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-   -   Looks like my engine is dying ( knocking ), but it doesn't seem to be FI related. (https://my350z.com/forum/forced-induction/503888-looks-like-my-engine-is-dying-knocking-but-it-doesnt-seem-to-be-fi-related.html)

GT-ER Oct 18, 2010 05:51 PM

Looks like my engine is dying ( knocking ), but it doesn't seem to be FI related.
 
For about a week or two I've been noticing that my engine is VERY LIGHTLY knocking at part throttle. It's a knock that's too light to even record so that I can show you guys.

I've been romping on it regardless of the noise and I've been taking it to 7K constantly....but the noise doesn't get worse and the car drives great.

In the past few days I've been without the SC and I've been studying it since it's easier to hear. It sounds like rod knock or maybe a wrist pin, but the car keeps on going with no change to sound nor power. I even changed to oil to a thicker oil ( went to 10-40 from 10-30 ) and still no change.

Has anyone ever had this happen? Did your engine fail soon afterwards?

BTW- I checked my compression to ensure no rods were bent and they all checked out between 180-190.

I'm curious because my GTI 1.8T did this for the longest time and it never failed...it just lightly knocked.

jonnylaw Oct 18, 2010 06:55 PM

I'm sorry, but I do not have any personal experience with what you are hearing.

However, I am confused as to why you state that "it doesn't seem to be FI related" You have been running ~17psi and over 400whp on you engine which was not designed to handle that amount of power for long period of time.

Imo at those power levels with your miles, and you romping on the car, it's not a question of whether you're motor with die, but when.

Hopefully, it's not that bad and it turns out ok for you. I'm sure some experts will chime in.

g/l

twitch579 Oct 18, 2010 07:36 PM

Thats 2 Vq's knocking in the same week. My friends car just started knocking the other day with me on the highway. Although his is very loud and sounds like a bearing. He was hitting 12.5afr with Greddy TT kit @ 7.5lbs though, im sure that had alot to do with it.

Sounds like its starting to come apart. Do you have a lightweight flywheel possibly tricking you? Mine makes all kinds of knocking sounds lately off idle.

GT-ER Oct 18, 2010 07:39 PM

Well, what I mean is that it doesn't seem to be a broken/bent rod or a broken piston of something of the sort...just maybe a bearing that's going bad or wear on the wrist pins which is usually a lubrication problem.

I have an external oil cooler if that matters.

I'm 5AT so no flywheel sounds.

phunk Oct 18, 2010 07:40 PM

are you sure you arent just hearing some piston slap from loose forged pistons? or are you still on stock engine

GT-ER Oct 18, 2010 07:55 PM

Stock engine.

GT-ER Oct 18, 2010 08:13 PM

Also, while it is rpm related ( not speed related ), it will only do it under load while driving, especially when going slow. In P it will not do it.

midz350 Oct 18, 2010 08:26 PM

Make sure before you do anything.

I had the A/C making noises at idle and decel that freaked the hell out of me three weeks ago.

redman333 Oct 18, 2010 09:01 PM

I had this issue, at least it sounds like it. Mine turned out bad though, i was driving home and had the cruise control set heard a loud crack and my motor locked up on me. This was about a week after I heard the small ticking first start. I've also had my stock motor boosted for over 75k miles now and don't ever drive easy on it. Now I have a hole in my block.

twitch579 Oct 18, 2010 09:08 PM


Originally Posted by redman333 (Post 8729995)
I had this issue, at least it sounds like it. Mine turned out bad though, i was driving home and had the cruise control set heard a loud crack and my motor locked up on me. This was about a week after I heard the small ticking first start. I've also had my stock motor boosted for over 75k miles now and don't ever drive easy on it. Now I have a hole in my block.

So u ran the TN kit for 75K miles? Thats awesome on a stock block.

maXmood Oct 19, 2010 04:39 AM

GT-ER, are you sure it's coming from the engine? unless if you have a knock listening device, it's a bit difficult to tell if it was ur engine or not.

GL

GT-ER Oct 19, 2010 05:09 AM

I had my wife accelerate my car while in D with the brake pressed and I could here a faint knock coming from the engine. It sounds like it was deep within, but not like it was something banging on my firewall or anything.

I'm hoping it's the same type of wear my GTI had. The wrist pins just had some play and they would lightly knock, but it never failed even at 425whp.

go-fast Oct 19, 2010 05:15 AM

could be carbon knock,drop a bore scope down a plug hole and see how nasty it is.

djamps Oct 19, 2010 09:16 AM

If it is knock (not ticking) gets louder under load it's probably bearing/rod related. G/L man...don't blow a hole in ur block!!!

str8dum1 Oct 19, 2010 09:18 AM

it still is knockin with the meth as well? my daily knocks if i use 87 octane. You guys dont have clean 93 there do you?

4SHIZZIL Oct 19, 2010 09:42 AM

sounds dumb but have you checked the oil levels?

Vince@R/TTuning Oct 19, 2010 10:39 AM

Cut the oil filter open and see what ya got. 9 times out of 10 that will tell you when you have a bottom end noise. we cut open just about every oil filter we take off a customers car during services..

Also maybe send the oil out to Blackstone Labs..they are real good with giving you an idea of what ya got goin on...

GT-ER Oct 19, 2010 11:38 AM


Originally Posted by Vince@R/TTuning (Post 8730941)
Cut the oil filter open and see what ya got. 9 times out of 10 that will tell you when you have a bottom end noise. we cut open just about every oil filter we take off a customers car during services..

Also maybe send the oil out to Blackstone Labs..they are real good with giving you an idea of what ya got goin on...

Too late...I just threw out the filter and the trash already came by. :icon8:


Originally Posted by 4SHIZZIL (Post 8730791)
sounds dumb but have you checked the oil levels?

Yup, I even changed it to a thicker oil to see if it went away. Nothing changed though.


Originally Posted by str8dum1 (Post 8730741)
it still is knockin with the meth as well? my daily knocks if i use 87 octane. You guys dont have clean 93 there do you?

It's not detonation, I have 93 here and have yet to hear any detonation at part throttle.

4SHIZZIL Oct 19, 2010 11:43 AM

maybe a valve going bad?

can you get us a video with sound?

djamps Oct 19, 2010 11:47 AM

Drop the pan and take a look (since you already tossed the filter)


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