Air Conditioning & Performance: What's the Link?

Hello.
You're probably wondering why I'm asking you this question. It's obvious... everyone thinks that turning on the air conditioning consumes power. But the question is, exactly how much? Is the power consumption of turning on the automatic climate control noticeable, even in a 131 HP TDI PD engine? I have to ask this question because I've noticed for some time that when I have the air conditioning on (both in summer and winter), the car doesn't run smoothly across the entire RPM range. It feels sluggish at higher RPMs and becomes louder. I often experience jolts in the mid RPM range (2000-3000 RPM). When I quickly release the accelerator, the car jerks noticeably (like a ball joint play), because it's being braked quite strongly. Furthermore, I notice on the highway at 130 km/h going downhill, when I release the accelerator, that I'm pressed slightly into my seat because the car is braking. When driving in a 30 km/h zone steeply downhill in 2nd gear, the speed remains almost constant. Maybe 2-3 km/h faster, and that over a distance of about 300 meters.
When I shift, I feel a jolt because the turbocharger pressure is completely released, and you essentially enter a void in the next higher gear at 2500-3000 RPM, and you are slowed down. It drives very disharmoniously. In particular, the 2.5-3 second (measured) turbo lag when starting or when shifting from 1st to 2nd gear is very concerning to me. Similarly, starting with the air conditioning on is a whole philosophy – throttle response is a foreign concept...

If I turn OFF the climate control or select the ECON mode, none of the above-mentioned problems occur anymore.

When I changed the wheels from 17 to 16 inch rims, and with the air conditioning turned on, I noticed that the jolting during acceleration was significantly reduced.

Is this all normal? A proper dynamometer told me I have 148 or 150 horsepower. It's been a while, but back then, these problems occurred equally.

I am counting on your support }.


cu moby

It's hard to tell from a distance, but I assume it's not the climate, and there's a different problem at play!

Are you perhaps as sensitive as I am? I can even tell when the compressor engages and disengages myself! It's especially noticeable in cars like a Polo 1.4 or a Fiat Punto/Seicento 1.1L gasoline engine. I hardly notice it in larger V6 or V8 engines. I do notice it in my Seat, but it's not bothersome. Or do you feel it strongly too? Was it noticeable from the beginning?

Hallo, mittlerweile habe ich einen defekten Kupplungpedalschalter ausmachen können. Der MWB zeigte andauernd, dass die Kupplung geschlossen ist. Also Status 0. Ich wechselte den Schalter und wie immer wenn an dem Wagen was gewechselt wurde fährt der Wagen wie ausgetauscht. Extrem agressiv am Gas. Man kommt kaum hinterher mit schalten. Wagen zieht sauber durch. Man merkt seinen Beifahrer nicht mehr. Dies dauerte dieses mal aber nicht 200 sondern 600 KM bis er wieder in alte Zeiten zurückfiel. Dies machte sich wie immer bemerkbar beim Gasgeben und dem Gefühl eher ins Leere auf einmal zu treten. Egal was bisher getauscht wurde.. AGRVentil Magnetventil LMM Turbo etc. immer fuhr der Wagen so 200-300 km sensationell und dann auf einmal kündigt sich das Ende der Phase mit sporadischem Schlechtannehmen des Gases an und am nächsten Tag komplett schlechter Gasannahme. Ab und zu gibts dann wieder mal Tage an denen man denkt.. wow der geht heute wieder mal ab (aber nicht ganz so gut wie in den Tagen nach Tausch)...ist auch keine Einbildung denn meiner Werkstatt ist das auch aufgefallen aber finden den Fehler nicht. Gestern kam ich auf die Idee den Kupplungpedalschalter mal abzuhängen um erstens zu schauen welcher Status dabei angezeigt wird und zweitens zu sehen was passiert. Status war 1 also geöffnete Kupplung also anders wie bei defektem Schalter. Dann fuhr ich los und das Teil ging wie Hölle und die Räder quitschen sogar im 1. und 2. Gang obwohl sie das nie tun da ja ESP sonst regelt. Die Gasannahme ist sowas von direkt, da ist ein BMW 330I der an sich sehr direkt Gas annimmt noch langsamer in der Annahme. W'agen' also cleans thoroughly.
However, if you let off the gas, it starts to kick in quite strongly. You might even find yourself nodding your head when you release the accelerator.

Is what happened to me with the switch being detached normal?
Can someone explain exactly what happens in the engine control unit (ECU) when something has been changed, and what happens overnight that causes it to suddenly behave differently again? Does the engine control module (ECM) perhaps reset itself, and then do the values gradually adjust over time?

Thank you very much.

cu moby

The only thing that seems to help is to log data when it runs well sometimes and poorly at other times (on the same route) and then look for differences everywhere.

Hello.
habe vor ein paar Wochen das Druckrohr neu drangemacht. Jetzt lief der Wagen bis vor ein paar Tagen bevor es kalt/nass wurde sehr gut. Das abrupte Abbremsen nachdem man von Gaspedal ging war weg...man konnte ihn endlich gleiten lassen und oben raus lief er richtig frei hoch. Das in den Sitzdrücken ist aber noch immer als Drücken von hinten vorhanden. Vorher war es ja immer ein Ziehen... Gasannahme war sehr gut. Jetzt auf einmal nach einer Standzeit von 2-3 Tagen fuhr ich los und merkte wieder dieses üble Turboloch im 1. Gang von dem ich 1.500 km verschont blieb. Ferner bremste er wieder ein wenig ab wenn man vom Gas ging und wenn er Richtung Leerlaufdrehzahl geht ruckelt er mehrmals ein wenig.( nur 2. Gang) Ich frage mich wirklich was sich in den 2-3 Tagen als er stand wieder geändert hat...ausser das Wetter. Die AGR-Rate ist noch immer doppelt so hoch wie das Soll obwohl das undichte Druckrohr direkt am AGR ventil getauscht wurde. Hängt es vielleicht noch damit zusammen dass am Innenrand des AGR-Ventils der abgeschliffene Bereich sich noch immer negativ bemerkbar macht weil das Rohr bei grossem Druck noch immer (aber nicht mehr so stark ) rausgedrückt wird ? Werde noch ein paar Bilder von dem komplett plan geschliffenen Aussenbereich des Druckrohrs hier hochladen. Wundere mich wirklich warum denen das in der Werkstatt beim Tausch des AGR-Ventils nicht aufgefallen ist, da die Schleifspuren auch beim alten AGR-Ventil vorhanden sind. Für meine Begriffe hängt da immer wieder was.... als würde ein Ventil nicht immer sofort komplett öffnen sondern erst dann wenn genug Druck da ist. Und wenn es dann mal komplett offen ist nicht mehr ganz schliessen... Was wäre am sinnvollsten zu tauschen ? Ventil AGR N18 ? Magnetventil ? Ladedruckventil ? Membrandose ?


'Something I've noticed for about 3/4 of a year now... as soon as I start driving, the outside temperature reading suddenly jumps up by about 5 degrees. Then, after driving about 1-2 kilometers, it drops back down. Could there be a hose that has a leak and is blowing warmer air towards the outside temperature sensor?'

Thank you very much for your help.

moby

Right below the climate/water cooler, there's a metal pipe from the intercooler system; it might be cracked. You should open the hood and look in front of the coolers.

Perhaps you see something.

"With a cross-mounted intercooler, there's no metal pipe underneath the cooler..."

Ugh, you're right, that's a cross-reference.

I'm somehow always fixated on the A4 model when it comes to cars with around 130 horsepower.

Okay, so the AVF and AWX engines are transversely mounted, as are the ASZ engine and its successor, which starts with a "B". Also, even in cars of the Polo size, there are 130 TDI models.

"Hi, I'm experiencing a similar problem with my Passat 3BG PD with 131 hp. The engine doesn't seem to pull properly in the lower RPM range, especially during cold starts, and doesn't reach its full power until around 1900 RPM. I deactivated the EGR valve, as there are known issues with the EGR system. There might be a connection there, even though it shouldn't be needed when the engine is cold, but I'll take a look. You could try deactivating yours as well and see if it changes the driving behavior."

Best regards, Thomsch.

'Hi, I let another Audi A3 driver with an ASZ engine drive my car. First, with the active clutch pedal switch engaged, then without it. Interestingly, he confirmed my feeling that it performs better without it. With the active clutch pedal switch engaged, the engine doesn't seem to rev freely at higher RPMs, and it feels like a trailer is slowing the car down. When the car was stationary, his car showed no changes in the climate control system, but in my car, the entire soundscape changed, and the car jerks when the climate control is turned on and off. We installed the mass airflow sensor from his car into mine, and it drove completely differently. He said it felt like driving a different car. However, the air mass at idle didn't change. That is, the target air mass is 250/260, and the actual air mass is 435-480.'

'With the air conditioning on, the acceleration time from 80-120 km/h in 4th gear (while driving and with a passenger) increased by a whopping 1.3 seconds. It went from 6.0 to 7.3 seconds. However, the clutch pedal switch was still active. I'll probably test it again with the clutch pedal switch disconnected.'

'Near the air filter box, there's a buzzing sound when the engine is idling, and it's been there since I've owned the car... This buzzing only occurs on my ASZ engine. If you press the lever on the EGR valve down slightly, the buzzing disappears. I haven't noticed any buzzing at all on other comparable vehicles. Could the problem be related to the EGR valve? And if so, where exactly?'

cu moby

moby wrote:

Near the air filter box, there's a buzzing sound at idle that's been present since I've owned the car... this buzzing only exists on my ASZ engine. If you press the lever on the EGR valve down slightly, the buzzing disappears. No buzzing can be detected at all on other comparable vehicles. Could the problem be located here? And if so, exactly where?

If you're referring to the lever for the shut-off valve (which is operated by a small diaphragm and a flimsy plastic rod):
If the exhaust valve (AK) closes partially during operation, it generally creates a lack of air, which can explain a loss of power, jerking, visible soot, etc.
A valve that is fluttering in the intake air stream can theoretically also produce humming noises, but it should normally be identifiable by an external lever that is moving back and forth – unless the connection between the valve and its rotating shaft, or the rotating shaft and the lever, is loose.

The membrane dosing holder can be adjusted by loosening the screws, allowing you to adjust the maximum spring force of the dosing unit towards the "AK open" position. It's perfectly fine to experiment with this.
Of course, this also won't really help if, while driving, the vacuum diaphragm creates enough negative pressure due to pneumatic malfunctions to cause the throttle valve to close -> to be sure, additionally disconnect the hose from the diaphragm (carefully, to avoid breaking the nipple) and seal it.

Hello, thank you for the tip . I'll try it out sometime if the weather cooperates . Bye, moby.

moby wrote:

We installed a mass airflow sensor from his car into mine, and it drove completely differently. He said it felt like driving a completely different car. However, the mass airflow at idle didn't change. That means the target mass airflow is 250/260, and the actual mass airflow is 435-480.

It sounds like you might have a faulty mass airflow sensor (MAF). The test at idle speed doesn't really tell you much. Pay attention to whether it reaches its target value under load, around 4000 RPM.

We installed a mass airflow sensor from his car into mine, and it drove completely differently. He said it felt like driving a completely different car. However, the airflow at idle didn't change. That means the target mass airflow is 250/260, and the actual mass airflow is 435-480.

It sounds to me like you have a faulty MAF sensor. The test at idle speed doesn't really tell you much. Pay attention to whether it reaches its target value under load, around 4000 RPM.

In my opinion, the LMM is not defective.

See here: https://community.dieselschrauber.org/en/viewtopic.php?t=18274