Replacing injector(s) on a Volvo V70 D5 185? Yes or no?

Hello!

Our Volvo V70 D5 185 (D5244T4) has a problem where the engine is difficult to start when warm, especially in warm ambient temperatures. I don't know why, as of yet.

The only error Vida reports is a fault with the differential pressure sensor (intermittent). This problem has existed for over a year. In July 2020, I performed a return flow test. Based on this data, injectors 1-3 would likely be classified as defective, and all five injectors would be replaced due to the vehicle's mileage of 326,000 km.

However, the Vida system's checks of the combustion and injector valves indicate that things probably aren't too bad yet (the maximum allowable fuel correction per cylinder is ±4 mg/cycle).


Measured at:

55°C coolant temperature.
Fuel temperature: 40°C.
56°C engine oil temperature

Refurbished injectors are available for €800, and programming can be done with VDASH for €15.

Do you swap them and everything is okay? Or do you switch them, and is there no noticeable improvement?

Measuring compression? Pressure drop test?

What would you do?

Hi,
The idle correction looks fine (at too low a temperature), but it's difficult to assess the return flow rates without knowing the manufacturer's specifications. I don't see any problem with that, at least not yet.
What readings can you observe when starting the engine, for example, rail pressure? Is that a CR-TDI?
hg
Herbert.

Hello.

Herbert wrote:

Hi, The idle correction looks fine (at too low a temperature), but it's difficult to assess the return flow rates without knowing the manufacturer's specifications. I don't see any problem with that, at least not yet. What readings can you observe when starting the engine, for example, rail pressure? Is that a CR-TDI? hg Herbert

At least, the injectors appear to be wearing down relatively evenly. I would base the decision to renew something on the overall condition of the vehicle and its planned lifespan.
Based solely on the spray pattern, injectors with new nozzles make sense for this mileage – provided that the newly installed nozzles are not mechanically defective.

Quote:

Our Volvo V70 D5 185 (D5244T4) has a problem where the engine is difficult to start when warm, especially in warm ambient temperatures.

Perhaps a similar issue with the starter motor speed as seen in some VAG TDIs?
If you have the ability to log the engine speed and fuel injection amount during the starting process, you should do so.

Best regards, Rainer.

Hello!

Here, I was able to record some data over the past few days. When everything fell apart, I started over.

According to Volvo, the fuel correction may be 4mg/cycle. The maximum backflow volume is 40ml. The pressure in the pipe should be 3.5 x 10^5 hPa when idling.

Back to the starter:
Why at warm temperatures? Does higher compression in the engine create more resistance for the starter motor? In return, however, better lubrication?

Hello,

Please review our terms of service again, and avoid linking all files externally.

I would say the support has reached a point where it goes beyond simple tips and enters the realm of professional assistance. See registration in the forum.
/profile.php?mode=register

Quote:

Why at warm temperatures? Higher compression in the engine, and therefore more resistance for the starter? In return, but better lubrication?!

No, because the software in the engine control unit may only allow fuel injection to occur above a certain minimum speed. See the search function. I have no idea if that's the case, but a log file would help, as it would provide the information needed to know.

I would be happy to continue that interpretation, provided a support key is available.
https://shop.dieselschrauber.org/en/obd-support-key-p-112.php

Best regards, Rainer.