Logo rotaautoservice.com
Category: New cars

Or Maybe Not A Candle?

2024

Video: Or Maybe Not A Candle?

Video: Or Maybe Not A Candle?
Video: Monika meets Senpai (Senpai but it's a Monika and Senpai Cover) 2024, March
Or Maybe Not A Candle?
Or Maybe Not A Candle?
Anonim

Some car shop customers, in case the engine does not start with the onset of winter, tend to blame only the candle pre-heating system for everything. It makes no difference to them when, in what condition - cold or hot, the engine starts badly or even stops doing it. “Blame the candles (control unit, timer, and so on), and the point. Let's do it!”However, upon closer inspection …

Somehow appeared at the gates of our Nissan workshop with an LD20–2 engine.

- What happened?

- Yes, candles, probably! - Confidently stated the client, - it starts up normally in the morning, and during the day, for example, if you drop into the store for a minute and shut it down, you can’t start it again!

The client seemed to consider himself an advanced specialist. - Relay number one glow plugs on and off immediately. And when I “threw” the “plus” on the candles on the battery, it started up immediately!

Well, what can I say … How to explain and prove that the reason, perhaps, lies much deeper (and more expensive in execution) - in the high-pressure fuel pump? In the high-pressure fuel pump, fuel from the internal cavity is pumped into the sub-plunger space using a special booster pump (usually a rotary type - not to be confused with a manual pump). Surplus through the pressure reducing valve is returned back to the pump cavity. After the hot engine stops (and the high-pressure fuel pump located on the block is heated no less than the engine), the fuel flows out from under the plunger space through a worn plunger pair and a transmission pressure reducing valve. Contributes to this process and the formation of vapor, creating a vapor lock. When trying to start such a motor, the booster pump is not able to immediately fill all the voids (do not forget that it also develops less pressure: hot diesel fuel has a lower viscosity). The plunger pair “starves” and produces less fuel. The engine is trying to start on a lean mixture. Until the high-pressure pump does not enter the operating mode, starting the engine is very problematic.

But what does the glow plug have to do with it? Just an overheated (forced on) candle helps the engine start in this abnormal mode. It masks the defect, but, alas, by reducing its own resource.

We had a car that “hot” required 10 seconds for the starter to start. When applying forced power to the candles, it was possible to reduce this time to 3-4 seconds. But “on the cold”, he started the “explosion” and immediately! In other words, these 3-4 seconds injection pump did not give fuel at all, then 6-7 seconds gave a reduced amount of fuel and only after that it returned to normal mode. Pouring it with cold water (removing steam plugs and slightly lowering the temperature of the fuel), it was possible to significantly reduce the start-up time without heating the candles. But they finally cured the car only by replacing the plunger pair and putting the rest of the iron in the fuel pump in order.

By the way, such a defect is inherent in many Nissan diesels (RD20, RD28 and others). Perhaps the reason lies in the peculiarities of the location of the injection pump on the engine block. In any case, forced heating of candles cannot be recommended under any circumstances due to a significant reduction in their life.

We tried differently to explain to the person the cause of the malfunction of his car. And they even made a “visual start-up” - they warmed up the engine thoroughly, poured diesel fuel and engine oil into a plastic bottle at the rate of “50 by 50” and put the hose from the bottle directly to the inlet of the high-pressure fuel pump. Started up almost immediately!

But no. It turned out to be a difficult person: he looked at us incredulously, did not say, but probably thought: “The guys want to untwist me …” We are not dragging anyone for repair by force. He does not want to believe - there are other workshops. Right?

I left. And we already forgot about him, so incredulous … Drawn somewhere in a month. On foot came. I walked in circles for a long time, did not dare to approach. Then he finally decided:

Recommended:

New

On-board Computers: I Want To Know Everything

Buy an on-board computer? But why is it needed when the car is already dubbed a computer on wheels! However, products are produced and do not dust on the shelves

Read More
System Changes

On March 1, a gradual restriction on the movement of heavy trucks in Moscow began. What measures are taken to organize the movement under the new rules?

Read More
On-board Control Systems: Menu Please

To reduce the number of buttons on the dashboard, we created control systems with an expanded menu. How comfortable are they in work?

Read More
Editor'S Choice
Best reviews for the week
Popular for the day