It starts badly on a cold
Content
“It doesn’t start well for me when it’s cold” - such complaints can be heard from men in cold weather, when discussing cars. If the car does not start well when cold, different symptoms and behaviors can be described, but the problems that cause it to happen are usually almost the same. The reasons for difficult starting differ depending on the type of internal combustion engine: gasoline (injector, carburetor) or diesel. In this article, we will consider the most common cases of such problems as:
Reasons why it is bad to start on a cold
It is important to distinguish situations in which problems appear. The main ones are:
- the car is hot and hard to start;
- does not start well after downtime, when it cools down (especially in the morning);
- if it refuses to start in the cold.
All of them have their own nuances and reasons that worth considering separately. We will understand in general terms what reasons lead precisely to a poor start of a cold internal combustion engine. Usually one or two rotations of the starter armature shaft are enough to start a car that is in good condition. If this fails, you need to look for why.
Main reasons:
| Causes | Carburetor | Injector | Diesel |
|---|---|---|---|
| Poor fuel quality | |||
| Poor fuel pump performance | |||
| Clogged fuel filter | |||
| Weak fuel pressure | |||
| Low fuel level in carburetor | |||
| Defective fuel line pressure regulator | |||
| Air leaks | |||
| Poor candle condition | |||
| breakage of high-voltage wires or ignition coils | |||
| Dirty throttle | |||
| Idle valve contamination | |||
| failure of air sensors | |||
| Engine temperature sensor glitch | |||
| Broken or incorrectly set valve clearances | |||
| incorrectly selected oil viscosity (too thick) | |||
| Low battery |
There are also less common problems, but no less significant. We will also mention them below.
Troubleshooting Tips
On petrol engines an indicator that it starts badly and dulls on a cold one, it can become candle. We unscrew, look: flooded - overflows, we are looking for points further; dry - lean mixture, we also sort out the options. This method of analysis will allow you to start clarifying with simpler ones and gradually approach more complex reasons for poor cold start of the internal combustion engine, and not look for them in the fuel pump, disassemble the injector, climb to the timing mechanism, open the cylinder block, etc.
Rђ RІRѕS, for diesel engine the first in the list of faults will be weak compression... So the owners of diesel cars should pay special attention to it. In second place is fuel quality or its inconsistency with the season, and in the third - glow plugs.
Tips for starting an internal combustion engine in cold weather
- Keep the tank full so that condensation does not form and water does not get into the fuel.
- Turn on the high beam for a couple of seconds before starting - it will restore part of the battery capacity on frosty days.
- After turning the key in the ignition lock (on an injection car), wait a few seconds until normal pressure is created in the fuel system, and only then start the internal combustion engine.
- Pump up gasoline manually (on a carburetor car), but do not overdo it, otherwise the candles will flood.
- Cars on gas, in no case should you start a cold one, first switch to gasoline!
The injector starts poorly on a cold
The first thing you should pay attention to when the injection car does not work well is the sensors. The failure of some of them leads to a difficult start of the internal combustion engine, since the wrong signals are sent to the computer unit. Usually it is difficult to start on a cold due to:
- coolant temperature sensor, DTOZH informs the control unit about the state of the coolant, the data of the indicator affect the start of the internal combustion engine (unlike a carburetor car), adjusting the composition of the working mixture;
- throttle sensor;
- fuel consumption sensor;
- DMRV (or MAP, intake manifold pressure sensor).
If everything is in order with the sensors, first of all you need to pay attention to the following nodes:
- Cold start problem is common. due to fuel pressure regulator... Well, of course, whether it be an injector or a carburetor, when a cold car does not start well, if there is a troit, the revolutions jump, and after warming up everything is fine, it means that the condition of the candles is checked without fail, and we check the coils and BB wires with a multimeter.
- Deliver a lot of trouble permeable nozzleswhen it is hot outside, the car will not start well on a hot internal combustion engine, and in the cold season, a dripping injector will cause of a difficult start in the morning. To test this theory, it is enough just to release the pressure from the TS in the evening, so that there is nothing to drip, and look at the result in the morning.
- We cannot exclude such a banal problem as air leakage in the power system - it complicates the start of a cold engine. also pay attention to the fuel poured into the tank, since its quality greatly affects the start of the internal combustion engine.
On cars such as the Audi 80 (with a mechanical injector), we first check the starting nozzle.
The carburetor does not start well when cold
Most of the reasons that it starts poorly on a cold carburetor, or does not start at all, are associated with malfunctions of such elements of the ignition system as: candles, BB wires, coil or battery. That's why first thing to do - unscrew the candles - if they are wet, then the electrician is guilty.
The main reasons why it won't start cold carburetor:
- Ignition coil.
- Switch.
- Trambler (cover or slider).
- incorrectly tuned carburetor.
- The diaphragm of the starting device or the diaphragm of the fuel pump is damaged.
Of course, if you pump up gasoline before starting and pull out the suction more, then it starts better. But, all these tips are relevant when the carburetor is correctly configured and there are no problems with the switch or candles.
Advice from an experienced car owner VAZ 2110: “When the engine does not start on a cold engine, you need to smoothly press the gas pedal all the way, turn the starter and release the pedal back as soon as it grabs, keep the gas in the same position until it warms up.”
Consider some typical caseswhen it does not start on a cold:
- when the starter turns, but does not grasp, it means either there is no ignition on the spark plugs, or gasoline is also not supplied;
- if it grasps, but does not start - most likely, the ignition is knocked down or, again, gasoline;
- If the starter does not spin at all, then there is probably a problem with the battery.
Why is it difficult to start a cold carburetor
If everything is normal with oil, candles and wires, then perhaps there is a late ignition or the starting valve in the carburetor is not adjusted. However, there may be a torn diaphragm in the cold start systemand the valve adjustment also says a lot.
For a quick search for the cause of poor starting of a cold ICE with a carburetor power system experts recommend checking first: spark plugs, high-voltage wires, carburetor starter, idle jet, and only then also inspect the breaker contacts, ignition timing, fuel pump operation and the condition of the vacuum booster tubes.
Difficult to start on a cold diesel
As you know, starting a diesel engine occurs due to temperature and compression, therefore, if there are no problems in the operation of the battery and starter, there can be 3 main ways to find the reason why a diesel engine does not start well in the morning on a cold one:
- Insufficient compression.
- No spark plug.
- Missing or fuel supply is broken.
One of the reasons that the diesel does not start on a cold one, namely, the poor start of the diesel engine in general - bad compression. If it doesn’t start in the morning, but grabs from the pusher, and then there is blue smoke for a certain time, then this is 90% low compression.
ICE compression check
Checking compression in an internal combustion engine with a compression gauge and without instruments with your own hands. How to measure compression in gasoline and diesel internal combustion engines. Compression diagnostics. More details
An equally common case is when the owner of a car with a diesel engine cannot start a cold engine, but a hot one starts without problems - if no spark plugs. They heat the diesel fuel until the diesel engine reaches its operating temperature.
Options, Why don't candles work?maybe three:
- the candles themselves are faulty;
- It's the spark plug relay. Its operation is controlled by the coolant temperature sensor. During normal operation, the relay makes quiet clicks when the key is turned in the ignition before starting, and if they are not heard, then it is worth finding it in the block and checking it;
- oxidation of the glow plug connector. It is not worth explaining here how oxides affect contact.
3 ways to check glow plugs
To check diesel spark plugs, you can choose several ways:
- measure their resistance (on the unscrewed candle) or an open circuit in the heating circuit with a multimeter (it is checked in the tweeter mode, both screwed into the internal combustion engine and unscrewing it);
- check the speed and degree of incandescence on the battery by connecting it to the ground and the central electrode with wires;
- without unscrewing from the internal combustion engine, connect the central wire to the positive terminal of the battery through a 12 volt light bulb.
If the candles are working, and they are properly energized when the ignition is turned on, then in some cases it is necessary to check the clearances on the valves. Over time, they go astray, and on a cold internal combustion engine they do not completely close, and if you start it and warm it up, then they cover up and the engine starts to start normally when hot.
Faulty diesel injectors, as a result of normal wear and tear or pollution (sulfur and other impurities), are an equally important aspect. In some cases, the injectors throw off a lot of fuel into the return line (you need to do a test) or a dirty fuel filter.
Fuel interruptions much more difficult to start the internal combustion engine. So, if the diesel engine stopped starting in the morning, regardless of the temperature outside, the diesel fuel leaves (the valve does not hold on the return line), or it sucks air, other options are less likely! Air entering the fuel system can cause the diesel engine to start poorly and stall.
fuel out of season or with third-party impurities. When it's cold outside and the diesel engine won't start or stalls immediately after starting, then the problem may be in the fuel. DT requires a seasonal transition to "summer", "winter" and even "arctic" (for particularly cold regions) diesel fuel. Diesel does not start in winter because unprepared summer diesel fuel in the cold turns into a paraffin gel in the fuel tank and fuel lines, thickens and clogs the fuel filter.
In this case, starting a diesel engine is helped by heating the fuel system and replacing the fuel filter. Frozen water on the filter element presents no less difficulty. To prevent the accumulation of water in the fuel system, you can pour a little alcohol into the tank or a special additive in diesel fuel called a dehydrator.
Tips for diesel car owners:
- If, after pouring boiling water on top of the fuel filter, the car starts up and runs normally, it is summer diesel fuel.
- If there is low pressure in the fuel rail, the nozzles are probably pouring, they do not close (the operation is checked on a special stand).
- If the test showed that the nozzles are poured into the return line, then the needle in the sprayer does not open (it is necessary to change them).
10 Reasons Why Diesel Engines Don't Start Cold
If a diesel engine does not start well on a cold one, the reasons can be collected in a single list of ten points:
- starter or battery failure.
- Insufficient compression.
- injector/nozzle failure.
- the injection moment was set incorrectly, out of sync with the operation of the high-pressure fuel pump (timing belt jumped by one tooth).
- Air in fuel.
- valve clearance incorrectly set.
- breakdown of the preheating system.
- Additional resistance in the fuel supply system.
- Additional resistance in the exhaust system.
- Internal failure of the injection pump.
I hope that all of the above will help you, and if it does not solve the problem with starting a cold internal combustion engine, then at least it will direct you to the correct way to eliminate it on your own or with the help of a specialist.
