Opel/vauxhall Vectra C 1.9 CDTI (Z19DTH) engine overview part 2

Continuing on what I wrote few days ago, here is part 2 of the Opel/Vauxhall Vectra C 1.9 CDTI (Z19DTH) engine overview. Some of the most common things were already pointed out, in this article I’ll add a few more.

For starters, the glow plugs:

z19dth-position-drallklappen-1804311767020540345The glow plugs makes sure that the fuel burns when starting the engine, afterwards they’re no longer needed with diesel engines. Here is a more closed up shot:

images (1)

Be carefull if you’re thinking of replacing them, they can snap quite easily. It’s good to already add some lubricant few days before you’re going to remove them. The biggest part of the glow plug is however hidden inside the engine and is not visable on the pictures above. In total, they look like this:

uvy7y8u7The big iron tube you see on top of the engine is the common rail:

Commen Rail schematics:


In the following video there is a good explanation about the common rail system in modern diesel engines:

In this video they also mention the swirl flaps. These flaps are located inside the intake manifold, but can sometimes be a source of error. Since using the EGR system involves reusing exhaust gas, the EGR valve and intake manifold’s swirl flaps might block or get damaged because of dust particles that stick around. A good tip is to check the EGR valve once in a time and clean it (does not take a lot of time since it is easily reachable). Alternatives is to block of the EGR valve so that no exhaust gasses are used anymore. On the internet you’ll probable find some blanking plates, but you can also make one yourself:

camerapics001Aside of this you also might want to check the boost (MAP) sensor as it is also located in the intake manifold and so it will take a lot of dust too. The boost sensor sits close to the EGR valve:

P1020135The sensor itself might have a lot of dirt on it, so cleaning is advised:

images (2)

The boost sensor, also known as MAP (manifold absolute pressure) sensor, measures the air mass flow rate. The ECU can then take the exact fuel amount to make a optimum combustion.

On the front of the car there is also the MAF sensor, located just next to the intake air filtering box:


The MAF (mass airflow) sensor senses the mass airflow of air being brought to the turbo. It may also be a source of problematic engine behavior, although it occurs less than malfunctioning EGR valves for example.


9 thoughts on “Opel/vauxhall Vectra C 1.9 CDTI (Z19DTH) engine overview part 2

  1. Nuno says:


    many thanks for your insights on this engine. I run a similar engine (zafira) and I am really struggling with maintenance of key engine elements (200000 km on the dash already).

    As you said the MAP is the boost sensor, also called Charge (boost) pressure sensor in Haynes´ Owners workshop manual.

    This is a very time consuming car. It takes several hours just to replace the headlight bulbs (dismount bumper, grid, remove full headlamp, go to shop to get headlights aligned.)

    My main challenge is to clean MAF, Charge pressure sensor, EGR and oil in the Intercooler, all with minimum disassembling , and without damaging the concerned parts.

    Once you have time could you share some insights on these 4 elements.
    Also, have been seeing some videos on water decarbonisation in VW TDI engines (please see youtube on this subject).I guess in Z19DTH the water intake leads directly into turbocharger, and that is something you don´t want to pulverize liquids in, right? Is there an alternative? using fuel vacum pipe(am I now saying a big nonsense).

    Best Regards,

    PS: I am Portuguese.

  2. Olá Nuno, bem vindo!

    I’ve owned the Vectra C since 150 000 km and now 220k+ km I can tell you I’ve also had my part of Vec problems: broken vacuum box, broken exhaust manifold bolts, a flywheel replacement, broken alternator, broken spring… not even mentioning the small repairs… It’s not designed with a long life cycle in mind, neither is it designed for easy maintenance. The things you have to do to repair the exhaust manifold bolts, it’s just nuts. Same goes for the headlamps! On the other end, I’m not a car mechanic, I’m a software programmer, so I can’t really compare.

    As far as your cleaning job goes, I did the MAP and EGR valve so far and they’re really easy to do, count less than an hour even if you don’t know where all the bolts sit. I also tried driving without the EGR valve plug plugged in or with the EGR valve blanked with an iron plate, but both give me errors on the dashboard so at least drill some holes in the blanking plate if you ever place one.

    The MAF sensor didn’t look any troubling for me so I’ve never cleaned it. As far as the intercooler goes, no idea either, never had a closer look at it, at this moment I care more about the intake manifold and swirl flaps and turbo, but I lack the time to really take it apart as it may take quite a while to disassemble, clean and reassemble. I have no knowledge of water decarbonization, by the looks of some videos it seems to work, but I’d rather not risk it myself yet. If it would flow directly into the engine than that’s a different story, but here there is also the turbo and EGR system. Using the fuel pipe is probable not going to work either because it’s pressurized. For the TDI engine, which is a turbo diesel engine, the poor in the water where the air intake filter and MAF sensor sit, so if you’d like to try it out I’d just do the same, but poor in the water gently so that no huge amounts have to compressed at the same time.

    Good luck, let me know the outcome!

    PS: Portugal is really nice 🙂

  3. Ales says:

    Wonderful article mate! I am z19dth enthusiast myself and going through your issues also 🙂 Currently experiencing hesitance in acceleration and giving p2279 error so going through EGR, MAP sensor in order to figure out what’s going on. Hope your vectra drives well. My zafira has got 196k+ km on the clock atm. Cheers

  4. Dave says:

    Z19DTH on a SAAB 9-3 (2005)
    Hello. I’m glad I’ve found a site with so much info 🙂
    It was great to see OBDII technical info. Has anyone been able to check DPF saturation, pressure differential or mileage since last DPF regeneration? I have torque app for android, but that information isn’t available, so I was wonder if anyone as the PIDs (and hopefully the syntax) to obtain that information.

    • Hi Dave, I was working on a tool before but so far I haven’t continued working on it: on one hand CAN is a lot to implement, on the other hand there is a lot that is proprietary and it holds development back. I also moved to a new place in the city center where I don’t have a wall socket available next to the car so it has become impossible for me to test the software in my car, unless I’m at a friends place, my portable’s battery runs out in just a few minutes… I’m actually thinking of selling the Vectra since I don’t need it anymore for my job.

  5. Deon van jaarsveld says:

    I have a 07 opel zafira 1.9cdti. I have replaced my mapcencor,cleaned my turbo,cleaned EGR valve but still have lack of power on the car. It goes in limp mode,need help ugently

  6. My car loses power after using Aircon selected at 4speed then sometimes comes with power and is fine again. It shows that map sensor was broken and Q bond was used on the sensor is it the course

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