I have a 2006 XC90 2.5T, The engine will surge only when the a/c is on. I can feel it drag when I am driving down the road, and when I stop. You can see the rpm's going slightly up and down......Is this a sensor issue or possibly low on freon? The clutch on the a/c is engaged when this surging happens!


Thanks

 

Whenever you have the A/C on it is just another load on the engine. Try cleaning the throttle body and see if it goes away.

 

Thanks for the reply, I will try this tomorrow!

 

My 2.5t was doing this and at stops it was very noticeable. I replaced the pvc system and clean the trottle body and it went away. It is a little of a pain to get to, compared to other n/a engines I worked on.

 

Thanks volvoxc90, when you said you replaced the pvc. is it the pcv tubing that you replaced, did you just spray the throttle body with carb cleaner? I will attempt this this weekend...


Thanks for the info

 

Yeah I replaced the tubing, charcoal canister under the manifold, but u should try to clean the throttle body first sense is the easiest and cheapest solution, see if that does the trick I just happen to do both at the same time due to the fact that i also had smoke coming out the dipstick which normally indicates a clogged pvc system.

 

Thank you for sharing this, I should have asked you this, this only happens when I have the a/c on, when the a/c is off, it runs great....is there a possibilty that it need more freon? Sorry for all the questions
Kevin

 

Well if its low on freon it causes the ac clucth to engage and disengage more often on the compresor and if thats the case u problably have a small leak somewhere , u could try buying a can of freon she if it works but im afraid the issue would return eventually as the freon leaks out.

 

If your clutch is going out on your compressor it can add an extra load. If all else dails you could replace that