Hello all, firstly sorry for the monster thread, ive tried to keep it as logical as possible as there's a lot of info.

I have an 2002 R53 MCS, and after reading about the joys of seafoam I decieded to try a "supossed" locally available Austraian equivilent called Nulon air intake cleaner.

The problem - I applied half a can (as directed) through the pcv hose as the engine was idling. Turned it off for 5 mins (again as directed) then started it up giving it medium revs with some high spikes but the engine would stall each time it got below 1k RPM. Initially not too phased I took it for a bit of a run (approx 30 mins in urban conditions) to clean the residue out of the engine but to no avail. The engine refussed to idle on 1k.

Trouble shooting - I removed the O2 sensor from the front of the intake manifold revealing that it was covered in the liquified residue of the cleaning product and delicatley cleaned it and left it in the sun to dry for a few hours. But still no improvement.

Trouble shooting continued - I removed the rear PCV hose from the crank case and hey presto it would idle nicely at 1k and a brief drive with the hose off was likw normal. Oh and I reset the ECU twice with no improvement.

Proposed solution - I created T junction in the PCV hose and added a crank case breather filter to the hose to give it the filtered air that it needs but provide a link from the crank case to the intake manifold.

Question 1 - will there be any long term problems to the engine from this solution?

Qusetion 2 - any advice on fixing the original issue of not idling under 1k, im a little hestitant to put further additives in but am willing to anything that keeps the dreaded overinflated dealer mechanics away from it.

 

All good now, took it for a good freeway run and it's back to normal @900rpm idle with a closed pcv hose.

 

any ideas what the problem was ?

 

Yeah that's a good question, I left a few steps out so maybe someone else might have an idea.

1. Removed and cleaned the O2 sensor agian, it had some residue but less than the previous day.

2. Started the car with pcv hose T junction open then plugged. The car came close to stalling but held in there.

3. Take it on a 120k round trip through a good mix of 17psi boosted urban back streets and freeway driving. The best step in my books.

After that it would start fine with the pcv hose closed, so im thinking maybe some carbon buildup was cleared from the sensor during the run?

Who knows I might even import some seafoam down the track.

 

Just thought id add a pick of the now removed mod, really just to check the attachment option on the NAM andriod app but incase anyone else has the same issues. Cheers Mark