1.2, P0106 error and a couple of other bits (n00b)

[Stain]

hi guys and girls, not my usual stomping ground as im a fiat man but ive recently managed to get involved with these quirky lil motors.

my wifes, work colleagues, son owns a 53-plate 1.2 he was complaining of it cutting out randomly and having difficulty keeping an idle when cold (it would cut out). he has very recently had it serviced and had a 'cat-back' mild steel exhaust system fitted. after the exhaust fitment he told me that it came out with the MIL light on... the garaged cleared it and 3 days later it came back on. its been in and out of numerous garages, incl. Seat, each one saying 'replace this, replace that' or generally not wanting to get involved without more in depth diagnosics costing muchos beer tokens

ive got Proscan on my laptop and had a quick look today and found a stored "P0106 Manifold Absolute Pressure/Barometric Pressure Circuit Range/Performance Problem" error. i cleared it and went out in it with him to see if we could get it it re-appear. as i suspected, it didn't . whilst we were out he mentioned that since he'd had it 'serviced':-
1) it makes a 'rattling sound' which at the time i put down to maybe a loose heat sheild (the engine on tickover does sound a little rattly almost like a diesel than a petrol)
2) it didn't feel as pokey as it usually did as if it was slugish like the handbrake had been left on slightly
3) it seemed to him that it was drinking more fuel than usual.
i thought it may have been a fuel related problem so when we got back to his house i hooked up proscan again and attempted to read some fuel trim data. turns out for whatever reason i couldn't get it to give me any live sensor values so that turned up blank maybe its a TB issue... took the airbox off and peered down yep the throttle body has been cleaned very recently, maybe i can get it to go through a re-learn procedure... wrong.... as far as i know you can only do a TBA with VAG-COM... so tonight ive downloaded RossTechs VCDS-Lite in preparation for further diagnostics. (i have an ebay special blue K-line VAG COM USB lead that i use for Airbag ECUs on fiats)

i found this lil gem of info in another thread:-

16490/P0106/000262 - Manifold / Barometric Pressure Sensor (G71) / (F96): Implausible Signal

Possible Symptoms
Erratic Idle

Possible Causes
Wiring and/or Connections from/to Manifold/Barometric Pressure Sensor (G71)/(F96) faulty
Leak in Air Intake and/or Exhaust
Manifold/Barometric Pressure Sensor (G71)/(F96) faulty
Engine Control Module faulty

Possible Solutions
Check Engine Control Module Software Version (See Special Notes for Details)
Check Timing (See Special Notes for Details)
Check Wiring and/or Connections from/to Manifold/Barometric Pressure Sensor (G71)/(F96)
Check for Leak in Air Intake and/or Exhaust
Check/Replace Manifold/Barometric Pressure Sensor (G71)/(F96)
Check/Replace Engine Controle Module

Special Notes
On certain smaller Engines we've seen cases where a buggy Engine Control Unit Firmware can cause these fault codes, additionally there are known Problems with the Timing Chain Tensioners which can also result in these fault codes. Please refer to the related TPL/TSB for more instructions.

SOOOO now i'm suspecting timing tensioner due to rattly tickover, unstable tickover, increased fuel consumption and slugish performance.

am i barking up the right or wrong tree with this?
what is this 'related TPL/TSB'?
does anyone have any 2pence to give?

 

[Nath.]

The 1.2 engine has a timing chain and the tensioners wear and make the chain loose. The chain can then jump a tooth or two and make the cam timing go out. If it jumps too much the valves will be damaged.

If this is the case fit new tensioners ( I think there are 2) and time up the chain, the chain should be good for the life of the engine.

 

[Stain]

good times.. cheers Nath. does this fourum have a 'guides section' maybe im just being stupid but i couldnt find it!!

 

[Stain]

Timing Chain = Done

after test running it there was a slight oil leak from the crank seal on the side casing, fitted a new one today.

its been running absolutely fine for a week but today when i started her up to re-check for oil leaks with the airbox OFF she ran VERY lumpy, as the temp rose she smoothed out a little. i put the airbox back on and left her ticking over for a little while, took her for a test run again and the MIL came on and tickover was around 1800/1900 RPM

i literally just took the airbox off, belt off, crank pulley off and replaced the seal and refitted pulley belt and airbox,

WTF happened???
(I'm gonna pull a DTC off it tomorrow)

 

[Stain]

school boy error vac pipe off... sussed it by putting my hand over the TB with engine running and tracing all the vac pipes from the manifold all done and should be good for life now!

for those of you who dont know about this or haven't had any issues with your 1.2, the forward most guide runner has been modified so that is longer. it prevents or, at the very least, minimises the risk of the timing chain jumping teeth again.
after looking at how the setup is from the factory i suspect that if the oil pressure drops too much the oil pressure fed tensioner can't do it's job. the tension drops off the front run of the chain and momentarily snags on the 'short' guide. off loading the chain from the exhaust cam sprocket, the cam jumps 'x' amount of teeth (seems to be pot luck whether its 1,2,3,4 or more teeth, but probably dependant on engine speed at the time of incident) when oil pressure returns the slack is taken back up with the exhaust cam in the wrong position. the modified guide prevents the snagging when oil pressure is lost and sits close enough to the exhaust sprocket to prevent the chain from jumping off the sprocket.

I have got an AWY,AZQ,BMD & BME Engine Workshop Manual in PDF format that i found kicking around on the internet (its actually for the Skoda Fabia, but they all use the same engines) if anyone is interested drop me a PM/Email and ill share