Help Please, Rav4 Intermittent Power Loss When Accelerating

[Verv]

Hi all, I asked this on another forum and was directed here.

My rav is acting the goat.
Its fine at 0-40 but I was on the dual carriageway and when I put my foot down to accelerate to pass another car it lost power on acceleration and sounded like shinola. Couldn't get any power back through the engine, its like the accelerator pedal ceases to deliver anything so I pulled over, switched off, switched on again and carried on.

It seems okay when you don't put your foot down and will ease itself up to 50 but above and beyond that it's sounding rough and if you go to speed up with any force it's just not having it.
The diff has an oil leak and is due to be replaced but this sounds like more of an engine breathing problem.
Had a vague wiggle of hoses and all seem to be attached and I can't see any splits.

No engine management lights come on when this is happening.
Its booked in to the garage later this week but if anyone has any clues so I can point the mechanic in right direction so I'm not getting billed by the hour while he narrows options that would be great.

Sorry to wander in and ask without any introductions!

[slowdahhn!]

Hi Verv

The symptoms you describe happened to me on a previous Merc E Class found a ruptured hose joint on the intercooler circuit so in effect when demand for power was required sharpish there was no corresponding rush of air via the turbo and intercooler circuit to feed the engine, sensors picked this up and strangled the engine down to limp mode.

Turn off and on and you could gently coax it up to speed by letting it build slowly through the auto box in its own good time.

9 times out of ten with a sluggish modern diesel that has a sound intake circuit it falls to the MAF sensor failed or dirty, which again effects fuelling and running characteristics

[Wai kwok man]

I have the same problem I think. When I'm driving and changing the gear it just won't speed up but go slower like no power until about 30 secs and it will pick up. Think I'll better take it in to my local garage to get it seen too but want to know what u guys think is the problem so I can point out to hi. Many thanks. Nic

[Avalon]

Sounds like a boost leak, check the IC pipework.

[Wai kwok man]

Is that an expensive job to fix Avalon?

[Sarah White]

Hi all,

Have been searching all over for topics like this one as my Rav4 XT5 2005 diesel has a similar issue - accelerates normally under usual/gentle conditions but if you want more power quickly when it's in a low rev state, it actively dies on you and goes into power failure for what seems like forever. You've just given up on accelerating and forgotten you've still got your foot down when BAM! in comes the power and you're off, but it's all too late. Have given up trying to overtake other vehicles as it's just not safe.

My mechanic ran computer diagnostics and no error codes. He checked all the hoses for leaks and then cleaned the EGR valve, which was full of muck, but made no difference when cleaned. He then replaced it (£128 for the part plus labour) but that made no difference. On advice from Toyota, he then replaced the SV solenoids (for those not in the know, Toyota made replacement parts for inside the fuel pump as it was thought to cause such issues) - parts have to come from Toyota at a cost of £303.60, plus labour. There was some improvement in the general power output after this but the intermittent fault still remains. So now I'm faced with replacing the turbo - parts alone would be in excess of £1000 from Toyota, but to at this point we're going for OEM parts as it's cheaper.

It's really frustrating that so many people have this issue across the range of Toyota diesel cars and yet no-one has a definitive cure for it. Surely there's a common cause??? Seems each of us has to go through the pain of trial and error to get it fixed which seems nonsense to me after all these cars/engines being around for years!

Rant over - hope someone finds this useful. I know I did when I found this and other forum posts on the subject. :0)

[graunch]

Hi sarah,

Sorry to hear of your troubles, of no use to you now but maybe to someone else the SCV valves you fitted are manufatured by a company called "DENSO" for toyota and are available from other sources (ebay} for about £170 the pair. Regarding your problem if you have not tried it aready try running a system cleaner like "Archoil 6400" or "BG244" as other people have found this successful.

regards colin

[Sarah White]

Thanks Colin, very useful about the cheaper SCV valves.

I'll ask my mechanic if he has run a system cleaner and if not, we'll do that before doing the turbo.

Much appreciate you taking the time to reply :)

Sarah

[Wai kwok man]

Hi the mechanic said I need a new scv valves and I had 2 faults came up on the diagnosis check so now have ordered them. Hopefully this will sort it out but now when it's fixed I'm thinking of part ex it and get something else as these rav4s doing my head in. Only had it for nearly a year n already had a new clutch and fly wheel after 2months of buying it and now this happens

[Sarah White]

Wai kwok, I feel your pain!

I bought this one in Feb 2014 with it having done 45,000 miles with full service history, so I thought it was a fairly safe bet. The fly wheel went after 3 months and 3 days - you guessed it, just outside the 3 month warranty and the dealer wouldn't do anything. At that time, I had Toyota fix it for me (fly wheel and new clutch) for a cost of £1700.00. (Have since discovered it's possible to get cheaper parts elsewhere). I then put 5 new Goodyear tyres on it to improve the ride (which it has considerably), had to re-do the cam belt and water pump as the pump was leaking and then it developed the 'turbo-lag'/power failure problem. In all, excluding the two full services it's also had, I have currently spent over £3500.00 trying to put this car right!

We so nearly sold it last week but have finally decided to keep it as long as we can sort out the power failure issue. So disappointing as I had a Toyota Corolla petrol for 10 years that did 98,000 with just usual servicing, tyres etc - such a reliable car, which is why I went Toyota when I wanted a 4 wheel drive.

[atkiman]

Wai kwok, I feel your pain!

I bought this one in Feb 2014 with it having done 45,000 miles with full service history, so I thought it was a fairly safe bet. The fly wheel went after 3 months and 3 days - you guessed it, just outside the 3 month warranty and the dealer wouldn't do anything. At that time, I had Toyota fix it for me (fly wheel and new clutch) for a cost of £1700.00. (Have since discovered it's possible to get cheaper parts elsewhere). I then put 5 new Goodyear tyres on it to improve the ride (which it has considerably), had to re-do the cam belt and water pump as the pump was leaking and then it developed the 'turbo-lag'/power failure problem. In all, excluding the two full services it's also had, I have currently spent over £3500.00 trying to put this car right!

We so nearly sold it last week but have finally decided to keep it as long as we can sort out the power failure issue. So disappointing as I had a Toyota Corolla petrol for 10 years that did 98,000 with just usual servicing, tyres etc - such a reliable car, which is why I went Toyota when I wanted a 4 wheel drive.

Have you had the vibrating 5th gear yet?. Mines done 42k and in 10k miles I've had new clutch/flywheel,new scv's and a new 5th gear.

I had a petrol nrg for over 10 years and in 105k miles all I changed were the sensors and the exhaust. My iq is rock solid typical toyota though

[slowdahhn!]

MAF/ Airflow meter as mentioned are so critical to these modern diesels these days as it affects the whole fuelling process from gentle driving to demanding power sharpish. I would try a substitution test with known good unit to eliminate this side of life

SCV, suction control valve?, seems to be an issue on these jap pumps and would to my mind replicate a low fuel, low power situation much like a failing/ faulty MAF has done to me in the past on a couple of diesels a Merc E class and a Vauxhall insignia

[Sarah White]

Wai kwok, I feel your pain!

I bought this one in Feb 2014 with it having done 45,000 miles with full service history, so I thought it was a fairly safe bet. The fly wheel went after 3 months and 3 days - you guessed it, just outside the 3 month warranty and the dealer wouldn't do anything. At that time, I had Toyota fix it for me (fly wheel and new clutch) for a cost of £1700.00. (Have since discovered it's possible to get cheaper parts elsewhere). I then put 5 new Goodyear tyres on it to improve the ride (which it has considerably), had to re-do the cam belt and water pump as the pump was leaking and then it developed the 'turbo-lag'/power failure problem. In all, excluding the two full services it's also had, I have currently spent over £3500.00 trying to put this car right!

We so nearly sold it last week but have finally decided to keep it as long as we can sort out the power failure issue. So disappointing as I had a Toyota Corolla petrol for 10 years that did 98,000 with just usual servicing, tyres etc - such a reliable car, which is why I went Toyota when I wanted a 4 wheel drive.

Have you had the vibrating 5th gear yet?. Mines done 42k and in 10k miles I've had new clutch/flywheel,new scv's and a new 5th gear.

I had a petrol nrg for over 10 years and in 105k miles all I changed were the sensors and the exhaust. My iq is rock solid typical toyota though

No! Oh lord, is that next?!!!

[Avalon]

This isn't by any stretch a definitive list but it's the basic order I was working through mentally when I had a similar issue. I went for the cheapest/easiest options first and tried to be systematic.

1) Scan it. A VCI lead is £15-30 and will usually come with a questionable copy of Techstream. You can use a simple ELM interface and one of the many (free) phone apps to do basic scans but Techstream will give you dealer level diagnostics and testing that the generic stuff doesn't. This may give you a pointer as to the actual fault but may not.

2. Inspect the air filter and intake, replace the filter for the 30 seconds it takes and make sure nothing is in the air box that shouldn't be, i've seen a plastic bag make it into a air box before and it basically choked the engine of air under load but was fine at idle. Check for leaks (smoke stick) and make sure the fastenings are tight, especially on the inter-cooler pipework. Clean the MAF sensor with contact cleaner, if you suspect a duff MAF then try and borrow a known good one. MAF sensors are one of those parts that are not cheap and the cheap ones are usually not good, eliminating a duff one by swapping it with a known good one can save you some money and let you move on. Also check the vacuum system is working as intended and look for perished/worn/fouled vac hose.

3. Strip/clean the EGR, if you run unbranded fuel it still meets the same standards as the branded stuff but it gets a more generic and less concentrated detergent package added even though most of it comes out of the same silo. Build up is unavoidable but if it's not able to open/close as intended it can cause issues and will trigger a MIL eventually.

4. On the 4.2 change the fuel filter while you're at it as the air box has to come out to do both. On the filter have a look at what comes out and the state of the cartridge, in my case even though the last garage to service it had charged for the filter they hadn't changed it and it had a coating of sludge/crap built up. Personally as i'm getting the tools out I changed the oil while I was at it, fresh oil and a filter is never a bad thing and costs very little.

5. Run a full tank or two of BP Ultimate or Shell V Power Nitro through, marketing asside it has significantly stronger detergent in it and in the case of Shell is actually a much cleaner burning product, supermarket fuel meets the same basic standard but it's detergent package is minimal and doesn't burn as cleanly. You could also try one of the additive's like BG244 or AR6400? or whatever the turbo cleaning version is as the variable vane system on most turbo's needs to be clean to operate smoothly.

After that you're looking at stripping the SCV's, you can test them, but if they aren't the revised version then you may be better off just replacing them as it's a known area of common issues. As stated they can be sourced for a lot less than the dealer charges for the same item from the same factory and are reasonably simple to swap out. After that it's time to look at the DPF/Cat (if fitted) and then you're onto the turbo side of things which starts to get expensive.

Sarah the warranty you were given was the minimum legally permissible by a trader, you could have still gone to small claims court and would likely have received a percentage contribution from the trader relative to the car's age/condition/price paid and the amount of usage you'd had after purchase (if you've put 50k on it in 3 months for example and only paid a grand you've had your money's worth). The timing belt is an annoying one, it's due every 5 years or 60k, whatever it hits first so on a 9 year old car that was always coming up sooner rather than later. the most expensive bit to fix the pump is the labor so for example if the gasket on the pump goes you replace the pump and do the belt at the same time and vice versa as the cost in parts is relatively small compared to the labor.

5th gear has a slight vibration on the lever on my Rav (55 plate) but it's been like that since new as far as i'm aware, it's going to hit 100k shortly so if/when it gets worse i'll do something about it, till then it's not worth stressing about.

[Wai kwok man]

Got my car back today and cost me £360 cash as he doesn't charge me vat. Had the SCV valves fitted and EGR removed and cleaned and now it's back to normal and got power. It's now done 106855 on the clock and I'll get the cam belt replaced on next service as don't want the belt to snap which would cost more to fix if it did or might just p/ex it for something else and petrol not diesel.

[Sarah White]

Hi All,

After all of you have been so helpful, particularly Avalon with your list of suggested fault finding actions, I though you might like an update...

My mechanic had already been through most of Avalon's list having checked the pipes for leaks, changed the fuel filter, changed the EGR valve and the CSvs. The breakthrough came with point 5 on the list - running two tanks of Ultimate Diesel through. I filled up the first tank full and within 20 miles, the 'turbo-lag' stopped! Couldn't believe it!

Filled up the second tank's worth just prior to driving to Devon from Sussex and I only had one suggestion of a hesitation where she ran rough for a few minutes near Honiton, but that soon cleared and she was fine for the return journey. I have since done a half tank of normal diesel with no return of the problem.

I spoke to my mechanic about it and he wonders if it is down to more bio-fuels being included in the ordinary diesel as he is having more cars coming in running rough since they upped the amount of bio-fuel in the mix to 20%. All I can say is that my Rav4 certainly runs great on the Ultimate diesel so am thinking of alternating tanks of ordinary and ultimate to keep her running sweet. Would be interested in your thoughts and experiences ...?

Out of interest I got 40 miles to the gallon over the whole trip, which I thought was good. Oh and I'm glad I decided to keep the old girl, despite the financial pain since I bought her... Running sweet, she is everything I hoped she would be - safe, spacious, comfortable, quiet, great visability, able to cope with differing road conditions, robust and does just as well muddy as polished!

I've fallen back in love with my car

[atkiman]

Hi

After having the scv's changed I fill up with Shell v power every time, it doesn't do a tremendous mileage , so I'll take the extra cost hit.

Over in france a couple of weeks ago , I got total excellium on the motorway at about 90p per litre, wish it was the same here.

Anything over 38 mpg I'm happy with, did manage to get her down to 32 mpg, running at 130 km/h fully loaded plus a Roof Rack in july , bit of a lead foot that day

Tony

[Avalon]

You're welcome Sarah - glad it's improved :) Its normally at least 200 miles before you see any real benefit from any fuel based detergent treatment so two tanks should either fix it or not. I'd give it two full tanks then try say 1 in 3-4 and see how you get on, even just taking it for a long run should help.

My issue is intermittent (car is fine, occasionally put your foot down up hill and it won't produce boost, then it kicks in and is fine) and I can't reproduce it on demand so I'm going with the variable vane system on the turbo having excess build-up. As I now do mostly short runs like you I've gone with a variation on option 5, Millers Eco Max fuel treatment, it's cheap at 80p per tank treatment, makes the engine sound noticeably smoother and as my local garage is down to 102.9 for regular diesel which is at least 5p cheaper than the supermarkets, let alone the branded stations, then it's difficult to say no to compared to spending £7.50 extra per tank for BP Ultimate/She'll Nitro. If they come down in price/when I know I have a nice long run then I'll shove a tank of the good stuff through.

[Sarah White]

Hi all, 

A further update - still love my car but as the problem with the turbo lag has come back and persisted, even with ultimate diesel, she is as we speak in the garage having a new turbo. Gone for a non-Toyota solution to keep the cost down (Toyota parts £1000+, non-Toyota parts £6-700). Fingers crossed that this solves the issue!

Will let you know what happens :)

[atkiman]

Hope you get it sorted, know your pain, i had to have a new shaft in the gearbox, plus yet another new 5th gear. Perhaps if we swapped all the good bits we'd have 1 stonking good car out the 2, my engine goes like a train.

[RAV4 2005]

Avalon you're my hero(ine?).

Recently purchased a RAV4 D4D from an auction with various issues, not least disconnected cables which could have been related to investigations of intermittent power loss but i suspect a dodgey dealer trying to secure a better price, which might have worked if I had been awake. A full service sorted most things except for a recurring EM light (Barometric Pressure = MAF sensor = area needed a good clean = improved responsiveness).

Everything great for a few day's, mostly around town & a few A roads, then I got the dreaded intermittent power loss once I hit the motorway (As described in this thread). It was fairly easy to reproduce on the motorway (almost any time I drove at 70 ish for a few miles, sometimes when dropping to 3rd at a roundabout after doing about 60).

WARNING : I don't suggest motorways if you're experiencing such issues !!!!!!!

Added some diesel treatment (basic option from toolstation) when tank 1/2 full. Things didn't improve by the time I was down to 1/4 tank & I topped up using BP Ultimate diesel, 10 miles later problem recurred for about 5mins but then has resulted in 200 plus trouble-free motorway miles.

NB: Since purchase I'd filled up twice using supermarket diesel......

My assumption now is that the previous owner used cheap diesel, experienced the power loss issues & decided the auction was their best way out rather than expensive repairs ??.

Thoughts:

I'm convinced the BP Ultimate did the trick but also wonder if a good motorway run would help avoid such issues as-well ?

A few people have told me such issues are common (all vehicle brands) due to cheaper supermarket fuel , Is there any info / stats out there (either from manufacturers or forums) that Identify whether such fuel is available in all countries and if so how this results in reported failures compared to countries that may have a higher standard?

Also makes me think there's probably a fair few accidents (possibly fatalities) as a result of sudden power loss at speed (no fun in the fast lane at rush hour).

Anyway, thank's again Avalon, you've saved me a fortune & an ear bashing from the Mrs.

Much appreciated

 

 

 

 

 

 

[Sarah White]

Further update on power loss issues on my Rav4: the main issue was power loss when wanting to accelerate and interestingly when we changed the turbo, it definitely cured this original problem, but only to switch it to lower revs - lack of or delayed power when pulling away in first or second!  So back into the garage to have another part changed - can't remember the name of it but it fits on the end of the turbo, contains a microchip and has a vacuum component on it. Had to come from Toyota at a cost of £200 + VAT but glad to say that this has fixed the problem of delayed power at low revs, so for the moment all is good and I have a fully functional car! Who knew it could be so lively 

So for those who still have the issue, if you read through my posts and Avalon's helpful comments, hopefully you should be able to work your way through to resolve the problem.

Good luck!

[Ant-Rav]

Hi Sarah,

Essentially, I think what cured ur loss of power problem in the end after trying various solution's was

1. Replacement of ur turbo.

2. Replacement of this part u say fit's on end of turbo, and ur not sure what it's called.

That's really it I think in ur case anyway, Did ur mechanic check ur turbo before replacing or just replace in hope it would solve the problem. And could u find out the name of this other we part he changed. U must feel pretty chuffed getting it fixed dare say.

[Sarah White]

Thanks Ant-Rav. It makes a huge difference when the car pulls properly - keep holding my breath in case it starts mucking about again. Would be jumping about with joy if it hadn't cost me so much to sort it out. Hopefully others reading my post can short cut the process now and not end up spending what I did.

The mechanic checked the turbo when he took it out and said 'it was knackered' so replaced it.

Need to remind my mechanic to send me a bill, so will ask him what the part was called and let you know...

[Ant-Rav]

Thank's  for that Sarah.