Please help me

[TOMPA3]

hello everyone,

ive recently had a few problems with my audi a3 1.6 bgu engine

VCDS-Lite Version: Release 1.2
Tuesday, 30 January 2018, 18:34:56:0

Chassis Type: 8L - Audi A3/S3
Scan: 01,02,03,08,15,16,17,22,35,37,45,55,56,57,75,76
 
-------------------------------------------------------------------------------
Address 01: Engine       Labels: 06A-906-033-APF.LBL
   Controller: 06A 906 033 DS
   Component: SIMOS71 1.6l 2V     5559
   Coding: 0000071
   Shop #: WSC 06435
   VCID: 73995CCF52AD
3 Faults Found:
16726 -  Camshaft Position Sensor (G40): Signal too Low
            P0342 - 009 -  Open or Short to Ground
17524 -  Oxygen (Lambda) Sensor Heating; B1 S1: Open Circuit
            P1116 - 009 -  Open or Short to Ground
17911 -  Load Signal from Alternator Term. DF: Implausible Signal
            P1503 - 008 -  Implausible Signal
Readiness: N/A

End   --------------------------------------------------------------------------------------------------

so far I have changed spark plugs, ht leads, coilpack and the camshaft position sensor and it has made no difference

the car has a lumpy idle after about 10 miles of driving the car will misfire on cylinder 4 (sparkplug covered in oil) once changed runs for another 10 miles then misfire returns its also worth noting the car will not rev over 5k

 I am positive this is as an electrical issue my question is do I bite the bullet and buy a new wiring loom or search for the short to ground ??

any help much appreciated as I really don't want to get rid of this car

[Magnet]

Hello Thomas,

Sory to hear of your problem, and it would seem you gave been spending some funds on replacing components without finding the route cause. It concerns that you are now considering replacing the wiring harness, which is both an insurmountable operation and an uneconomic proposition on a 14 year old car.

Appreciating you seem to be capable of continuing to try to sort this, bit I think it may now be far cheaper for you to put this in the hands of a trusted local independent. 

Kind regards,

Gareth.

[TOMPA3]

Hi Gareth i don’t actually mind replacing the parts as I was unsure of the vehicles history when I first bought it partial service history ect so for my own piece of mind at least some is done what I should of asked was is the short to ground problem likely to be a broken wire if changing a cps did nothing to relieve the fault I am quite mechanically minded but this little gremlin is puzzling 

ps engine wiring harness was all I was going to change 

[Magnet]

Thanks for the further information Thomas. 

As Steve Q often says- "they are a friendly bunch on here" and I too would like to think we are, but it's sometimes difficult to clarify things without coming over as being critical of what the poster is trying to do. I have a feeling this may be one such case, and I must apologise in advance if any if this isn't in line with your thinking, but here goes Thomas. 

Appreciating changing components such as coil packs, leads, etc can be considered good maintenance, it should be pointed out that the quality of such replacement parts is often very questionable, and runs the risk of introducing faults which were not there before. Depends on where you source your bits from, but experience shows its better not to fix it if it's not sure it's broken - unless you are replacing with genuine VAG components which of course you might have done, and that would be fine and only likely to affect your wallet.  

Your question - "Short to ground problem likely to be a broken wire...?" This and changing harnesses concerns, since it must be clear in the mind that a "short" is where a current feed wire's insulation etc. is damaged, and the wire then touches the earth-return bodywork - at which point the fuse in that curcuit should blow. Any wire which is broken would be an open curcuit not a short curcuit. If you have any intermittent issues in a curcuit where the fuse hasn't blown, it means you have an irregular supply or poor earth, and things like connector plugs etc come to mind -or of course the consistency of the supply is fine but the component is faulty. 

So back to your issues:- as I see it you have to establish why No.4 plug is oiling up - is it oil or unburnt/partially burnt fuel? . If it were mine, I would now be doing a basic compression test on this engine to establish if it's mechanically sound before chasing electronic problems. If it is good in that respect (and your replaced coil packs and leads are proved to be good) then it's possible - just possible- that the injector may be an issue.

All of this is ifs, buts and maybes, and this is why I suggested you get this checked out at a good independent who can check things like O2sensors etc. etc. (even MOT emissions test would help). OK Thomas I well appreciate you want to sort this out yourself , but it could be a costly route, and as I said may even introduce issues you didn't have before! Buying expertise via. specialist equipment can provide you with useful knowledge and experience - don't dismiss it. 

"Won't rev over 5000rpm" . Can we take it this is at standstill rather than during driving? 

Hope all of this is taken in the spirit it is intended.

Good luck in getting it sorted,

Kind regards, 

Gareth.

 

 

[TOMPA3]

Thankyou for the reply Gareth I do understand it is a costly way to go about things compression test came back fine the Rev issue continues whilst moving just to clarify I do appreciate the help and I understand it would be easier to take it to a garage and get them to fix it Which is probably the route I am heading all parts have been replaced with vag parts no cost cutting it has been a long couple of months I have never really trusted a garage to deliver a fix after I was stung as a new driver 😓 hence the reason I learned how to fix myself I will ring a couple of garages to see what they say and hopefully I’ll have a fixed car at the end of it 

thanks again

tom

[gokiwi64]

Just to throw my 2 pennies worth in (and add to the confusion maybe)

I had both camshaft sensor and lambda sensor issue's as well as the lumpy idle, changing the camshaft sensors (2 in my case) did not fix the problem, however changing the lambda sensor cured all 3 issues  - I understand that a lambda sensor isnt cheap (please do not get a pattern part go for a known brand) but it might just be worth it.

I think I'm right in saying that the 8L and the 8P arn't true canbus but use a derivative called serial canbus so that if one thing fails those behind it will also show as failed.

Check your earths very carefully as by now there maybe some corrosion around the earthing points this corrosion will increase not only resistance but heat and this can cause random issues.

If you keep losing a plug to oiling the coil pack could be faulty , what sort of coil packs do you have ?

 

 

 

[cliffcoggin]

I can add little to Gareth's comments, except to say that a faulty wiring loom is the most unlikely cause of the problem imaginable. I would look at every other thing involved in the injection and ignition systems before changing the loom.

[Magnet]

I'm very much with Scott on this, but would suggest a double check (probably done though) of swopping No4 plug with one from another trouble free cylinder - appreciating you have used VAG coil plugs and leads which should not be at fault.

The next test I would do is to find a friendly MOT station who would be prepared to carryout an emissions test and give you a diffinitive lambda reading. If that proves the O2 sensor is within range then perhaps you could look at getting tests done on No 4 injector incase it is getting over fuelled.

Kind regards,

Gareth.

[TOMPA3]

Thankyou for the advice guys I will check the lambda readings at mot station then see where I go from there :)

[Envy]

I saved a mate a fortune when he was told his ECU was shot on his Volvo V40

Electrical connections will deteriorate over time - this was the case on the Swede's ECU.

Unplug , clean the contacts, dress them and pug back in and hey presto - hundreds of the Queens faces saved. 

Please give credit to the poster above regarding the Lambda Sensor - CANBUS Serial means what it says - the sensors are connected in series - if one pops - they all suffer. Not sure the Lambda readings will tell you much - maybe a continuity test on the sensor will tell you - !Removed! to get at but a multimeter is a valuable diagnostic aid. Also Lambda Sensors will go as are sat in exhaust stream for their lifetime.