Volvo L110F, fam low speed

[remus]

Hello,
Please help me with the following problem
I have a 2008 Volvo L110F front loader that overheats the engine. The fan works but at low speed.
Please tell me if the measuring point for pump P3 is on the central block below, and what value the pressure should have.
Thank you.

 

[sfrs4]

Hi Remus welcome to the forum, take a look at the attached documents

 

[remus]

Thanks for the reply SFRS4. I come back with the results obtained.

 

[remus]

Hello,
I replaced the P3 hydraulic pump, the charger worked correctly for two days, today it has the same problem with the fan rotation, in addition the display shows "break system failure", I can no longer enter the "test mode" to check the fan speed.
When replacing the pump I measured the pressure and I had 30 bar at idle and about 150 bar at 1500 rpm. The fan speed was about 50 rpm faster than the engine speed.
Today I connected the manometer to the measuring point and I noticed that when I start the engine there is a short increase in pressure, after which it drops to about 20 bar.
Is there a problem with the pressure regulator (PWM2601) or do I have an oil leak to the tank?
Anticipated thanks for the answer.

 

[sfrs4]

At this point I am out of my depth. did you replace the pump with a new genuine item? the brake pressure is also supplied from pump P3 so maybe the new pump is faulty or you have debris in the system?

 

[funwithfuel]

Step 1, start machine and allow to idle. Within 30 seconds of start up, curl your bucket back and hold it over relief for 10 seconds. Now enter service mode. Once in service mode, access brake pressure. Your brake pressure should be between 122 and 150 bar. Step on brakes , count how many applications before pressure begins to rise , pay attention to what pressure it stops building at. I suspect either you have flat brake accumulators or a weak brake charging pressure reducing valve. Please report your findings so that I might point you in the right direction without changing unnecessary parts.

 

[remus]

Hello,
Thanks for the guidance but the braking pressure visualization procedure did not work. I can't enter service mode.
What I noticed is that when I press the button for the parking brake the message "low brake pressure" appears and if I operate the bucket after your procedure the message "break system failure" appears.
Is there a measuring point where I could measure this pressure with the manometer? Thank you once again for your kindness and for your time in helping me resolve this issue.

 

[funwithfuel]

On the accumulator manifold, there is a measuring nipple. That's where you measure. If your brake pressure isn't satisfied, all the oil from pump 3 continues to try to go to brakes and leaves very little oil for engine fan.

 

[funwithfuel]

Let's try something a little different. Try to enter service mode before starting. Does brake pressure have a value or is it just ------? If it's just dashes , the sensor is probably failed or disconnected. Starting with key off. Start the engine, as soon as you start the engine curl your bucket over relief and hold it there. What we're doing is using the working oil from pump 2 to backfill the accumulator pressure. If after 30 seconds, the brake pressure is not satisfied, the brake failure warning will appear. It's at this time we need to know what the pressure is in the manifold. The pressure should be between 1780 and 2200 psi. If you're holding bucket over relief, the pressure should read 2340 to 2400 psi. When you let the bucket control return to neutral, the pressure should maintain if it drops off fast, the accumulator inlet check valve has probably failed.

 

[remus]

Unfortunately, a few seconds after making contact, a "break system failure" appears. I switched to the manometer.
I started the engine at idle I have a pressure of 1000 psi.
If I accelerate the pressure becomes 2600 psi.
With the engine idling and the bucket running, the pressure is 3000 psi.
After the bucket control returns to neutral, the pressure drops to 2000 psi in about 2 minutes.
If I accelerate, I return to the pressure of 2600 psi and I disengage the parking brake, the pressure drops to 1000 psi.
When I operate the brake pedal the pressure drops to 500 psi and then returns to 1000 psi

 

[funwithfuel]

Those pressures are too high. When curling bucket over relief you should be no higher than 2400 psi. We need to adjust that down in the central valve.
You want to adjust the pressure reducing valve PB closest to the edge of the block to get your 2400. You also may want to check that the sensor on the accumulator manifold is plugged in properly. If it is, you may want to replace it.

 

[funwithfuel]

Since the sensor is never reporting to the computer that the brake pressure has been satisfied, it keeps all the oil going to the brakes and ignores the fan. Safety first.

 

[remus]

Hello,
Thanks for the guidance.
I ordered the sensor, it will arrive next week. After mounting, I will send you a message.
PS. Can this sensor be checked with a multimeter?

 

[funwithfuel]

Please see attached information. You will see the relationship between brakes, cooling fan and pump 3 via the central block. Without the accumulator sensor telling the ECU what's going on, it fails to brake charging only and will not allow oil to the fan. This is by design so that the machine can be stopped in an emergency.

 

[funwithfuel]

The same sensor gets used in L110F as L120G. I attached measuring for 120G since it has the pressure graph. Good luck.

 

[funwithfuel]

Forgot to attach

 

[remus]

Hello,
After the last post I was away on vacation. After I came back from vacation, I replaced the sensor, but the messages remained: "brake system failure" and "low brake pressure".
Now I'm going to start checking the wiring and the voltages on the sensor.
Thank you for the information sent and for the time given.
A good day.

 

[funwithfuel]

Were you able to adjust your maximum brake charging pressure?

 

[remus]

Hello,
Due to some health problems, I could no longer advance with the charger repair.
I came back yesterday. I did the following operations:
1. with the bucket overturned I adjusted the pressure to 2400 psi
2. With the couplers removed from the SE5218 sensor and from the V-ECU (VOE 11443500) I checked the wiring that goes to the SE5218 sensor.
Everything is ok, but when I measure the resistance between +5V (VA55) and ground (VA24) I have a resistance of approx. 38 kohms.
I removed the UA coupler, and from this to the sensor coupler, that resistance is infinite.
From the UA coupling, to the V-ECU coupling, this resistance appears again (38 kohm).
I measured the voltage of 5V at the SE5218 sensor coupler (between pin 1 and pin 2) and it is ok.
3. I put everything back, then I noticed that "brake system failure" and "low brake pressure" no longer appear.
4. I entered the service menu, started the engine and with it at idle I went to the "test brake" but there the computer says that I must accelerate the machine to a minimum of 20 km/hour.
4. I returned to the service menu and pressed key 4 "axles/brake" and there the brake pressure appears.
0 appears on the display, and if I press the brake pedal, the pressure increases to 31 bars (435 psi). Pressing the brake pedal, "low brake pressure" appears again.
If I release the pedal the message disappears.
5. With the bucket overturned, pressing the brake pedal again on the display the pressure is max 73 bars (1058 psi).
This time the "low brake pressure" message no longer appears.
Conclusions:
probably by adjusting the pressure to 2400 psi, part of the problem was solved once the "brake system failure" message no longer appears.
The other problem "low brake pressure" needs a little more work.
Thank you for your attention. A good day.

 

[funwithfuel]

So you've established passive brake charging, now we have to figure out active brake charging. That is controlled by the pressure sensor in the accumulator block (SE5218)and the V-ECU. Have you a gauge up to 3k psi to measure pressure in the accumulator block?