Need Help Identifying Knock - '93 Tsi FWD Options

[RacerX11]

Ok, here's the scoop. A co-worker has a '93 Tsi FWD 5 spd. Around 80K on the clock. Over the last week and a half it has developed a strange knocking sound. He has described it to me the past several days, and this afternoon I had the opportunity to listen to it. It has the sound of a rod knock, but it is very strange. It isn't a constant knocking. It comes and goes with a pattern. With the car started cold, and at idle, it gows gradually louder, then quieter, then repeats, about every 5 seconds or so. If you raise the rpm above idle 500 rpm or so, it goes away.

The sound appears to be coming from the rear driver's side of the egine. I am thinking something with the balance shaft(s). Maybe a bearing, or loose pulley, or something. It doesn't seem to be engine-load related, as you can lug it down around idle speed, and it will still make the noise, the same as just sitting at idle.

It definitely doesn't sound like valvetrain, and I am pretty sure it isn't a rod (not 100% ruled out, but I doubt a knocking rod would have lasted this long, and it would still knock at higher rpm's). The noise has been getting worse over the past week, so I'm not sure how much longer it will last before it becomes terminal. He is still driving the car to work (I haven't been able to convince him to park it yet).

Just a little history, the car broke a timing belt 3 years ago. I took a look a look at it, put a new belt on, and ran a compression check. The middle two cylinders were at the low end of spec, the outer two cylinders were at the high end. I figure some slightly bent valves. We put on a new belt, crossed our fingers, and he has been driving it ever since (20K miles or so). Other than this, no major engine problems.

Any thoughts? Has anybody had similar problems with the balance shafts? Anybody around Peoria want to take a listen to it?

Marcus, how much would you guys at SloPny charge to take a look at it? I hate to see him take it into the dealer and get raped, and I don't have the time to work on it.

Thanks,
Marty

[90GSX]

unless its been totally abused, 80K is too early for rod knock. Does anyone think it could be a case of 1G crankwalk?

[akamiami]

there was a blue awd talon that got passed around quite a bit that had a knock sound something like what you're describing before spy ended up buying it. It turned out to be the hydraulic tensioner for the t-belt which was fixed by ::ducks for cover::......hughes. The pulleys, as spy mentioned, would also need to be replaced as well. They're recommended replacement timeframe is the same as the t-belt.

[RacerX11]

He doesn't seem to have any problems with the clutch, so I don'tthink it is crankwalk.

I don't believe the tensioner or pulley(s) were replaced with the belt. If I remember right, there are two idler pullers. Do they both need to be replaced?

If it is the tensioner and/or pulleys making noise, should the T-belt be replaced again as well?

Thanks guys!

Marty

[AWD DSM 1]

Oil pump?

[RacerX11]

I am pretty sure it isn't the lifters. I am pretty familiar with DSM lifter noises, and this sound just isn't right. The noise coming and going every 5 seconds is very rythmic, and regular, almost like it is some harmonic between the frequency of the engine and the pulleys.

It does it with the engine warm as well, I just happened to hear it on a cold startup. By the 500 rpm, I meant raise it 500 RPM above idle, which is around 800-1000 rpm cold. The oil pressure seems to be good as well.

Right now, the tensioner/pulleys theory is sounding the best to me.

I just about have him convinced to take it in and get checked. I am figuring on having the t-belt, tensioner, and pulleys replaced.

Do you guys reccomend Mitsu parts, or what? I know when I had my Talon, the factory parts were expensive, but not many places caried aftermarket parts.

Thanks,
Marty

[akamiami]

For god's sake, don't have him take it to mitsu. those dumb f*&^s misdiagnosed the blue car as rod knock and said it would need a new bottom end.

Yes, the hydraulic tensioner, tensioner pulley, and idler pulley should all be replaced with genuine mitsu parts. I'd estimate the total cost to be around 100 for the parts. I'd say to go ahead and use the same timing belt, since it's only got 20K on it. The water pump should also be replaced about now, so I'd put that on the list if it wasn't recently done.

Right now I'm 90% sure it's the tensioner that's making the noise, that little lever arm clicks when it hits the brackets down there if the hydraulic tensioner is shot.

[turbohcar]

I would agree with Akamiami. Make sure you replace the water pump and all the tensioner/pulleys too. I've never had this problem but I've seen several bad pulleys off of high mileage motors. Good luck

[awd4kicks]

Sounds like you guys have this pinned down, but I'll throw out another one for you to look at just in case.

The crank dampener/pulley often comes apart on the DSM's as they get older. granted the accessory belts would probably get thrown in most cases, but it's easy to check.

Good luck.

BTW - If you friend wants to get it checked out, we would be happy to diag it for $20 at Slo Pny.

[99Spyder]

Pulling this one back from the past to see if anyone remembers the resolution...

I seem to have the same symptoms and hope that the end of this story was a t-belt tensioner.

[RacerX11]

Wow...blast from the past. If I remember right, the problem turned out being a loose/broken crank damper/pulley. Shortly after this thread, it came apart, taking the accessory belts with it. It was repaired at SloPony under Marcus' watchful eye.

Marcus,
Do you recall if it was a broken damper, or was it just loose?

Marty

[99Spyder]

As soon as I get done skimming the board here I am going to go tear into it. I am expecting the tensioner still as at one point yesterday the belt was loose enough that I think I could have slid it off of the cam gears