Diesel Temperature Sensor 2.5AEL, VP37

Hi.

I have an interesting "warm start problem" that somehow relates to temperature.
I just checked the dynamic pump settings and noticed that the fuel temperature is 70°C - or, rather, that's what the display indicates.
The outside temperature is 30°C, and the car has been standing for 1 hour.
The reading on my program stops at 60° - that's why I noticed.

What would be a plausible fuel temperature?

Thank you.
best regards, uwe

Simply let the motor stand for at least 12 hours and check if the value then approximately corresponds to the ambient temperature.
But 70°C is already a very high temperature for a VEP TDI engine.

Hello.

Yes, it's okay and correct to say it's cold.

If you think it's a lot, then I'll go ahead and replace the "frog" with a ball valve.

"Thank you."
Sure, here is the translation of the text from German to English:

"Hello"

In the VEP (Vehicle Electric Power) system, the temperature inside the engine compartment can sometimes be higher than the ambient temperature. When a hot engine is turned off at an ambient temperature of 30°C (possibly in direct sunlight), the heat from the engine spreads throughout the entire engine compartment. As a result, the VEP system initially becomes warmer for a certain period.

What temperature do you get in the VEP (Vehicle Electrical System) at 30°C ambient temperature when the car is running? Have you monitored the temperature increase over time (logged it) and checked if there are any sudden jumps or fluctuations?

Greetings.
Guste.

Okay, I'll log that and get back to you!

Sure, here is the translation of the text from German to English:

"Hello"

Hi.

I haven't done any logging on mine yet, but I recently had another 2.5-inch drive on my PC, and the temperature was similarly high. So, it seems plausible.
Okay, but there's still something wrong – the engine starts worse at 30°C than it does in the winter, which isn't normal. And if I disconnect the coolant thermostat (although the value seems reasonable), it starts perfectly with a replacement value. I don't understand it. It seems like something in the VP37 might be "misadjusted/broken."
It doesn't seem to get worse over the years, so I'm going to leave it for now.

"Thank you."

I suspect that when you say "thermostat," you mean the temperature sensor?
The moment you pull it, it glows with - and it turns on.
In the newer EDCs, there was no emission (above a certain temperature).
below a certain speed) is determined by a lookup table. In the case of the MSA11 - 12, which is used in the...
I would be surprised if Volvo were to be involved in that.
Weak battery? Starter motor failing? High-current electrical connections.
Is there corrosion between the starter and the battery? Possibly under the insulation?
Mass connection OK?
If none of that is the issue and everything else seems to be working normally, I would try manipulating the temperature sensor (for the starting process) by adding a resistor (so that the reading shows a total of -10°C).

Best regards,
Micha

Hello.

Okay, you mean the temperature sensor. Then the fan runs and it glows, right? But - I skip the preheating quite quickly. It starts after the first rotation.
With the temperature sensor installed, it needs 4-5 turns before it runs normally.

And everything else can be ruled out - it must be thermally related. If the engine/pump/fuel is cold, it starts immediately - I would notice a problem with the starter or battery.

Okay, as I said, as long as it doesn't get worse, I can live with it. Let's see how it behaves on vacation in 35°C .

"Thank you."
best regards, uwe

Quote:

However, I recently had a different 2.5-inch drive in the PC, and the temperature was similarly high.

So, that seems plausible.

Yes, that's correct. All five-cylinder TDI engines have a 11mm distributor head.
It produces a bit more waste heat than a 10mm pump on a 1.9 engine, and it also pumps five times per pump revolution.

Does he smoke afterwards if the engine doesn't start properly?

No - doesn't smoke either.

Interesting - then it suggests that he's not injecting anything.

How is the fuel quantity adjuster calibrated? (The fuel quantity at idle, as displayed in MWB 001, with all consumers - lights, radio, fan, air conditioning, etc. - turned off). It's possible that with a worn high-pressure component and a low warm-start fuel quantity, the leakage losses are so high that the injector opening pressure is not reached evenly.

If you don't mind a little spilled diesel, you could remove the cover from the quantity adjuster (not the entire adjuster itself) and check the position of the adjuster during a warm start, or whether it is deflected from the beginning of the starting process. Also, check if there is voltage at the shut-off valve.

If you don't have a broken cable, then this might help you -> https://community.dieselschrauber.org/en/viewtopic.php?t=28123

THANK YOU.

The thread was actually started by me - I've already re-posted that part, but it didn't make any difference.

Best regards,