EJ20 engine knocking...2nd engine

[Asante]

Hi guys, I need some serous help. I have a GC8A WRX fully imported from japan,

full Jap Spec everything in it. I've had it for a year and a half.

A while back I slid into a curb and damaged the right rear suspension, everything was replaced and all

went well. I noticed the alignment was getting worse after 6 months and after close inspection I was told that the rear crossmember (cradle) was bent.

Since the car is Jap spec the parts are totally different so I arranged a replacement part. After the part was replaced (which involves removing the rear diff), on collection

Of the vehicle I was informed that the engine had a knocking sound. It was the fst I've ever heard of it as the car has been totally reliable and I drove it into the workshop with a running engine.

I was told to buy a new engine, which I did. A week later and a new engine later, the imported EJ20 was in, I was present when it was started for the first time, about 30 seconds in, the engine developed a knock too!!!

Now I can't buy a 3rd engine, financially its killer! But any ideas why this would happen twice?

 

I have ideas for the guys in the workshop but I need some help please...I've driven Subarus for 6 years now and never any problems.

 

Could it be incorrect fuel added by the agent? Faulty knock sensor? Rear cranckshaft/drivetrain refitted incorrectly? Spark plugs?

ECU? Water in the fuel tank?

 

The knocking occurs exactly as with the replaced engine, at 2000rpm and I know the engine was replaced I witnessed everything...

 

Pls assist me...

[bheinen74]

is this car a 5spd or auto. if auto, it could be cracked flexplate.

 

You left out a lot of details.

[Asante]

Its a 5 speed manual, the engine block was replaced with the other one

[EVOthis]

Hmmmm are you 100% sure this is not normal and that the block hasnt been modified in any way such as forged internals?.....In my WRX..I have a EJ257 block with EJ20 heads... My cars knocks its rump roast off.. a tad quieter when warm but not much..however I made 100% sure this is normal due to the full floating wrist pins and the forged rods/pistons... there used to be a video up on youtube from someone but for the life of me I cant find it...lol...

[Asante]

My original engine was standard, the one they replaced it with is also

A standard engine. No mods as far as I know. Could it be something as simple

As the wrong fuel or bad fuel? The car had no history of engine problems

Before I took it in for a replaced rear crossbar so I'm very

Suspicious but I need the car functioning. Any ideas anyone?

I drove the car into the workshop with a sound engine, and Subaru themselves serviced

The car 2 months ago with no major recommendations or sugestions of a critical

Engine meltdown in the near future...and 2 engines giving identical symptoms???

[Quidam]

"The knocking occurs exactly as with the replaced engine, at 2000rpm and I know the engine was replaced I witnessed everything..."

 

Post a file of the noise and someone here may be able to identify that.

 

Could you hear it in the car?

 

Odds are that it's not the two engines...I would think...Or it's normal as has be said.

 

Are these Subaru mechanics?

 

Doug

[naru]

Its a 5 speed manual, the engine block was replaced with the other one

 

Hard to say,but,since only the block was replaced,I would suspect the components that were not.Heads and ......?

[Asante]

It is highly unlikey it's the engines, or maybe its just bad luck, but I paid good money

For the replacement engine knowing it would solve the issue.

 

Ok, after the full engine change the car started with initial start with no problems.

The knocking started after a few seconds, the engine was fine initially. The sound

Is like a light tapping, that is consistent with rpm, inside the vehicle you must

Turn off the music and open the windows to hear it above any ambient sound, but it is

Loud (in comparison to what sounds I'm used to out of the motor) there isn't any vibration

As such, the engine turns on, is quiet, then seems like something takes over and it starts making

The knocking sound, its non existant below 2000rpm but beyond there its evident. On both engines!

And if I do record a sound I'm assuming it would have to be with a mic placed above and dead centre

Of the engine block?

 

Would removing the rear differential and reinstalling it incorrectly somehow cause the sound?

The workshop is not a subaru workshop however they only work with Subaru's, but I am in doubt and

Maybe I need to get an actual subaru tech to listen to that noise. I will do that first thing in the morning.

What bugs me most is that the vehicle had no engine trouble before at all, until that rear crossmember was replaced

Now its a mess...

[Asante]

To explain, the engine was a complete unit with its own turbo and intake manifold.

It was a matter of lifting the old engine out, dropping in the new one, and reconnecting

All the cables and stuff, the old motor is not in the vehicle. So could this be symptoms

Of an ECU that's stuffed? Or maybe the pinging is from something loose within the drivetrain?

[The Beast I Drive]

throw some octane booster in the gas tank and top it off with the highest octane gas you can afford, and see if it still knocks. If it goes away, then it was probably bad gas, if not, then at least youve ruled out the gas theory. Check the ECU for codes, is the CEL on?

 

-Bill

[Quidam]

"Or maybe the pinging is from something loose within the drivetrain?"

 

So it's pinging and it starts at 2000 rpm?

 

Doug

[Asante]

Hi Bill

 

Thanks for that, I too assume it must be something other than both engines

I will get Subaru to diagnose the ECU, I do recall passing by a gas station about 20 kms before

Taking the car in, ithe tank was empty and I only added about 8 litres as it was heading

To get the rear crossmember changed, and I planned to fill it up once it was fixed.

I mentioned that it could just be bad fuel but the guys don't take me seriously, they insist I

Need a new motor, which is not viable. The new engine started up first time, ran a bit, then started pinging

Like the old motor, so I'll tell the guys to swap fuel filters, drain the tank, top it up and let it run.

The subaru diagnostic to engine metallic knock states either *loose flywheel mounting bolts

*damaged engine mounting *wrong spark plug *improper gasoline. so, refuell her and change fuel filter,

Then diagnose the ECU. I've heard another scoobie with an engine knoc and it sounded terrible,

Here its more of a pinging and I actually hope its fuel starvation or pre detonation

We'll see tomorrow, the car starts with one crank and if left to idle there is no knock, only when rpm increases

 

I hope this helps a bit more with diagnosing the problem. 2 different engines, same symptoms...its blowing my mind.

[Asante]

Hi Doug

 

The noise starts at about 2000rpm but we haven't run it much in fear of damaging

The engine...the old engine ran perfectly till I took it in for the rear suspension fix, now its

A nightmare...I somehow wish you guys were with the car. It could be the engine itself but

Thing is to get a 3rd engine to check is a timely and costly option. If its something else

Then I guess I have 2 EJ20 motors that can run perfectly...I will start with the fuel, then ECU

And maybe check that when reconnecting the lot the flywheel mountings were conncted properly.

I drove the old engine a bit and the sound definitely increases when the engine is under load,

Its quiet when just coasting on the throttle, ignition timing is a factor here as well...what's the best

Way to start checking stuff, and in the process eliminate improbable causes?

[Quidam]

If by some chance what you're hearing is preigniton-pre-detonation, leading to detonation, your engine can't conpensate for it through the engine management.

 

But IDK about your engine...if it's detonation in that manner, it will start under load...

 

hth

 

Wild rump roast guess. Change the plug wires.

 

Doug

[Asante]

The plug wires, would there be any physical signs to look for

Maybe on the wires? I am going to ask the guys to change that too.

Another question is, if the trial and error takes a while, it is possible

To damage the engine, correct?

My other option is to let them put in another motor, I paid for a new engine

And they might've got a bad one, I wait till I get what I paid for, which is

A servicable vehicle. They have 3 days to put in a new engine and the price

Was already agreed to so I'm not paying another cent, it sounds harsh

But they quoted me a price including labour to get the vehicle running

I've paid for the parts, now they must replace the engine at their own cost

Cos if it turns out they bought a faulty motor, I can't be held accountable.

 

I will get a Subaru mech to take a look in a few hours seeing as it could

Be a host of issues. Fingers crossed...

[Quidam]

Hey,

 

I was just thinking and if your EJ-20T has coil on plug, you don't have any plug wires.

 

Doug

 

Yea, no use in my speculating, a good bet is to have the Subaru mechanic look it over and go from there. You have plenty of info to run past him.

 

Again, I doubt that both engines are bad.

 

Subaru suggests you look for physical damage to the wires. Check the terminals for corrosion. Test resistance with an Ohm meter.

Edited February 15, 2010 by Quidam

[Fairtax4me]

Two sounds here. Which one does it sound most like?

 

This is rod knock.

 

This is lifter tick.

http://www.youtube.com/watch?v=N5oIg14ndqk

[94Loyale]

I was also figuring this, on lifter noise that is. This is a DOHC motor. If you start the motor after sitting for a while. They sound like complete garbage. Anyone that does not know Subaru's will figure the motor is going to explode. Take it out and give it a good run, see if it quiets down some. Even after idling for a while, they will quiet at idle, but still tick when revved up until you run them pretty hard. If it quiets down, its just lifter noise. Maybe the motor they swapped in had been sitting for a while?

[Asante]

That is an idea, I'm sure the new engine has been standing for a really long time

We haven't run it hard or even driven the car to give it a chance to settle, what I'll do is drive

The vehicle to a petrol station, put some fuel, and drive it back to the workshop

And if it still sounds like garbage that's that. Will advise once this is done...

 

There is another fuel filter which I also would like to swap and refill the tank with high octane

Fuel. The new engine hasn't been let to run for 10 mins so let's just see. Hope that's

The solution, also the MFI could be the problem....

[94Loyale]

I wouldn't bother putting any more parts or anything into it yet, before you try driving it. It's real common for these motors to make a lot of noise after they sit. They do sound nasty at first. Take it out, tach it up a few times. Normally within 10 miles of a good run, it should quiet down, If* it's the noise I think it is. If the motor actually is knocking....then you got sold a junk motor, and you needed a new one anyways. So you don't have anything to lose in taking it for a drive.

[94Loyale]

One other quick thing, if the no one even left the engine run for 10 minutes, How did your mechanic purge the cooling system? Before you drive it, I'd make the system is purged properly. Or else you'll have other problems to worry about on your test drive.

Edited February 15, 2010 by 94Loyale
spelling failure

[Asante]

Yes that is another factor, the engine importers are coming in

Today to listen to the motor they supplied us with and it seems like

They will replace it...I still believe there's more to it. I'll keep everyone posted

And hopefully by weeks end I can upload pics of the car back on

The road, where she belongs! Subaru pulled the history of my

Vehicle and also informed me that there was never anything wrong

With my engine since I always take it there for services and checks

So how the mechanics on changing the rear crossmember managed

To get the engine to knock, is beyond all the guys who know

My vehicle!

[naru]

Very high rpm "test drive" w/cold oil.

Edited February 16, 2010 by naru

[Asante]

Ok guys, new engines in, seems to be working fine...only driven it about 20 kms so far, the turbo 'hiss' is very loud in the car now, i kept the original turbo on there from my old engine, any ideas?

 

As for the test drive with the engine cold, i agree, the engine wouldn't knock while doing a rear cradle change...not sure why the car was started in the first place...but we learn as we go along and i should keep the car keys on me if i take it in for anything that doesn't involve the engine...

[Fairtax4me]

Loose hose. Glad you got it back running decent.