I currently owned a Toyota KDH200. Manfactured year 2006. The Engine is 2KD (2490 cc). (Fuel Type : Diesel)

I had an issue with fuel Consumption so I went to a mechanic. He scanned the vehicle (he plugged an OBD scanner that connected to his laptop), then he told me that one fuel injector was blocked. So he disconnected the fuel line and he ran the engine with a 1 litre of Diesel and some cleaning liquid to clear the blocked injector. With that 1 litre my Toyota KDH van ran for like 1 1/2 hours and then stopped. Then he reconnected the fuel line back to the fuel system, and then accelerate (for full rpm, kind of) and black smoke was coming out. They did this until the black smoke stopped. Then after a couple of minutes there was no smoke and was back to normal. Then he tuned the engine and then we changed the fuel filter, because the earlier one was "black" :D Then that's it on that day. He again connects the OBD scanner, and there were no issues, all was back to normal.

Then this month (October) again I got that earlier issue with fuel consumption. Again it started to reduce. I called that mechanic again and I told that again the problem has returned. So he told that the last option is to unplug the spark plugs and look at those, whether they are working. But he recommend not to do that now. Because it's only 2 months that we have done that engine tune-up and cleared up those blocked injector.

I don't know what to do.. Please help me out..

Thanks !! :)

  • 1
    Not knowing your location I would look at where your fuel is purchased and try another source if possible. Persistent injector clogs many times are from dirty fuel sources. I had more injector problems in Louisiana after the hurricanes do to dirt in the station tanks and another time by buying at stations with older storage tanks. Commented Dec 16, 2016 at 1:51

1 Answer 1


Um, diesel engines do not have spark plugs. Either this is a translation error, or you misunderstood your mechanic, or he's using drugs. In any case, there's a number of things that affect fuel consumption, not least of which is the air temperature. In winter, all vehicles use more fuel, it may only be that.

We need more information to help you solve this:

  • Is there a pattern for the high fuel consumption or is it always doing it?
  • How significant is the fuel consumption change? 10% more? 50% more?
    Double what it used to be?
  • Is the check engine light on?
  • How long have you owned the van?
  • Was any recent maintenance or repair done on the van other than the injector cleaning and tune up?
  • Good answer, but also add the question about the use : do you have a regular use pattern or have you had an odd trip : slow, traffic jam, mountain trip etc?
    – Solar Mike
    Commented Mar 16, 2017 at 7:41
  • Well, they do often have glow plugs, so perhaps he is simply referring to those.
    – Hari
    Commented Mar 16, 2017 at 17:17
  • @HariGanti the glow plugs of a diesel engine have to do with warming fuel up for startup and have nothing to do with the actual combustion.
    – tlhIngan
    Commented Mar 17, 2017 at 8:36
  • @tlhIngan I am aware of that. I am simply saying that when the OP said "spark plugs," the OP likely meant "glow plugs." I agree that it shouldn't affect anything, but I was simply pointing out a slight miscommunication.
    – Hari
    Commented Mar 17, 2017 at 17:31

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