Difficulty starting the engine due to preheating system?

Hello,

Now that I've finally managed to install my auxiliary heater (Webasto Thermo Top), the first problem has already appeared.

'If I turn on the pre-heater when the outside temperature is around -2 degrees Celsius and it runs for about 20 minutes, then when I try to start the car, it only glows briefly, maybe for 2 seconds. I think this is because the water is already warm (the temperature gauge shows around 75 degrees). However, I always have to keep the ignition on for 15 seconds before I can start the car, otherwise I don't get full power (this has been discussed before). So, I wait my 15 seconds and then start the car. Then, the starter probably takes about 4 seconds before the engine starts. Normally, I start the car and it starts immediately, regardless of how cold or warm it is.'

'Does anyone have any idea why this phenomenon only occurs when the auxiliary heater has been turned on beforehand?'

Okay, and one more thing... when I press the instant heat button on the clock, does that just send a pulse to a control line, or is there a holding circuit that provides power for the duration that the heating is active? I want to connect this to a free channel on the alarm system that sends a ground signal for 1 second when I press the remote control. Can I simply connect to the black wire (probably after converting it to '+')?

I hope this isn't all written in a confusing way .

best regards

Outside is cold --> Battery is weak --> The auxiliary heater consumes electricity --> Battery becomes even weaker --> Starting performance is poor.

Remedy: Check the battery voltage before starting after using the auxiliary heater. Otherwise, consider buying a new battery. My car starts perfectly in winter thanks to the ThermoTop .

I completely agree with matthiasTDI96; the colder it is and the longer the starter motor runs before starting, the more noticeable it becomes that the battery is weak or partially discharged.
But what do you mean by full performance not being reached until after 15 seconds??? Even if you preheat and the temperature display shows the (alleged ) operating temperature when starting, the MÖL is still not at its operating temperature because it's located in the oil pan and is not (or hardly) preheated.

Oh, I think you really need to explain that thing about the 15 seconds; I completely understand it differently... I hope you don't think that the engine reaches full power after 15 seconds. I would have a very hard time understanding that.

Sure, here's the translation:

"P.S. Here are some logs from Gremlin regarding liquid temperature, both with and without SH!"

I can't imagine it's a battery issue... firstly, the motor is running very powerfully, and secondly, the battery was probably only replaced two years ago, and it's not some cheap, generic brand.

So, I can just install a voltmeter and see how much it drops when I turn on the engine, with and without the auxiliary heater, right? Or should I use an ammeter instead? Which one is better?

'@matthiastdi96, did you also experience the very short pre-glow even when the STH (likely referring to a specific system or process) was running?'

Here's the thread about the 15-second issue:

/viewtopic.php?t=1659&highlight=


kann mir mal jemand bitte sagen wo ich diesen log-file finde?? habe schon die suche bemüht, aber gremlin hat soviel geschrieben, da finde ich das nie.

best regards

Okay, mine heats up very briefly before [something]. However, I'm usually so clumsy in the mornings that I just turn it on directly without waiting, which has always worked so far.

Regarding your battery, read some reviews; there are some generic brands that perform very well compared to branded ones. You can't really describe a battery as "new" if it's already 2 years old. Sure, many last longer, but there are also circumstances where they fail after a short time.
Okay, I'm sticking to my opinion that it could be the battery, especially since batteries are already weak in cold weather, and the auxiliary heater with its fan consumes quite a bit of power. As a general rule, you should drive for at least as long as you heat up. I can't say how much your sensor problem might be influencing this... but if you experience this issue every time you start the car warm, I would definitely consider replacing that part.

Okay, I know...I think there was a report about that recently...Varta apparently didn't perform very well, even though it's the most expensive brand. VW probably did the best. It doesn't really matter anyway...mine is from Class and it's actually intended for tractors. I'll install a voltage meter sometime; then I'll know more.

'What do you mean by: '...if you experience this problem every time you restart the device, then I would definitely recommend replacing the relevant part'?'

Do you think I haven't already tried to get a new sensor? It looks pretty difficult to find one. So far, it's been working okay... with a 15-second delay.

'Does anyone have any ideas about how to remotely turn off the auxiliary heater?' or 'It seems like no one has a solution for remotely turning off the auxiliary heater.'

As long as the burn indicator on the clock is lit, the control line of the STH is set to 12V. Once the indicator disappears (due to timeout or power-off), the line no longer remains active at 12V.

If you want to activate the strobe light (STH) via the remote control (FB), you need a monostable multivibrator (timer circuit); otherwise, the strobe light will only turn on as long as the FB receiver is sending a signal.

Please pay attention to the decoupling of the power-on signals (clock and control board) using diodes.

Regards,
Sure.

Here is the translation of the text from German to English:

"Guste" means "gust" in English. It refers to a sudden and strong gust of wind.

kann mir mal jemand bitte sagen wo ich diesen log-file finde?? habe schon die suche bemüht, aber gremlin hat soviel geschrieben, da finde ich das nie.

greetings bb

http://www.ralfhandel.de/images/oel-wasser-mit-SH.gif

http://www.ralfhandel.de/images/temperatur.gif


btw: where do you get the fuel for the heating system?

CU Gremlin.

'@guste100 thank you... so I'll figure out a way to do it. Let's see what great building blocks there are that are called 'monoflops'.'


'@gremlin, thanks for the logs, I'll take a closer look at them. I'm taking the fuel shortly after the diesel filter from the return line to the tank, as described in the manual.'

To be honest, I've also been wondering if it might be due to air trapped in the pipes that got introduced into the system during the installation of the SH (heating) lines. Could that be the problem?

'@gremlin, thanks for the logs, I'll take a closer look at them. I'm taking the fuel shortly after the diesel filter from the return line to the tank, as described in the manual.'




Or is it a real, genuine thermal top with its own tank that's then connected to the return flow?

'With heating systems that have their own pump, there are all sorts of potential fuel extraction points. Anything that doesn't come directly from the tank (and I mean *directly*!) is a potential source of problems.'

Otherwise, I don't have a clear explanation for your problem.

This morning, I had to start the ALH in -4°C weather, and it didn't crank like usual; it didn't even turn over at all on the first attempt. Because I immediately released the key as I normally do. Just a 'huff' and silence. On the second try, after three turns of the key, it grudgingly started (note: check glow plugs) and smoothly settled into 1000 rpm.Starting the engine makes no difference when the temperature is above 10°C. It doesn't matter if the engine is cold, warm, slightly warm, or preheated.

It's possible that the problem is with your battery or starter motor. Try supplying the power needed by the auxiliary heater using a charger, so that the heating process doesn't put too much strain on the battery. Then try it out and see if that makes a difference...


CU Gremlin.

eine idee wegen des fernschaltens der standheizung hat aber anscheint keiner, oder?

Sure...

I bought a 3-channel remote control from Conrad some time ago. There's also a switching stage with a bistable relay for it. Button 1 turns it on, button 2 turns it off, and button 3 is a momentary contact. I was thinking of connecting it to the horn so that I can find the car again in the parking lot at night .

CU Gremlin.

oder ist das ne richtige echte thermo top mit eigenem tank, die dann in den rücklauch eingeschleift wird ?

Okay, yes, that's a standard Thermo Top heater... you just connect it into the return line... then its own fuel tank fills up with fuel, which lasts for about 30 minutes. Other Webastos that draw their fuel directly from the main tank also have their own dosing pump; I don't have anything like that.

'Glow plugs are also a good idea... mine are probably still the originals. I should take a closer look.'

Well... I actually didn't want another remote control... So, it should work with the existing remote for the alarm system. Or, I could build it in a way that I can control it with my phone. Let's see what the winter brings.

Yesterday evening, I tried it again... it was around 0 degrees Celsius, and it started up better then. It had previously run for just under 30 minutes. Well, if I'm lucky, maybe it will fix itself .


best regards

@Blaubaer

What surprises me is that your engine is still preheating even when the temperature gauge shows 75 degrees. I have a Thermotop C, and it heats up the engine block to 70 degrees within 8 minutes (with ventilation off). When I then turn the key, it doesn't preheat, and it starts on the first rotation. It also doesn't re-preheat; instead, it behaves as if it were already warm (of course, the oil is still cold, but you wouldn't notice it).
/Jan

1Z, 1994

Jan03 wrote:

@Blaubaer What surprises me is that your engine is still preheating even when the temperature gauge shows 75 degrees. I have a Thermotop C, and it heats up the engine block to 70 degrees within 8 minutes (with ventilation off). When I then turn the key, it doesn't preheat, and it starts on the first rotation. It also doesn't re-preheat; instead, it behaves as if it were already warm (of course, the oil is still cold, but you wouldn't notice it). /Jan 1Z, 1994

It also surprises me.

Well... you can't really call it a pre-glow. The glow plug turns on briefly and then immediately shuts off (I see it for maybe 1-2 seconds). Normally, it glows for about 9 seconds when I start the engine at around -2 degrees Celsius without any other assistance.


best regards