The situation when the engine ZMZ-405 It starts, but stops right away, is a classic for the injection motors of this series. The driver turns the key, the starter briskly spins, there are flashes in the cylinders, but as soon as you release the starter or add gas, the engine dies. This is annoying, but most often the problem lies in the engine control system or fuel supply.
Unlike the carburetor versions, here all the processes are responsible for the carburetor. Electronic Control Unit (ECU). He gets the data from the sensors and forms a command on the nozzles. If the data is inconsistent or absent, the safety system will shut down the engine. Most often it's my fault. suction-pump or the idle regulator failure.
Don’t panic and immediately disassemble half the car. Diagnosis should be consistent. First we check the simplest and most accessible, then we move on to the complex. In this article, we will examine all the possible causes, from banal gasoline to wiring problems.
Problems with fuel supply system and pressure
The first thing to avoid is the lack of fuel. The engine can start at the residual pressure in the ramp, but the pump does not have time to supply the right amount of gasoline to work under load. If fuel-filter It's clogged with dirt, and the bandwidth is dropping critically. The engine choked immediately after start.
The second important element is fuel pressure. On the engines ZMZ-405 it is often installed on the ramp or in the tank module. If the regulator valve is jammed in the open position, the gasoline goes into the reverse, and there is not enough pressure for the injectors. Checking with a pressure gauge is mandatory: after turning on the ignition, the shooter must confidently grow to 3 atmospheres and hold on.
It is also worth paying attention to fuel-pump. It can hum, creating the illusion of work, but not develop the necessary pressure due to wear of the impeller. Mud in the tank often causes the pump to fail or quickly clog the net-filter of rough cleaning.
- 🛑 Check the pressure in the fuel ramp with a pressure gauge (normal 3.0-3.2 atm).
- 🛑 Replace the fuel filter if the mileage from the last replacement is high.
- 🛑 Listen to the operation of the gas pump when turning on the ignition.
When checking the fuel pressure, be sure to use rags so that the gasoline does not get on the hot engine parts or in the eyes.
Failures of the idling regulator (RX)
The idle regulator is an actuator that controls the air supply bypassing the closed throttle. It is responsible for the stable operation of the heated and cold engine. If RXX contaminated with carbon or jammed, the engine will start only when the gas pedal is pressed, and when it is released it will stall.
Often the problem is solved by a simple cleaning. Nagar, mixing with oil vapors from the ventilation system of the crankcase, forms a hard crust. It prevents the valve rod from moving with the desired amplitude. The electrical circuit can also be broken: the contacts on the chip have been oxidized or the wire has broken.
When installing a new or cleaned regulator, it is important to carry out an adaptation procedure. The ECU must "learn" the new step of the valve. To do this, it is usually enough to reset the battery terminal for 10-15 minutes, then put it on and let the engine work on idles without a load for 5-10 minutes.
☑️ Diagnostics of RX
Suction of unaccounted air through the intake manifold
One of the most insidious problems of injection engines ZMZ - air sucking. The engine runs on a mixture that the ECU calculates. If the intake manifold gets excess air past Mass Airflow Sensor (MAAC)The mixture is getting too poor. The engine starts, but it can not work and stops.
Often the intake manifold is to blame. Over time, they tan and cease to seal the joints. It is also worth checking the vacuum hoses going to the receiver, brake amplifier and adsorber. A crack in a millimeter diameter hose can completely destabilize the engine.
Diagnosing the pump can be done in several ways. The easiest way is to spray the joints of the collector and hoses with a “Quick Start” or carburetor cleaner with the engine running (or trying to work). If the speed changes, you find a hole.
⚠️ Caution: Using flammable liquids to search for a sucker is dangerous! Be careful, keep a fire extinguisher handy and do not pour liquid on the hot release.
Another common reason is the sealing rings of nozzles. The rubber bands lose elasticity over time, and air is sucked around the fuel frames. This is treated only by replacing the sealing kit.
Sensors: DMRV, DPDZ and crankshaft position sensor
The electronics of the ZMZ-405 engine are based on the readings of several key sensors. If DMRV The EBU is pouring the wrong amount of fuel. Often, when the DMRV malfunctions, the engine stalls immediately after removal from the starter, since the system cannot adjust the mixture for the XX mode.
Throttle position sensor (PDPDD) tells the "brain" how much you have pressed the gas. If the initial position (0%) contact is broken or the readings jump, the ECU thinks you are gasping, and turns off the idle mode, supplying less fuel than you need to start.
The most critical. Kolenwala Position Sensor (DPKV). Without its signals, there will be no spark at all, but if the contact is poor (for example, the end of the sensor is contaminated or there are tips from high-voltage wires), the motor can grasp and stall. Check the gap between the sensor and the pulley crankshaft, it should be about 0.5-1.0 mm.
How to check for DMRI without a scanner?
Try to drop the chip from the mass air flow sensor. If the motor starts and will work (even if unstable), then the sensor is faulty and gives incorrect data that the ECU cannot ignore.
Ignition system and coils
Although the ignition system on the 405 engine is usually reliable, problems do occur. If the engine starts and stalls, it may break through one of the coils or high-voltage wires in wet weather. There is a spark, but it is weak or disappears under load.
Special attention should be paid spark-plug. If they have not been changed for a long time, the gap could increase, and the soda could block the spark canal. Turn the candles: if they are black and wet, then there is a fuel overflow (rich mixture). If white and dry, the mixture is poor or there is no spark.
Check the integrity of the armored wiring. In the dark, start the motor and look at the wires – if you see the “northern lights” (sparkling), the wires need to be changed. Also check the ignition coil (or module) for cracks in the case.
Table of the main symptoms and causes
For ease of diagnosis, we will bring the main symptoms to the table. This will help to localize the problem faster without going through the entire engine.
| Symptoms. | Probable cause | Method of verification |
|---|---|---|
| It's dead if you don't hold the gas. | RX, air suction, DPD | Cleaning of RXX, checking the leakage of the intake |
| Deafness in 2-3 seconds. | DMRV, gas pump | Disabling DMRV, measuring the pressure in the ramp |
| It only works on the cold. | Temperature sensor (TCP) | Scanner diagnostics, sensor vertebrae |
| Troit and deaf | Candles, coils, nozzles | Turning off the cylinders |
Software failures and ECUs
Do not discount the program errors. Control units Mikas or Bosch.The zmz-405 can accumulate errors. Sometimes the "glitch" of the firmware leads to the fact that the fuel cutoff is turned on immediately after the start.
Try to complete the adaptation reset. Turn off the battery's negative terminal for 20-30 minutes. During this time, the capacitors in the ECU will be discharged, and the memory of errors will be cleared. After connecting the key, do not rush to start the engine: turn on the ignition, wait 10 seconds (so that the pump pump pumps the pressure and the ECU interviews the sensors), then turn off. Repeat 2-3 times, then start.
If the reset did not help, you may need to reflash the control unit. This is done through the OBD-II diagnostic connector using a laptop and adapter. Often helps install a more recent version of the firmware, which corrected errors in calibration of the idle.
⚠️ Note: Flashing the ECU should be carried out only with a stable power source. A voltage surge during recording can "brick" the control unit, and then expensive repairs to the service will be required.
Mechanical problems of the engine
In rare cases, the reason lies in the mechanics. For example, if you've turned pulley At the camshaft, the gas distribution phases will be confused. The engine will start with difficulty and stop. Checking the GRM labels is mandatory if all the above did not give a result.
It's also worth checking the compression. If one of the cylinders is "dead" (due to the failure of the valve or the occurrence of rings), the engine will not be able to work steadily at low speeds and will stall. Compression measurement is the basic procedure for a mileage motor.
90% of cases when the ZMZ 405 starts and dies are solved by cleaning the RXX, replacing the fuel filter or eliminating the air sucker.
Why does the engine stop in traffic hot?
This is a classic sign of overheating or steam stopper in the fuel line, as well as a malfunction of the DMRV. On a hot engine, the air density changes, and if the sensor is lying, the mixture is disrupted. Also check the cooling fan and the thermostat.
Can the alarms shut down the engine?
Yes, if the engine lock is installed. Often contacts are oxidized or glitched by the alarm unit. Try to temporarily eliminate locks from the chain (only if you are sure of your actions) or contact the installers of security systems.
What if after replacing the belt, the car stops?
Most likely, the GRM tags are incorrectly displayed. We need to double-check the matching marks on the pulleys of camshafts and crankshafts. The phase sensor could also be lost if it was not removed or installed incorrectly.