PreFL GT inlet and exhaust avcs diagnosis

by **phuriouss** » Sat May 09, 2015 5:38 pm

Hi team,

Car has been rough idling and hesitating on low rpm, had it on the scan tool today and on idle and :
VVT adv. ang amount L = 0 deg
VVT adv. ang amount R = 0 deg

I then revved it to about 3000-5000rpm and noticed that the degrees only increase to about 3 or 4 degrees with only after holding the revs for abit; it looked something like this:
VVT adv. ang amount L = 3 deg
VVT adv. ang amount R = 0 deg
Is that normal..

Where do I go from here? I've read some of the posts on here in regards to avcs and banjo bolt filter clogging issues,
my question is how many banjos are there that I need to check/remove/clean?
Also something about cleaning ocv solenoids? Abit confused about it all sorry
Does anyone have diagrams of what it looks like where they are located in the engine bay?

please advise!

Thank you

by **BillyCorgi** » Sun May 10, 2015 12:17 pm

When the engine was revved was it stationary or moving on the road?
ACVS will operate differently in each scenario?

Some other may comment further if we can get their attention?
Matt McLeod, are you able to comment on the operation of the ACVS system in the 2 litre Gen4 Turbo?
Cheers!

by **phuriouss** » Sun May 10, 2015 12:44 pm

Thanks man!
Oh you're right it was stationary...it was in neutral both times
Thought the angles would change according to the rpms
Anything else I can look for?

Btw is there a thread here that has all the baseline readings (what all the scantool numbers should look like) for a GEN4 GT?

Cheers

by **bigBADbenny** » Sun May 10, 2015 4:42 pm

You want to log inlet and exhaust avcs for a complete picture.
The fsm has the diagnostic procedure, but with the car in gear hold the revs at 1500rpm for a minute, then at 3000rpm.
Then log it on the freeway at 100kph in 3rd 4th and 5th etc or similar for an auto.

So the forum search is limited to 5 characters so use the google this forum link in my sig:
https://www.google.com.au/search?output ... sn.au+avcs

There's my huge thread, postfl specific but general info is useful to you, first result :good:

viewtopic.php?f=6&t=30056&p=406662#p406662

Tl/dr: oscillation or lag of vvt angles where they should otherwise match = replace both ocv's after doing uec, clean, replace or remove all banjo filters, oil flush and oil change. Exhaust avcs same but clean the ocv manifolds and remove banjo bolts.

.

by **bigBADbenny** » Sun May 10, 2015 4:50 pm

So it's a deeper shit proposition for prefl as there are banjo filters that can clog, affecting the avcs and potentially starving the turbo of oil.
You need to dianose the issue and take remedial action if required immediately

Luckily the fixes are inexpensive and easily DIY able.
Partsouq will probably have the best prices but ymmv.
But first log inlet and exhaust avcs on both left and right sides.

Get your fsm here:
https://www.google.com.au/search?q=site ... ent=safari
Look for Australian domestic market my05 liberty.
http://sl-i.net/FORUM/forumdisplay.php? ... mp-Manuals

Lastly if you use the forum search link with exhaust avcs as the keyword that will bring up most instances of prefl avcs issues:
https://www.google.com.au/search?q=site ... ent=safari

.

by **phuriouss** » Sun May 10, 2015 5:28 pm

Thanks for that mate, I'll start reading up on those links you've posted

So to clarify there is only 2 avcs one on the intake side and one on the exhaust? 2 solenoids and 2 banjos I'll need to check?
Appreciate the help, will update when I've made some progress on the matter

by **bigBADbenny** » Wed May 13, 2015 10:33 am

Its a flat four DOHC engine, so theres 2 cam gears per head and an OCV for each cam gear.
Meaning 2x inlet cam gears and 2x inlet OCV's and 2x exhaust cams and 2x exhaust OCV's.

Should change the thread title too: by editing the original post's title, to something like PreFL GT inlet and exhaust avcs diagnosis

by **Bugalugs** » Thu Jun 18, 2015 10:21 am

My car (05GT 2.0) has had a stutter/hesitation issue since I have owned it (9 months).

The hesitation ONLY happens between 2000 - 2600 Rpm, once above or below this, it runs smoothly again. Also, it is prominent when driving/under load, when revved similarly at idle its way less noticeable. Also when driving, it happens anytime the cars between 2000-2600 Rpm, no matter if in 2nd gear or 4th/5th on the highway at 110kph. Anytime its 2-2.6k when driving regardless of speed, it does it.

Am i correct in thinking I should remove my Banjo filters and replace all the OCV's? This problem has bugged me since the day I got the car, I am very keen to get to the bottom of this!! Any thoughts on this would be much appreciated. Car always run on BP 98. Any idea what part numbers I need to order for the new OCV's? I could buy them and get my mechanic to install at next service.

Thanks heaps if I can solve this I will be one HAPPY man

by **bigBADbenny** » Sat Jun 20, 2015 10:19 am

Rather than relying on guesswork, log the inlet and exhaust vvt angles with a tactrix or btssm. I can help out if you're in Melb.