a heck of a lot of carbon buildup in the exhaust manifold of my HZJ81 (2 Viewers)

[John Young]

Wow MG... that is interesting and a lot to think about. Thank you. I will try to find a gauge on the market.

 

[John Young]

I've been doing more poking around the 1HD-FT and reading and find that the engine already has a turbo boost pressure sensor. I think it is the module at the top here:

I was thinking that I could patch into that and read it with a voltmeter.

And that lower module was partly unplugged. I think it is a vacuum regulating device according to ToyoDIY. I plugged it back in but it seemed to have no effect.

Here is a photo of the turbo sensor:

Does anyone know how to find the voltage characteristics of the turbo sensor by chance? I think it is a 89421-60030. My googling has not produced much in terms of operational specs.

 

[dan1554]

Just get an off-the-shelf boost gauge. You do have vacuum lines coming off the intake, as evidenced by the picture you showed of the one with the screw in it. I'd just tap in to that. Can't make anything worse. FWIW, like @mudgudgeon said they don't actually carry any notable vacuum in a diesel, so you could almost call them boost lines.

Install is very simple, you just run the vacuum line in to the interior and attach it to the gauge. Don't need to wire it in anywhere.

Unless you are very good with electronics and know what you're doing I wouldn't touch any factory sensors.

 

[AussieHJCruza]

If this is an emissions spec 1HD-FT it would have a cat wouldn't it?
If there's that much soot in the exhaust manifold, I would bet the exhaust itself is pretty clogged, especially a cat if it has one, which wouldn't be helping the turbo spooling.

 

[John Young]

If this is an emissions spec 1HD-FT it would have a cat wouldn't it?
If there's that much soot in the exhaust manifold, I would bet the exhaust itself is pretty clogged, especially a cat if it has one, which wouldn't be helping the turbo spooling.

It's a JDM truck converted to LHD. I will take a look tomorrow and see if it has cats. But it was the intake manifold that had all the carbon fouling.

 

[chapel gate]

Nice 1HD FT!

The disconnected hose is the boost pressure hose which runs to the top of the diaphragm on the boost compensator. This pushes the fuel pin down in relation to boost.

The turbo sensor is for over boost and lights up the orange light on the binnacle at about 15 psi.

All that soot I'm afraid is pretty normal with EGR on these engines. Clean it out and bin the EGR.

No cat.

 

[John Young]

The disconnected hose is the boost pressure hose which runs to the top of the diaphragm on the boost compensator. This pushes the fuel pin down in relation to boost.

The turbo sensor is for over boost and lights up the orange light on the binnacle at about 15 psi.

All that soot I'm afraid is pretty normal with EGR on these engines. Clean it out and bin the EGR.

Thank you CG. That's useful information. The red light on the dash has never come on despite how hard I punch it--which is more evidence that the turbine is not spinning. On that turbo pressure sensor, does that mean it is a binary on-off thing? Or is it an analog sensor in case you happen to know.

And regarding the boost compensator, from what you say, it sounds like the missing line would not stop the turbine from running entirely, would it?

On binning the EGR, I plan to import this truck to the US once it becomes eligible under the 25 year rule. That implies maintaining the engine in the original configuration, so binning is, unfortunately, not an option.

 

[chapel gate]

Stock boost is about 10 psi, so you won't see it come on.
Don't know. The ft is a pretty analogue engine though...

It won't effect the turbo at all, it will effect your on boost fueling.

Just loop the vacuum lines on the egr then. This will stop it working.

 

[MonsterCruiser]

Thank you CG. That's useful information. The red light on the dash has never come on despite how hard I punch it--which is more evidence that the turbine is not spinning.

No....Until you reconnect the vacuum/boost line your finger is pointing to in the third photo of Post #15, the light will not come on. With that line open, you a bleeding all of your boost pressure out of the system and therefore, the sensor will not see an increase in pressure to trigger the light coming on.

 

[chapel gate]

The 1hdt had a green and orange light in the middle of the speedo. Green; boost pressure building. Orange; over boost.

The 1hd ft has the green light replaced with a timing belt due light.
Still has the overboost light.

 

[John Young]

I went on amazon.ae and bought a cheap boost gauge and hung the cheap clear tubing out the passenger window and under the hood to the small outlet just above the turbine output. (This is the outlet that normally is connected up over to the mess of hoses adjacent to the MAP sensor.

Anyways, I got out to the street and, surprisingly enough, it did show boost on hard acceleration. The most I could get was a little over .5 bar or about 7.5 psi. The FSM says 36.8 to 50 kpa or 5.6 to 7.25 psi, so maybe all is well. GTS mentioned above that I would not be easily able to get to 120 kph if the turbo was not running--looks like you were 100% right. What I can't get over is that I can't hear the damn thing. But when I happen to be standing near the test of the same engine (minus EGR--most of them don't have EGR), they make the turbo whine I expect. And I'm honest enough to admit that part of the fun of having a turbocharged diesel is the sound.

But this is real progress. And it does drive plenty fast for me. Sometimes a little slow to get going but really not bad.

Thanks again for all the advice!

 

[dan1554]

If you had the turbo rebuilt with a modern compressor wheel, they are quieter than stock. I like to think its just more efficient.

 

[chapel gate]

Stock, I could never really hear the turbo.
3" stainless exhaust, I could hear it pretty good.
Plus intercooler, it whistler away like a blackbird! So much so at first I kept looking for a boost leak..
At the tail pipe I can here the turbo winding down.

 

[John Young]

Stock, I could never really hear the turbo.
3" stainless exhaust, I could hear it pretty good.
Plus intercooler, it whistler away like a blackbird! So much so at first I kept looking for a boost leak..
At the tail pipe I can here the turbo winding down.

Hmmmm... As far as I know, it still has the original exhaust system.... maybe I need a new one....

 

[Jroc561]

Yeah 3inch really opens up the turbo sound.

 

[mudgudgeon]

3" exhaust is the single biggest gain in performance and bang for buck upgrade if you're looking for more juice.
This along with a fuel pump tune up soon get it to 120km/hr really nicely

Turbo noise is a nice by-product to go along with extra performance