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-   -   Misfires, urgent help needed!! (https://www.6speedonline.com/forums/996-turbo-gt2/395601-misfires-urgent-help-needed.html)

pete95zhn 08-24-2016 10:06 AM

Misfires, urgent help needed!!
 
So, engine runs like sh*t, stumps at idle but basically over 3k rpm there's no hickups...
Codes thrown:
P0040 Oxy sensors in front of cats changed
P0130 O2 sensor ahead of cat bank 1
P0300/0301/0302/0303 Misfire detection total/cyl1/2/3

Then from Durametric, engine idling:
Camshaft position 1 deviation 0.14 deg Crk
Camshaft position 2 deviation -4.59 deg Crk
EDIT: Unfortunately I did not check actual cam values when engine was running.

So, is it the camshaft position sensor or adjustment solenoid at bank 1? I'm in a bit of a hurry, there's this Time Trial I was about to attend next weekend...

EDIT: I have checked that both cam actuators operate when 12V is fed directly, their wiring is also OK, like wiring to Bank 1 Cam Pos Sensor. As per WSM's test also the LH O2 sensor seems to be OK. LH Valve actuator bracket is OK and the actuaror moves is 12V is fed directly. So it's either the Cam Pos Sensor or something more serious.
BTW, I just changed to Castrol TWS 10W60, does thicker oil have any effect on VarioCam Plus' operation?

996tt550hp 08-24-2016 10:29 AM


Originally Posted by pete95zhn (Post 4552857)
So, engine runs like sh*t, stumps at idle and basically over 3k rpm there's no hickups...
Codes thrown:
P0040 Oxy sensors in front of cats changed
P0130 O2 sensor ahead of cat bank 1
P0300/0301/0302/0303 Misfiredetection total/cyl1/2/3

Then from Durametric, engine idling:
Camshaft position 1 deviation 0.14 deg Crk
Camshaft position 2 deviation -4.59 deg Crk

So, is it the camshaft position sensor or adjustment solenoid at bank 1? I'm in a bit of a hurry, there's this Time Trial I was about to attend next weekend...



Sounds like your cam bracket is broken or cam sensor is bad or timing chain broke.

MadWhip 08-24-2016 04:06 PM

have you checked the fuel pressure? ~ maybe fuel pump is dying, split hose - at low rpm car runs and bugs, it can throw all kind of errors, dirty TB?

Zippy 08-24-2016 08:03 PM

coil packs and plugs

996tt550hp 08-24-2016 10:36 PM


Originally Posted by Zippy (Post 4553085)
coil packs and plugs

Nah coils and plugs wouldnt fail on just bank 1 like that on all those cylinders.

GT996 08-25-2016 07:10 AM


Originally Posted by pete95zhn (Post 4552857)
BTW, I just changed to Castrol TWS 10W60, does thicker oil have any effect on VarioCam Plus' operation?

No sweat. We run that oil all day here. Absolutely no problems at all.

mrmaass 08-25-2016 08:40 AM

Those cam numbers are on the high end of deviation but on these engines there is usually a degree or two of difference. They are never identical no matter how carefully the engine is assembled. Yours may be a tooth off but that isn't your issue. Have you checked your o2 sensors ahead of your cats?
An easy test would be to swap them between banks.

pwdrhound 08-25-2016 09:00 AM


Originally Posted by GT996 (Post 4553192)
No sweat. We run that oil all day here. Absolutely no problems at all.

Doesn't Manthey run TWS10-60 in all their GT2/3s also? I've been thinking about trying it out. I run M1 5w50 but I'll see oil temps peak at 260F on long track sessions in the summer. Curious if the TWS would be better...

pete95zhn 08-25-2016 03:14 PM

Move on, move on, there's nothing to see here!

But if you're still around, this was a quite good guess:

Originally Posted by mrmaass (Post 4553229)
Have you checked your o2 sensors ahead of your cats?

Namely after teasing/clicking all actuators with direct 12V, replacing LH O2 sensor with another (used) one and adding a new gasket between TB and IPD plenum, the engine runs now quite nicely, thank you.
The previous gasket had gone with the wind -or boost...it was still there, but severly damaged and streched and the TB was loose. Reason unknown. Noticed this just by a chance, before starting to drop the engine.
Lambdas in both banks are now normal, as well as camshaft angles. No deviation there anymore.

GT996 08-26-2016 03:04 PM


Originally Posted by pwdrhound (Post 4553235)
Doesn't Manthey run TWS10-60 in all their GT2/3s also? I've been thinking about trying it out. I run M1 5w50 but I'll see oil temps peak at 260F on long track sessions in the summer. Curious if the TWS would be better...

IDK about Manthey, but most Turbos here I know run either M1 5W50 or Castrol 10W60. It would be interesting to see if a change would help with your high oil temps, but I doubt it.

My car used to have a separate oil cooler in the front (which I took out). If you often run into oil temp problems, that solution might be an option for you.

pwdrhound 08-26-2016 06:28 PM


Originally Posted by GT996 (Post 4553773)
IDK about Manthey, but most Turbos here I know run either M1 5W50 or Castrol 10W60. It would be interesting to see if a change would help with your high oil temps, but I doubt it.

My car used to have a separate oil cooler in the front (which I took out). If you often run into oil temp problems, that solution might be an option for you.

260 is not a problem as far as oil temps go. I only get that on 100+ degree days at the end of 30 min sessions. Just heard good things about TWS 10w60. Might try it for the hot summer months..

pat 08-27-2016 06:44 PM

https://www.6speedonline.com/forums/...-misfires.html


It the bracket or the variable valve lift . Have had it before. Disconnect the connector and put it on . Do that a few times .

Macster 08-28-2016 03:56 PM


Originally Posted by pwdrhound (Post 4553235)
Doesn't Manthey run TWS10-60 in all their GT2/3s also? I've been thinking about trying it out. I run M1 5w50 but I'll see oil temps peak at 260F on long track sessions in the summer. Curious if the TWS would be better...

The high oil temps -- 260F ain't that high btw -- could be a sign the oil is doing its job.

The oil comes in contact with the some of the hottest parts of the engine: the underside of the pistons, the valve stems, the rings, the rod/main bearings, and part of its job is to remove heat. Thus elevated oil temps is a sign it is doing this.

Going with a thicker oil while one could see lower oil temperatures it could be because the thicker/higher viscosity oil is not able to absorb heat as well and thus the hot parts of the engine are running hotter than they would otherwise.

996tt550hp 08-28-2016 03:58 PM


Originally Posted by Macster (Post 4554348)
The high oil temps -- 260F ain't that high btw -- could be a sign the oil is doing its job.

The oil comes in contact with the some of the hottest parts of the engine: the underside of the pistons, the valve stems, the rings, the rod/main bearings, and part of its job is to remove heat. Thus elevated oil temps is a sign it is doing this.

Going with a thicker oil while one could see lower oil temperatures it could be because the thicker/higher viscosity oil is not able to absorb heat as well and thus the hot parts of the engine are running hotter than they would otherwise.

260F is high for oil temps.

mrmaass 08-28-2016 10:07 PM


Originally Posted by pete95zhn (Post 4553403)
Move on, move on, there's nothing to see here!

But if you're still around, this was a quite good guess:

Namely after teasing/clicking all actuators with direct 12V, replacing LH O2 sensor with another (used) one and adding a new gasket between TB and IPD plenum, the engine runs now quite nicely, thank you.
The previous gasket had gone with the wind -or boost...it was still there, but severly damaged and streched and the TB was loose. Reason unknown. Noticed this just by a chance, before starting to drop the engine.
Lambdas in both banks are now normal, as well as camshaft angles. No deviation there anymore.

Glad to hear you've resolved your problem. Those gaskets can cause some loss of boost if deformed enough and I keep a spare on hand. In your OP everything seemed to point to the left bank pre-cat o2 sensor though.
The Cam deviation being within a few degrees is normal and if you see it again don't be too concerned.
I've gone through so many misfire troubleshooting sessions on different cylinders over the years I have lost count.
In the beginning I couldn't tell who knew what they were talking about or who was just guessing when I would post to ask about my misfires but now certain symptoms under specific conditions along with Durametric diagnosing misfires has become far less frustrating.


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