Misfire and other faults

[andyg plym]

Same rude individual upsetting people again i see

Check the injector connector and wiring harness in that area Andy, very common problem and I'm yet to see an original harness that doesn't need some attention!

Cheers Alex, I again checked voltage at the injector plug and even did it whilst running and had 13.5. Volts. Admittedly the wiring was hard and must be getting brittle by now. Thinking about the bigger picture perhaps the 5 second misfire I've had on cold start up could of been a sticky valve - potentially on number 4.

[LHD_Kid]

Check the injector connector and wiring harness in that area Andy, very common problem and I'm yet to see an original harness that doesn't need some attention!

I agree with Alex - stinks of a breakdown at the crispy #4 plug wiring

[andyg plym]

I agree with Alex - stinks of a breakdown at the crispy #4 plug wiring

Thanks Chris even though I'm getting consistant voltage there ?

[Mikes2]

You may need to consider checking the resistance of the wire back to the ecu. If it's brittle it may be breaking down. The +12v is common to all the injectors

http://s2-audi.co.uk/workshop/schematics/motronic_aby/page5.png

[andyg plym]

You may need to consider checking the resistance of the wire back to the ecu. If it's brittle it may be breaking down. The +12v is common to all the injectors

http://s2-audi.co.uk/workshop/schema..._aby/page5.png

Many thanks Mike that's really helpful, il do that and report back. Think I've made my mind up to do a compression test anyway as I can borrow a kit from work. So much quicker with these tfsi coilpacks !

It would be nice to find its a simple wiring fault though

[Error404]

You may need to consider checking the resistance of the wire back to the ecu. If it's brittle it may be breaking down. The +12v is common to all the injectors

http://s2-audi.co.uk/workshop/schema..._aby/page5.png

[UrS4boy]

Injector wiring fixes and output tests

Same rude individual upsetting people again i see

You poor poor sensitive guys. You must have gone to the Nico Rosberg school of whining.

What I was suggesting with my post to Andyg_plym that he had not been thorough enough with the diagnosis to jump to anything mechanical solutions (burnt valve, head gasket, etc.) just yet.

Swapping the injectors and finding that the miss didn't move does potentially eliminate the injector from the list of suspects *BUT* it does not eliminate a) the spark plug or b) the injector wiring.

I would suggest that he have a look at my injector wiring post (link below) and also do the output test:

Output test:

3B: http://www.sjmautotechnik.com/troubl...f20v.html#out3

AAN/ABY: http://www.sjmautotechnik.com/troubl...20v.html#outs4

Injector wiring info: http://forums.quattroworld.com/s4s6/msgs/90802.phtml

The issue could be as simple as a badly burnt injector connector plug:


Photo courtesy of Andy P.

Solution:


Photo courtesy of Andy P.

I trust no one takes offense to this post.

If they do... Well, they can get stuffed.

[newsh]

Misfire and other faults

Some more injector plugs here Andy, if the linky thing works in Tapatalk


My 3B to RS2 project

https://r.tapatalk.com/shareLink?url=http%3A%2F%2Fwww%2Es2forum%2Ecom%2Fforum%2Fshowthread%2Ephp%3Ft%3D4476&share_tid=4476&share_fid=7870&share_type=t

[andyg plym]

Oh my feking word! FFS!

Found the fault.... Turns out number 4 Bosch spark plug had given up - unexpected as only about 1k old. I checked it right at the start and it appeared to be in good condition so cleaned the end and refitted, well tonight I thought as its a quick win I'd swap to number 3 just like the injector. Fired it it up and pulled number 4 injector plug to find the tone changed, yep you guessed it pulled number 3 off and no change.
Swapped the suspect plug for an old Bosch unit from the toolbox and straight away fixed it. Running sweet as a nut.

Just goes to show how the simple things can be easily over looked you think it's fine as its fairly new....think again.

As ever, many thanks for all the input and links guys

[newsh]

Good work!

Another thumbs down for Bosche plugs then!

[Tridac]

It's partly the age of the vehicles. The connectors may have been fine when new, but get damp into them through the wire entry and as the seal hardens with age. Silicon spray is your friend and I go round all the snap on connectros every couple of years or so. Only takes a few minutes and provides a film that stops the damp getting into the contacts...

Chris