Surging / hesitation at 2100rpm (and it’s killing me!!!).

[aussiearthur]

G’day team,

long post, but really need some help, as this problem is killing me!!! And also my wallet.

Car is:
- 1kd 2007
- 213km
- auto

Fault:
- whether hot or cold, there is a fairly significant amount of hesitation/ surging occurring at 2100rpm, 2300rpm and 2400rpm. The car physically slows and rpm drop, lasts about a second and then surges forward. A few seconds later it repeats, and will continue until I move out of this rev range.

- no issues evident at other rpm ranges
- it is repeatable every drive.
- am concerned that this is damaging the engine.
- NO fault codes
- no smoke
- car runs beautifully otherwise.
- issue occurs using either the accelerator pedal or cruise control (so have assumed it’s not an accelerator position sensor issue).

There are a few threads in Pradopoint and New HiluxD4D forums which state similar issues (vehicles have similar manufacture dates too), but none of them ever reach closure on this issue.

I have:
- checked and cleaned heaps of electrical connections
- cleaned MAP and MAF sensors and filters, cold start idle values look ok.
- replaced MAP sensor
- cleaned EGR valve, the manifold and the cooler.
- turbo and stepper replaced at about 190k
- fuel filters (x2) and air filters recently replaced.
- SCV replaced ( with the long version)
- injectors replaced.
- swapped the whole throttle body with another.
- I performed a fuel leak test via Techstream, which saw the system hit its target set point and hold there with no codes thrown.

I feel like this is related to RPM, as I can consistently repeat this issue at the stated rpm levels.

could there be a link here to a sensor that is feeding the ecu some dud information - ie transmission speed sensor, egr valve, or a fuel temp sensor???

I would be absolutely grateful for any assistance on where to look next.
kind regards.
chris

 

[Fry1988]

I am having the exact same issue with my 07 1kd Auto. I have just removed and cleaned entire manifold, + replaced the EGR valve. Has not made a scrap of difference.
Have taken the car to multiple service centres and they have no idea what the issue is.
Don't particularly want to spend thousands $'s on someone trying to diagnose the issue.

 

[Shayne]

I don't know much about auto's but i believe there is a very important speed sensor on the gearbox ?

 

[Higgy]

Does the 120 Have a Throttle positioning sensor (TPS)?... If so did you swap the TPS.. When you swapped the throttle Body?

 

[Shayne]

MAP sensor might pass a multimeter test but still fail because the vacuum line on it is blocked ?

 

[aussiearthur]

@Fry1988 - sorry to hear you’ve the same issue - it is really odd that it’s the same build year! I’ve done the full egr clean down too and same result- zero.
I’ve not been able to resolve mine as yet and it is literally frustrating the hell out of me.

@Shayne - I’ve considered the transmission speed sensor, but because the readings of rpm are so stable and not fluctuating in other ranges, I’ve kinda assumed it to be ok. Definitely a test for a really good auto elec, as I’m quite sure this is not an intermittent fault.
With the MAP vac Hoses, I’ve taken them off, put compressed air through them and inspected for holes. I’m actually still thinking this is perhaps still an area needing a revisit. A small crack or hole in these hoses could absolutely be the root cause of these issues.

@Higgy - the TPS is integrated with the throttle body, so when I changed out the body it basically addressed this too.

Wondering if there is a chance that excessive back-pressure on the turbo (from the likes of a heavily blocked catalytic converter) could be a likely scenario. Do people have regular issues with the cats.?

 

[Shayne]

Variable vane turbo is computer controlled , somebody on here had problems with one , a 120 i think and swapped out some electrickery directly related to the turbo to fix it .

I'm a bit distracted right now or else i'd do a search for what that electrickery is actually called

 

[karl2000]

If you can repeat it, can you get some live data on techstream and upload it so we can have a look?

 

[Shayne]

Turbo stepper motor .

Is this it ?

CT16V Turbo Actuator compatible for Toyota Landcruiser Hilux 3.0 D 1KD-FTV Solenoid Valve

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[Fry1988]

I have read some other threads that suggest the issue can be fixed with an ECU update. There is a toyota bulletin (TNF52/12). I will be having a chat to Toyota tomorrow and see if it can be done.

Link to a thread in pradopoint site with similar issues:

1KD Surging at 2200 rpm - Toyota Prado How To's, Technical Information & Reviews

Performance, Fuel consumption, maintenence, mods

www.pradopoint.com.au

 

[Fry1988]

@aussiearthur, I've not had any luck with info out of Toyota, basically the car needs to get booked in for them to investigate. $140-$150 per hour is what they will charge.

 

[Shayne]

A wild card but have a look inside the fuel tank ,could the pickup sock strainer be clogged up ?

 

[aussiearthur]

@karl2000 - I’ve been trying my hardest to collect tech stream data on a range of simple variables - but the sample rate of the data is like 1.5seconds apart at best. If I choose more than about 4 parameters the frequency increases to like 2 seconds.
If the sample rate was faster then it would be an awesome diagnostic tool.

I’ve tried different downloads and stuff, but just can’t seem to get it working sufficiently.
It could be the cable - which I bought through OB2 here is oz.

@Fry1988 - off the back of that earlier thread I too have booked into Toyota for late next week. Had sworn to myself that I would never go back there!!! I don’t hold too much hope…..

 

[aussiearthur]

I had thought there might be issues with the fuel delivery.
Here are screenshots of the fuel pump pressure test done via Techstream. When car is running it ramps fuel pump to max output, which forces engine to about 2100rpm (no load).

Interesting the pressure fluctuations - I posted to Pradopoint to get a sense if it was normal - no responses received.

 

[karl2000]

I’ve been trying my hardest to collect tech stream data on a range of simple variables - but the sample rate of the data is like 1.5seconds apart at best. If I choose more than about 4 parameters the frequency increases to like 2 seconds.
If the sample rate was faster then it would be an awesome diagnostic tool.

Ah :-( So does your problem appear, then disappear within a couple of seconds, so that the sample rate of a few seconds will miss the problem?

I haven't tried recording several variables so not sure if your sampling rate is normal or not - I will try when I get some time!

Just a thought - how fast does your normal live data screen update? It's always seemed pretty responsive to me - maybe you can just record the screen (either on the PC or get someone to hold a camera at it while you're driving!) and see if theres any clues there. If you have a friend videoing it, you can speak exactly when you hit the problem so that we know what the data is at that point, and around it!

Good luck!

 

[karl2000]

Interesting the pressure fluctuations - I posted to Pradopoint to get a sense if it was normal - no responses received.

I know pressure fluctuations can point to a possible SCV issue. Has your SCV been changed, have it got the long or short version?

 

[karl2000]

Might also be worth posting this on TLOC and see if TonyC has any advice.

The Toyota Landcruiser Owners Club :: View Forum - 120 Series / Prado Technical Forum

 

[Tractionman]

Arthur, when you take it in to Toyota, tell them you want a print out of anything they find when hooked up. They have been known to give wrong info to generate parts sales/labour ??
Some members have found just that !
+1 for contacting TonyC.

 

[Fry1988]

@aussiearthur, did Toyota have any luck with the diagnosis?

 

[aussiearthur]

Hey team - thanks for the info and comments - genuinely stoked for your input and ideas.

I have done the SCV and went for the new longer version via Fourby4. Not a noticeable change unfortunately.

I’ll certainly chase TonyC down - as I am pretty skeptical about Toyota.
Car is currently in their workshop. Was able to take their service manager out for a solid drive so he could see and experience the surging. Hope this might support better analysis.

@Tractionman - this is exactly what I’m worried about. Should know some more in early part of next week.