P0121 and a bang

[deathrider311271]

replaced ETM with a BBA remain one, replaced all coil packs, spark plugs, accelerator pedal and MAF, all gen parts used and new.

Symptoms are:

erratic idle 500-1200rpm, stuttering on pick up, previously boosted to 9psi without boost cut now will only boost to 4psi and get boost cut, very loud dump of the boost when it cuts and finally intermittent misfire. Only code stored is still P0121.

All vac pipes replaced and all boost pipes checked and seem to be ok

Anyone got any ideas?

[Jamest5r]

Al point's back to the ETM, is the replacement ok?

[deathrider311271]

Al point's back to the ETM, is the replacement ok?

it tests all ok and this one is contactless so in theory there is nothing to go wrong now. When it banged it was a massive backfire from a faulty MAF gen bosch, thats why so many parts have been replaced. Dot get me wrong it runs a lot better than yesterday but its still not right and thats the only code im getting

[Dave86]

I had similar issues with my me7 c70 turned out 3 coil packs were knackered and in turn it blocked the cat. it always started fine and run until warm then would just cut out and wouldn't restart until it had cooled. only code that ever came up was for 'random or intermittent misfire'

[deathrider311271]

I had similar issues with my me7 c70 turned out 3 coil packs were knackered and in turn it blocked the cat. it always started fine and run until warm then would just cut out and wouldn't restart until it had cooled. only code that ever came up was for 'random or intermittent misfire'

all coil packs replaced today and mine is fitted with a race cat, i dont get any cutting out either thanks anyway

[JamesT5]

Have a look at your Intercooler, I've experienced a turbo pipe blowing off an intercooler on a Skoda VRS before now and it was because the Intercooler cracked and it caused a massive backfire as you described.

Let me know what you find.

Regards

James

[PHIL V70R]

what about the bcs....

[deathrider311271]

what about the bcs....

could that cause bad running?? sat here thinking about it logically and the path a backfire would take, is it possible it could have damaged the turbo?

[PHIL V70R]

mine went but was po 243...bad runing and a low type of backfire sounds as if its from the turbo...b4 u bye one i have a spare u could try mate..

[JamesT5]

My money is on the Intercooler.

[deathrider311271]

update time again

had intercooler off and it appears to be fine now at this point im not saying its good but does look fairly new, had all intercooler pipework off no splits or holes, all vac pipes off no splits or holes. Also changed both lambdas and bcs.
im thinking i have 2 issues here, 1 being a boost problem, 2 some sort of ignition/ecu problem

thoughts please guys

[JamesT5]

Ok, maybe something inside the intercooler or the turbo has said bye bye.....

[Dangerous Dave]

I'm guessing you've checked the turbo in some way (taken the intake pipe off and felt the blades, taken a photo to inspect further)?

[deathrider311271]

Ok, maybe something inside the intercooler or the turbo has said bye bye.....

poked finger into turbo and all seems fine there also no broken splines or movement, im not convinced its not the intercooler

[Dangerous Dave]

Have you pressure tested the intake system? I did a quick test by undoing the top of the maf to turbo pipe, sealing it around my face and blowing into it, very crude way of doing it and doesn't taste very nice, but could highlight a problem. Make sure the throttle flap is wedged open so you can test the manifold too. Alternatively you could hook up an airline to it somehow or have it smoke tested at a garage.

Have you cleared the code and did it come straight back up?

Thinking about it a bit more, mine had a problem which had the same symptoms, misfire, rough idle. Turned out the spark was shorting to somewhere in the distributor cap. Obviously yours is the coil packs so no dizzy, but it could be something to do with the ignition. How about the wiring to the coilpacks? There was something on here not long ago about the wiring chafing in the block?

[JamesT5]

Have you pressure tested the intake system? I did a quick test by undoing the top of the maf to turbo pipe, sealing it around my face and blowing into it, very crude way of doing it and doesn't taste very nice, but could highlight a problem. Make sure the throttle flap is wedged open so you can test the manifold too. Alternatively you could hook up an airline to it somehow or have it smoke tested at a garage.

Have you cleared the code and did it come straight back up?

Thinking about it a bit more, mine had a problem which had the same symptoms, misfire, rough idle. Turned out the spark was shorting to somewhere in the distributor cap. Obviously yours is the coil packs so no dizzy, but it could be something to do with the ignition. How about the wiring to the coilpacks? There was something on here not long ago about the wiring chafing in the block?

Oh yes, coil pack wiring, one of my least favourite subjects given I ended up accidentally slicing through the insulation to cylinder 4 coil pack wiring when I was messing about with it the first time a few months ago.

[deathrider311271]

another update:

still got this problem, replaced the ETM with a BBA Remain one, the only code i get is for accelerator pedal, so replaced this with a new one today, yes its slightly better so was probably on the way out. However im still getting the same code telling there is still a faulty signal to the ETM this is on a generic code reader, Vida Dice tells me faulty accelerator pedal even tho new as is the ETM, still hesitant and little to no booste and constantly drops down to 3/4 cylinders but never goes into limp mode.

So where the hell do i go from here???

[Harvey]

Have you looked at the ecu loom/plug water in loom or plug or green corroded pins ,is there a loom plug onto the engine or is it straight to ecu?,is the engine earthing strap ok battery cables tight what is the battery voltage with engine running.
Your problems do sound like a bad joint/earth as you have changed so much so far and not getting to the bottom of the problem.

[deathrider311271]

Have you looked at the ecu loom/plug water in loom or plug or green corroded pins ,is there a loom plug onto the engine or is it straight to ecu?,is the engine earthing strap ok battery cables tight what is the battery voltage with engine running.
Your problems do sound like a bad joint/earth as you have changed so much so far and not getting to the bottom of the problem.

had the ecu out a few weeks ago and all looked fine, what do u mean by loom plug onto the engine? As far as im aware the only plugs to the engine are the ones for the sensors and ignition side of things.All battery conections are tight and getting over 14v when engine running.
All the replaced new parts have been tested on my mates S60 and they all work fine on his car with no codes. So as you say i think its an electrical problem which im crap at lol

[Harvey]

Just thinking outside the box does you car have traction control,could it be cutting in ?.
Can it be turned off on the dash.