Landcruiser 100 lacking power and using lots of fuel

[YvesNL]

Short intorduction to the diesel section:

I am Yves, 23 years old and an electronical engineer. I have always liked Land Cruisers, especially the 100 series with the 1HD-FTE. Previous year I bought one. It had been standing still for two years, had broken AHC and a lot of other repairs and maintenance were needed. At the moment it is my daily driver with only 426 000 km / 264 704 miles on the clock.

In the past half year I drove the vehicle 20 000km / 12500 miles. fuel consumption and power have been the same all the time.

When I bought the car I had the engine(oil) cleaned and replaced. Replaced fuel filter, air filter, brake fluid, brakes, etc, etc.


Skip forward to today and I am trying to find two problems that are probably related. High fuel consumption and low power.

My fuel consumption is on average:

5.5 – 6 kilometres per litre
16.67 – 18.18 litres per 100 kilometres
12.9 to 14 miles per gallon

If I drive fast or offroad it uses more, if I drive slow all day it gets slightly, just slightly better.
I have the factory single tank and almost never get 500 kilometres / 310 miles out of one full tank.


Now I know that the 100 series is a thisty vehicle, but a few of my mates (with LC100’s) get far better fuel economy. More like 700+ kilometres / 434+ miles out of a full 80L/21.13Gal tank.

Most of the time my Cruiser is unloaded, stock height (may have a very slight 15mm lift), 285/75/16 tires, winch in the front, snorkel, no rear seats and I drive mixed traffic.

When I drove other 100 series I also noticed that there was more power available. In my Cruiser it takes quite a while to get up to 130km/h / 80mph. I also notice a lack of power when towing.


My turbo made a different noise than the other 100’s. So the first thing on the list was to check the turbo pressure. The turbo pressure builds up nicely to 200kPaa / 2.0 bara / 29 psia (100kPag / 1.0 barg / 14.5 psig) and it builds pressure quite fast. I also checked the valve that regulates the turbo pressure and the vacuum. All look good and I can not find a problem here.


Since the car has been sitting for a while I suspected the MAF and injectors. The car starts perfect every time (most likely compression will be good) and does not smoke at all. I did a "soot measurement" (used google translate, dutch word is “roetmeting”) and the K value was only 0.4 to 0.5. If injectors were bad this value would rapidly go up.

Next up was the MAF readings:
The manual states 6 to 12 gm/sec when idling, my Cruiser did 19.10 gm/sec.
The manual stated 52 to 62 gm/sec t 2000rpm, my Cruiser did 77.06 gm/sec.

These numbers were a little high, since the MAF sensor is not too expensive I ordered a new (original) one (Hitachi). After replacing the MAF the values were 18.92 at idle and 80.47 at 2000rpm. Little to no change there.

Below is a Techstream picture of idling with new MAF sensor and no load:

2000rpm no load with new MAF sensor:

3000rpm no load with new MAF sensor:

During all those measurements the outside temperature was 22 degrees C / 71.6 degrees F.

All the values are correct according to this sheet (except the MAF):

At the moment I don't know what to check and what to look for. If anyone has experienced these problems or could point me in a direction I would really appreciate that.

EDIT: turbo values, see post #3.

 

[IanB]

My turbo made a different noise than the other 100’s. So the first thing on the list was to check the turbo pressure. The turbo pressure builds up nicely to 2.0 bar / 29 psi and it builds pressure quite fast. I also checked the valve that regulates the turbo pressure and the vacuum. All look good and I can not find a problem here.

This jumped out at me, 29psi?!? You don't mention an aftermarket turbo or boost controller, something is off here. I'm not sure about the 1HD-FTE but stock a 1HD-T sees about 10psi, with the stock turbo being safely capable of 14-15psi, I expect you are WAY out of your efficiency range at 29psi.

 

[YvesNL]

@IanB I probably didn's write it down too well.

There is a difference between the measured pressure (absolute kPaa/bara/psia) and the one that we always "talk about" (gauge kPag/barg/psig).

All the pressures I stated are coming from the "MAP" reading in techstream.
The MAP reading is the absolute pressure inside the intake manifold. Absolute pressure is measures from 0bara / 0psia.

Let's say that the atmospheric air pressure "around us" is 100kPaa / 1 bara / 14.5 psia then a MAP pressure of 200kPaa / 2 bara / 29 psia is only 100 kPag / 1 barg / 14.5 psig.

Idling the MAP (manifold air pressure) is 98kPaa / 0.98 bara / 14.21 psia;
2000RPM no load is 126 kPaa / 1.26 bara / 18.27 psia;
3000RPM no load is 145 kPaa / 1.45 bara / 21.03 psia;
Under hard acceleration (full throttle) it is 200kPaa / 2 bara / 29psia.

Gauge pressure (kPag, barg, psig) is measured from atmospheric pressure.

I used absolute pressure because that is what techstream used.

So in "gauge pressure" i get:
Idling the MAP (manifold air pressure) is -2 kPag / -0.02 barg / -0.29 psig;
2000RPM no load is 26 kPag / 0.26 barg / 3.77 psig;
3000RPM no load is 45 kPag / 0.45 barg / 6.53 psig;
Under hard acceleration (full throttle) it is 100kPag / 1 bara / 14.5 psia.

I edited my first post to not cause anymore confusion.

 

[serenity]

First thing I would check is for blockages in the intake. When I was rolling in a 100 series I pulled apart my intake around the egr valve and found it severely choked up with soot and oil. There is a heap of info out there already on the subject of cleaning the intake and diasabling the egr valve.

Cleaning the intake manifold however requires removal of the injector lines so is a little more involved.
Also check the cleanliness of sensors in the intake, a dirty sensor could cause over fuelling.

 

[roscoFJ73]

Using all that extra fuel I would expect it to be making some black smoke. What tyre pressure do you have? I was also curious at the the air intake temp of 52c and the fuel temp of 58c. Seems a lot, even for summer in the Netherlands , but maybe not if its measured close to the combustion chamber and fuel pump respectively.
And have those injection volumes and timing been checked against the specs in the manual?

 

[hj 60]

I think a compression test is needed to see more of the engine condition, can you compare blowby above oil filler cap?
Roetmeting is perfect, but injector service maybe good to do it for peace of mind.

Maybe take a picture with infrared to see if brakes are dragging?
maybe it is a sum of wheel bearings and drivetrain, gearbox wear?
Alternator dragging and not working properly?

 

[YvesNL]

Hi Guys, thanks for all the comments.

Using all that extra fuel I would expect it to be making some black smoke. What tyre pressure do you have? I was also curious at the the air intake temp of 52c and the fuel temp of 58c. Seems a lot, even for summer in the Netherlands , but maybe not if its measured close to the combustion chamber and fuel pump respectively.
And have those injection volumes and timing been checked against the specs in the manual?

The truck does not smoke at all. At hot starts, cold starts, really cold starts or high revving and hard driving there is no visible smote at all.
I have seen LC100's that use less fuel and produce more black smoke.

My tire pressures are 2.5 to 3.0 bar / 36 to 43 psi.

I also thought 52 degrees C (126F) was quite hot, but it is quite warm in the engine bay and this was after 60 minutes of driving. Maybe I can have a look at temps under the hood with an IR camera. I could also do a temperature check in the morning before the truck is started.

Injection volume and timing has been checked with the 2 pictures I posted under the measurements. They seem to be within spec.

A reason for the MAF to be high is my EGR being blocked off by the previous owner.

I think a compression test is needed to see more of the engine condition, can you compare blowby above oil filler cap?
Roetmeting is perfect, but injector service maybe good to do it for peace of mind.

Maybe take a picture with infrared to see if brakes are dragging?
maybe it is a sum of wheel bearings and drivetrain, gearbox wear?
Alternator dragging and not working properly?

I personally don't think that the compression is off, but I am not 100% sure. The car starts very fast, in hot and cold weather and on any type of available diesel. If I turn the key to the cranking position and immediately let go it almost always starts. The experience I have with diesels and low compression is that they take longer to start. But again, I could be wrong.

I can turn the wheels freely by hand, no serious dragging.
I replaced the front calipers 6 months ago, and also re-greased the pins of the back calipers.
I also greased the needle bearing and repacked the front wheel bearings with the right amount of preload.

I also replaced the alternator, a few weeks ago I had the cruiser on the lift and decided to check/clean the alternator for dirt (after driving through some deep over the hood muddy water). I also pulled off the belt and could rotate the alternator easily by hand.

After my commute to work today I touched the brakes by hand, I could not hold them for long. I will take a picture with IR camera to confirm temperatures. How hot may brakes be after driving and braking for a few bumps here and there?

First thing I would check is for blockages in the intake. When I was rolling in a 100 series I pulled apart my intake around the egr valve and found it severely choked up with soot and oil. There is a heap of info out there already on the subject of cleaning the intake and diasabling the egr valve.

Cleaning the intake manifold however requires removal of the injector lines so is a little more involved.
Also check the cleanliness of sensors in the intake, a dirty sensor could cause over fuelling.

This weekend I am going to wrench some more. I will take off the intake around the EGR and check for soot and oil. I have no idea where in its life the EGR was capped off.

If the intake manifold is dirty I will also take that off and clean.

If I can't find a problem there I might just take out the six injectors and the pump. I will bring them to a local diesel shop and let them test the injectors and the pump. If anything is wrong they would be able to diagnose and possibly rebuild.

Any tips on taking out the injectors?

 

[roscoFJ73]

Any tips on taking out the injectors?

Having the correct tools to take them out and replace them. Pipe spanners for the injector lines, deep socket for the injectors and torque wrench to put it all back together. And of course you will need the gaskets and seals etc.
You will need a good puller to remove the pump.

 

[Locked79]

Check the boost line pressure damper and hose for cracks, these quite regularly fail causing the boost signal at the map sensor to read low, thus not delivering correct fueling. It causes the exact symptoms you are describing.

 

[YvesNL]

Check the boost line pressure damper and hose for cracks, these quite regularly fail causing the boost signal at the map sensor to read low, thus not delivering correct fueling. It causes the exact symptoms you are describing.

View attachment 1738337

I checked the lines and the damper, these seem to be in good condition.

The first thing I removed was the intake (not the manifold mounted to the block) but the rest of it.
After taking the EGR pipe off I noticed some dry black soot inside, but not that much. There was no EGR blanking plate, the previous owner only capped off the vacuum line going to the EGR valve. There is some oily black film on the side of the intake manifold, but not like some pictures I've seen online.

After that I removed the two covers from the head and saw the injectors. I removed the injector lines and the rubber inserts. Undid the injector bolts and used a slide hammer to get them out. They came out pretty easy.

Then i took off the timing belt (which wasn't necessary) loosened the front nut, the four m8 nuts and the two mounts that are bolted to the engine block. At first I couldn't get the pump out and discovered that there were two mounts.

Cover off:

Injectors out:

Pump:

 

[YvesNL]

So I got the pump and injectors checked and it turn's out they are both in bad shape.

The pump needs a rebuild, I will receive a rebuild (exchange) pump on Friday.

The injectors will be fitted with new nozzles tomorrow.

I did some more things:
- Ordered all new gaskets;
- Cleaned the injector lines with compressed air;
- Cleaned out a lot of build up carbon (mostly on swirl flaps) but also on intake manifold and the cilinder head.

If all parts arrive this week I will put it together this weekend, service the truck, finish my drawers and go for a 5500km / 3700 miles roadtrip next friday.

 

[roscoFJ73]

At the moment it is my daily driver with only 426 000 km / 264 704 miles on the clock.

With those klms, a rotary pump is on borrowed time. Did they say what was wrong with your old pump or which parts need replacing?

 

[YvesNL]

With those klms, a rotary pump is on borrowed time. Did they say what was wrong with your old pump or which parts need replacing?

I will receive a fully remanufactured pump. They told me that the pump does not reach the required pressure and output.

I will ask them for some more details. I also heard something about bearings and metal shavings. No exact info on that yet.

 

[roscoFJ73]

I will receive a fully remanufactured pump. They told me that the pump does not reach the required pressure and output.

I will ask them for some more details. I also heard something about bearings and metal shavings. No exact info on that yet.

Thats pretty much the signs of a fully dead pump. The plunger and pump head wear out and allow the pressure to fall. The timer piston wears the housing and allows metal shavings. And the roller bearings on the main shaft allow it to overheat and vibrate.

 

[YvesNL]

I've just received the rebuild pump. Going to fit it tomorrow.
I have also received some OEM Toyota gaskets and 15L engine oil + filter.

For the rebuild injectors I'll have to wait till tuesday. The Denso parts have to come from Spain

The diesel specialist also told me that the internal pump pressure only reached about 2,5bar/36psi while it should be 16bar/232psi.

 

[hj 60]

Now you know what is wrong did it show the problem in techstream?, curious what the new readings will show.
8.73 injection volume seems in the range 4-11 idling (if this is related) so just wondering if this problem is only occurring when under load?
I thought a bad leaking injector would create soot but in this case it does not deliver enough fuel spray, it must have been running lean?
Dont know if a diesel even has that term for it like gasoline engine.

 

[YvesNL]

I've installed the rebuild injection pump and rebuild injectors.

The car drives a tiny bit different. It does not "drone" as much as it did when at 2000rpm on the highway and sounds a bit different.
The car is a little bit faster but still thirsty.

At the moment I'm in Estona at the beach and I'm enjoying the cruiser.
On the highway I drove 110kph / 68mph and did 7 kilometres per litre / 14.3 litres per 100 kilometres
16.5 miles per gallon. This was only highway @ 110kph / 68mph. Seems a little low to me but better than first.

I don't think the engine had all it's power yet.

At the moment I am experiencing another problem. If I'm driving slowly off road the engine gets hot. If I drive at 30km/h / 19mph it stays cool. My rad is clean, fan is turning (and does not keep spinning if I turn off the engine), radiator hoses get hot (thermostat opens).

I had the engine getting hot once before. This was while towing at slow speed and before I replaced the injection pump and injectors.

Does anyone know anything of this overheating problem. It only occurs when driving slowly, at speed there is no problem.

At the moment I'm trying to install techstream under win10 and will report back with data.
All suggestions and questions are appreciated.

 

[VX 12HT]

generally low speed overheat its your fan at higher speed its your radiator.

 

[Tapage]

Define hot ..

Did you measure it properly .? laser temp gauge ? did you have an aftermarket good temp gauge .?

Slow driving my first check would be fan clutch for sure .. check resistance ( and not only if stop when engine stop ) also will check fueling at low rpm range ..

 

[YvesNL]

Sorry for my late response.

The rest of my holiday temp gauge (my only way of measurement at the time) kept going up. Only when 4wd'ing or driving faster than 105kph / 65mph.

Drove it for 19 hours straight home (Gdansk-Poland to Utrecht-The Netherlands) on the last day at 105kph, could've been faster through germany ha.

I tried cleaning the radiator before but at home I spent a good amount of time with the garden hose to flush out the radiator.
Out came some dirt and a plastic bag that was stuck between the AT cooler and the radiator. I couldn't see it but it flushed out.

It was only a small bag, but combined with the dirt that was still left there I think I found my overheating problem.
The car does not get hot anymore, I drove long distances faster that 105kph/65mph and the car did not heat up.
The ambient temperature is a little bit lower here but I still think that this was the problem.

More on the repair:
The car drives different, before there was some "droning" at some rpm's that is completely gone.
I do notice more low end torque and power, the car drives smoother now.
Fuel consumption has lowered a bit but I am still not where it needs to be. Next thing to check is the turbo I think.
The car also sounds healthier right after starting the car.