T4 stutter again

[Slomo]

I bet.

Where abouts are you based?

J

[Midnightt4]

Central Scotland.

Comtemplating taking the 500mile trip down to RT mechanics as most places up here are usless.

[Midnightt4]

well an update.

havent had the datalogger put on yet.

but found that if i take the car up past 4k on half throttle it does it no problem but as soon as i sink the foot it stutters.

So hoses may be the culprit but im buggered if i can see anything

[Midnightt4]

HAd the data logger on the car when it was stuttering and managed to get the engine management light to flash agin but the datalogger didnt record any faults.

Its as if the car is fine all readings lambda and oxygen are fine. Although on the upstream of the lambda it was reading and displaying a percent the downstream value only showed a voltage change and no percentage reading.

When reving the car i noticed that the little ring around the wastgate actuator arm actually moves and spins around the arm but doesnt pop out of the housing. Is this normal.

Here is a pic of the ring im talking about on the arm.

[Midnightt4]

Right Installed a bost gauge today.

Im running 12.5-13psi so no problems with overboost.

I even changed coilpack 4 to number 3 cyl and vice versa but no change.

I think the last step might have to be a remap.

[Filterlab]

When reving the car i noticed that the little ring around the wastgate actuator arm actually moves and spins around the arm but doesnt pop out of the housing. Is this normal?

Yep, the wastegate actuator arm won't move unless there is enough boost to trigger it, and if the vehicle is stationary there won't be enough accumulated boost as the engine is not under enough load.

You know, I've tuned and fiddled with turbocharged cars for 13 years, and I've never come across a problem that refuses to go away like yours mate. As you said, a remap might be the only way.

[Midnightt4]

on another note. The boost gauge still shows 13psi when it hits 4k and is stuttering.

[Midnightt4]

It just gets worse with this car.

The service light now comes on for 5 mins after every start then goes off.

The car also now only boosts at 6-7psi. Is this the sign of a knackered turbo or just a hose?

No smoke or anything through the exhaust.

I have reset the service light since i serviced it at the mot last week.

I thought I would try unplugging the Boost control solenoid to see if there was any difference but the car still boosts at 6psi so could this be the culprit afterall?

[PNuT]

to test the bcs you should by pass it but leave it plugged in....

does the T4 engine managment system have a safe mode?

what was the thinking behind swapping coilpacks 3 & 4 over? do you know which cylinder has the missfire?

[Midnightt4]

Not to sure about a missfire.

It sems to have a thud nd then goes sometimes when applying the throttle.

was really just to see if there was a fault.

Would safe mode not through on the management light.?

[PNuT]

it all seems a bit odd, 13 psi sounds high to me for a standard car? maybe its cutting fuel/spark for that reason....

[Midnightt4]

Std boost on a T4 is 12.8-13psi.

I had it at the volvo garage today to clear ther engine management code. Probably from me disconnecting the BCS last night to see.

Needless to say lass at counter didnt tell mechanic this was the reason for the engine managegment light so he searched for the stutter problem down that route for the fault and came up with nothing.

Its booked back in for tuesday to let him have it for the full day to search ther probelm out.

[Midnightt4]

It seems as tho its a coilpack issue.

Getting car back today hopefully.

[jimka]

just read through to clear up some point

- the boost pressure is fine
- if the coil packs don't solve it - try unplumping the bsc but leave it connected, slowly build the revs up through 1st and 2nd - the standard limit of 7, and 11 psi for these gears will be removed.

what sparkies have you got? and what do they look like... the ecu might be cutting fuel thinking it's pinging (knocking) as the spark isn't strong enough.

let us know how you get on...

[Midnightt4]

hey mate its fixed.

But what the hell do you mean the limit of 7 and 11psi as far as im aware it still boosts at 12-13psi on the gauge pulling in first and second.

Will double check tomorrow.