What are the symptoms of a failed Knock sensor

[andydunn2]

As above can anyone advise what the symptoms are for a failed knock sensor?

I am trying to get this pig of a Cab sorted and it was mentioned that it could be the knock sensor.

Ta
Andy

[msh]

Engine?
Problems?

[andydunn2]

Originally Posted by msh

Engine?
Problems?

Yes would help wouldnt it.....

2.3 10V (NG)

Its a running saga but.......

• 1. Down on power
  2. drinks fuel
  3. missfire that gets worse when very hot (in town driving etc) at which point car misses backfires stinks of fuel and throws its toys out the pram.
     
     So far its had new dizzy, Lambda sensor & both temp sendors.....

[msh]

Sounds more like usual problems with KE-jetronic

Dead knock sensor would mean detonation, especially when driving around town using throttle enough and backfire when turning off engine, maybe some "dead spots" at low rev range, but negligible impact on fuel economy and very small on performance.

Long time ago I had 3A with dead knock sensor, I came to conclusion that that KE-Motronic can't provide proper ignition without it. While driving without it, I had adjusted a bit later ignition, so it didn't detonated while driven on road [as was most of my usual route], but when I got new knock sensor and readjusted ignition, max speed increase was 30 kmph

[msh]

Are you changing that stuff or someone else for you? I have a couple of recommendations what you could check, but it requires some tools and pair of straight [not curve ] hands

[andydunn2]

Originally Posted by msh

Are you changing that stuff or someone else for you? I have a couple of recommendations what you could check, but it requires some tools and pair of straight [not curve ] hands

I am doing the work myself.........hmmm maybe thats the problem...

[missfire]

Originally Posted by andydunn2

[*]Down on power[*]drinks fuel[*]missfire that gets worse when very hot (in town driving etc) at which point car misses backfires stinks of fuel and throws its toys out the pram.

mine did that. fault codes said lambda and knock sensor. replaced them. now it doesn't do that.. dunno if its the same cause though. you never know... well, at least i never know...

[andydunn2]

Originally Posted by missfire

mine did that. fault codes said lambda and knock sensor. replaced them. now it doesn't do that.. dunno if its the same cause though. you never know... well, at least i never know...

Lambda's been changed and it didnt make a difference, should be able to pull the fault codes next week when my replacement 2x2 cables arrive.....yes i put the old ones in a "safe" place and now I cant find the "safe Place".....

[msh]

Originally Posted by andydunn2

Lambda's been changed and it didnt make a difference, should be able to pull the fault codes next week when my replacement 2x2 cables arrive.....yes i put the old ones in a "safe" place and now I cant find the "safe Place".....

Sorry, but I just started to laugh... If you are going to use that cable just for this one car, you can send your cable to me [as a present, I might have use for such item ] just as you will receive it, because it won't work with your ECU The only audi engines from 80's, which have ECU's with "fast data" option are the ones with 20 valves - 7A, 3B, and I think, NM and RR. Others are simply missing that wire in that 2 pin connector, because ECU doesn't have such ability. If you want to read fault codes, you have to use LED or small 12v bulb, some wires and that's about it Actually I don't know why very often check engine light circuit is missing in dashboards wiring harness, because that light removes need for any other stuff to read codes, apart from fuse, and I had to retrofit that wire to my A80's dash wiring harness.

Are you able to read the current at which ECU is driving pressure regulator?

[mikes2]

I had a knock sensor fail on my 90 20v.

It would misfire at about 4k and feel like it was holding back the power. Once you got to 4500rpm, it would take off again.

it made overtaking quite entertaining