Injection Data: Start Volume & Injection Timing Needed

Hello.

I would like to develop a simple and elegant solution for the common warm-start problem, ideally without using relays if possible.

Based on previous experiences and opinions, the cause appears to be an imbalance in the calculation of starting quantities.
Cold start, abundant fuel -> starts immediately.
Warm stingy -> organ organ

So, you essentially need to trick the engine's computer into thinking the engine is colder than it actually is -> by adding a resistor in series with the coolant temperature sensor.

However, beyond a certain point, the injection timing is advanced to compensate for what is perceived as an increased ignition delay, and I want to avoid such side effects as much as possible.

Therefore, I need data/maps regarding...
1. the relationship between engine temperature and starting amount.
2. The relationship between engine temperature and injection timing correction.

Please send the files to my email address.
Okay, bitte gib mir den deutschen Text, den du übersetzt haben möchtest.

Thank you .

You can get characteristic maps; please contact me by email!
[email protected]

Hello.

Are there any other reactions of the EDC (Engine Control Unit) that should be considered when dealing with engine temperature irregularities, besides advanced injection timing and "more generous" pre-glow and post-glow?

Or could emergency safety functions be lost, for example, if the EDC normally reduces the fuel injection amount when overheating is imminent?
For example, if you connect a 330-ohm resistor in series with the motor's NTC thermistor, the EDC will never report a temperature higher than approximately 77°C – even if the engine block is actually at 150°C.

Deleted upon request.

diesel.gustav wrote:

If you generally lower the temperature level, then the EGR system will start operating a little later after a cold start, if it is still active. And the coolant heater with the three glow plugs will also remain on for a slightly longer time. It's probably all rather insignificant.

Hello Gustav.

I once created an Excel spreadsheet that allows you to estimate the results.
With a 330 Ohm resistance, I would also increase the 750 Ohm pull-up resistor in the motor controller to 820 Ohms.
Between 0 and 30°, the error would be less than 3°C. At 50°, it becomes 43°, and a real temperature of 90° would appear as 65°C.
That would be worth a try - if no other negative consequences occur .

Quote:

Why aren't you making the series resistance switchable?

Probably too much work, I can imagine.

First, that's exactly what I mean, and second, I have concerns that the EDC might record error entries when the temperature sensor values fluctuate rapidly – which is something I also wanted to avoid.
Okay, one could eliminate these jumps through "gentle" electronic transitions, but that would require a significantly higher level of effort.

Therefore, I would like to gather as much information as possible about the desired effects and potential side effects.

Deleted upon request.

diesel.gustav wrote:

If you don't install an extremely "slow" switch, the EDC won't detect it. This is because an interruption is only stored in the error memory after a certain "debouncing time" (which is applicable, approximately 500 ms or longer).

Hello Gustav.

I don't quite understand that.
"Rapid" or "sharp" temperature changes, for example from what appears to be 30°C to 80°C, are not recognized as errors, but the same change occurring slowly (over > 0.5 seconds) does trigger an error message?

Quote:

... Have you identified the pull-up resistor on the control unit circuit board yet? And is it less work to replace it with an 830 ohm resistor than to use a switch?

Yes, there's still a patch in the engine computer from previous attempts to address the "summer sag," and behind it (in terms of circuit traces) is the pull-up .

Deleted upon request.

diesel.gustav wrote:

In my previous response to you, I did not mention temperature fluctuations, but rather interruptions and the associated debouncing time for an entry in the error memory.

Hello Gustav.

Okay... I'm planning to bypass the series resistor using the normally open contact of a relay. When starting, the relay would be activated, and the temperature input would jump, for example, from 90°C to 65°C, and then return to 90°C after the engine starts.
In this case, there is no complete interruption of the temperature line.

Quote:

Was your question a rhetorical one?

No, I absolutely mean it.

Quote:

Because you surely know that: The computer in the EDC control unit requests current values, not historical values.

At the beginning of my time working with TDI engines, I read that temperature developments occurring in a "reverse" manner (i.e., a decreasing water temperature well before the thermostat opens) would be logged as errors during sensor monitoring.
I don't remember where it is anymore...

Quote:

Based on my tests, temperature fluctuations achieved by a simple toggle switch, ranging from -15° to +80°, did not trigger any error messages in the system's memory; however, they did affect the start of injection and the engine speed.

Ah, that gives me encouragement again . Thank you!

At the beginning of my time working with TDI engines, I read that temperature developments occurring in a 'reverse' manner (i.e., decreasing water temperature well before the thermostat opens) would be logged as errors during sensor monitoring.
I don't remember where it is anymore...



Definitely NO...

I would get warning messages every morning... it's a few kilometers all downhill, so the thermometer just keeps dropping... especially when it's -15°C outside and the climatronic is trying to maintain my desired +25°C inside .

Similarly, starting the engine with it already warmed up causes a sudden circulation of 6 liters of automatic transmission fluid, which significantly draws heat away from the engine block. In the first few seconds after starting the engine in this way, the water temperature can drop by as much as 20°C. Again, no error message appears.

CU Gremlin.

Gremlin wrote:

Definitely NO...

Hi Gremlin.

Then it was probably one of those ducks that you occasionally find in "specialized" magazines, and which are likely to blame for the fact that so many nonsensical phrases circulate among newcomers.