First signs and ways to tell if you have rod knock??

[Turbo Habanero]

So here's the deal today I decided to clean the crappy out of my motor and re grounded a couple of wires replaced the heater hose I had that bypasses my heater control valve also.

Well when i went to start the car (hood open) and heard what sounded like rod knock.

I remembered that rod knock shows up around 2,000rpm or at the least is very audible.. so i gave it a little gas and the sound goes away completely.

So far what I've concluded is that

1. It's not rev dependent
2. It only seems to be there when i first start the car
3. It's not temp related
4. I have plenty of oil
5. It's only audible at idle and goes away if a tap the throttle while normal driving I can not here it at all at idle or speed.

Only way I can describe the noise is in the movies every time a car runs out of fuel it always makes that signiture sound of knocking as it comes to the side of the road.

So my question is there any way to diagnose rod knock ?

 

[IJ.]

Pull an injector clip at a time and see if it stops doing it, no fire = no cylinder pressure and no knock.

 

[Turbo Habanero]

Thanks Ian

I've read this before slipped my mind.

One problem though knocking does not last long enough to test it.

 

[IJ.]

Pull the clip and start it, shut down replace the clip and pull another and so on.

 

[shaeff]

Aside from the standard rod knock test as Ian stated above, check to make sure everything is tight. Check the pulleys (especially the crank pulley), motor mounts, brackets, etc... There are a lot of things that can cause a knocking sound.

 

[AJ'S 88NA]

Aside from the standard rod knock test as Ian stated above, check to make sure everything is tight. Check the pulleys (especially the crank pulley), motor mounts, brackets, etc... There are a lot of things that can cause a knocking sound.

Diluted oil from too rich AFR?

Kind of thought that was going to be one of your next threads.

http://www.supramania.com/forums/showthread.php?20486-Rod-Knock-Diagnosis-and-FAQ

 

[GrimJack]

If it's an auto, loose flexplates make the same sound, too.

 

[Turbo Habanero]

So here is what i've done so far.

1. Followed Ian's post and pulled every injector clip one by one (When sound was present) but nothing changed but the motor ran a little rough due to being on five cylinders

2. Followed Shaeff's advice started checking everything plugs wires,pulleys,brackets,mounts

3. Last oil change i did was about 500miles ago and it was to make sure i didn't have fuel or coolant in the motor and it checked out fine. I drained about a quart to check it today and it still is in good shape.

Grim it's a R154 with a Stock Clutch and pressure plate replacement about 5,000miles on the clutch.

 

[IBoughtASupra]

I know 1JZ/2JZ runs rich on thr stock ECU, like 10-11 AFR cold. I believe 7Ms are 10AFR in boost, so I don't think that would foul the oil.

And if it was running rich like that, wouldn't it have black smoke indicating how rich it was?

Thoughts?

 

[GrimJack]

So here is what i've done so far.

1. Followed Ian's post and pulled every injector clip one by one (When sound was present) but nothing changed but the motor ran a little rough due to being on five cylinders

2. Followed Shaeff's advice started checking everything plugs wires,pulleys,brackets,mounts

3. Last oil change i did was about 500miles ago and it was to make sure i didn't have fuel or coolant in the motor and it checked out fine. I drained about a quart to check it today and it still is in good shape.

Grim it's a R154 with a Stock Clutch and pressure plate replacement about 5,000miles on the clutch.

Have you checked the torque on the front main damper pulley yet?

 

[Turbo Habanero]

Grim do you mean the Crank Pulley ?? if So i do not have a Torque wrench but i took a 19mm wrench and tried to tighten it

You can here the knock around 0:55 Also seems to be louder around the CPS and Turbo Does not get any more Audible with the oil cap off

[video=youtube;cBNsuyW--nU]http://www.youtube.com/watch?v=cBNsuyW--nU[/video]

 

[IJ.]

The Damper bolt is 195ft/lbs a wrench isn't going to cut it... :nono:

 

[Turbo Habanero]

The Damper bolt is 195ft/lbs a wrench isn't going to cut it... :nono:

Ah got ya I will go borrow a Torque wrench from Autozone and make sure

 

[IJ.]

If it's been ran loose at all it shags out the bore and snout and will rock back/forward till it destroys the keyway, not saying this is your noise but it'sd a possibility.

 

[Turbo Habanero]

Okay for what its worth it does not move in or out or side to side. But i will still make sure it's nice and tight

 

[gsxr141]

pull out the crankshaft pulley bolt, put some loctite on it and tighten it to 195lbs.
i had an intermittent noise like that, and suddenly there was a "lighter" second noise. turns out the bolt was loose, and just finger tight.
i do still have another noise around 2,000 rpm, but that's for another day.

 

[radiod]

Have you tried going around the motor using a stethescope yet?

 

[Turbo Habanero]

Not yet for now I'm just letting the car sit. Hopefully I will find the problem.

But I don't want to make it worse if it is rod knock.

It only happens some times and only at idle sounds like the engine is trying to stall out more then anything as soon as you give it a little throttle sounds fine.

 

[Skeezix]

From the video, seems like an injector, every time you make a pass by the fuel rail I hear it more. I had the same noise on my car right after I rebuilt. Stethoscope it for sure. I just put a screwdriver on the injector and it was rank loud, put it on intake runner and valve cover on same cylinder, still there but no where near as loud as on the injector. Would love to take a video for you but I spun some more bearings Sunday. PS. don't push the 7M to 150 MPH lol, bad idea

 

[IJ.]

From the video, seems like an injector, every time you make a pass by the fuel rail I hear it more. I had the same noise on my car right after I rebuilt. Stethoscope it for sure. I just put a screwdriver on the injector and it was rank loud, put it on intake runner and valve cover on same cylinder, still there but no where near as loud as on the injector. Would love to take a video for you but I spun some more bearings Sunday. PS. don't push the 7M to 150 MPH lol, bad idea

You're doing it wrong then mine used to cruise @ 150