Hello,

 

 

ABS action on braking (sensors changed - now told it's likely to do with very poor tracking)
Start-up and cut-out issues: Need to rev the accelerator when turning the key to start up and cut's out in low revs. (progressively gotten worse)
Gears often don't change up or respond while in auto mode - works fine in manual mode

 

BACKGROUND:

Car: LK auto octavia estate 2007

Mileage 76000 miles

Owned this car for 7 years and in that time it's been a dream. Love the car to bits and was lucky enough to buy it from an older chap who regularly serviced but hardly used it.

The only issue I started to have that has progressively gotten worse is laboured start-ups and frequent cut-outs at low revs (more so in reverse). I almost always have to rev on the accelerator as I turn the key otherwise it mostly won't start. It makes a judder, clunk, spluttering sound as I turn the key. As I say, this has mostly gotten worse with time  to now do as described above. I have asked mechanics to take a look but they always seem to just shrug their shoulders and because it wasn't as profound as it is now, I just didn't bother.

Anyway, perhaps a year back, I had a blowout on the motorway, I had to drive with the tyre flat and on the rim in places for a mile or more to get off the motorway (smart motorways' don't have a hard shoulder anymore)

Not long after that, I started to get the low tyre pressure light come on. Every few weeks i'd top up the tyres and  and reset that. I'd change the tyres several times but the tyre (s) would always lose pressure within a matter of weeks. Changing the tyre several tyres didn't resolve this. I then started to get the traction control , ABS, handbrake and low tyre pressure lights. Took it to a mechanic who changed the ABS sensors but the lights would come back. I then went to a decent tyre place where they checked and repaired a couple of vales that were leaking air. After that the mentioned lights mostly stayed off but would flash up now and then. Not long after that I started getting the ABS breaking action. At my witts end I took the car to another mechanic who first said it was the sensor. 

Upon some advice in this forum, I asked the mechanic to check the wiring to the sensor. He said the sensor and wiring were fine and changed some other part (wish I knew what it was but it cost my over £150and didn't resolve this issue).

I then serviced the car with the same mechanic and now long after I started having gearing issues. In auto mode the gear would not change up and the speed would not increase as I pushed the pedal harder. Changing manually worked fine but not in auto.

Anyway the last thing the mechanic said was that he now thinks the ABS braking issue is to do with the car badly needing tracking as it veers to one side and the cut-out/start-up issue is the injectors which are expensive!

I don't want to just keep on pumping money out for things that probably just didn't need changing.

I'd really really appreciate some advice.

 

A mate suggested a swp around the wheels to help figure out if the issue is the wheel and also use some injector cleaner to see if it helps with the start-up/cut out problems (I ordered some Liqui Molly). Was also told to check if the gearbox needs oil changing or a filter changed to be the cause of the gearing issue?
I'm also contemplating changing the wheels but they seem hard to find.

Are there any tests a mechanic can do to rule out injector issues?
 

 

Edited 18 July, 20241 yr by Gazawee

Adjusting the tracking, if it is actually out, will not remedy the vehicle pulling to one side, or was he referring to the vehicle veering to one side under braking?

 

In either case I would not give much credence to much that he says, ask around for recommendations of another place for a second opinion.

@Gazawee - Suggested actions:-

1. Tell us which engine and transmission you have.
2. Change your garage.
3. Get fault codes read using VCDS or OBD II.

41 minutes ago, J.R. said:

Adjusting the tracking, if it is actually out, will not remedy the vehicle pulling to one side, or was he referring to the vehicle veering to one side under braking?

 

In either case I would not give much credence to much that he says, ask around for recommendations of another place for a second opinion.

Not holding a straight line.

1 hour ago, Paws4Thot said:

@Gazawee - Suggested actions:-

1. Tell us which engine and transmission you have.
2. Change your garage.
3. Get fault codes read using VCDS or OBD II.

 

It's a 2l auto

For the engine codes, I suppose id need to pay a mechanic to run the software?

Are you able to recommend a good mechanic in the Berkshire, Buckinghamshire, Surrey or West London area?

Probably worth trying to get someone (garage or individual) to try to get some live data from the wheel speed sensors. VAG use these in place of actual tyre pressure monitors to detect a pressure drop by one wheel reporting a higher speed than the others. It could be linked to the ABS kicking in too as if one is under-reporting speed it might think there is a lock-up.

Pulling to one side could be a stuck caliper, but you should be able to feel that as added heat compared to the other wheels.

Road speed issue could be affecting the auto box too, as that is likely to figure in the inputs for when to change, along with engine speed.

If all the sensors have been changed it could be that one is duff, or the sensor ring on the back of the wheel bearing is damaged or defective.

Not sure the starting issue is related to any of that and could just be coincidental. I'd be looking for MAF/MAP faults, or inlet temp sensor.

On 18/07/2024 at 20:51, Me-109 said:

Probably worth trying to get someone (garage or individual) to try to get some live data from the wheel speed sensors. VAG use these in place of actual tyre pressure monitors to detect a pressure drop by one wheel reporting a higher speed than the others. It could be linked to the ABS kicking in too as if one is under-reporting speed it might think there is a lock-up.

Pulling to one side could be a stuck caliper, but you should be able to feel that as added heat compared to the other wheels.

Road speed issue could be affecting the auto box too, as that is likely to figure in the inputs for when to change, along with engine speed.

If all the sensors have been changed it could be that one is duff, or the sensor ring on the back of the wheel bearing is damaged or defective.

Not sure the starting issue is related to any of that and could just be coincidental. I'd be looking for MAF/MAP faults, or inlet temp sensor.

Is this reading of live data that most garages can do or does it require special equipment?

'Most' I suppose depends on the individual places and their equipment/software for diagnostics. A VAG specialist shouldn't have an issue. For others they might use an Autel or similar computer and that would depend on the licences and modules they have paid for as to whether it works on VAG cars and/or of a particular age.

23 hours ago, Me-109 said:

'Most' I suppose depends on the individual places and their equipment/software for diagnostics. A VAG specialist shouldn't have an issue. For others they might use an Autel or similar computer and that would depend on the licences and modules they have paid for as to whether it works on VAG cars and/or of a particular age.

 

Is their a particular test or program I can ask them about?

By the way, is there a sure-fire way of confirming if an injector is defective?

Back after giving up for 1.5 years or so. Took it to another mechanic a tyre fitter recommended.

Go a call to say they checked it on the diagnostic and it needs to have a sensor changed. They went on to say if that doesn't fix it, it will be the wiring. They didn't fill me with much confidence and I'm reluctant to have the change the sensor again given I had it done before to not avail.

Annoyingly the car no longer has an MOT so legally getting to anywhere is going to be an expensive problem itself. Pointless getting it tested with all the dash brake lights coming on!