2006 XC70 hesitates on heavy acceleration after changing PCV system

[dksoutha]

Howdy folks,

I replaced the PCV system on my XC70 with the kit from IPD. I also cleaned the throttle body with brake parts cleaner and replaced the gasket. Whole thing went faster than I thought it would, though a couple of the injectors needed replacing as the tips came off during removal. Changed the oil and filter when all that was done. Engine appears quieter and smoother.

However, the engine struggles and at times even stalls when I try heavy acceleration. Gentle acceleration has no problems. Did I screw up the throttle body by using brake parts cleaner? Could it be something else causing the issue?

Thanks in advance

[Blacklab467]

Any codes present or check engine light? You should use Throttle body cleaner and use caution not to allow it to run into the electronics. I spray it on a rag and then clean the throttle body to avoid doing any damage. I would think that could be your issue, did you replace the injectors with new Bosch ones?

[jonesg]

did you install new o rings on all the injectors and apply lube ?
try spraying brake cleaner around the seals at idle to check for leaks.

[dksoutha]

The new injectors are Bosch...what a pain to find any in stock at the local stores here in Chicagoland (many stores said they had them, only to shrug their shoulders once I actually came in for the claim.) I changed the O-rings and lubed them before installation. I'll grab another can of brake cleaner to check for leaks.

The current code I get is P0017, which I had before changing the PCV system. Others on this forum have suggested the code points to an issue with my timing belt, which I had changed 4 years ago along with the water pump. I'll have somebody look at that since I don't know what to look for. More codes may be on the way since I erased all codes just after replacing the PCV system.

Could I have gotten the Mass Airflow Sensor dirty or whatnot during the maintenance? The symptoms suggest an issue with it, though I suppose leaks around the injector seals may give similar symptoms. When flooring the pedal the engine seems to be gasping for air.

Thanks again, folks

[jonesg]

Its timing related, not necessarily timing belt, can be caused by old/wrong engine oil , dirty oil filter, causing the vvt response to lag.
If you have vida you can run the cvvt response test, it will tel you if its lagging, responding too slow.
I did it on mine and it failed the test, a simple oil and filter change made the problem disappear.

Check anything intake related that has been recently disturbed, charge air pipe coupler hose clamp behind the engine,
air intake nozzle where it connects to the throttle body.

Test the MAF by unplugging it , see if the symptoms go away, it will run rich but run nonetheless.

[dksoutha]

Folks, I really want to thank you for your time. Seriously, thank you.

I unplugged the MAF sensor and it ran better. I then removed the MAF and cleaned it with MAF Cleaner, and now it runs much better with the MAF sensor connected. I still get a lag accompanied by what sounds like a growling noise - not unlike somebody farting in a tuba - from deep in the engine when I hit the throttle, but no more engine shutdowns. I have not yet checked the injectors for leaks. I did find that the short hose attached to the very front-right of the intake manifold had cracked, likely from me folding the manifold over towards the air filter while I worked on the PCV system. I wrapped it in wide electrical tape in an attempt to seal whatever that hose is. Perhaps the culprit?

I replaced the Intake VVT in June and used an ultrasonic washer on the exhaust VVT several months ago, being careful to not get the rubber grommets or electrical parts in the liquid. New gaskets for both. Perhaps there's still an issue with the exhaust VVT? The internal part that moves was a total pain to extract, and I may have scratched it in the process of getting it out of there. Seemed to move freely after the cleaning.

The oil and filter are new as of Sunday.

This weekend I will check how well the hose leading to the throttle body. The other hoses appear to be clamped tightly down. I will also check the injectors for leaks. What am I looking for when I spray the injectors? Bubbles?

All the best to ya, folks

[dksoutha]

For those gather data:

Car ran okay this morning, though still a low growl when accelerating. I read that resetting the EMC can help zero things out after major Volvo engine work, so that I did (unplugged battery and kept the bland and red cables together for half an hour. Car was hard to keep running for several minutes afterwards, but then it ran well for the few minutes it took me to get back to work. Later, the engine would stall after running for perhaps 5 seconds. Took awhile to get home...

Unplugged the MAF and most symptoms went away. I certainly screwed up the MAF with brake cleaner (that stuff is just so impressive and handy.) New MAF on the way and brake cleaner moved a little farther out of reach.