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996 Turbo Engine Issues

stubbsy

Well-known member
Joined
28 Nov 2011
Messages
192
Need some assistance got a bit of a weird issue with my engine that would appear hasn't been fully diagnosed when run through the diagnostics, so:

Last Saturday engine wouldn't start, called out breakdown recovery after the bloke played around with a few wires and managed to get it started.

heres where my issue started driving it home I tried opening it up momentarily (was in residential area so just tried a quick blast of full throttle) engine threatened to wind up, started feeling the power being delivered and boost kicking in then the engine done this weird jolt/shake where you could literally physically feel it.

Took it for another spin same thing again, so parked it on my drive and left it as I thought best not to drive it when it is not right, I called a recovery vehicle and took it to my local independent, so diagnostics on it was showing a boost value fault, new part ordered and fitted got the car back today.

just taken it for it first spin and still having exactly the same issue giving it full tilt on the throttle it starts kicking in and then getting the engine jolt/stutter with power being lost.

Really not sure what the issue could be as after the new part was fitted my indy informed me there were no faults displayed, they did take it for a test drive but I don't think they gave it full throttle otherwise they would have noticed you can't not.

in general It drives finel under light and medium acceleration, engine sound is ticking over as per normal, its just when I go to open it up it is not working right, any fellow turbo members have experience of this sort of issue or anyone else I can contact for a second opinion.

Help appreciated, thanks!
 
Need more info dude... Is it standard or modified? What boost do you get to before it starts spluttering? When it does splutter does it keep running or shut down completely? When were coils and plugs last changed? Have you made sure the waste gates are free and moving easily? What exhaust is on it?

If its a standard car and everything else being equal it could be something as simple as a coil pack or plug.

Other extreme it could be the ECU pulling the timing because of 'knock' caused by all sorts of variables.

:thumb:
 
ragpicker said:
Need more info dude... Is it standard or modified? What boost do you get to before it starts spluttering? When it does splutter does it keep running or shut down completely? When were coils and plugs last changed? Have you made sure the waste gates are free and moving easily? What exhaust is on it?

If its a standard car and everything else being equal it could be something as simple as a coil pack or plug.

Other extreme it could be the ECU pulling the timing because of 'knock' caused by all sorts of variables.

:thumb:

It's modified , I have a carnewal gt exhaust (basically a reworked standard exhaust) and it's had a remap, also got custom steering wheel with flappy paddles fitted that's all the notable mods.

Re splutter it keeps running but just a shake of the engine and loss of power then obviously i have to ease off and drive steadily continuing on my journey .
Not sure re coil and plugs it had a service about three months ago,
Waste gates what are they and how would I check that ?
 
Yeah forgot about the coil packs, I changed mine and they were in a pretty poor state. Don't know what it's like to visually look at them on a 996 but on a 997 it's about an hours work. You will see straight away if they have started to swell/corrode and then split, the 4 furthest rear ones seemed to be the most susceptible.
Check your service book to see if the plugs have ever been done, it should be ticked if they have been. It's common for customers to leave them when they get a quote for the cost of changing them, around £700!
 
I would get a code reader and check for codes. If that doesn't show anything get it to a well respected indy for a proper check. If somebody who doesn't know what they are doing tries things it could get very exoensive very quickly.

MC
 
Sounds like it's under fuelling for the boost it's making, if experience with my Volvo translates to the Porsch world at all.
 
If the code has come come back and is boost related then it could be maf, actuators or n75. The symptoms you describe sound more like coils and plugs. Could also be a bad batch of fuel, fuel pump, failing injector, blocked fuel filter. Start with getting the codes checked again. Then depending on what codes are there if any be logical with your next steps. Go for a long drive to burn the fuel then fill up with fresh vpower, obviously not from the same garage you used last time.
 
I'd guess an actuator stuck causing over-boost, ECU detecting this and shutting off fuel.

Vaguely related but my Cossie did this many, many years ago. Wastegate actuator was goosed causing a similar problem when the boost wound up.

Hope you get sorted without too much hassle. :thumbs:
 
Thanks for the advice so far , sounds like a few things to check , as a few of you have mentioned Ecu issues potentially, I've disconnected the battery to see if that makes a difference as I guess once I drive it again the Ecu will have to re learn my driving style not sure if it will make a difference but thought it's worth a try .
I did take it to a well respected Indy however I'm trying to get a second opinion from the reputable links on here I've left a message for rpm and nine excellence to see if they can potentially shed any light on the potential issues /cause
 
So just taken it round the block same issues, I had the boost guage on and once it's get to 0.7/0.8 that's when the engine jolt happens , it fine below that just when you want to open it up fully, will get straight on phone to my indy on Monday to find out more , i spoke to him earlier and he said it drove fine on the test drive and was put back on the p wiss recorded no faults
 
You have 2 issues here ..

1/ it didnt start .. why ?

2/ you have a "stutter / holding back " on heavy acceleration / high boost .

On paper they would be seperate issues and may well be as i dont know what the recovery driver did .

But if you want to combine the two then its a fuel pressure issue .. ie the pump is not generateing high enough pressure at load to supply the fuel the engine needs and may well not have been working causing the non start .

Thats my 2 pennys anyways :)
 
I'd check the vario cam bracket the one that sits between the spark plugs on both banks.
 
I'd be inclined to carry out leak tests on the boost pressure points, check the waste gates and actuators, presume N75 valve is fine or has been replaced.

Next suspicion would be the remap and fuel issue highlighted by Demort.

I assume you have a new set of plugs and new coil packs all-round.
If you don't know when/if BOTH were changed, I'd change them to establish a new line in the sand.
 
Could be car going into 'limp' mode? do you lose all boost after the event occurs?
 

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