JasonS4+Festicle

So, I was at Blackhawk Farms (review and pics to come)......middle of my 3rd run session on the first day, I get bucking and a flashing check engine light.

I pit knowing it's multiple misfires - - pull codes and sure enough, cylinder 5 has multiple misfires. Before logging anything, I swapped coilpack 5 and 6. (Oh, I pulled plug 5 and it looked fine)

Log block 15 and 16 - - multiple misfires on cyl 4,5 and 6 (hmmmm, only Bank 2) - - must not be the coilpack. ONLY misfires under load. I can sit at idle and the car ran fine with no odd noises and it could be revved to 7000 without ANY misfires. So, misfires only under load.

I swap ignition amplifiers and go log again - - misfires on cyl 4,5 and 6.

I try a new ECU - - same thing and same thing with the MAF unplugged.

Anyway, we drink beer at the track, I drive easy back to the hotel and this AM, the car is fine.

Full boost, no misfires, the car runs perfectly.

I decide not to track it again today since something must be wrong and I don't ever plan on tracking a car that might be broken.

Anyway, on the way home from the track tonight the car is running perfectly. Full boost, full power, no misfires under boost(and I was watching VAG-COM while driving).

I go to pass someone, downshift to 4th and NO BOOST. Zero - - zilch - - nada.

Codes - NONE.

No smoke, no turbo noises, nothing (except the car feels like a 1 cylinder).

Anyway, thoughts?

Oh, I'm running KO4s with home brew (green tops, TCD and AVC-R)...

It's not the AVC-R either since I pulled it out and popped in my MBC just to see if maybe the valve inside the AVC-R was broken.

HELP, the straight line ***** is broken

Oh, a few sidenotes:

1. I seafoamed the car a week ago - - 1 day later I was getting misfire codes so put in new plugs - F5DPORs. The oil was changed just after the sea foam was done. The car ran perfectly ALL week after replacing the plugs. Tolerated repeated beatings just to be sure it was track-worthy! The sea faom treatment was done for the hell of it since the car has 140,000miles on it and was planning to do an oil change anyway.

2. I tracked the car earlier in the year and got multiple cylinder misfires (both banks) after my last run session. I didn't think much of it since my plugs were old, swapped new ones in the next AM before tracking and the car ran fine. I have done another 2 day track weekend since then and the car ran well with no misfiring (on the same plugs that were replaced at track event #1).

Mike2kS4

I start sending you on a direction.

Ah10@WMS

have you check ignition amp? is one of the plug got unplug from Lateral G?

OldSkewS4

In my past experience, they only act up when HOT.

JasonS4+Festicle

and block 15 and 16 to see where the misfires were.

What would like and I can get some data together tonight. I have ECUx and VAG-COM.

Nothing like coming home from a track weekend, kssing the wife and kids and going logging!

Good thing she's the coolest ever

JasonS4+Festicle

for the track and since changing to homebrew, I ONLY use black zip ties

Seriously, my brain is aching from stress since I couldn't track on day 2 and got to get rides all day. When you're at an event with a straight-line ***** like mine and you can use it, it hurts!

So, what's a POS?

JasonS4+Festicle

The plugs were installed Thursday PM and torqued to 20ft-lbs each.

I only pulled #5 to look at it but it was tight when I pulled it.

NOTE: The misfires are gone now, but so is my boost

OldSkewS4

POS= power output stage. AKA Ignition amplifier.

JasonS4+Festicle

swapping the sensors around for a week or so and the drive the crap out of it to get it really hot, like "track hot".

That was my plan until this boost thing crept up on me.

Now, I can't even see if there is a misfire problem because I can't get under enough load to cause the problem.

Can the POSs (or POSi for pleural) cause boost issues? Remember, I'm running basically stand alone boost control since I have the n75 unhooked completely and either a MBC alone or the AVC-R.

OldSkewS4

have you checked ALL the hoses?