Is there really a problem with the Innova's diesel engine?

By Ferman Lao
 

Hi, Ferman!

I am new to Top Gear and I have been reading your columns which I find very informative and educational. I would like to ask you regarding my Toyota Innova G diesel with automatic transmission.

I recently purchased a brand-new 2011 Innova AT diesel variant. From the very first time I drove it I was impressed by its performance. It's a smooth ride. Engine performance and response are very good for a diesel engine. It has a somewhat bare interior but it suits my taste. Overall it's a good buy with my hard-earned money.

But recently, as I was browsing the Internet, I chanced upon a forum where the thread topic is about problems encountered by owners of Innovas, particularly the ones with D4-D engines. Most of their Innovas were 2005 to 2009 models. The most common problems cited were hard starting, choking and stalling. Most of them had to bring their Innova to the casa to have it repaired. At first the common reason given out by service advisers was that the fuel filters were clogged. And the culprit was dirty fuel. Repairs were done but after a few months the problem occurs again. Some had to have their fuel pump replaced. On the extreme side, one unit had to have the CRDI system replaced. There was one who only had 2,000 kilometers on the odometer when this problem occurred. It would be of no concern to me if this was an isolated case but a lot of Innova owners had gone through this. Most of them have been saying that the D4-D engine has a design flaw and that the fuel pump is flawed. It's okay if this happens during the warranty period. But what if it happens after? These parts are expensive. Toyota never admitted a design flaw nor did it announce a recall. All they blame is dirty fuel.

From the posts at the forum others say that the problem has been resolved in the newer models and that the defective parts have been upgraded by Toyota. Some say that the problem still persists. Now I am pondering whether I made the wrong decision in buying the Innova or not. I chose the Innova diesel because of fuel-consumption concerns as my old 1998 Revo was a guzzler.

Have you encountered or heard of this? If you did, is it true that these problems have been resolved or do they still exist?

Hope to hear from you. Thanks in advance.

David

Hi, David!

To better understand the problem, we would have to look at how the modern EFI diesel engine works. Much like its gasoline equivalent, it relies on the engine's myriad of sensors to tell the engine control unit (ECU) what's happening and what the corresponding action should be.

The electronics for the most part are practically identical to the petrol engine counterpart save some.

Most petrol and diesel engines will normally have a crank sensor and a camshaft sensor. These tell the ECU where the pistons are, and when and how often the fuel is going to need to be injected into the engine. The amount of fuel required will be based on a few more sensors: the throttle position sensor and either the mass air flow meter or manifold absolute pressure sensor or sometimes both on some cars.

Other sensors like the coolant temperature sensor also have a hand in determining how much fuel is required.

One of the more critical sensors in diesel engines, which at the moment are not common yet in petrol engines, would be the fuel-rail pressure sensor. This monitors the fuel pressure and is used by the ECU to control the fuel pump to maintain a certain level of pressure required for proper operation.

When this sensor gets clogged with foreign matter such as contaminants from fuel, it will read a lower fuel pressure. What happens next is that the ECU increases the fuel pressure to maintain what it thinks should be the proper pressure.

Should the fuel pressure read excessively low (for whatever reason) and the check-engine light activates, the engine will be operating at a greatly reduced performance to prevent anything else from failing.

Most of the problems encountered will generally be caused by either the rail-pressure sensor or fuel pump failing over time because of the contaminants that accelerate the wear of the moving components.

I don't have much first-hand information on the issues that the Toyota owners encountered when the D4-D system was first introduced here. Like you, I've only heard about the issues thru other parties and what they were told that was the cause of the problem. What would be interesting to know though is how many units were actually affected by the problem from the total number of vehicles sold at the time, and the quality of fuel at the time compared to the fuel quality that's available now.

On that note, there doesn't seem to be much of those stories circulating now.

Best regards,
Ferman Lao

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  • mindkinetic Nov 30 2011 @ 12:25am
    honestly diesel engines should be tough as nails...unfortunately as we live in this exponential times and technology in diesel engine advances we have to be concerned of more issues... some are wary about their turbo and now in the case of a d4-d ..the crdi . luckily we have sir fernan to enlighten our very limited knowledge on this.
  • spiderpig2894 Nov 30 2011 @ 12:25am
    2007 Toyota Fortuner 4x2 AT 2.5 D4-D (same engine ata sa innova) --- nagkaproblema kami noon nito, kapag full throttle in overtaking nag.stall ang engine namin, sometimes at traffic naman bigla na lang mag.stall kapag aapakan na ang throttle. Pero ngayon ok na, ang cause pala ay ang maluwag na battery cable hndi na mag.stall ang engine at full throttle at overtaking.
    Ewan ko lng sa ibang D4-D vehicles, wala pa kaming na.encounter na major D4-D problem.
    • Kyoichi Sudo Nov 30 2011 @ 08:18am
      yup, the 2.5L D4-D engine of the innova is same w/ the 2.5L fortuner and hilux
      • Kyoichi Sudo Nov 30 2011 @ 08:23am
        if i were you, trade-in your fortuner for an Everest or Montero Sport
        • spiderpig2894 Dec 02 2011 @ 11:44pm
          No, maybe my dad will keep it for my mom or for me then trade it when it goes old. He is planning to buy the new Ford Explorer.
    • Feeter Silverster Nov 30 2011 @ 09:11pm
      di ba kahit maalis ang battery dapat hindi mamatay ang engine dahil saa alternator?
  • dohc_ivtec Nov 30 2011 @ 01:14am
    Sana na solve na nga Ito. How about in hilux? I'm planning to buy this january a 3.0 d4d hilux MT.
    • spiderpig2894 Nov 30 2011 @ 08:41pm
      wala atang mga problema sa mga 3.0 D4-D wala kasi akong naririnig about it.
  • car.L Nov 30 2011 @ 09:43am
    well..thats a very inquisitive info regarding d4d's..its nice to be informed.
  • ying Nov 30 2011 @ 12:11pm
    Dear Ferman,

    You did not answer the question. Stop playing safe. So is it a good engine or not?
    • Feeter Silverster Nov 30 2011 @ 09:13pm
      generally it's a good engine, just proper maintenance is needed which soem of us taken for granted. The complicated diesel engine of today differs altogether from the engine of olds.
  • HypnoticSpectre Nov 30 2011 @ 02:15pm
    I researched on this issue when I was choosing which diesel SUV to buy. Reading from different forums and automotive clubs forums, found out these issue persist majority on Toyota/Mitsubishi CRDi engines. I never read about any unhappy owner of Isuzu or Hyundai/Kia CRDi vehicles.

    Based from that, IMHO, this issue is more than just about dirty fuel.
    Anyway I believe these car manufacturers are continually improving their products. Just follow the recommended maintenance for your vehicle and not worry to much.


  • 17Sphynx17 Nov 30 2011 @ 02:50pm
    That pretty much sums it up. The engine may have been fed dirty fuel which caused the problem of the parties concerned.

    We just have to be careful with regards to where we top up our tanks to avoid these problems.

    @ ying

    What answer are you looking for anyway? He said he has heard stories from friends or acquantaines. And regarding the stories, the issue pretty much died down, other than being viewed by the next set of prospective buyers.

    So is the engine good? I can pretty much say it is and he is just saying be careful when you fill your tanks. And if there seems to be a problem in performance from "normal" immediately bring it to the casa/service center to be checked.
  • sealander Nov 30 2011 @ 07:50pm
    @17Sphynx17

    It could be a dirty fuel issue for these parts to malfunction. The question is where should you get your tank filled up? Which has the best diesel fuel? Shell, Petron or Caltex?
    • Josh Miranda Sep 19 2013 @ 05:41am
      SHELL has the best fuel. Seriously. My uncle's Montero were repaired twice because of the "dirty" diesel fuel of Petron.
  • 17Sphynx17 Nov 30 2011 @ 08:06pm
    @sealander

    That i think is answered mainly by preference. In terms of regular diesel among the big 3, leanest for me is peton, then shell then caltex.
    But regardless of this, you have to be wary of unscrupulous dealers which is somewhat rare in manila but i am wary when i am in the provinces. You really cant tell there. I try to avoid topping up in the middle of the trip as much as i can. But of course , there are unavoidable instances you need so it ends up sometimes luck based. So just be careful, but if a problem arises, bring it immediately to the casa and dont make the problem worse.
    Thats the best answer i can give you as a driver and vehicle owner.
  • HKB Nov 30 2011 @ 10:21pm
    You know guys the most common problem is not a dirty fuel or some foreign particles can enter to the engine because you have a very fine filter, the most common is water which is mixed in the retailer tank because of flooding. I don't know why MR FERNAN did not know the answer. If you undergo change oil always ask the service man to drain your filter, because water cannot be filtered. Our rail having a maximum of 1900 bar of pressure, if there is any small amount of water can through it i'm sure you are in trouble. this is very simple but most of everybody ignore it.
  • pickandcarry Dec 01 2011 @ 09:16am
    For all using diesel engines with models 2000 and up, try using biodiesel. Your engine is design for that. We are one of the few countries left using raw diesel. The reason is political. We already passed the Biodiesel Act of 1999, yet we are not complying. Biodiesel is cleaner, less if not zero black emission. Gives you more power. Give it a try. You have nothing to lose. It is distributed by Filoil. If you are not satisfied, you can always go back to your old fuel.
  • crispinbasilio86 Dec 02 2011 @ 07:29am
    "Cleanliness is one of the key elements on any fuel system".
  • crispinbasilio86 Dec 02 2011 @ 08:29am
    It's very relevant that the fuel oil properties (with normal and maximum values) should be shown in official receipt issued to consumers by Gas Station. Some say including me one factor that the FO injection and fuel pump prematurely damage because of low sulfur (sulfur one properties of FO) FO.
    http://wiki.answers.com/Q/Will_using_low_sulfur_diesel_fuel_damage_an_engine_that_calls_for_ultra_low_sulfur_diesel_fuel
    There is possible now a days that our diesel oil has content of low sulfur to control of emission of sulfur oxides (air pollution prevention).
  • crispinbasilio86 Dec 02 2011 @ 09:00pm
  • ying Dec 03 2011 @ 06:14am
    17sphinx17
    The Question in the caption is quite clear. It is answerable by yes or no.
    • 17Sphynx17 Dec 03 2011 @ 11:12pm
      If you notice the way of the statement and also the comments you can pretty much get the answee.

      The engine itself is not the problem, its what you put into it that may cause the issues you are concerned with.
  • Ferman Lao
    Ferman Lao Dec 08 2011 @ 06:26pm
    Ying,
    I don't have enough info on the problem to tell you that there's a problem with it.
    As with all technologies there's always bound to be something that can't be foreseen despite real world testing.
    What I can tell you is that we can bump up the power the on the 2.5 Toyota D4D by a good chunk(IIRC, as much as or close to 50horsepower) with some tuning, relatively minor mods and bolt ons; and the owner of those cars that we've bumped up the power on haven't reported any issues like those being described to us yet.

    HKB,
    Anything thats not supposed to be there (like water) I would classify as foreign particles, but you are correct water(however you get it) in the fuel is a factor in the increased wear of the fuel systems components.
    On most modern diesels, taking out the filter is no longer the easy task like it was years ago tho.
    I did encounter a very good fuel filter that actually does separate the water from the fuel many, many years back but it does cost more(at the time) then the ones that most car owners are accustomed to.
    Do I think it's worth the additional cost? Yes, I do but I didn't see it appear in the parts stores since that time, so most likely the car owners that would've benefitted from it did not.
  • safariboi Dec 09 2011 @ 07:17pm
    @pickandcarry

    In addition, biodiesel has higher cetane rating which means efficient combustion and cleaner engine. A good substitute for high performance diesel fuels.
  • ximonne Dec 24 2011 @ 08:58am
    I think the D4D engine in the innova is superb, it's probably the dirty fuel lang talaga. I experienced the stalling and hard starting problem on the innova yesterday, when some friends and i went to tagaytay. Biglang namatay ung engine. Kept on pumping the fuel filter, ayaw talaga mag-start. nung tinanggal ko ung filter, nag-start agad, meaning nagbara na ung filter sa dumi. Eh bago lang ung filter, pero visually makikitang ang dumi na talaga.
  • safariboi Dec 24 2011 @ 07:59pm
    No doubt that D4D is superb. It happens that the only problem was poor fuel quality. So select the best fuel for your precious car. Happy Christmas!
  • Sheriff_Clarenz May 01 2012 @ 09:36pm
    pano mag tanong ng ganito? kasi may tanong ako kaso di ako marunong eh. salamat.
  • 0005GUY Sep 14 2012 @ 01:16am
    HI
    I WAS ALSO FACING THE SAME PROBLEM AND DID A LOT OF RESEARCH FOR ABOUT 6 MONTHS.
    I OWN 2009 D4 INNOVA , 43000 KM DONE.
    GOT THE PROBLEM MANY TIMES LIKE WHILE ON RIDE I STOP AT THE SIGNAL AND NEXT TIME THE CAR WONT ATART,
    THE SELF LOCKS IN BETWEEN , THEN HAVE TO GET IT JUMP START .
    I MET SUCH THING FEW TIMES AND ALWAYS REPORTED THIS TO TOYOTA , AND THE SIMPLE REPLY WAS TO CHANGE THE BATTERY BUT I NEVER DID THAT .
    AFTER AROUND 6 MONTHS STUDY I FIGURED OUT THAT THERE COULD BE A PROBLEM WITH THE SELF AS I FACED SOMEWHAT SIMILAR WITH MY SAFARI ,
    I DID THE SAME THING HERE ALSO WENT TO THE TOYOTA AND ASKED THEM TO FIRST OVERHAUL THE SELF AND IF IT STILL NOT WORK THEN WE WILL THINK OF CHANGING THE BATTERY.
    THE ANAND TOYOTA GUY TECH SURENDER DID HIS JOB , CLEANED ALL THE CARBON AND AFTER THE REINSTALL FIRST HE CHECKED THE BATTERY , IT WAS LOW ON CHARGE BUT STILL HE DECIDED TO CRANK THE ENGINE .

    THE ENGINE CRANK WAS SO SWEET I CANT EXPRESS .
    THEN WAS THE TIME TO CHECK THE BATTERY HEALTH AND ALTERNATOR .
    ELECTRONIC METER WAS USED TO CHECK THE FUNCTIONING WHICH ALSO GAVE OUT A PRINTER RECEIPT AFTER THE DIAGNOSE .
    IT STATED THAT EVERYTHING IS OK , EVEN THE BATTERY.
    I HAVE CRANKED THE ENGINE APPROX 20 TIMES AND STILL ITS SWEET.
    I AM POSTING YOU THE PIC OF THE METER
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