Posted this in reply to another thread a few days ago but I guess wouldn\'t have been seen by most:
On track at the weekend, early on (i.e. still very cold) I hit around 6k in third (around peak boost on the second turbo I would think) and experienced what felt like a rev-limiter, only not as violent and with the heat lamp flashing (i.e. some kind of PFC error). It didn\'t happen on subsequent sessions or at lower RPM.
As the knock didn\'t get over 74 (same as on warmer trackdays), I assumed it was the PFC cutting boost as it approached unhealthy levels. Was that the case, or was something else happening!? :eek:
Nobody got any ideas then? :(
Would like to know as I don\'t fancy shattering a tip or something doing 100mph+ on track! :Hammer
Most likely fuel cut mate. The power FC will cut the fuel if you over boost too much. I think it\'s if you go more than 0.2 bar over the set boost level.
I\'ve hit it a couple of times and not done any damage yet but it\'s not a good thing too be running into!
exactly....thats why im fitting a pfc pro to mine:D
Ed, where did you manage to get a PFC pro? That means you can enable the anti lag function aswell as a few other extras doesn\'t it?
Blimey! :2eek
I don\'t know enough about the way the whole thing works, but that does seem an odd thing for an ECU to do, knowing that running lean normally means bad things... or have I misunderstood what\'s happening when it cuts the fuel?
Is there any way to stop it happening? Does the PFC not just chuck more fuel in knowing the A/F has changed (assuming there is the capacity to do so)?
Would I therefore be advised to notch the boost down on very cold days - or would that just exacerbate the problem?
I R confused! :2Confused
The power FC completely cuts all fuel, the theory being that with no fuel at all there will be only air in the housings, this obviously won\'t ignite hence there is no explosion or combustion cycle at all during this time.
I used to have this happen quite a bit on my first FD. It\'s never happened on my current one, which is odd, cos it\'s got the engine out of my first one transplanted! Only thing I can think of is that this one has a cat and the other didn\'t, I seem to remember that deleting the cat can cause big ol boost spikes.
Thanks for the explanation. So what\'s the likelihood of damage occurring from this? I understand it\'s better to have no combustion than pre-detonation, but could something nasty still happen?
Also, would I be right in my suspicion of the low ambient temperature being the cause, or could it happen at any time (never seen it before!)?
It is better to completely shut off the fuel than have an overboost which can seriously lean out an engine or cause det even if there is enough fuel with lower octane pump gas than race fuel.
This is a protection for the engine,so you need to find out why it has done it and rectify asap.
Regards
Carl
Hmm, so it isn\'t as simple as it being too cold = dense air = more boost? I don\'t really understand why it didn\'t do it again in three flat-out sessions afterwards. :3Confused
Quote from: LumEd, where did you manage to get a PFC pro? That means you can enable the anti lag function aswell as a few other extras doesn\'t it?
A friend of mine had it brand new and never used it. I got it off him....just got to fit it now:D .... its just a chip,,,that apexi did... got to open up the pfc and fit it now.
Clive\'s explanation is that cold air does cause slightly higher boost, hence the cut and also why it didn\'t happen again (i.e. it got warmer during the day!)
So, I rest slightly more easily... ;)