AC question

Mk4 tdi 5 speed

When i have the ac on and im accelerating in first gear and i believe in all gears the acceleration feels sluggish and then all of a sudden randomly there is a surge as im pushing in the pedal

Anyone know whats going on. Drives perfectly when ac is off and ac is cold (takes a few minutes ~5 to get cold)

1st you need to consider that there is a large plenum space in the a/c lines. It may take a few minutes for the a/c to cool. Then again, maybe the refrigerant charge is a little low.

As far as sluggish performance, this could be that while the a/c system is starting and trying to cool, the load is affecting the engine performance, and then when the system is cooled off and the load is not so great, the perceived engine performance returns.

If I were you, I'd get a set of gauges and check the fill level first. Everything else might sort itself out after you get that taken care of.

Cheers,

PH

The AC compressor on these cars does NOT cycle in and out as it does on most American and Japanese cars -- it's always engaged (but under moderation by the RCV in the compressor itself) when on, UNLESS the ECU says "shut off."

Which it does when you floor it, OR if the coolant gets too hot, OR if the high side pressure gets too high.

If you floor the accelerator what you're experiencing is normal. If you're NOT under full acceleration, however, then go through the checklist on the AC system, because if your fans are not working when it gets hot the high side pressure will go over-limit OR the coolant will get too hot and the ECU will command "AC compressor OFF!" and the conditions that cause this will eventually damage or destroy your compressor and now you're looking at a large bill and a lot of work to fix it (even if you fix it yourself.)