ST184R - 5S-FE Noises. What to do?

[DazzaJay]

Hi all, Got a '93 WRC Trophy ST184R and the engine as just started making some pretty bad sounds.

Here's the symptoms:

• Sound only happens when engine is hot.
• When warming up the engine, sound will be only present above 4,000RPM.
• When engine is hot, Sound will be present all the way down to 1,200RPM.
• Sound only present when there is combustion in Cylinder 1. (Disconnecting the spark lead stops the sound)

See Video:
This video shows the engine after warm up, I rev the motor and disconnect/reconnect Spark Lead 1. - the sound only occurs when lead connected to cylinder 1.

Help in diagnosis is requested.

So far, a mechanic looked at it for 2 seconds, pulled the lead and said "It's the Piston"
Another person has said "Engine is totaled"
and another recons there's something wrong with the spark lead or injector (I don't see how)

Extra Info:
No Exhaust Smoke.
Radiator is Green and Clean.
Oil is good, Replaced 5,000km ago has no signs of metal filings.
Car has done 359,000KM and has always been serviced on time.

[ZZT86]

Engine sounds OK despite the rattle/knocking when you re-connect pot 1. I would connect a scan tool to ecu for some clues but it sounds like a conrod bearing failure. I wouldn't drive it.

Edited December 15, 2021 by ZZT86

[Tony Prodigy]

Haha, the look on your face is priceless. I know that baffled look lol..

That's a very interesting issue. I suspect it also could be the conrod bearing as the noise is more prevalent when the spark plug lead is connected creating that cylinder pressure on the "bang" stroke. When the lead is disconnected, the rotating assembly just turns freely without cylinder pressure, hence no noise.

An endoscope camera could be helpful in determining piston/cylinder wall damage, but I would say that engine is done. Time for a bottom end rebuild mate.

 

[DazzaJay]

14 hours ago, ZZT86 said:

Engine sounds OK despite the rattle/knocking when you re-connect pot 1. I would connect a scan tool to ecu for some clues but it sounds like a conrod bearing failure. I wouldn't drive it.

I would, but i only have OBDII Compatible devices laying around, and this celica predates OBDII.

Don't worry, haven't been driving it like this. (Other than returning home when it first started making the noise)

7 hours ago, Tony Prodigy said:

Haha, the look on your face is priceless. I know that baffled look lol..

That's a very interesting issue. I suspect it also could be the conrod bearing as the noise is more prevalent when the spark plug lead is connected creating that cylinder pressure on the "bang" stroke. When the lead is disconnected, the rotating assembly just turns freely without cylinder pressure, hence no noise.

An endoscope camera could be helpful in determining piston/cylinder wall damage, but I would say that engine is done. Time for a bottom end rebuild mate.

 

I HAD a endoscope, but it broke a few months ago. so i will get a new one and take a look.
So far we've been quoted around $7,500 for a new engine by North Vic Engines in Cobram. But if it hasn't damaged the cylinder i could probably do piston/conrod/bearing replacements myself. (IF that's all that has gone wrong) (My Total Experience = 1x Daihatsu Mira piston/conrod/bearing replacement)

[ZZT86]

They're a good car with an average motor. Not sure how difficult it would be in ADM cars/looms but a 3S-GE or GTE conversion would be nice 😉 Otherwise just re-build the block.

[Hiro]

2 hours ago, DazzaJay said:

I would, but i only have OBDII Compatible devices laying around, and this celica predates OBDII.

 

Toyota's diagnostics of this period consists of a paperclip or short length of wire bridging the TE1 and E1 pins of the diagnostic plugs, and counting the flashes of the Check Engine Light.

[DazzaJay]

1 hour ago, Hiro said:

 

Toyota's diagnostics of this period consists of a paperclip or short length of wire bridging the TE1 and E1 pins of the diagnostic plugs, and counting the flashes of the Check Engine Light.

yeah, ive read about doing that, but some things ive read state that you need to use a resistor rather than a paperclip. so, i havent tried it due to conflicting info.

 

speaking of, has anyone tried one of these toyota to OBDII adaptors? do these work?

[Tony Prodigy]

15 hours ago, DazzaJay said:

So far we've been quoted around $7,500 for a new engine by North Vic Engines in Cobram. But if it hasn't damaged the cylinder i could probably do piston/conrod/bearing replacements myself.

$7,500 is ludicrous. Take the head off and get a bottom end rebuild done. If your confident enough to rebuild it yourself, I say more power to you. You could get away with just replacing bearings etc, but you'd want a machine shop to double check your clearances before assembly. I wouldn't just swap bearings out. The clearances will need to be in spec for it to last. If it seizes up then you're done.

Let us know how you go mate.

Cheers 

[Tony Prodigy]

11 hours ago, DazzaJay said:

speaking of, has anyone tried one of these toyota to OBDII adaptors? do these work?

If it's cheap enough, and it should be, why not give it a go ? I think it should work ok. 

[ZZT86]

I used to own one of these things back in the day & did try the "paper-clip" method - it works, you should give it a try. Or you could try the adapter which would allow you to do other stuff like reset DTC etc.