1KV-TE Diesel - Drives excellent on flat, loses power up hill?

[SamSta Member Find all posts View Profile Close SamSta]

**Update 17th August 2020**

2000 GLX Prado 3.0L Turbo Diesel (1KZ-TE motor) (330000km) 4 speed auto

Hey all, I have just bought my first Prado and am trying to work out a couple of minor problems. I've done extensive reading throughout this site on the subject and have learned heaps of great knowledge! So thank you all! Though I have made some improvements, I still have not completely resolved my issue(s).

Overview: Hard to start on cold mornings but runs beautifully throughout the day. It runs very well on flat road however it loses its power up longer inclines.


Cold starts: Have been an absolute drama. The colder the morning, the harder it is to start. Had a couple of much warmer mornings recently and the engine started much quicker but still unacceptable. I have to keep cranking the engine for about 10 seconds while it slowly starts igniting. Once it gets going, starting is pretty much instantly any other time throughout the day. I did have an issue where the primer pump wasn't holding prime. Have replaced that and it now holds prime however still having start issues.

Update: solution found! Spill Control Valve was causing issues. No need to replace. See final post for fix.

Sluggish up hills: Driving with just myself in the car, no load, 120 km/h on the freeway (110km/h speed zone) no problems and some headroom to go faster. Suddenly get to a long gentle incline and the car slows right back to 100 km/h with foot down and no more acceleration. I am learning this is a common issue with this motor due to timing and fuel delivery and am in the process of exploring options to adjust these.

Things I have tried:

• New air filter and fuel filter
• Cleaned MAF and MAP sensors/filters
• Replaced MAP sensor filter (oil separator)
• New higher rated crank Battery's - slight improvement in starting)
• Replaced Glow Plugs (No difference)
• Used an Injector cleaner
• Checked the ECU mainboard - it is in excellent condition. No swollen components or leakage.
• Replaced fuel hoses either side of fuel primer pump.
• Replaced fuel primer pump (now holds prime - still slow to start)
• Timing belt within its service date
• Tipping a cup of warm water onto the Spill Valve body (Didn't help)

The above fixes have notably improved the situation for driving on the flat. Truck was feeling a lot more zippy driving around today but still didn't feel 100% on the hills. Anything else I have missed?

Cheers in advance!

[t303 Senior Member Find all posts View Profile Close t303]

Hard starting: glow plugs, and the genuine ceramic ones are better. Also be aware that the glow light is only there to fill up space on the panel, it's illumination bears no resemblance to the actual working of the system. If you put as meter across the battery as you glow you will see the volts dip quickly, then taper down over a long period. From observation and some tech stuff that I can't put my hands on atm the timer gives you full glow for about 4secs, then the timer reduces the volts (it's 11v by the way, so careful what voltage you might test them with) but the afterglow lasts for a surprisingly long time. My drill in the colder climates is to switch to "on", count to 4 (the light goes out at 1-1.5secs) then start. The 4 count seemed to work pretty well for me and aligned with what the graph I found said. Your battery has to be able to supply the amps for glow and crank fast enough to get the compression high enough to fire.
Lack of performance: you seem to have changed all the right (cheap!) parts to start the diagnosis. If your ECU plays up (overfuelling or dead cut) it may need recapping (see my other post ref this) but I have never heard of it dropping performance intermittently (not saying it couldn't happen!). I assume you don't have a catch can fitted? If not then another possibility is a coked up intake butterfly that can choke the airflow and clog the IC. If you lift the intercooler you can look down the throat. This may only manifest itself if it was under high load like towing. Check you hose connections on the supply hoses to discount sucking air. There is no header pump in these, they rely on IP suction to move the fuel, so can have an air rather than fuel leak. Valves ever been adjusted? They don't go out much, but it is a possibility if you are running out of other options. Open valves are no good from both a performance and longevity POV.
Let us know how you get on.
cheers
Steve

[SamSta Member Find all posts View Profile Close SamSta]

Thanks for the info Steve! Was reading up more on the symptoms last night and again this morning following another slow start. I'm still learning about these motors (only owned for less than 2 weeks) and came from a Ford Transit T/Diesel before this.

I am fairly confident at this stage that the issue is fuel supply related - or possibly a couple of issues. I have the truck in at the Auto Electrician as we speak just checking over the glow plugs + relay and making sure they work (just to rule them out for the cold starting side of things).

The fuel primer is always soft when I prime it before cold starting and requires quite a few pumps before it becomes firm so this supports the air leak. I have a new fuel primer pump assembly on its way and will install that in case theirs the common issue of the air leak in the pump diaphragm. The hose that goes from the fuel filter assembly down to the fuel pump I remember was a bit oily down the bottom where it plugs into the FP barb. It's got a sleeve over it so is hard to see or feel any leaks. I might just replace that to be sure!

Assuming their is an air leak in the fuel lines, would this be the reason for lack of power under load?

Cheers for your response and info. Greatly appreciated

[adrian5800 Advanced Member Find all posts View Profile Close adrian5800]

Glow plugs on these engines should be changed every 100,000km regardless, the tips break and can cause catastrophic engine damage. Being that you don't know the history of the vehicle (you didn't state how many km it has done) I would get them changed anyway. From your symptoms I would say most if not all of them are u/s.
An air leak on the fuel side of things will absolutely cause starvation issues like you are seeing, a simple check to see if there is an air leak is to temporarily fit a clear pvc hose to the inlet of the pump from the fuel primer head. There should be minimal bubbles when the engine is running.

[SamSta Member Find all posts View Profile Close SamSta]

Glow plugs on these engines should be changed every 100,000km regardless, the tips break and can cause catastrophic engine damage.

I did read that somewhere. Something about when the glow plugs get old, they overheat the head and eventually crack it? Should be changed every 90000km I think it said? I will get onto doing those asap!

I also saw that home made clear tube device in a thread about an hour ago so will certainly make one up and try it! Have updated post with KMs. (330000km) Cheers

[SamSta Member Find all posts View Profile Close SamSta]

Ok, so Auto Electrician said glow plugs are fine (though I'm gonna change them soon).

Made up one of those clear hoses and placed between fuel primer pump and fuel injector pump. No air bubbles in normal/ high revs but many bubbles when pumping the accelerator with small presses. Didn't get to test under load though.

Another thing I picked up on... When I was at the Auto shop buying new fuel hose, the bloke had some generic brand fuel primer pumps for my truck in stock. When I inspected up inside the pump mechanism of a new one, I noticed what looked like a black rubber valve with a small ~0.5mm hole in it. When I looked inside the one currently on my truck during the filter change the other day, I didn't see that valve but two triangular shaped flaps/things pointing into the middle of the circular hole which the filter screws into (possibly the remains of the old valve). This would totally explain the fuel flowing back into the tank situation and hopefully the cause of the troubles I'm having! I guess I'll know once the new fuel pump primer arrives and I install it

I also replaced the hose going from the fuel primer pump to the fuel injector pump for good measure!

Thanks again for the suggestions. Learning so much. Really enjoying getting to know my truck better.

[SamSta Member Find all posts View Profile Close SamSta]

Update:

• Installed new Fuel filter/primer assembly.
• Replaced rubber hose on tank side of filter.

Have not tested cold start yet. Tomorrow morning! We have snow expected so that will be the ultimate test!

Re being sluggish on hills: (FYI, this is a 4 speed auto). Tested before and after primer pump installation on a stretch of freeway which includes a long gradual incline in a 110km/h zone. Still feels like its struggling a bit on the hills. However what I also noticed which I never noticed before is that when going up the hill in top gear, when the truck starts running out of revs around 100 km/h, it drops down to a gear which revs high but doesn't seem to have any progressive power? Almost a tad less power than the previous gear but higher revs. Then when it eventually shifts back up again, I only just noticed it seems to shift to a gear momentarily where where the revs are at the right place to pickup speed but then a couple of seconds later shifts into top gear again. In other words, its like it is missing a gear on the hills jumping between 4th and 2nd? Maybe? I only just noticed this tonight by visually watching the RPM gauge. You can see the gauge when it shifts up gear go from high revs to 2500 rpm and then a second or so later drop to 2000 rpm. So it looks like it hits the right gear for a second then changes again to top gear which is not right for the situation.

I hope this all makes sense. Maybe this is normal for this transmission? Maybe its due to the gear ratio? Diff ratio? Maybe the transmission needs a service? Or tuning?

Any ideas??

Cheers

[carco Advanced Member Find all posts View Profile Close carco]

What you’re describing is the converter locking/unlocking.
Find a deserted bit of flat road and from a standing start in D, gently accelerate and count your gear changes.
It will go 1, 2, 3 pretty quickly then 4 and finally locked 4. This will feel like the car actually has 5 gears.
Do this again but with the button pressed in.
It will go 1, 2, 3 same as before but around 70 you’ll feel another change. This is not 4th gear, but the converter locking 3rd. The car is now just like a manual and will pull quite hard.
Of course if you really boot it, it will come out of converter lock and you’re in 3 but with slipping converter.
Understanding how the converter works is the key to making an auto pull.
You can buy a converter lock up kit which will force the converter to lock above certain road speeds and then you have the best of both worlds. Starts off like an auto but after about 30-40Kph it becomes a manual.
Not keen on a lock up kit for a trany. with 300,000k’s as the converter lock up clutch and thrust bearing is not the best from stock Toyota.

[SamSta Member Find all posts View Profile Close SamSta]

Right that's all starting to make sense now. Thank you so much for taking the time to explain that. Really appreciate it! My last car of 10+ years was an auto shifting manual (Ford Transit) so completely different animal all together. I've never really learned how to properly drive an auto.

I took the truck for a drive up the same gradual incline section of freeway (110km/h zone) without the overdrive on and it drove much better! Wasn't jumping back down to that gutless high revving gear. Pretty confident I could have achieved and maintained 110km/h if a car in front of me entering the freeway wasn't doing 90km/h and stuffed my run up. So that's definitely a win!

Thanks again Carco! You've been most helpful

[carco Advanced Member Find all posts View Profile Close carco]

You can also make good use of the button (when driving as car only) for overtaking.
If you’re driving at perhaps 90 and you go to overtake, when you boot it the first thing it will do is drop out of converter lock.
So then it’s in 4th but slipping the converter. The idea of this is to move the engine rpm higher so it’s making more hp, but in real life all that happens is the old 90 just sits out there revving but not actually going much faster. And the trany computer isn’t real fast so it will spend some time thinking about things.
The better method is to anticipate the overtake, hit the button and after a second or so it will go to locked 3. You will have similar rpm but as the converter is locked, she will really pull, same as a manual.
Once she’s gone past, ease back, hit the button and she’ll change up to locked 4 again.
The old 4-speed auto was fitted to heaps of different models, the diesel was probably not the most exciting.
Same trany in a Celsoir or Aristo with 2JZtt or UZ power were absolute rockets.

[SamSta Member Find all posts View Profile Close SamSta]

Still having cold start issues in the morning. Has to crank for about 2 minutes before is slowly ignites into a low rev idle for a minute of so then the revs pickup to normal. New fuel primer is holding prime now so I've eliminated that. I am about to get new glow plugs and injectors installed in the next few weeks (hopefully sooner rather than later) as I have no record of when they were last done by the previous owner and want to get the maintenance up to date.

But in the meantime, i'd like to try and troubleshoot other possibilities. Can anyone tell me what this plug is in the images below? It plugs into the side of the engine above the fuel injector pump and directly under the intake manifold. I noticed the last 2 starts i've had, when the engine finally ignites it idles at really low revs for a minute or two then eventually idles normal. I am not sure it is a coincidence but when the engine was running in the low revs stage, wiggling that red connection to that bodged up plug made the revs come back again? What does that mean? I'm going to repair this connection soon. I'd just like to know what it is. Any ideas?

[carco Advanced Member Find all posts View Profile Close carco]

Engine coolant sensor.
Not to be confused with the temp. gauge on the dash.
This one tells the ecu engine coolant temp.
The one for the dash gauge is up top on the alloy casting, top radiator hose.

[SamSta Member Find all posts View Profile Close SamSta]

Engine coolant sensor.
Not to be confused with the temp. gauge on the dash.
This one tells the ecu engine coolant temp.
The one for the dash gauge is up top on the alloy casting, top radiator hose.

Thanks again Carco, maybe I should just be asking you these questions

So part of the starting process, the ECU needs accurate data from this sensor to help with the starting procedure?

*Update* I removed the intercooler yesterday and cleaned the rail connections for the glow plugs. Also attempted to check and tighten that ECU bolt down the back of the engine. Impossible to get to! I think it was tight anyway but would have been nice to get a spanner on it and give it a nip up just in case.

Now looking into timing issues with the E injection pump.

While intercooler was off, I checked the throttle body for gunk. Thing was immaculate! Previous owner his given this engine a proper clean at some stage.

[carco Advanced Member Find all posts View Profile Close carco]

The coolant temp the ecu receives will alter timing and glow plug active time.
Timing will affect power, glow plug is more for emissions once the engine is actually running. The glows stay active until coolant temp reaches about 60 deg C, nothing like the light on the dash suggests.
I’d check the logged faults in the ecu, use the wire across the two pins on the diagnostic port.
Google it up so you get the correct pins as well as how to read the codes.

[carco Advanced Member Find all posts View Profile Close carco]

Here you go.
Use the diagnostics port mounted on the transmission hump, near your left leg.
I found the one in the engine bay didn't work on my 90.