2005 BA MkII XR6T 6-speed manual Magnet ute (stock standard, 210k kms)

I’ve been chasing these intermittent problems for a little while now.  What could they be?  Could they be related?

The first issue encountered; when accelerating to 3,500 to 4,000 RPM, it feels like it hits a rev limiter.  It misses & loses power.  Once you back off it seems to reset & is back to normal.  I don’t recall the engine light coming on when it happens.

Just recently, the other intermittent issue, which can be rather exciting at times, is when overtaking (mildly).  You generally just get ahead & it feels like it goes into limp mode.  It loses power & won’t rev past 2,000 RPM.  If I pull over, shutdown & restart everything is back to normal again.  Once again I don’t recall seeing the engine light come on but it may be because I am too preoccupied with the car I have just overtaken.  Can be a tad embarrassing after overtaking just to pull over to shut it down & restart!  Last time I had this happen a mate checked the codes & it came up with an overboost issue.

The two scenarios are slightly different.  The coils, plugs, fuel filter & boost control solenoid have been replaced recently.  I have a new stock standard Garrett wastegate actuator to fit.  I’m thinking (hoping) this may be the issue as the one on it is still the original at 12 years old.  I understand they are a PITA to change with the turbo still on.  disconnecting the catalytic converter & dump pipe makes the job easier though I believe.

I don’t believe it would be necessary to get a tune when replacing like for like actuators.  Would this be a correct assumption?

Cheers . . .

if you're keeping it stock, then yes, there's no need for a tune.

 

From those symptoms, it seems to be a coils issue, but if you replaced the coils with genuine ford ones, it won't be that... maybe the cat has collapsed...

Yeah I replaced with genuine ford coils K31th.  Any easy way to determine whether the cat is faulty?  it doesn't rattle or the like if you knock it.

yeah, it should rattle if it's faulty, but that's not 100% ... you need to unbolt it and attempt to look through it to be sure.

 

Could also be a vacuum leak, that only really leaks when it's under significant load...

Probably a good time to check it out when removing the dump pipe to change the wastegate actuator.

 

Vacuum leaks can be a pain to chase but will keep in mind.

 

Thanks . . .

Vacuum leaks are easy to find, use something flammable, eh, ‘brake cleaner’ or ‘start ya bastard’ engine should rev up slightly/ping if a leak is present when you spray the vacuum lines.

Good info, will give it a go.  Thanks . . .

Just checked my records, the code that came up was P1227 "wastegate actuator failed closed".  Had a quick look today.  Tried blowing into the tube going to the wastegate actuator & no resistance at all.  I assume there should be if it is working properly?

hmm... the diaphragm in the actuator may have failed, by those symptoms. I've never blown into the tube going to the actuator myself, so I don't know what it should feel like from that perspective. All I know is a compressor supply should make it move based on the rated PSI (around 5-6 for a stock one).

On 12/01/2017 at 10:33 AM, Cormo said:

2005 BA MkII XR6T 6-speed manual Magnet ute (stock standard, 210k kms)

I’ve been chasing these intermittent problems for a little while now.  What could they be?  Could they be related?

The first issue encountered; when accelerating to 3,500 to 4,000 RPM, it feels like it hits a rev limiter.  It misses & loses power.  Once you back off it seems to reset & is back to normal.

It may be a long shot, considering the car is still stock but I had a similar issue with my car just after the first flash tune. And it was due to softened valve springs. Exact same as you have described. It would rev real nicely to around 4000 rpm then it felt like it hit the limiter.

Just food for thought.