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Mazda Familia

Mazda Familia 1

Mazda Familia

Without keyword

A Mazda Surname arrived in a station wagon with a YD22 engine … what’s it, what kind of Mazda it is – from Mazda on this car there is only factory application on the tailgate and logo on the steering wheel airbag. Actually it is Nissan AD (Nissan AD) in 11 body (“drove the car repairmen – Hell Nissan”) :).

Of the obvious problems (visible and audible to the naked senses of perception), this is a very tough diesel operation, especially when you press the gas pedal, the bluish-white color of the exhaust gases and the still burning CHECK on the tidy.

When connecting the scanner we have, we can say, the most unpleasant code for Nissan diesel engines such as YD and ZD, this is P7 code – “the wrong angle of advance of fuel injection”.
In “DATE” at XX, the load parameter of the valve for advancing the fuel injection angle is only 11% with a norm of 40-60%, we know that the lower this indicator, the earlier the computer tries to make the injection time, the more – the computer wants to delay the fuel injection.

There are several reasons for this code:
– mechanical failure of the fuel injection timing valve
– open circuit – closing the valve and its wiring
– malfunction of the injection pump computer (failure of the transistor controlling this valve)
– low fuel pressure inside the high-pressure fuel pump (due to air leakage, dirty filter, kinked hoses, faulty booster pump, etc.)
– dirt in the fuel injection angle control channel (there is such a tricky little channel in the TNVD case with a nozzle inside and with a very small bore: if there is dirt in it, the problem can be solved only by replacing the TNVD case, the price of which, even in the best of times, was about 25,000 rubles).

The easiest way to deal with this problem (all the more so, having such inadequate data in the current parameters) is to make a visual inspection of the wiring of this valve, and only then eliminate possible fuel problems and look for air leaks.

Without even moving the fabric cambric from the valve wiring, it was possible to see a drop of insulation and bare wires. Next, I carefully measure the resistance between the wires for a short circuit between them – I received 9 Ohms (this is the resistance of the valve itself), there is no “short”. Then I very carefully connect the oscillator to the control wire and start the car motor (here we must act together so as not to short-circuit these wires to each other).

As a result of the body movements, we see an absolutely straight line with a level of 14 volts, and even more so when the ignition was not on, a characteristic humming of this valve was not heard for 2-3 seconds (as well as when the ignition was turned off), that is, with a probability of 99.999999% to claim that there was a closure of the wiring of this valve, as a result of which the transistor of the injection pump computer that controls the injection advance valve received the first disability group.

There are three ways out of this situation:
1 – replacement fuel pump assembly;
2 – replacement of the fuel injection pump computer;
3 – replacement of transistor fuel injection pump computer .

When replacing the injection pump computer, the cable from the injection pump shaft rotation sensor can, of course, not be soldered from the injection pump computer itself, but removed with the computer, unscrewing it from the pump housing; but in this situation we will get additional problems during the subsequent installation of this sensor in place (on the mounting screws it has a movement of about 2 mm, which is fraught with a change in the dose of fuel and leads to some loss of ICE power), and drop the mounting screws inside the injection pump – far from the best prospect?

TNVD shaft rotation sensor

Due to the fact that I have not yet reached the necessary qualifications for replacing enclosureless planar transistors, and the owner of the car would not have pulled financially to replace the fuel injection pump assembly (the “contract” fuel pump from 14 tr + replacement), it was decided to change the fuel pump computer , the benefit was the opportunity to purchase a coveted serviceable device for purely symbolic money. Below I enclose a small photo report on the replacement of the injection pump computer on a YD 22 engine. I previously dismantled the intake manifold, before that I had to unscrew the fuel pipes to the nozzles.

View of the removed intake manifold. As you can see, the carabiner connecting the fuel pipes together can not be unscrewed. This will save a lot of time when removing and installing..

Engine view with intake manifold removed

The photo shows: after removing the injection pump computer from the pump housing itself, there is dirt in the cooling chamber of the injection pump computer. This is a very bad sign. the dirt has been removed, but what’s inside the injection pump itself?

After unscrewing the injection pump computer, dirt was detected in the cooling chamber of the injection pump computer.

The dirt was removed with cotton swabs (at that time nothing better came to mind), although it was possible to pump out the fuel with a syringe and rinse the chamber with a carbcliner.

This is what happens to the insulation of the fuel injection timing valve wiring during vehicle operation. For some reason, the insulation becomes dry and brittle, which leads to a short circuit. We solve this problem by shrinking..

The removed faulty ECU was prepared for scientific purposes 🙂

We cover the plastic cover of the control board of the TNVD ECU along the perimeter with sealants (the ECU was bought open), solder the loop of the rotation sensor.

We solder the wiring of the injection pump valves and do not forget to use heat shrink.

At the end of all work, the engine started working as it should, only there was a very unpleasant moment – the presence of dirt in the fuel injection pump housing, how many of these “diesel drivers” on the Nissan were told to use ONLY ORIGINAL fuel filters or their doubles from BOSCH and MAN, designed specifically for this type ICE with fuel pump VP 44 (in the original packaging is a product from BOSCH).

The fact is that there are 3 types of fuel filters according to the degree of filtration:
– for conventional plunger injection pumps – the degree of filtration is exaggerated – particles with nut M12;
– for rotary fuel injection pumps (VP ​​44 among them) – conditional filtration degree – particles with M8 nut;
– for COMMON REIL power systems – the highest degree of filtration, conditionally – particles with an M4 nut.

As a rule, the vast majority of owners of such cars buy filters for conventional plunger injection pumps, okay, good quality, but as usual – a product from SAKURA, TOPFILS, etc., as a result of which we get the P7 code, gray-white smoke, loss power and complete bewilderment when they find out the approximate cost of repair.

Many thanks for the technical and informational support to my friends and colleagues Timur Aleksandrovich Lukich and Mikheev Dmitry Alexandrovich!


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