Venturi Ass'y Leak (1 Viewer)

[afnos]

Been lurking for a while on the 2LTE issues, but finally have one of my own. It's not overheating or head cracking, thank goodness.
I was accelerating from an intersection and halfway through heard a sudden, loud escape of air that sounded like a serious tire puncture. I pulled over immediately and checked all my tires... nothing. I opened the hood to look for any signs, but couldn't find anything. I manually engaged the throttle and could hear the air escape beginning again at around 1.5-2k rpm. I couldn't isolate it right away so I limped it home staying under 2500 rpm. Long story short, I found the leak area, but I'm not sure it's the exact source. The leak is from the venturi assembly (parts diagram nomenclature, not sure of the generic name). The pictures below are of the left side, and aft, where the throttle pulley is attached. The hole I've circled is where I believe is the leak. The second picture, taken from the left side, is of a cap that I suspect blew out of the aft hole. I don't know if it was there to begin with, so I'm not sure if that is the case.

1991 LJ71 brought over from Japan. I bought it there about a year before moving back to the states. 103,000km and no modifications, that I'm aware of. The prior owner was a mechanic, so he may have changed some things.

 

[JimmyPrado]

I'll check mine when I get home. Has yours had the EGR stuff deleted off? I'll get you a few links too.

 

[JimmyPrado]

Here's mine from the top looking down. Mine is a 2Lte. If yours is as well, it appears your are missing the circled stuff. MegaZip diagrams don't show that side of the Venturi, so I'm stuck as far as what exactly that is.

If you don't have this, bookmark it. It's a great source for diagrams and parts.

Toyota LAND CRUISER Car & Auto OEM Parts | 38286

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www.megazip.net

 

[afnos]

Thanks! I’ll take a look. Still has EGR system.
Thanks for the link. I’ve been using the Toyota EPC site. Has the same diagrams, just formatted differently, and gets you to the same parts ordering process.

 

[afnos]

It looks like I have that part. I have found another potential culprit that is very close to the air leak. It’s hard to tell by feel, since it only leaks when the boost builds.
The second picture shows a small crack in the gasket. I’m not sure if the pressure is high enough for that small of a crack to be a factor, but I’ll tear it apart this weekend and see.

 

[Nas90tdi]

Unlikely that gasket is your source of that sound.
Check your intake hoses between the turbo and the intake. If they are original they get very hard and brittle.
Loose/split intake hoses will make the exact sound you describe. Did you lose power at the same time as the sound started? My guess is you immediately let off, but if not, you should have felt a substantial decrease in power.
I have had the misfortune of popping several intake hoses off on various diesels, usually leading back to something I had done. But that's another story. Really disconcerting the first time it happens, but you will never mistake that sound for anything else again.

 

[afnos]

The intake hoses are all new-ish. That was my initial thought so I pulled them off, inspected them, reinstalled with new clamps, and used soapy water to check for leaks. Nothing. There is a definite air leak on the aft side of the Venturi assembly somewhere.

 

[Nas90tdi]

Unless something cracked, not a lot back there to leak. Is it maybe the exhaust return on the EGR system? There is a pipe that goes completely around behind the engine back there. Attaches directly below the intake. That's the only thing I can think of back there to leak air since you still have your EGR system in place.

Certainly not going to doubt you that there is a press fit cap back there however. It's been a minute since I have all that apart on my truck last. I will go out and take a look at my truck later, with a mirror. I have too much intercooler and stuff to easily see back there.

 

[afnos]

Finally got an inspection mirror to fit between the throttle pulley and venturi assembly. I’m 99% sure this hole is the culprit, and I had a press-fit cap departure.
Anyone know if this is a simple task to re-cap? Maybe by a machine shop?
Probably wouldn’t hurt to research an EGR delete while it’s apart.

 

[JimmyPrado]

Here's your EGR delete info. Just keep what's inside the green. All the rest can come off. I have a bunch of pics of this in my build thread in my signature as well. Hope it's helpful. As for the press fit, I would imaging a machine shop could do it.

 

[afnos]

I’m gonna try to bung & clamp it for a quick fix until I have time to take it to a machine shop. I don’t want to weld anything or gunk it up to much and make later repairs more difficult. It’s my daily driver right now until my wife heads out of town and I can use her car.

 

[afnos]

I cut some rubber pieces off of a cheap bungee strap and hose-clamped it over the hole. It interferes with throttle operation a little bit, but it doesn’t get stuck. More of a trail-fix, but I think it will get me the 1 trip to work I need it for.

 

[afnos]

My “trail fix” has lasted as long as needed (long enough to pick up a cheap, reliable Subaru for my daily).
After some minor exploratory surgery I found remnants of clear RTV around the hole, and directly opposite, a small bolt secured with more RTV, covering the other hole. Also, a missing/removed disc from the valve (any issues with that?)
I took the existing bolt/plug out and it looks like it actually belongs based on the rubber washer and plastic sleeve over the threads.