed up at 10. LMK what you guys think. I assure you the AF reads in the 10.8-11.2 range at WOT. The only time it drops below is when im slowing and the injectors are off according to the duty cycle.

The knock sensor is brand new also. Hand tight and a 1/4 turn more.

 

[MY1GDSM]

About All I can say for certain is Your missing a lot of things in that log...

Try only logging your Low mid and High fuel trims when you first start the log and the end to help speed up the logging...

But still have the info and Add to the log FTo2, o2-r, Maf, and Air temp

You don't need the EGR-t logging unless your logging a wideband to it and have it set up to log right see the pic below it should be like that...

If you do have a wideband there and it doesn't log right you can pick 0-5v instead and it will at least have something to go off of...

 

[CrawlinZX14]

I had everything setup like your pic with the exception of 1920bps, and 02 non lin was checked. Everything else was the same. It was odd that the EGRt showed up in the excel format and not the WBO2. WBO2 shows up on the logger itself. I have an LC-1 setup to read both the analog and the digital. Analog is read thru the OEM O2 input, and the digital is read thru the EGRt pin 15. I will make another log with RPM, INJD, KNCK, O2R, TPS, WBO2,TIMA, AIRT, ALL 3 FUEL TRIMS AND FTO2, and finally MAFS. Does that about cover the info you need? I will not be able to post the log until sunday however, i leave for work in about an hour and will not get back to test until then.