BMW X5 35i E70 engine malfunction high pressure fuel pump replacement

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BMW X5 35i E70

The check engine light was on and the vehicle was brought in due to engine malfunction.

Check light comes on while driving

The engine suddenly stopped running.

I'll hook it up to a diagnostic machine and check it out.

It is an inline 6 cylinder turbo engine.

almost all cylinders

Misfires have been recorded.


Contains the pressure drop in the fuel high pressure system.

If multiple cylinders misfire

In many cases, the cause is in the area where the problem is controlled.

We suspect a malfunction in the fuel supply system and will conduct an inspection.

This N55 engine is a direct injection engine.

It has two fuel pumps, one on the low pressure side and one on the high pressure side.

The low pressure fuel pump is located under the rear seat.

There is no problem with the power supply.

Test fuel pressure. Standard value is 5-7bar.

6bar is within the standard value.

The low pressure fuel pump appears to be working normally.

Next, check the high pressure side.

A high pressure pump increases fuel pressure from about 5bar to a maximum of 200bar.

Approximately 50bar at idle.

It seems to be working properly now

Looking at the data when a failure occurred on the high voltage side

Only 8bar was coming out while running at 1600rpm.

There was almost no pressure rise.

Considering that the low pressure pump is normal

It was determined that the high pressure pump was at fault.

We will proceed with the exchange.

The high pressure pump is located inside the intake manifold.

Old part on the left, new part on the right.

In cases of severe failure, the tip may be broken.

After replacement, the numbers are stable.

Repeat the road test to confirm that there are no abnormalities.

The work will be completed.

High-pressure fuel pumps often have trouble.

There are few cases where it suddenly stops working.

In fact, there may be signs of failure.

"First thing in the morning, cranking takes a long time. Engine is difficult to start."

"Even when I stepped on the accelerator, the engine wouldn't start."

Such malfunctions may be a sign of high-pressure pump failure.

Even from the initial symptoms, faulty memory may remain.

If you notice anything unusual, please contact us as soon as possible.

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