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Loss of power under hard acceleration

ManOfTheWest

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Feb 12, 2017
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wales
Well, it didn't take me long to have my first problem with the Land Cruiser. Today, the wife had her first drive in the LC. As we were going up a steep hill a few minutes after setting out, she commented favourably on the power. I urged her to floor the throttle and storm up to the top. She did so but as we came over the crest of the hill the vehicle started to decelerate, though she still had the accelerator pedal firmly down.

We managed to get it over to the side of the road and park it, then we sat there puzzled. The engine was fine. When I gave it some throttle the car would try to move forward but just not go anywhere. Reverse worked fine. Eventually after a few minutes it recovered (how?) and we were able to carry on with our journey. On the way home it was fine, though I was careful not to accelerate hard.

Then I remembered that yesterday on the way home after buying the car I had overtaken a slow vehicle and floored the throttle. The LC was doing about 60 mph as I passed the other car and for a few seconds I felt the engine sort of surging; accelerating and falling back, accelerating and falling back. Then as I completed the overtake, I pulled back into my lane and slowed down and forgot about it.

So, are the two issues related? A problem that only emerges when the vehicle accelerates hard? My local mechanic is going to inspect it next week but he thought, without having had a chance to look at it, that it might be fuelling. He knows his onions, so I'm confident we can sort it out, but in the meantime does anybody have any suggestions as to what might be the cause? A bit of crap in the fuel filter perhaps? Or, in a different area, something to do with the clutch?

EDIT: It's an automatic, sorry for not making that clear.

Thanks
Dan
 
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Manual or auto? Sounds like an auto and more of a trans issue than engine problem. You might want to check the trans fluid, and change it to be on the safe side. Check your coolant to make sure it's still coolant and not a mixture of anything else. Something's slipping...
 
Boost leak ? dirty sensors ? caked up egr ? when the engine isn't getting enough fuel it does feel like the clutch is slipping in a manual .
 
Manual or auto? Sounds like an auto and more of a trans issue than engine problem. You might want to check the trans fluid, and change it to be on the safe side. Check your coolant to make sure it's still coolant and not a mixture of anything else. Something's slipping...
Automatic. Thanks, maybe I will ask him to change all fluids so that we know exactly where we stand. It's not seen much use, particularly longer journeys.

Dan
 
Boost leak ? dirty sensors ? caked up egr ? when the engine isn't getting enough fuel it does feel like the clutch is slipping in a manual .
Which sensors - lambda? Sorry, should have said, this is an auto.

Dan
 
Petrol or diesel?
In an auto there is no clutch but you have a torque converter instead.
You say it was surging? Do you mean the engine was gaining in speed while the truck lost speed or do you mean the engine was faltering and losing power?

If it's the former, it's likely a transmission problem. Sounds like it could be low on automatic transmission fluid (ATF) As its best to check the level hot, after cycling through the gears (there's a particular sequence to follow that's in a thread on here if you do a search). As Beau said, check in the ATF for water, this can get in if the gearbox breather has become waterlogged or if the cooler in the bottom of the radiator has sprung a leak allowing coolant from the engine under pressure to enter the gearbox cooling system.

If it's the latter, there are several fuel filters. One that you change in the engine bay which could be plugged or if it's a diesel could have water in. There's usually a light for this but if that's not working, unplugged for example, then water could build up in the filter. If a petrol, and it's not been used for a long time it may have old fuel in it. This smells bad. Diesel can also get diesel bug after a long time of non use.
Then there's a strainer filter in the tank which is accessed through a panel in the floor along with the tank level sender.

Others may be along with more specific info especially if you tell us a bit more about the truck. With specifics like 'it was laid up for 4 years', every relevant fact.

Good luck with it and keep us posted.
 
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I am with @Beau sounds more like a transmission issue. Replace gear fluids and also check for metal in the oil that comes out as step one.
 
Auto boxes are a voodoo i don't want to understand i was just thinking both boost and fuel are digitally managed in the D4D and the oxygen sensor is the pied piper . To pull it out and clean it can't cost much .

Automatic. Thanks, maybe I will ask him to change all fluids so that we know exactly where we stand. It's not seen much use, particularly longer journeys.

Dan

When i bought a 2002 D4D Corolla with only 40k on the clock a couple of years ago i felt sure it was a pensioners town car so i ran egr cleaner through the intake right there and then on the forecourt and was rewarded with a belch of black smoke from the exhaust not 300 yards on , our daughter in law who was happy with the car on the test drive was giddy about the difference following the belch .

Your enthusiastic driving could be blowing the crap out if its always been a townie toodler .
 
Had very similar symptoms on my 150, was a blocked engine bay fuel filter – easy cheap fix.
 
Petrol or diesel?
In an auto there is no clutch but you have a torque converter instead.
You say it was surging? Do you mean the engine was gaining in speed while the truck lost speed or do you mean the engine was faltering and losing power?
Thanks for the comments. It's a diesel.

With regard to the "surging", it's a bit hard to describe, not least because it only happened for a couple of seconds. It felt like the engine was revving then cutting out for a split second then revving again.

I drove it 16 miles today with 5 people on board through hilly terrain, down backroads and along a faster A-road. I made sure that I didn't mash the throttle and in return the LC behaved impeccably.

Thinking of getting a TechStream kit. Will they all work with the LC, and where is the best place to buy one? I see lots on eBay, just not sure if they are relevant to my particular vehicle.

Dan
 
I would check the basics first, fuel,air filters. clean the egr. the lights come on pretty quick to show most faults so i would guess its something simple.
 
I'd go with fuel filter. See my thread here. Same symptoms.
https://www.landcruiserclub.net/community/threads/monetary-loss-of-power.129945/

Try a new filter (Check Simon here: https://www.landcruiserclub.net/community/threads/genuine-toyota-parts-suppliers.131926/) They not that expensive.

What was finally my problem was a couple of leaves in the fuel tank. They were blocking the strainer. It would get enough fuel for normal driving but a prolonged thrashing (like overtaking) would cause it to starve.
https://www.landcruiserclub.net/community/threads/changing-the-fuel-filter.129979/#post-1236856
(I'll try fix the images now if I can find them)


C
 
No idea. It has the strainer in the filler neck so clueless....

After the cleaning though it was fine which was a relief. Hope yours is equally as simple. Start with the filter.
 
+1 on the filter, start with the basics. Simon Holton is good to deal with, but there’s a new stealership opened in Carmarthen by Tescos. Haven’t tried them for parts yet, but might be worth a call if passing.

http://frfcarmarthen.toyota.co.uk
 
My local mechanic is going to inspect it next week but he thought, without having had a chance to look at it, that it might be fuelling.
This is interesting. I spoke to the garage this morning and they reckon there's a problem with turbo and it's over-boosting.

Both the main man and his assistant took it round the block and were able to reproduce the problem. It's fine if you're just trundling around, but if you floor it, goes into limp mode temporarily. They also plugged into diagnostics and found fault codes related to the turbo. They've stopped work on it for now as going forward the cost is going to mount up. The boss will call me later to discuss that aspect.

They also found that one of the front coils was broken, though it's all still in one place and fairly tidy.

There is quite a bit of rust underneath, which needs treating.

So, can anybody help me with the following questions:
1a) Are there any obvious turbo issues I should ask them to look out for? Hopefully it's just a sticky wastegate or something cheapish.
1b) If I need to buy a full turbo, what's it going to cost me? Where is the best place to buy?
2) If I'm going to replace the coil, I may as well do the other front coil at least, and maybe all four of them. Should I go for OEM or are there better options out there?
3) Rust, a perpetual concern, and rust-proofing is hard to evaluate. I see Krown has been reviewed in the forum. Buzzweld, maybe? I'd like a service that includes a full cleaning of the underside. Any suggestions?

Thanks as always,
Dan
 
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Krown will give the underside a good go with a pressure washer before treating inside and out.

The thing is, you have fuel and air, you'll get the symptoms you describe with fuel starvation rather than too much air. A Diesel engine just needs enough air to get the pressure in the cylinder to the correct level for ignition. It then varies the fuel sprayed into that air to vary the power it delivers. So, turn too much air on its head, you get too little fuel. Hence, check the filters first. I can only see that a worn or aged turbo would be down on pressure and this I don't think is your case.
It's ok reading fault codes, it's applying the correct interpretation that really sorts the wheat from the chaff.
 
It's ok reading fault codes, it's applying the correct interpretation that really sorts the wheat from the chaff.
Thank you for your comments - I agree that an overreliance on diagnostics is not healthy! Fortunately the boss is very much an old school mechanic and I will have a chat with him soon as to whether it is really the turbo but is at fault and report back. For what it's worth, he thought it was probably a fuel filter.

Dan
 
Boost is managed by the ecu and I don't think you have a wastegate so lack of fuel might be read as overboost .

Ask him to clean out the egr before you start looking at expensive parts .
 
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