low rpm knock advice

[ATL88Supra]

ok the facts, 1988 supra 7mgte, rebuilt by me, 20k miles so far, automatic

aftermarket blow off dont know the name of it. was on the car when i got it

new plugs coper gaped to spec.


fresh oil changed last night 15 w 40

sounds like rod or spark knock

when i go above 900 rpms sounds is gone

please advise

-David

 

[IJ.]

Dave: What's the static timing set at?

Is this under load or free revving?

 

[ATL88Supra]

Dave: What's the static timing set at?

Is this under load or free revving?

free revving, note if i turn on the AC the noise will increse untill 1000 rpm is reched then it go's away or if i put the car in gear, mostly it happends when ever the rpms dropto 900 or below

ie, the car is sitting idling i turn the wheels some and the knock gets loud cause of the load of the power steering

also note there is no knock when the car is cold.time

edit: timing is set correctly per tsrm checked it 10 mins ago

Edit edit: when i put the car in gear and drive the sounds dissapears

 

[IJ.]

I'd try it without the Pwr Steer and AC belts and see if it's still there.

If it is check the balancer bolt it needs to be 195 ft/lbs.

 

[ATL88Supra]

I'd try it without the Pwr Steer and AC belts and see if it's still there.

If it is check the balancer bolt it needs to be 195 ft/lbs.

checked that last night bolt is at 195ish pounds

 

[IJ.]

Good!

Try it with the belts off and see

 

[ATL88Supra]

Good!

Try it with the belts off and see

did it, could still hear the sound not super loud but it was there

 

[IJ.]

Try pulling injector clips one at a time?

 

[ATL88Supra]

Try pulling injector clips one at a time?

ok now it just runs like shit(when testing the injectors) but no knocking noise

when testing one by one

 

[TurboStreetCar]

what weight oil do you use? you said it only knocks/makes noise when hot?

 

[IJ.]

So the noise didn't change at all pulling the clips?

 

[ATL88Supra]

what weight oil do you use? you said it only knocks/makes noise when hot?

15 w 40

it only makes the knocking sound when at idle or if the rpms drop below 900, lower the rpms go louder it is but higher the rpms the sounds is gone

 

[ATL88Supra]

So the noise didn't change at all pulling the clips?

nope
still there, not as loud but still there.

 

[supraguy@aol]

nope
still there, not as loud but still there.

Hold the rpm at 2500 by hand. Is there a rattly sound there?

 

[ATL88Supra]

Hold the rpm at 2500 by hand. Is there a rattly sound there?

no like i said above 900 rpms the sound is gone

 

[CyFi6]

hook up an oil pressure gauge, you might have low pressure at idle. Mine has really low pressure at idle but normal at all other rpms. If i blip the throttle to the floor when its idleing at around 750 rpms i hear a light knock, not sure if thats cause of my oil pressure or what, but ya, put a pressure gauge on it and check the pressure at warm idle

 

[ATL88Supra]

hook up an oil pressure gauge, you might have low pressure at idle. Mine has really low pressure at idle but normal at all other rpms. If i blip the throttle to the floor when its idleing at around 750 rpms i hear a light knock, not sure if thats cause of my oil pressure or what, but ya, put a pressure gauge on it and check the pressure at warm idle

i am sure its not oil pressure, as i have a new oil pump that is shimed

 

[CyFi6]

its not the pump itself that would result in low pressure in most cases, when clearances are made larger (wear) oil pressure (resistance to flow) goes down

 

[IJ.]

It's worth chucking a mechanical guage on it and checking idle pressures.

Could be something stupid like a stuck Squirter bleeding off the Idle pressure.

 

[TurboStreetCar]

defiantly sounds like low idle oil pressure.