The situation when the starter actively spins the crankshaft, but the Renault Logan engine does not start, can dishearten even the most optimistic driver. Sometimes the search for the cause of a malfunction takes more than one hour and takes a lot of strength and nerves. To reduce this time, it is necessary to navigate in typical breakdowns and know the algorithm for their search. Today we will talk about what can be the reasons why the 8-valve 1.6 and 1.4 engines of Renault Logan, Largus, Sandero do not start.
The main causes and ways to eliminate them
Cause 1. Idle adjustment is broken
In some cases, a violation of the idle speed control leads to the fact that during the engine start, the fuel mixture does not enter the cylinders. It is quite easy to diagnose an electronic malfunction. If the problem is in this node, then just press the accelerator pedal and slightly open the throttle - the engine will start immediately. The solution to the problem is cleaning the idle speed controller. 
Reason 2. Faulty crankshaft position sensor (DPKV)
(DPKV) sends pulses to the electronic engine control unit (ECU). In the future, the microprocessor interprets them into signals that control power systems, ignition, etc. Therefore, a breakdown of the crankshaft sensor can be detected not only by direct replacement, but also by indirect signs associated with a lack of voltage at the key components of the internal combustion engine.
How to check the crankshaft position sensor
In order to check the serviceability of the crankshaft sensor, we check for a spark. To do this, they remove the tip from any cylinder and attach it to a known-good spark plug. Its body is connected to the "mass" of the car, after which the crankshaft is scrolled with a starter. The absence of a spark is not a direct indication of a breakdown of the DPKV - in addition, you should check whether power is supplied to the fuel pump.
Checking power to the fuel pump
To access the fuel pump, move the Renault Logan back seat and lift the gas tank flap - it is held by plastic latches that are easily wrung out with a screwdriver or other flat object. Next, remove the block from the fuel pump connector and connect a test 12-volt light bulb to its black and brown wires (the other two are responsible for readings from the fuel level sensor).
It is not recommended to measure voltage with a multiammeter due to the fact that its readings will not allow judging the current strength and power consumption. After switching on the ignition, the control lamp should light up for just a few seconds. This will give confidence that the fuel pump is receiving power, and it regularly carries out the primary pumping of fuel into the fuel rail.
If after that the light does not light up (there is no further fuel supply), then, combined with the absence of a spark, this fact is direct evidence of a breakdown of the DPKV, which is the reason why the 8-valve Renault Logan, Sandero, Largus engine does not start.
Reason 3. Malfunctions of the fuel pump
Among the reasons why the fuel mixture does not enter the cylinders, in the first place are malfunctions associated with the fuel pump. Next, we will tell you how to diagnose the performance of the fuel pump itself and check the health of the electrical part.
The fuel pump has failed
After gaining access to the top of the fuel pump, clean all surfaces of dust with a brush or compressed air. Remove the fuel supply fitting (in the photo it is indicated by an arrow) and take it along with the hose to the side.
Checking if the pump is pumping fuel is very simple. To do this, a thin tube is connected to the pump outlet, the second end of which is lowered into a small container. It is enough to turn the ignition key for a few seconds and crank the engine with the starter to make sure that fuel is entering the line. And, nevertheless, even if this does not happen, do not make hasty conclusions - it is possible that the pump is not supplied with 12 V power. How to check the electrical part has already been mentioned above. If everything is in order with the power supply, then you can safely change the pump turbine - with a high degree of probability, the cause of the breakdown lies in it.
No power at fuel pump connector
If, as a result of checking the fuel pump, it was found that no power is supplied to its connector, then first of all we check the fuse. The fusible element is located on the left side (in the direction of the car) of the engine compartment, in the safety block. In the power supply circuit of the fuel pump of 8-valve engines of 1.4 and 1.6 volume, Renault Logan, Largus, Sandero and other similar cars use a fusible element rated for a current of 25 A - its location in the block is indicated by an arrow in the photo.
A blown fuse is 99% indicative of problems with the fuel pump, although the possibility of a short circuit of its positive wire to ground cannot be ruled out. It is not difficult to check the latter - it is enough to insert a working fuse into the unit with the connector removed from the pump. If at the same time the control lamp lights up, then you can proceed to dismantle and replace the pump. Otherwise, you should ring the wires of its power supply and eliminate the short circuit.
If, during the examination of the fuse, it was revealed that it remained intact, then you should check whether “plus” is supplied to its contacts from the on-board network of the car. In addition, check the operation of the relay, which is responsible for switching the fuel pump power.
To do this, the device circled in the upper photo is removed from the block, and a jumper is installed in its place. The connectors corresponding to the power contacts of the switching element are closed last. The appearance of power at the pump terminals indicates the health of the circuit. Otherwise, you need to make sure that the switching element itself is working and that there is a control signal on its contacts.
To find out if the control voltage is supplied to the relay, they check the presence of a constant “plus” at the corresponding terminal in the fuse block block and diagnose whether the control “minus” comes to the block.
Keep in mind that "-12V" appears on the input contact of the relay only when the engine is running, so you should not only turn on the ignition, but also crank the engine with the starter. If the lamp connected to the control "minus" and the positive terminal did not light up, then the cause could be either a broken wire to the control unit, or problems with the computer itself, immobilizer, etc.
Something else useful for you:
Wiring problems
The situation when voltage does not appear on the fuel pump even when the power terminals in the relay block are bridged occurs quite often. Of course, the only thing that can be assumed in this case is a break in the wiring along the way from the engine compartment to the fuel tank. However, not everything is so clear. The fact is that the developers of Logan or Sandero included a weak link in the design in the form of a connector, which is located under the passenger compartment rug right at the left pillar.
In a dry environment, all its contacts are in good condition, so there are no wiring problems. However, the location of the connection was chosen so poorly that over time, moisture (and it somehow penetrates the interior) does its dirty work and the contacts oxidize. Of course, in this case, it is impossible to guarantee the operability of individual components (including the fuel pump), which leads to the failure of the power unit to start.
To gain access to the ill-fated connector, it is necessary to remove the trim of the left side pillar and lift the carpet. After that, disconnect the block and check for voltage at the lowest terminal, which is indicated by an arrow in the photo - it is responsible for the positive wire.
If there is a signal, then it is enough to clean the contacts so that the power to the fuel pump is restored. If this does not happen, then you should look for an open circuit on the side of the tank. In the case when the voltage does not even reach the connector, it is necessary to ring the circuit to the safety block and eliminate the open in this section.
As you can see, there are many reasons why the Renault Logan engine refuses to start. Of course, we cannot take into account all possible factors and mention every malfunction, however, if you act according to the scheme proposed above, you will most likely be able to start your Logan or Sandero.
A three-part video that explains in detail and shows why the 8 valve engine does not start on Renault Logan, Sandero or Lada Largus.
Seal
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asks: Mozart Valery.
Essence of the question: Renault Logan starts when cold, but Renault Logan does not start when hot.
I bought Logan from the former owner, a car from "phase 1". The mileage is small, but recently a defect has appeared: when starting “cold”, everything works, but when starting “hot start”, the engine does not start. It turns out that you have to wait 5-6 minutes until the engine cools down. The starter turns, but the motor does not "pick up". This was not the case before.
Still, why doesn't my Renault Logan start right up?
Main reasons
There can be only one reason for the defect indicated in the question - a faulty DTOZH sensor. This sensor itself will need to be replaced, but one test can be done first.
coolant temperature sensor
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I own a Renault Megan 2 car, before that there were Citroens and Peugeots. I work in the service area of the dealership, so I know the device of the car "from and to". You can always turn to me for advice.
So, let's simulate the problem situation:
- We start "on a cold", warm up the engine;
- It is necessary to achieve that the engine stops starting. There is no need to wait 5 minutes;
- If the engine cannot be started, open the hood and turn off the DTOZH sensor. Let's try to start right away.
Conclusions: if at “step 3” the engine started up again, then the reason is in a faulty sensor. Further comments are unnecessary.
Another possible reason
Connector that causes problems
Disconnect the connector when the ignition is off. Do not forget to collect everything as it was.
Line B8 in connector R212 is connected to the ignition switch. If it breaks, the starter will work, but the engine start is blocked.
Consider the reasons when Renault Logan does not start "cold". They look trite:
- Frozen or discharged battery;
- Water got into the tank;
- The fuel pump is faulty;
- Etc.
But there is another reason that is unique to the Logan family.
ECU program defect on an engine with Euro-3
If the engine complies with Euro-3 standards, then the ECU controller may need to be replaced with firmware. At one time, a review was carried out, but not everyone responded to Renault's request.
The only "letter of happiness" from Renault
Logan sedans, which are subject to recall, have been produced since December 2007, just before the restyling. We are talking about the transition to "phase 2" (to Euro-4 standards).
Renault Logan won't start? We check the DTOZH sensor ourselves - an example in the video
Renault Logan is a modern car that practically does not cause its owner any inconvenience and problems in operation. However, even such a reliable car can sometimes fail. Often the owner is faced with the fact that Renault Logan does not start. Let's look at the main reasons why a car may refuse to start, and find out how to fix these malfunctions. This information will be useful to every owner.
Most Common Problems
Experts identify several main reasons that may prevent the engine from starting normally. If the car starts with difficulty, constantly stalls or refuses to start, then the following malfunctions can be distinguished:
- If the Renault Logan does not start, do not immediately panic. The fuel pressure regulator may have failed. If there is insufficient pressure in the fuel rail, the electronic engine control unit will simply not give a command to start.
- If the timing marks are incorrectly set, the engine will also not start. In this case, the Renault Logan does not start because the synchronous operation of the ignition phases of the fuel mixture in the cylinders is disrupted. Such a problem may occur rarely, but it should not be ruled out. In addition, the marks may shift due to the fact that the belt has jumped one or more teeth. In this case, poor timing belt tension can be diagnosed. Experts recommend periodically inspecting the condition of this belt and, if necessary, changing it.
- The start will be poor or the engine will not start due to throttle malfunction. It is necessary to regulate the amount of air that is supplied to the intake manifold when you press the gas pedal.
- Starting problems are also possible due to the failure of the immobilizer system. Owners often complain about the loss of feedback from the immobilizer unit with the chip on the key.
- If the car often stalls on the go, experts recommend checking the nozzles - perhaps, due to various reasons, the quality of the fuel spray jet has deteriorated. Often the cause of such a serious problem can be a clogged or clogged fuel filter.
- If the Renault Logan does not start well or stalls immediately after starting, then this may be due to an insufficiently efficient fuel pump. The pump may also fail.
Starter turns, engine does not start
If the Renault Logan does not start, and the starter turns the flywheel, then the first step is to make sure that the fuel pump is working properly. Sometimes the sounds of the fuel pump can be heard in the cabin. Most often, the sound of the knot is heard especially well in the area of \u200b\u200bthe rear seat. There should be a short characteristic buzz.
If during such diagnostics it was possible to find out that the pump is not working, then the first step is to check whether the fuses are intact and whether the ECU system relay and the fuel pump relay turn on.
If the fuses are fully functional, then you should make sure that the relay is turned on. If it turns on, a characteristic click will be heard.
Fuel system
If the Renault Logan does not start, the reason may be in the fuel system. If the fuel pump turns on and then functions normally, then check the pressure level in the fuel rail of the car. For diagnostics, an ordinary pressure gauge is suitable. You can also perform eye check. At the end of the ramp there is a spool - it is pressed with a suitable device. With a normally operating pump, the pressure should be at least 2.8 atm.
When you press the spool without a pressure gauge, the fuel should flow in an even stream. In this case, the pressure must be constant. If the pump is working normally, but there is no pressure in the rail, then either there is no fuel in the tank, or the fuel filters are clogged, or there is no patency in the fuel line. Maybe the fuel pump itself is faulty.
Checking the pressure regulator
If there are failures in the pressure regulator, then it must be changed. To diagnose this unit, it is enough to disconnect the hose through which the fuel flows back into the tank. When the hose is disconnected, turn on the ignition. If fuel immediately under pressure comes out of the hose, then the regulator is faulty.
To eliminate this malfunction on the road, jam the edge of the regulator or pinch the tube. After completing these measures, the car will be able to drive to the place of repair.
Ignition system
When it was possible to make sure that there is pressure in the fuel rail, it is recommended to proceed to the diagnosis of the ignition system. Experts advise checking the spark with a special spark gap. If there is a spark, but the Renault Logan does not start, it first stands visually, and then, using special equipment, check the candles for serviceability. If they are correct, then move on.
throttle valve
If the damper does not work correctly, then this breakdown can be diagnosed in different ways. To fix the problem, unscrew the supply pipe and visually check the body inside and directly the damper for possible damage or wear.
If the engine is not running, the damper is always closed. If for some reason it cannot close completely, then the node must be cleaned with special means. Then it is necessary to carry out the procedure of computer adaptation.
Runs and dies
Renault Logan starts and stalls if there are malfunctions in the immobilizer. This can be diagnosed by the corresponding lamp on the dashboard. If it blinks, then you can safely talk about node malfunctions. Usually the immobilizer loses communication with the chip on the key.
Fuel filter
A clogged filter can significantly affect engine performance. The motor will refuse to start or start and stall. If the Renault Logan car does not start and there are no other serious reasons for this, then you need to check and replace the filter.
Open the hood and remove the fuel supply hose. Then turn on the ignition. If fuel is supplied at low pressure, then the filter capacity has decreased. To increase throughput, remove the element and blow it in the opposite direction. They also try to clean the filter as much as possible.
After cleaning the element, it is installed in its original place. If the engine does not try to stall, but its speed is stable, then you need to change the fuel filter.
Doesn't start hot
Among the reasons for this behavior of the car, only one possible one can be distinguished - this is a malfunction of the DTOZH sensor. The sensor, of course, needs to be changed, but first it is worth diagnosing.
The engine is started cold and warmed up. Next, the ICE is silenced. If it is no longer possible to start the engine, then DTOZH is turned off under the hood. If after that the car started properly, then the reason is a faulty sensor.
If the engine does not start, then under the hood you need to find a connector with the number R212 - experts recommend wiping and cleaning the contacts. Line B8 in this connector is directly connected to the ignition switch. If there is an open in the circuit, the car will turn the starter, the Renault Logan will not start at the same time - the start is blocked automatically.
Won't start when cold
Here you can highlight all of the above malfunctions and causes. But there is another small breakdown, which is inherent only to these models of cars. This is a minor defect in the ECU firmware on Euro-3 motors. The ECU needs to be reflashed. Sedans produced since December 2007 are subject to flashing. Owners should know this moment, if suddenly the Renault Logan does not start in the cold.
Conclusion
These are all the reasons why the Renault Logan engine may refuse to start. Knowing this information, the owners will be able to troubleshoot on the road and get to the place of further repair or parking. But most often the car will not start because there is no fuel in the tank or the spark plugs have worn out and are faulty. Many people forget about this, but you need to start with this.
The fuse has blown. Check main fuse.
The starter is defective. Make sure the electrical wires are properly connected to the starter. Make sure the starter relay clicks. in this case, the starter or electrical wires are faulty.
Starter relay defective. Check it out.
Starter relay switch contact missing. The contacts may have become wet, corroded or contaminated.
Disassemble and clean the switch
An open circuit or a short circuit has occurred. Check all electrical wire connections and the wires themselves to make sure they are dry, secure and not corroded. Also check that the wires are not damaged or broken (see wiring diagrams).
The main ignition lock is defective. Replace the lock if it is defective.
Starter cranks but engine does not crank
Starter clutch defective. Check and repair or replace it.
Damaged starter mechanism or gears. Check and replace damaged parts.
The starter works, but the engine does not turn over (jammed)
A seized engine may be caused by damage to one or more internal components, the damage could be due to wear, improper operation, or lack of lubrication. Causes of failure can be stuck valves, tappets, camshafts, pistons, crankshaft, connecting rod bearings, gears or gearbox bearings.
There is no fuel in the fuel tank.
The fuel line in the fuel tank is clogged.
The fuel filter is clogged. Clean or replace filter.
The fuel pump is defective. Check it out.
No spark or spark is too weak
The ignition switch is in the OFF position.
The ignition circuit fuse has blown.
The battery voltage is too low. Check it and recharge the battery if necessary.
Spark plugs are dirty, worn or defective.
Spark plug caps or high voltage wires of the ignition system are faulty. Check their condition. Replace components if they are cracked or damaged.
Spark plug caps do not make proper contact. Make sure. that the caps are properly installed on the spark plugs.
Check the control unit.
The ignition coils are defective. Check coils.
Short circuit in the ignition system. This is usually caused by water ingress, corrosion, component damage or wear. The components can be disassembled and cleaned with a special cleaner for electrical contacts. If cleaning does not help, replace components.
Short circuit or broken wire in the area between the following components:
ignition switch (or blown ignition fuse); ignition control unit and high-voltage ignition coils; high voltage ignition coils and spark plugs;
Make sure all electrical connections are clean, dry and secure. Check systems for damaged or frayed wires.
Low compression in the cylinders
Spark plugs not properly secured. Remove the spark plugs and check their threaded part. Install spark plugs and tighten to specified torque.
Elements of fastening of a head of the block of cylinders are not tightened properly. If you think the cylinder head is not properly secured, there is a possibility of damage to the cylinder head and gasket if the problem persists for a long period of time.
The cylinder head nuts must be tightened to the torque specified in the specifications.
Incorrect valve clearance. This means that the valve does not close completely and compression flows through the valve. Check and adjust valve clearance.
Piston and/or cylinder worn. Excessive wear will cause compression to leak through the piston rings. Usually this problem is accompanied by worn piston rings. Overhaul of upper engine components is required.
Worn, damaged or loose piston rings. Damaged or sticking piston rings usually indicate problems in the lubrication or fuel supply system, leading to excessive carbon deposits on pistons and piston rings. Overhaul of upper engine components is required.
Gap between piston ring and groove is too large. This can be caused by excessive wear of the bridges between the piston ring grooves. The pistons need to be replaced.
The cylinder head gasket is damaged. If the cylinder head is not secured properly, or if there is excessive carbon deposits on the piston crown, the compression in the cylinders will be too high and the cylinder head gasket may leak. Tightening the cylinder head fasteners does not always help to fix the problem. so the gasket needs to be replaced.
The cylinder head is deformed. Often this is caused by overheating or improper tightening of the cylinder head nuts. Workshop grinding or cylinder head replacement is required.
Valve spring damaged or weak. This may be caused by component failure or wear. The springs need to be replaced.
Valve not seated properly. This can be caused by valve distortion (due to too high engine speed or inappropriate valve adjustment), burnt valve or seat, or carbon buildup on the valve seat. Valves should be cleaned and/or replaced, and seats should be serviced, if possible.
Engine stalls after starting
Incorrect operation of the air damper. Make sure the choke valve has full travel.
The ignition system is faulty.
Fuel is contaminated. The fuel may contain impurities, water, or may change its chemical composition if the vehicle has not been used for several months. Drain the fuel from the tank.
Unstable engine idling
Malfunction in the ignition system.
Incorrect idle speed.
Incorrect composition of the air-fuel mixture.
Fuel is contaminated. Fuel may contain impurities, water, or may change its chemical composition if the motorcycle has not been used for several months.
The air filter is clogged. Replace filter element.
The engine is unstable at idle
The battery voltage is too low. Check and recharge the battery.
The spark plug is damaged or worn.
Spark plug caps or high voltage wires are faulty.
The control unit of the ignition system is faulty.
The ignition coil is faulty.
Incorrect composition of the air-fuel mixture
The air filter is clogged, not sealed or not installed.
The air filter housing is not hermetically sealed. Check for cracks, damage or loose fastening, replace and repair the damaged component.
Low compression in cylinders (see above)
Inappropriate acceleration settings
The viscosity of the engine oil is too high. Using engine oil with a viscosity grade that is too high can damage the oil pump or lubrication system.
Unstable engine operation or power loss at high speed
The air filter is clogged. Clean or replace filter
Spark plugs are damaged or worn.
Caps or high-voltage wires of the ignition system are faulty.
Spark plug caps not making good contact
Wrong spark plugs: Wrong type, heat rating or wrong cap shape. Check and install suitable spark plugs.
The control unit of the ignition system is faulty.
The ignition coils are defective.
Low compression in cylinders (see above)
Accumulation of soot in the combustion chamber. Using fuel additives that dissolve carbon deposits is the easiest way to eliminate carbon deposits. Otherwise, the cylinder head will have to be removed and decarbonized.
Use of unsuitable or low-quality fuel. Old or unsuitable fuel can cause detonation. This will cause the pistons to knock. Drain the old fuel and always use only the recommended type of fuel.
Using spark plugs with the wrong heat setting. Uncontrolled detonation indicates that you are using a spark plug that is too hot. Thus, you will get the effect of glow ignition, which will significantly increase the temperature in the cylinder. Install spark plugs rated for the correct heat.
Incorrect composition of the air-fuel mixture. This can cause an increase in temperature and detonation in the cylinders.
Throttle valve does not open fully. Adjust the throttle.
Clutch slip. This can be caused by loose or worn clutch components.
The ignition timing has not been set.
The viscosity of the engine oil is too high. Using the wrong viscosity grade engine oil can damage the oil pump or lubrication system.
The brakes are stuck. This is usually caused by contamination on the brake piston seals or deformation of the disc or axle. Carry out the necessary repairs.
The capacity of the fuel pump is not high enough. Check the pump.
Engine overheating
The coolant level is too low. Check and add coolant if necessary.
There is a leak in the cooling system. Check the cooling system hoses and radiator for leaks or other damage. Replace or repair any damaged components.
Thermostat stuck open or closed. Check and replace if necessary.
Expansion tank cap defective. Remove the cap and pressure test it.
The channels of the cooling system are clogged. Drain and flush the coolant from the cooling system, then refill the cooling system with fresh coolant.
The water pump is defective. Remove pump and check components.
The radiator channels are clogged.
The cooling fan or switch is faulty.
Incorrect ignition setting phases (see above)
Incorrect composition of the air-fuel mixture (see above)
Cylinder compression too high
Accumulation of soot in the combustion chamber.
Incorrect processing of the cylinder head or installation of an unsuitable gasket when assembling the engine.
Clutch slip. This can be caused by damaged, loose or worn clutch components.
The engine oil level is too high. An increase in engine oil level can cause increased crankcase pressure and inefficient engine operation. Check specifications and drain engine oil to correct level.
The viscosity of the engine oil is too high. Using an engine oil with a higher viscosity grade (than recommended in the specifications) may cause damage to the oil pump or lubrication system.
Brake sticking. Usually caused by foreign particles on the piston seals of the brake system or deformation of the disc or axle. Carry out the necessary repairs.
The engine oil level is too low. Friction is caused by a constant lack of lubrication or the use of bad oil, which can also cause overheating. Engine oil performs the function of cooling in the engine. Check engine oil level.
Low quality engine oil or inappropriate viscosity grade. Oil is classified not only by viscosity, but also by type. Some oils are not of good quality for use in an engine.
Modification of the exhaust system. When installing such equipment, always consult qualified personnel beforehand.
The presence of extraneous noise during engine operation
Clearance between cylinder and piston is too large. This is most often caused by a mismatched build. Check and overhaul components.
The connecting rod is deformed. This may be caused by high RPM, attempting to start a flooded engine, or foreign particles entering the combustion chamber. Replace damaged components.
Piston pin or piston pin bore damaged due to wear or lack of lubrication. Replace damaged components.
Piston rings worn, damaged or seized. Overhaul the upper components of the cylinder.
Damage due to piston seizure. Usually caused by lack of lubrication or overheating. Honed cylinder liners and install new pistons.
The clearance at the top or bottom of the connecting rod is too large. This can be caused by wear or lack of lubrication. Replace worn components.
Incorrect valve clearance. Adjust clearance.
Valve springs are too weak or damaged. Check and replace valve spring assembly.
Camshaft or cylinder head worn or damaged. Lack of lubrication at high speeds is usually the cause of this damage if there is not enough oil or you have not changed it according to the maintenance schedule.
Other extraneous noises during engine operation
Leakage through the cylinder head gasket.
The exhaust pipe is leaking at the connection to the cylinder head. This can be caused by improper pipe installation or a loose flange connection. All fastening elements of the exhaust system must be properly tightened. Otherwise, it may cause leakage.
The crankshaft runout is too high. This can be caused by deformation of the crankshaft (at too high a speed) or damage to the upper cylinder component.
Engine mount bolts not properly secured. Tighten all engine mount bolts.
Watch an interesting video on this topic
In pursuit of efficiency and environmental performance of motors, engineers annually make a lot of efforts to improve these units. This need is caused by an increase in the number of malfunctions caused by unstable operation or unauthorized shutdown of a running engine. Renault Logan owners are well aware of the problem of difficult starting. If the unit has stalled, then the first thought that came to you is to immediately go to the service. Often the most common problem is when the car engine does not start on a cold one, many car owners immediately have a question, what are the reasons?
Here we will consider the most common breakdowns in the operation of the Renault Logan engine and give methods for their elimination. And most importantly, you need to understand the reasons why the engine does not start, especially when it is cold.
What are the most common faults?
If the Renault Logan engine is difficult to start, does not start, or constantly stalls, then the following may be among the main causes of this breakdown:
- the fuel pressure regulator is out of order;
- poor spark production due to malfunctioning spark plugs or coils;
- incorrect installation of gas distribution labels, which causes a lack of synchronous operation of the fuel ignition phases;
- violations in the operation of the throttle valve, which regulates the volume supplied to the intake manifold of air;
- possible failure of the immobilizer due to frequent cases of loss of feedback from the key chip by the control unit;
- if the engine tends to stall on the move, check the injectors for the quality of the fuel spray;
- another reason for stopping the engine may be fuel filter contamination;
- poor start-up of the unit or its stop immediately after start-up indicate inefficient operation or failure of the fuel pump;
- if the engine starts, but after some time stops functioning, then a faulty crankshaft sensor may be the culprit;
- also, a worn camshaft or its sensor can provoke the engine to unstable start-up and unstable operation.
Now let's proceed to the analysis of the causes of the unstable operation of the engine and try to diagnose malfunctions with our own hands.
Features of diagnostics
- When the pressure regulator fails, it must be replaced. To confirm its faulty condition, disconnect the fuel return hose and subsequently turn on the ignition. If fuel under pressure immediately begins to flow from this hose, then this is a direct indication of a malfunction of the regulator. To eliminate the breakdown on the road, it is necessary to muffle its edge or pinch the tube, which will ensure a reduction in the cross section. After completing these manipulations, you can be guaranteed to get to the repair station.
- If there is no full spark, then this causes interruptions in the operation of the motor. To exclude this aspect from suspicion, you must use a special candle key. Having unscrewed the candles, we connect them to the tips of the high-voltage ignition distribution cables and scroll the starter a few turns. If there is not enough spark, then the assembly must be replaced. With such a malfunction, the car is able to arrive at the place of repair without outside help.
- Attention! When working of this nature, compliance with the safety rules is a mandatory condition! High voltage is very detrimental to health!
- Incorrect installation of marks on the valve timing provokes the engine to significant interruptions in speed. The fact is accompanied by specific pops. The malfunction cannot be eliminated without resorting to the use of specialized equipment. If the breakdown caught on the road, then his own attempts to eliminate it are contraindicated. It is recommended to tow the car to a service where qualified technical assistance will be provided to it.
- If the damper that regulates the airflow does not work correctly, a breakdown is diagnosed in several ways. After checking, you should start troubleshooting. To do this, we unscrew the air supply pipe and inspect the inner surface of the housing and the damper itself for the absence of damage, as well as working out on the walls.
- On a stationary motor, it is in the closed position. If the impossibility of complete closure is noticed, then the node needs to be cleaned. After that, the damper will have to be computer adapted. In practice, it is confirmed that the occurrence of a malfunction is of an increasing nature. Its abrupt occurrence on the way is impossible. It is recommended to carry out the corresponding list of repair measures in a specialized workshop and in advance, at the first symptoms of a deviation in work.
- When, after starting and short-term operation, the engine immediately stalls, we pay attention to the behavior of the immobilizer lamp located on the dashboard. When it blinks, you can classify the specified node as one of the causes of the malfunction. This usually happens due to the loss of electrical communication with the chip located in the key by the immobilizer unit. It will be possible to resume movement only after changing the faulty key to a spare analogue.
Special equipment, available in the arsenal of specialized services, allows you to "register" the key to the block software. - Tip: For long trips, we recommend having a spare key with you.
- Checking the performance of fuel injectors is diagnosed using a special stand. This procedure should also be entrusted to specialists.
- When the fuel filter is clogged, it must be replaced. If an unpleasant malfunction occurs on the road, when the engine tends to stall, we recommend that you use the recommendations below to eliminate the defect.
- Open the Renault Logan hood and dismantle the fuel supply hose, then turn on the ignition. If the fuel supply is carried out at low pressure, then the filter began to show insufficient throughput.
- To increase this ability, we dismantle the filter element and blow it in the direction opposite to the normal fuel supply mode. You should also clean the filter as much as possible. To do this, use a screwdriver or a suitable thin object necessary to influence the paper insert.
- We install the filter in its original place and start the Renault Logan engine. If the unit does not stall, and its speed does not “float” or “jump”, we head to the nearest service to replace the unusable element.
- In the event of a sudden stop of the engine, we check the performance of the fuel supply pump. To do this, open the hood and remove the fuel supply hose. At the same moment, we turn the key to position "2", which initiates the activation of the pump relay.
When the flow of gasoline is not detected, the pump is faulty. In this case, it is not possible to issue specific recommendations for temporary troubleshooting. The only measure is to tow a Renault Logan car to the nearest workshop. - If the failure of the crankshaft sensor turned out to be the cause of the malfunction, then eliminating this failure on the road in the absence of special equipment is also impossible.
- It happens that the engine does not start at all, especially when cold, in this case, it is advisable to contact the specialists at the service center.
Carrying out repair activities in the Renault Logan car is carried out in this case only under the conditions of a specialized service. - Diagnostics and repair work due to wear of the Renault Logan camshaft or its sensor, when the engine does not start, are performed in a service based on engine repair.
In custody
In the article, we have given a short list of malfunctions that occur with Renault Logan engines. This material is recommended to be used in the form of instructions that allow you to determine the indicated breakdowns. We hope that our article is useful.
