HELP! Inconsistent acceleration, rpm gauge jumps down and then up - prado 2001

gmr Oct 20, 2015

  1. gmr

    gmr New Member I am in israel

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    Gritting to all prado fans

    I own a 2001 prado 90 3000cc diesel kdj95l, i bout it 11 years ago and it's an amazing car

    The car is serviced by the book by a 4x4 specialist mechanic

    Unfortunately few weeks ago a problem started that we can't solve

    The problem:
    1. Inconsistent acceleration:
    0-2500 rpm – acceleration is linear and pretty good
    2500-3200rpm – acceleration is not linear it's bumpy, the rpm gauge jumps down and then up like its acceleration is steps, (its sounds like when the engine gets to the rev limiter)
    3200-and up – the jumps stops but the pull of the engine is weak
    2. Top speed only 100kmh
    3. Having difficulty climbing roads up hill
    *** When in N' gear it revs good all the way 0- 4000 rpm

    Tests that we preformed
    1. Cleaning the fuel tank
    2. Cleaning the fuel lines
    3. Replacing the fuel filter
    4. Overlapping the fuel system and filter and inserting direct fuel to the engine
    5. Disconnecting the catalytic converter
    6. Testing with a Toyota computer – haven't found any problem
    7. Testing with a Toyota computer - injectors – good results
    8. Turbo pressure - o.k.
    9. Exhaust gases - normal color and density
    10. Vacuum hoes checked
    11. The cars start easy
    12. Toyota mechanics tested the car and they couldn't pinpoint the problem

    Injector's \ fuel pump \ sensors are very very very very expensive to replace!!! both in parts and in labor.

    The worst part is that they don’t even know if it will fix the problem. Replacing all of doe's parts will cost a fortune!

    Is this problem happened to anyone before? Do you know how to solve it? Can you pinpoint the problem?

    Looking for a solution
    gmr
     
  2. Shayne

    Shayne Well-Known Member Guru

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    2500 - TO 32OOrpm is when the turbo is at work and i would guess the engine can't breathe . Look for a blockage or leak in the intake and run a bottle of Wynn's egr cleaner through it . A blockage in the exhaust is worth investigating to .
     
    Last edited: Oct 20, 2015
  3. jbecks

    jbecks Well-Known Member I am in great_britain

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    Under the bonnet is a diagnostic port and check for fault codes, put a jumper wire between te1 and e1 and count the flashes, if the ecu light is flashing constant 1 second intervals then there are no logged fault codes, with the jumper wire connected press the o/d button and check the same thing, this will flash any fault codes with the auto box,

    I would check the turbo too for excessive horizontal and lateral play, inspect the oil tract for excessive amounts of oil, I would then check the egr valve is not stuck open as that can cause very similar symptoms to a blown turbo. But generally both these do show excessive smoke from the exhaust.

    How are the gear changes? My gut feeling is its fuel related.
     
    Last edited: Oct 20, 2015
  4. alfonso

    alfonso New Member I am in philippines

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    Hi GMR. Did you get the problem sorted out? I have exactly the same problem. I also did all the checks and all the cleaning you did but still no luck. I took the turbo apart, It was perfect. No fault codes, no smoke, no knocks. Pulls ok below 40 MPH on all gears then goes to limp mode when it goes over 40.

    Any help please. It's a 3 liter diesel manual.
     
  5. Shayne

    Shayne Well-Known Member Guru

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    Suction control valves have been known to fail
     
  6. Beau

    Beau Well-Known Member I am in guyana

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    These things don't have a catalytic converter. Can you confirm what engine you have, the 1kz or D4D?

    What boost levels were you running? Can you hear the turbo work? If turbo is functioning as it's supposed to it would point to the fuel delivery.

    The KZ pump has two (some have three) filters located inside the pump. I have made a video which is on youtube. Might be worth cleaning these out before you replace anything mechanical.
     
  7. alfonso

    alfonso New Member I am in philippines

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    I did change the SC valves. It improved but not a lot. I might be missing something. HEEEEEEEELP!
     
  8. alfonso

    alfonso New Member I am in philippines

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    I got a D4D. Changed the SC valves. It had improved but not a lot. It can now go above 50 MPH but hesitates to accelerate below 2000 RPM. Cleaned the tank filter as well.
     
  9. alfonso

    alfonso New Member I am in philippines

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    Not sure about boost level but I can hear the turbo whistle like it always did.
     
  10. Shayne

    Shayne Well-Known Member Guru

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    Assuming this is the 1KD otherwise known as the D4D engine i'd suspect engine management which is petty exhaustive on these , the ECU would be the obvious suspect but before looking at that i'd be inclined to take both fuse boxes off to inspect and clean connections .

    It's a vague memory but someone who had a 1KZ 90 (very similar component lay out) with a similar problem found (i think) a bad connection hidden under the fuse box .

    I'm clutching at straws and my memory is poor but there's nothing worse than running out of ideas on what to check .

    I'm not very familiar with the D4D engine but knowing the turbo is electronically managed having no wastegate as we know it i was trying to figure how it might fail and chanced upon this https://www.turbochargersplus.com/t...kd-ftv-turbo-actuator-stepper-motor-problems/
     
  11. alfonso

    alfonso New Member I am in philippines

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    I took the turbo apart. No clearance on the bearings, no wear on the blades and no contact on the casings. The actuator ring however got a bit of clearance between the yokes and the vane shafts. I thought this gap may cause delay when the stepper motor closes or opens so I nipped the yokes closer to get rid of the clearance but still no luck.

    I will check the connections under the fuse boxes tomorrow and hoping to find the gremlins. I will also try to disconnect the batteries in the hope it will reset everything. I am running out of ideas and getting more gray hairs!.
     
  12. alfonso

    alfonso New Member I am in philippines

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    Hi everyone.

    Still in a pickle with my horse. Any one out there who are more experienced in land cruisers, I need your help!

    I narrowed it down to throttle pedal or throttle body. No bad connections as Shayne suggested. Cut open the CAT but its not blocked. cleaned it and re installed.

    At stand still, RPM can climb up to 2200 and stays there with the pedal down to the floor. Any suggestions please?
     
  13. Beau

    Beau Well-Known Member I am in guyana

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    Throttle position sensor failed?
     
  14. Shayne

    Shayne Well-Known Member Guru

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    If fuel and electrics are ok it can only be an air problem - fuel can't burn without air . So i did a little googling and it seems suction control valves failing to deliver sufficient fuel will cause the turbo to compensate by overboosting which in turn throws the truck into limp mode .

    Could it be that you have cured the problem by changing the valves but the fault recognized by ecu activating limp mode has not been cleared hence the cars brain doesn't know its been fixed ?

    I came across fault codes while looking into this which though it may not help you because it doesn't mention how to clear codes but it should be on the forum nevertheless perhaps as a sticky Mr Moderator ? so i will post it separate .
     
  15. Shayne

    Shayne Well-Known Member Guru

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    Seeing as you can't plug in right now, you could check the blink codes instead by using a small piece of wire to short out pins 4 and 13 on the DLC3 connector (where you connect your code reader). The check engine light will blink out a code that you will be able to cross check.

    1) Ensure the ignition is off
    2) Turn the ignition on, but don't start.
    3) Put the wire across the connector pins. (pin 4 and pin 13)
    4) Read codes displayed via the engine check light.
    5) Disconnect the wire when finished retrieving codes and turn the ignition off.

    The D4D error codes are below, and the blink codes are in brackets (for instance, I'm getting 7x flashes…. 1.5 second pause…8x flashes, which is code 78)

    P0045 (34) - Boost control solenoid circuit malfunction

    P0087 (49) - Fuel rail pressure sensor or rail pressure too low.

    P0088 (49) - Fuel rail pressure too high.

    P0093 (78) - Fuel system leak (Large leak)

    P0095 (23) - Intake air temperature sensor circuit (open/short/failure)

    P0097 (23) - Intake air temp circuit low input.

    P0098 (23) - Intake temperature sensor circuit high input.

    P0100 (31) - Mass air flow meter or circuit (open/short/failure)

    P0102 (31) - Air flow meter circuit low input.

    P0103 (31) - Air flow meter circuit high input.

    P0105 (31) - Manifold absolute pressure sensor circuit (short/open/failure)

    P0107 (31) - Manifold absolute pressure sensor circuit low input.

    P0108 (31) - Manifold absolute pressure sensor circuit high input.

    P0110 (24) - Intake air temperature circuit (open/short/failure)

    P0112 (24) - Intake air temperature circuit low input

    P0113 (24) - Intake air temperature circuit high input.

    P0115 (22) - Coolant temperature circuit (open/short/failure).

    P0117 (22) - Coolant temperature circuit low input.

    P0118 (22) - Coolant temperature circuit high input.

    P0168 (39) - Fuel temperature too high.

    P0180 (39) - Fuel temp sensor “A” (open/short/failure)

    P0182 (39) - Fuel temp sensor “A” low input.

    P0183 (39) - Fuel temp sensor “A” high input.

    P0190 (49) - Fuel rail pressure sensor circuit (open/short/failure)

    P0191 (49) - Fuel rail pressure sensor circuit performance/range

    P0192 (49) - Fuel rail pressure sensor circuit input low.

    P0193 (49) - Fuel rail pressure sensor circuit high input.

    P0200 (97) - Injector circuit (open/short/failure)

    P0234 (34) - Turbo over boost condition.

    P0299 (34) - Turbo under boost condition.

    P0335 (12,13) - Crankshaft position sensor circuit “A” (open/short/failure).

    P0339 (13) - Crankshaft position sensor circuit “A” intermittent fault.

    P0340 (12) - Crankshaft position sensor circuit “A” no signal after cranking.

    P0400 (71) - EGR position sensor (valve out of position)

    P0405 (96) - EGR position sensor low input.

    P0406 (96) - EGR position sensor high input.

    P0488 (15) - EGR throttle position sensor/motor/circuit fault.

    P0500 (42) - Vehicle speed sensor “A” (open/short/failure)

    P0504 (51) - Brake switch.

    P0607 (89) - Control module fault (ECM internal fault)

    P0627 (78) - Fuel pump control circuit (open/short/failure)

    P1229 (78) - Fuel pump fail.

    P1251 (34) - Turbocharger stepper motor circuit (intermittent fault)

    P1271 - Fuel regulator circuit malfunction. (open/short/failure)

    P1272 - Fuel pressure regulator malfunction (simultaneously with P1271)

    P1601 (89) - Injector correction circuit (E-prom)

    P1611 (17) - ECM run pulse.

    P2008 (58) - Intake manifold runner control circuit (open/short/failure)

    P2120 (19) - Throttle/pedal position sensor “D” (open/short/fail)

    P2121 (19) - Throttle/pedal position sensor “D” (range/performance)

    P2122 (19) - Throttle/pedal position sensor “D” low input.

    P2123 (19) - Throttle/pedal position sensor “D” input high.

    P2125 (19) - Throttle/pedal position sensor “E” (open/short/fail)

    P2127 (19) - Throttle/pedal position sensor “E” low input.

    P2128 (19) - Throttle/pedal position sensor “E” high input.

    P2138 (19) - Throttle/pedal position sensor “D” and “E” voltage correlation.

    P2226 (105) - ECM barometric pressure circuit.

    P2228 (105) - ECM barometric pressure circuit low input.

    P2229 (105) - ECM barometric pressure circuit high input.

    U0001 (102) - ECM open or short.

    B2799 (99) - Engine immobilizer malfunction.

    Hope this helps you diagnose the problem!

    DCL3.jpg
     
  16. alfonso

    alfonso New Member I am in philippines

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    Thanks guys!

    I tried disconnecting the batteries in the hope that it will re set everything but to no avail.

    I will try the blink code route Shayne and will keep you posted.

    Thanks again.
     
  17. grantw

    grantw Well-Known Member Supporter

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    I'm guessing you would have seen this by now but just in case ... have you checked that the air in take hoses aren't collapsing restricting airflow in the higher revs?

    It would also be worth posting your problems on this face book page. Julian from Overlandcruisers quite often helps out with his expertise. https://www.facebook.com/groups/Toyota4x4Support/?fref=nf
     
  18. alfonso

    alfonso New Member I am in philippines

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    Hi everyone.

    Still an on going saga!

    I tried Shayne's blink code but no stored codes. Just a consistent blink. Although thanks for posting this method.

    I changed the throttle body but no joy!

    I checked the boost as Grant suggested and all is OK. No leaks, no restrictions. I will try posting it to Overlandcruiser hope someone will have a solution.

    Thanks again guys!
     
  19. alfonso

    alfonso New Member I am in philippines

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    Is there another method to reset the ECU? Shayne might be right that the ECU needs to relearn as new SCV that were installed.
     
  20. alfonso

    alfonso New Member I am in philippines

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    Hi everyone!

    At last I got a code!

    I was able to borrow an expensive TEXA TXT diagnostics but unfortunately it will not communicate with the car so decided to have a go at Shayne's blink code method again and wala! It gave a code 19. All 8 code 19 are for the Throttle/Pedal sensor. I will be ordering one tomorrow.

    Is there a special method of changing the sensor? Looks like it will need to be set right.
     
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