Rattling sound under engine RPM increase, any ideas?

[MisterTurbineTwister]

Well, I'm kind of sceptic of the lower half of my engine right now. Recently, I noticed what sounds and acts exactly like detonation (ping) when the RPM of my engine increases, even when it is not under a load (in gear).

I don't understand what is making the sound. I don't think it's the injectors making the sound. I can hear the injectors and they are operating fine. The engine actually runs perfect other than this sound. It's not a typical rod knock sound. It comes in at about 2000-2400 RPM and it sounds like it goes away at 4000+...The sound is NOT present at idle and load changes (in gear or in neutral) doesn't affect the sound to any degree.

I have confirmed that the initial timing is set at 10 degrees BTDC with my light and I'm starting to think that I may have a problem with a connecting rod.



I would almost label it as detonation ping, but why wouldn't the ECU pull timing for detonation? I am always running 91 Octane fuel and I have no modifications made to the engine what so ever. Anything that was redone was done factory replacement.

The thing that scares me is that the oil pressure gauge reads normal at idle, but it doesn't seem to increase like it usually does with RPM increase.

I don't know if it's telling me the truth because it is the original pressure sending unit and this thing did go through it's normal head gasket at about 115,000 and it has about 124,000 on it now. I'm thinking that whatever gunk got ran through the engine may have fouled up the pressure sending unit, but I'm not entirely sure on this. It could be telling me that something is not right (clogged oil pickup, dead pump, etc.) or it could be false.

The two different issues here may or may not have anything to do with eachother.

Should the ECU throw a check engine light when the knock sensor detects detonation? I am not getting a check engine light.

What is the likely cause of this sound? It does sound identical to detonation ping, but I don't know why it would do that, because of the ECU and the knock sensors in the side of the block. I just don't know where else to go for diagnosis.

I have changed the oil and checked it for metal and it's clean. I ran a magnet around through the draincock hole of the pan and I got nothing as well and the filter was the same, which is comforting.

Any experience and help on the matter would be appreciated.

Thanks for the input!

 

[huntin5L]

If you have a camera that does mpegs, try to do what i did. Take a small video of it and throw it up on www.putfile.com. This may help the more experienced help determine the problem by the sound. It will only allow you to do about 25 seconds of movie time, but it should be enough. By the way its free !

 

[MisterTurbineTwister]

That's a nice resource you've got there! Thanks for the information. I did some more brain storming and discovered and eliminated the problem.

I decided to fill the crankcase with oil after draining it and changing the filter. I turned it over with the fresh oil and the new filter and both of the problems are now long gone. I drove the car up to running temperature and put it through it's normal numbers and the problem is genuinely corrected.

What I DID discover from this research and diagnosis is something that is VERY importaint and somewhat overlooked and I think other Supra owners should note and pay careful attention to. It literaly saved the life of my engine.

Do NOT run 20W50 oils. I don't think that this was the entire cause of the problem, but I discovered that the viscosity of the 20W50 oil is too high to operate within the clearances of the 7M-GE and 7M-GTE engines. It will carry the bearings and they will have adequate float and protection for about 2,000 miles and maybe a little longer, but it will give you somewhat of a false read out in your oil PSI gauge (usually read low) due to the very small passage that it functions on.

It is better to run thicker oil than too thin (like 10W30) because of the tolerances within the bearing clearances needing higher viscosity oils to safely protect and float bearings accurately, but I discovered that 20W50 oil, when it begins to break down after about 2,000 miles will become very unstable in viscosity and actually become too heavy for the filter, bearings and the pressure sending unit to use. It actually keeps itself OUT of the smaller areas that the oil needs to get into after the oil was cooked for the 2,700 miles that I put on this change I was going to go to the normal 3,000.

Ultimately, it was the filter that caused the flow restriction from having the 20W50 oil pass through it and create thicker contaminates in the filter element.
This was what was creating the quiet rattling noise that I experienced (bearings slapping) as well as the drop in oil pressure read out.

My car does not burn any more than about 3-5 ounces of oil inbetween oil changes and it doesn't leak anything.

The oil pressure read out was at about 20 PSI at idle and 35-40 at 3000RPM with the 20W50 until about 2,600 miles on the oil, then it dropped off horribly and I did not drive it more than 1/4 mile back to my house at near idle speeds to put it up on jackstands.

Once I put the 15W40 oil in with the new filter, the car now idles at 35PSI and is up around 50PSI at 3000RPM.

I'm going to back off the milage from 3,000 to 2,500 miles for each oil change and strictly use 15W40 oil from here on out and I would strongly suggest this to every other Supra or Cressida owner on this forum with a 7M or JZ powerplant.

Also:

I did change the head gasket (like everyone else) at about 115,000 miles which was about 3 oil changes ago. I did NOT run a detergent cleaner through my oil system and drain it after the head gasket was replaced. MAKE SURE YOU DO THIS if you don't have the bottom half of the engine rebuilt! All of the crap from the antifreeze mixing with the oil may have had some factor to this problem (although it didn't show up in any of the other two oil changes), it's just not a bad idea and it's cheap insurance for your oil pump and your bearings!

 

[huntin5L]

i run 20w50 no problems as of yet, i do have a noise which im trying to narrow down. I think it is related to my fuel pump. Is there a second pump for the fuel?

 

[huntin5L]

It is weird i had a post about this earlier. If i am parked and i go to turn my key to the off position, little by little the electronics turn off, but the motor still runs, noise goes away. It is some kind of pump of sort, but don't know what it is. It does increase with revs, but not as noticeable as with it just being at idle.

 

[huntin5L]

congrats on finding the issue too.

 

[MisterTurbineTwister]

Well. Like I said, I had absolutely NO problems with the 20W50 oil for about 8,600 miles after the head gasket and the noise just started to rear it's ugly head 2 days ago. The 20W50 that was in my car when I drained it had 2,635 Miles on it exactly and it caused the oil starvation problem. If I were you I would step away from the 20W50 oil and buy any good 15w40 oil to replace it as soon as possible.

What is the sound coming from? Is it a whirring sound or a tapping or rattling sound? It may be your fuel pump, but if what you are hearing is anything close to a tapping or rattling sound that is NOT your fuel injectors, I would change the oil immediately. I was at no feud with 20W50 until it almost ran my bearings out of lubrication. I had absolutely not a single problem until this week with it. If you go from 20w50 I gaurantee that your boost will spool quicker and you will also run significantly higher oil PSI. The difference in the 15W40 performance over the 20W50 is immediately noticed on the oil change. You'll be glad that you did it!

You may want to check that your fan clutch moves smoothly like it should.

Do you have the sound posted on an mpeg like you suggested I did? I could try to pinpoint it.

 

[shaeff]

Should the ECU throw a check engine light when the knock sensor detects detonation? I am not getting a check engine light.

no. the only thing that is related to knock sensors code-wise is CODE 52 which is NOT when the sensors detect detonation. 52 is when there is a bad connection between the sensor(s) and the ECU, or when one of your KS's are malfunctioning (read dead).

when knock and/or detonation is detected, the ECU will retard timing and enrichen your fuel mixture. it will most likely not throw a code.

-shaeff

 

[Idealsupra]

I would step away from the 20W50 oil and buy any good 15w40 oil to replace it as soon as possible.

thats the stupidest thing ive ever heard....really it is...

hell some of the MANUALS for the supras say to use 20w50... ive run 20w50 forever now and have had zero problems...i also know of at least 5 other supras who run 20w50 with no problems...

the oil itself wasnt the problem...if you ask me...you were low on oil...you put in new oil at the correct level and the noise went away because you were probably hearing the beginning of your bearings being toasted....

 

[MisterTurbineTwister]

Thanks for playing, but no, the showroom goes to Bob with 300 points. The oil was full at the time of the change. I pulled 5 quarts out and replaced it with 5 quarts.

How do you explain the increase in oil pressure showing on the gauge going from 20W50 to 15W40? Even when I wasn't experiencing any problems with the 20W50 oil, I got an easy 15-20PSI increase over my 20W50 PSI numbers just by switching over to 15W40. Like I said, I didn't think that this was ALL of the cause of the problem and I am also suspicious of the sludge from the BHG swap about 8,600 miles ago, but I know that the heavyer 20W50 viscosity was a significant factor to this problem, because the oil level, filter and change milage were not neglected and it should NOT have done this.

Like I said, ultimately it was the oil filter restricting the flow from the pump. I was dumbfounded when I saw the globby mess inside the filter and what bothered me about it was the fact that the oil was still a respectable color on the dipstick and in the drain pan. The car does not use oil, smoke or leak anything and it runs perfect.

I also noticed quite a bit of spool increase in the lower end of the engine RPM from the turbo as well once I changed it. The manuals say to run 20W50 in hotter climates (that stay at 75 and up constantly).

 

[MisterTurbineTwister]

The only exception to this matter would be synthetic oils. I don't know what running a 20W50 synthetic would act like under 2,500+ milage in this engine because I haven't run synthetic in it. Synthetic oils are far superior in protection and heat breakdown resistance levels.

 

[Idealsupra]

Thanks for playing, but no, the showroom goes to Bob with 300 points. The oil was full at the time of the change. I pulled 5 quarts out and replaced it with 5 quarts.

How do you explain the increase in oil pressure showing on the gauge going from 20W50 to 15W40? Even when I wasn't experiencing any problems with the 20W50 oil, I got an easy 15-20PSI increase over my 20W50 PSI numbers just by switching over to 15W40. Like I said, I didn't think that this was ALL of the cause of the problem and I am also suspicious of the sludge from the BHG swap about 8,600 miles ago, but I know that the heavyer 20W50 viscosity was a significant factor to this problem, because the oil level, filter and change milage were not neglected and it should NOT have done this.

Like I said, ultimately it was the oil filter restricting the flow from the pump. I was dumbfounded when I saw the globby mess inside the filter and what bothered me about it was the fact that the oil was still a respectable color on the dipstick and in the drain pan. The car does not use oil, smoke or leak anything and it runs perfect.

I also noticed quite a bit of spool increase in the lower end of the engine RPM from the turbo as well once I changed it. The manuals say to run 20W50 in hotter climates (that stay at 75 and up constantly).

1) the engine take 5.5 qts...problem ONE
2) problem TWO.. WOULD BE YOU SAID IT YOURSELF...IF THE FILTER IS FUCKED IT WILL STARVE YOUR WHOLE SYSTEM...

its NOT the oil viscosity...it was the filter and the lack of half a quart...

 

[MisterTurbineTwister]

You still haven't said anything about the oil pressure increase when going away from 20W50 and going to 15W40. Even if the problem was entirely from the filter being fouled up from something else other than something caused by the 20W50 oil, the higher PSI level readout gained when going to 15W40 should be reason enough for changing over to it. That's just a no brainer.

The numbers for the Oil capacity are as follows according to the Toyota factory service manual:

Oil Capacity (7M-GTE):
Dry fill (This means a DRY, new or rebuilt engine only! Ask a machinist why.):
5.4 US Qts.

Drain and refill without filter change:
4.3 US Qts.
(I don't know why you would do this, but they list the numbers for it)

Drain and refill WITH oil filter change (the way you're supposed to do it):
4.7 US Qts.

Look it up in the TSRM and you will see the exact same numbers.

If you're putting 5.5 Qts. in your pan, you're probably getting oil slapping the crank ( otherwise known as windage) which whips air into your oil and then air gets fed into your pressure system.

I just go by the factory recommendation and I put an extra .3 Qts in just to get rid of the few ounces left in the last bottle.

The dip stick reads full after it has been idling for 1 minute and shut off for 1 minute after.

 

[IJ.]

Not even close to the crank with 5.5 qts.

 

[Dirgle]

I'm willing to bet you have the early signs of rod knock. That would be the correct RPM range for it to be heard at. And I'm also willing to bet the sound returns as the viscosity of your newer oil breaks down. And as the oil breaks down it becomes more fluid and doesn’t build up pressure because of the greater clearances caused by the wear on the bearings. At least that's what happened to me.

 

[MisterTurbineTwister]

The more oil you have in your pan over recommended level, the more oil will splash on to your crankshaft under acceleration and deceleration. If you've got oil touching the crank from idle at a dead stop, you're at least 1-1.5 quarts too full and then you've got some serious problems.

The common windage problem occurs when the vehicle is moving and the oil is sloshing around. Windage usually occurs when the oil quickly waves towards the back (or side) of the oil pan under acceleration before the oil pickup sucks more oil into the system and is able to lower the mass of fluid in the pan. The more fluid you have in the pan, the more windage will occur. (and there is no way around some windage even at normal levels without a windage tray and or a crank scraper)...

dirgle, That's what I suspected, but I don't think that this is as permanent as a typical connecting rod bearing slap. The sound was as quiet as the injectors (about half as loud) and it would only happen under those RPM numbers, never at idle and only then at lower oil pressure read outs in those RPM ranges.

I know some oil starvation did occur, but it always had at least 15lbs. It just wouldn't increase with engine RPM any higher than 1800 with the old filter.

As soon as I noticed the problem, I suspected detonation, took it home (1/4 mile from where I was) and drove it at no more than 1500RPM before shutting it off and correcting the problem.

The problem has since gone away and I am actually seeing much higher oil PSI numbers than I ever have with the car now (at least 25-30 at idle and about 50-55 at 3500RPM, which doesn't fit the typical symptoms of early rod knock. I think I'll just keep a close eye on my pressure gauge and check the pan at every oil change until I am satisfied that the problem definately is gone. I'm very positive that it was something that didn't do much damage, if any at all, but only time will tell.

 

[IJ.]

You might want to take a pan and fill it with water and see how much it takes to get anywhere near the crank before stating absolutes on this subject.

I'm trying very hard NOT to be a cock here MTT.

 

[Allan_MA70]

check to make shure the crank pully bolt is still there! i have found them siting on the stone tray of many a M series engined car!

 

[MisterTurbineTwister]

by the time you fill the pan completely full of any fluid, some part of the crankshaft will be touching the fluid. Just look at a cross section of the 7M engine (2nd page of the TSRM engine section) and note how far the balancers and connecting rods and journals go down below the gasket mating level of the pan. It happens with most other engines as well for that matter.

The matter of windage doesn't care if the fluid touches the crankshaft at a dead stop. The problem with overfilling can cause the crankshaft to touch the fluid (if you go way overboard), but even a correctly filled oil pan, that has absolutely no chance of having the crank touch the surface of the fluid at a dead stop will get windage, just from having the fluid slosh around in the pan from the vehicle moving. You can't avoid it. Even with a windage tray and a crank scraper, some windage does occur.

The problem that arises with overfilling a pan, even if the oil still doesn't touch the crank at a level and dead stop, is that you are simply adding fluid mass into the pan that can and will make more contact with the crankshaft when the vehicle is moving. Windage occurs when the fluid moves within the pan and adding more fluid will bring on more windage occurances (fluid to make contact with the crankshaft). It's just a plain and simple physical fact.

It's just an increase in factor that the fluid will make contact with the crankshaft as the oil level is disrupted when the vehicle is in G force changes.

Here's a simple example:

If you have a jar of water that is 3/4 full and you shake it side to side, there is a chance that the water will touch the lid of the jar. Add more water into that container and you increase the amount of water touching the lid of the jar when it is shaking.

If the objective was to not have any water touch the lid of the jar, but you had to shake it, increasing the amount of water would only make the objective harder to reach.

 

[Idealsupra]

well regardless of what you think..im sticking by my previous statements...TOYOTA says 5.5 quarts when doing an oil change with a filter...so maybe you should check THAT out...

and if you want to go by toyota so damn much...like i said before...the supra MANUAL says 20w50 in some of the models.... so why would 20w50 be bad for the engine?