Strange problem with Toyota fortuner

[HRV]

Hi All,

I've a Toyota Fortuner petrol (Auto) 160,000KM. It started to develop an issue about 1 month ago. When under heavy load the engine stalls. When it is started again it runs fine. 

- It doesn't matter if it the morning or after a long trip - Eg : Ran to Nuwara Eliya without an issue and at the end of the journey engine stalled.
- No check engine light. Scanned at Toyota Lanka and another place. No error codes.
- Issue happens when AC is On/Of - Not relevant.
- As I see the problem.. when the RPM goes down, it suddenly drops going below 700-800 and if there is additional load (Eg : Climbing, Turning) car struggle to keep on and if I don't press the accelerator it dies.
- Idle is correct it seems 700-800, Verified by Toyota too.
- Can simulate the issue by having the car on Park, pressing the accelerator pedal till RPM 1500 - 2500 and then taking the foot off suddenly. RPM drops suddenly, car shakes and then catches on after struggling(on P). On Drive (D) if same is done specially on a hilly road + turning while braking - It would try to die.
- Happens on flat road too - I drive mostly in Colombo.
- Throttle body and spark plugs inspected/cleaned at Toyota Lanka -No Change
- 3M intake cleaner and 3M injector cleaner applied, Petrol filter checked at another place - No Change.
- Pick up etc is fine, Idle is not super smooth but OK (Not very rough/vibrating).
- My first thought was MAF sensor. Cleaned it - No difference, replaced with few other MAF sensors from Toyota's (Not the exact model though, Makabass @ work) - Nothing changed (Didn't want to buy a new One without being certain.)
- Makabass style of vacuum leak check was done - Will have to redo properly.

Planning to put the car @ Toyota lanka, but before spending big bucks, I would like to know what you experts think ? Thank you guys ! 

 

[peugeot407]

What about engine temperature?

[HRV]

It's at the normal range - half on the temp meter. Never saw it rise above. Have happened on occasions on very short drives (5 Mins) - when the engine is not that hot as well as on occasions when the engine would have been very hot (Eg : 6 hours of driving)

[NRX]

Was the fuel pressure checked at any point ?

[Rumesh88]

Did you inspect/change the injector washers? They may have got cracked due to heat stress causing a vacuum leak. Once I had a similar issue (engine simply died abruptly at times) with a 121 due to leaky injector washers. There are two washers per each injector - one at fuel rail and another at the manifold side. It is the manifold side one I am referring to here. Similar issue discussed in 

 

Edited September 15, 2016 by Rumesh88

[HRV]

Thanks NRX and Rumesh88. Thanks for the pointers - I'm very sure that Toyota would talk me into doing a full overhaul/tune-up and that's what I'm exactly trying to avoid. Too bad they don't allow us to be with the car and give our opinion on things while they check. I'll check everything you guys told. I just wish this damn thing throws up a code somewhere to make life easy.

Rumesh - The strange thing is I can simulate this issue every time (Even though not the stopping of engine). As I mentioned earlier If I press the accelerator to RPM of around 2.5K and take my foot off. It stabilizes on idle only after going well below the idle RPM.. I want to try remove the MAF sensor and see if it try to take a default value (Maybe from MAP but don't know even that exist in Fortuner) and simulate the issue ? Do you think it is a good idea. Also I would like clean the MAF sensor myself again and see - Is carburetor cleaner good enough for this job ? 

 

Edited September 15, 2016 by HRV

[Rumesh88]

You cannot simulate the issue by removing the MAF sensor (physically/electrically). Now if you can simulate the issue by taking the foot off suddenly after revving up to 2500, try taking the foot off very very slowly and see if the idle speed stabilizes itself at its nominal value. If you still get the issue check your TPS sensor as well. If the issue appears only when you take off the foot suddenly then it can mostly be due a vacuum leak behind the throttle (injector washers, PCV valve etc..,)

A few things I forgot to add - clean the OCV filter of the VVTi mechanism if you have not done it by now. Also check the OCV valve for accumulated gunk. If the MAF elements appear clean (white colored) to the naked eye then there is no need to clean. If you use a cleaner  make sure it does not flow over other parts of the sensor and remove its o-ring before cleaning.

Edited September 15, 2016 by Rumesh88

[NRX]

Rumesh. I think we need to mention that he should not use Carburetor cleaner on the MAF sensor, right ?

[Rumesh88]

  On 9/15/2016 at 10:21 AM, NRX said:

Rumesh. I think we need to mention that he should not use Carburetor cleaner on the MAF sensor, right ?

Expand  

In fact I wanted say that but I myself have used carb cleaner on MAF sensors but nothing bad has happened so far! What I usually do is to put a couple of diesel drops on to the element, leave for few minutes, blow away with compressed air, then very carefully wash diesel residue off the elements using carb cleaner making sure that the carb cleaner would not dissolve any plastic parts around and leave a residue on the element. You need to make use of compress air to blow off carb cleaner as soon as possible. Or else OP can use a good quality contact cleaner but still above precautions shall apply.  

Edit: Let me put the message across this way. No solvent is safe with a MAF sensor unless you take precautions against the possibility of residue left over by the evaporating solvent.

Edited September 15, 2016 by Rumesh88

[HRV]

Hey Rumesh/NRX,

It's a great community we have over here - Thank you. I already spent nearly 11,000 Rs for this (2 Scans, Throttle body cleaning, 2 x 3M cans etc). So thought to check the MAF myself. So I unplugged the MAF - Check engine came ON as I thought but voila the problem seemed to have gone. I ran a bit with the MAF disconnected - all the symptoms I had were gone. When I give gas up to 2500 RPM and take out the foot - RPM comes down nicely and settles at the idle. So I thought this was the culprit. (Funny a garage already cleaned the MAF but they sprayed only a little amount.) I did some research on the internet last night about cleaning MAF, EGR etc - and many had actually advised against using carb cleaner and they recommended a MAF sensor cleaner spray (Which I couldn't find anywhere around.) So settled in for a Wurth carburetor and injector cleaner (Shop guy also advised against some carb cleaners leaving bubble like residue but said this was good..). .Cleaned for few seconds and put it back... No luck - I thought what the heck and emptied half a bottle at the little thingy. It is running fine now, but I'll have to run few hundred Kms to see if the cleaning helped long term. If not I'm going to buy the part and swap it. Since the situation improved after cleaning, I don't think it is with the connectors/wiring too. I'll keep you guys updated.

Thanks.

 

[NRX]

Great! Now we know what the culprit was. Hope you let MAF element to dry completely before connecting again. Anyways, keep us updated on the progress.

[The Stig]

  On 9/15/2016 at 12:16 PM, HRV said:

Hey Rumesh/NRX,

It's a great community we have over here - Thank you. I already spent nearly 11,000 Rs for this (2 Scans, Throttle body cleaning, 2 x 3M cans etc). So thought to check the MAF myself. So I unplugged the MAF - Check engine came ON as I thought but voila the problem seemed to have gone. I ran a bit with the MAF disconnected - all the symptoms I had were gone. When I give gas up to 2500 RPM and take out the foot - RPM comes down nicely and settles at the idle. So I thought this was the culprit. (Funny a garage already cleaned the MAF but they sprayed only a little amount.) I did some research on the internet last night about cleaning MAF, EGR etc - and many had actually advised against using carb cleaner and they recommended a MAF sensor cleaner spray (Which I couldn't find anywhere around.) So settled in for a Wurth carburetor and injector cleaner (Shop guy also advised against some carb cleaners leaving bubble like residue but said this was good..). .Cleaned for few seconds and put it back... No luck - I thought what the heck and emptied half a bottle at the little thingy. It is running fine now, but I'll have to run few hundred Kms to see if the cleaning helped long term. If not I'm going to buy the part and swap it. Since the situation improved after cleaning, I don't think it is with the connectors/wiring too. I'll keep you guys updated.

Thanks.

 

Expand  

Good that you found out the issue, but you shouldn't put it back until at least 2-3 hours after cleaning since the wiring inside the maf could short circuit (trust me i have done this and paid the price) when there is still cleaner liquid inside. Also you cant find MAF cleaner in Sri Lanka for sure but electrical contact cleaner is the recommended alternative, try CRC or Philips contact cleaner. And finally hope you dont run without your maf anymore, its going to ruin your O2 sensor.

[AJ84]

  On 9/14/2016 at 1:50 PM, HRV said:

Hi All,

I've a Toyota Fortuner petrol (Auto) 160,000KM. It started to develop an issue about 1 month ago. When under heavy load the engine stalls. When it is started again it runs fine. 

- It doesn't matter if it the morning or after a long trip - Eg : Ran to Nuwara Eliya without an issue and at the end of the journey engine stalled.
- No check engine light. Scanned at Toyota Lanka and another place. No error codes.
- Issue happens when AC is On/Of - Not relevant.
- As I see the problem.. when the RPM goes down, it suddenly drops going below 700-800 and if there is additional load (Eg : Climbing, Turning) car struggle to keep on and if I don't press the accelerator it dies.
- Idle is correct it seems 700-800, Verified by Toyota too.
- Can simulate the issue by having the car on Park, pressing the accelerator pedal till RPM 1500 - 2500 and then taking the foot off suddenly. RPM drops suddenly, car shakes and then catches on after struggling(on P). On Drive (D) if same is done specially on a hilly road + turning while braking - It would try to die.
- Happens on flat road too - I drive mostly in Colombo.
- Throttle body and spark plugs inspected/cleaned at Toyota Lanka -No Change
- 3M intake cleaner and 3M injector cleaner applied, Petrol filter checked at another place - No Change.
- Pick up etc is fine, Idle is not super smooth but OK (Not very rough/vibrating).
- My first thought was MAF sensor. Cleaned it - No difference, replaced with few other MAF sensors from Toyota's (Not the exact model though, Makabass @ work) - Nothing changed (Didn't want to buy a new One without being certain.)
- Makabass style of vacuum leak check was done - Will have to redo properly.

Planning to put the car @ Toyota lanka, but before spending big bucks, I would like to know what you experts think ? Thank you guys ! 

 

Expand  

Did you check the idle adjuster? 

I had the same issue and got rid of the same by fine tuning. Tech said it had something to do with Aircon and some kinda signal it sends through.

Try accelarating to max and release it on P and see if engine stalls. If it is the case I guess u r having the same prob (most probably )

[HRV]

Hi Stig,

I guess I was lucky and didn't fry the MAF - Anyway the car works fine now, no more trying to die when turning etc. It was good to know that running around without MAF can ruin the O2 sensor. I just ran it only for 2-3 Kms to test, and hope nothing serious happened to the O2 sensors.

AJ84 - Hmmm. Did you mean throttle/accelerator cable adjuster by idle adjuster ? This got e-throttle. Anyway I don't think it was a problem with idle - idle was perfect.

  On 9/16/2016 at 1:34 PM, The Stig said:

Good that you found out the issue, but you shouldn't put it back until at least 2-3 hours after cleaning since the wiring inside the maf could short circuit (trust me i have done this and paid the price) when there is still cleaner liquid inside. Also you cant find MAF cleaner in Sri Lanka for sure but electrical contact cleaner is the recommended alternative, try CRC or Philips contact cleaner. And finally hope you dont run without your maf anymore, its going to ruin your O2 sensor.

Expand  

 

Edited September 17, 2016 by HRV

[Davy]

  On 9/16/2016 at 1:34 PM, The Stig said:

Good that you found out the issue, but you shouldn't put it back until at least 2-3 hours after cleaning since the wiring inside the maf could short circuit (trust me i have done this and paid the price) when there is still cleaner liquid inside. Also you cant find MAF cleaner in Sri Lanka for sure but electrical contact cleaner is the recommended alternative, try CRC or Philips contact cleaner. And finally hope you dont run without your maf anymore, its going to ruin your O2 sensor.

Expand  

Maybe Wurth has it? Also, I recently saw that LIQUI MOLY agents have set up shop in Sri Lanka. They might actually be having MAF sensor cleaner.