What are the symptoms of a failed Knock sensor - Page 2

andydunn2 · 06-08-11, 06:17 PM

Quote:

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".....

andydunn2 · 06-08-11, 06:21 PM

Quote:

Originally Posted by msh

First thing to check, I think, should be cold start injector, because it's the least difficult part of all

Disconnect connector, undo both bolts, remove it, point it away, close that hole in manifold with your finger or something else that won't be sucked in manifold

and ask someone to start engine. If injector is squirting fuel, you have found fault.
But actually before that you can try to disconnect air mass meter potentiometer and pressure regulator - one at once. When everything's fine, disconnected potentiometer should only make strange, fluctuating idle but nothing more, while disconnected pressure regulator should decrease performance, probably some starting issues and it also removes redline

Thanks, I checked the cold start previously and it seems fine and I also ran it for a while with the CSV unplugged and it made no difference. Will try the air mass and pressure reg as soon as I get a chance.

Cheers
Andy

missfire · 06-08-11, 06:30 PM

i know you said you replaced the lambda already. sounds more like a mixture 'thing' than a timing 'thing'. is all i meant.

andydunn2 · 06-08-11, 06:40 PM

Quote:

Originally Posted by missfire

i know you said you replaced the lambda already. sounds more like a mixture 'thing' than a timing 'thing'. is all i meant.

Yes completely agree, i certainly "feels" like a mixture/fueling issue. I am hoping the fault codes can tell me something cos I cant keep throwing new parts at this hunk of junk..

Cheers for your help, much appreciated....

mikes2 · 06-08-11, 07:24 PM

Quote:

Originally Posted by msh

hitachi MPI is a bit different opera than bosch KE-jetronic's

Not sure what point you're trying to make here.

he asked for the symptoms of a failed knock sensor which is what I've posted.

The system on the car is irrelevant as the symptoms of said component failing will be the same

andydunn2 · 06-08-11, 07:36 PM

Quote:

Originally Posted by mikes2

Not sure what point you're trying to make here.

he asked for the symptoms of a failed knock sensor which is what I've posted.

The system on the car is irrelevant as the symptoms of said component failing will be the same

Thanks it certainly sounds like a very similair sympton to mine, pulled out to overtake on a duel carriageway and when I got alongside I relaised I didnt have enough power to get past the truck

and by that time I had a t****r in a Range Rover welded to my boot lid waiving his hands like he was parking a plane. The only good thing was that I had the roof down so my hand signals to him were VERY clear....

msh · 07-08-11, 12:43 AM

Quote:

Originally Posted by mikes2

Not sure what point you're trying to make here.

he asked for the symptoms of a failed knock sensor which is what I've posted.

The system on the car is irrelevant as the symptoms of said component failing will be the same

The point is that ECU's of different manufacturers may have different emergency modes

For example, one latvian some time ago said that his AAN with one faulty detonation sender run fine, apart from fault show'd by ECU.

msh · 07-08-11, 12:51 AM

Quote:

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?

andydunn2 · 07-08-11, 11:35 AM

Quote:

Originally Posted by msh

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?

This is a 92 year B4 cab with the NG unit which appears to have the 2+2 diagnositc ports......

Looking in the fuse box I have 3 x 2 pin diagnositc ports a black port marked +/-, a white port marked KL and a brown port which is marked not used. So hopefully I can pull the fault codes an no this isnt the only vehicle is use this for we have a little bit of a fleet at our house these day....

msh · 07-08-11, 06:14 PM

B4 probably. One connector has +12v from separate fuse and ground [I guess that's your black one], another should have two wires in it, if your ECU supports fast data, or one if it don't.
But in any case any fault codes should be taken with caution. For example, my 3A had glitchy lambda, when it worked, I got "too lean mixture", when it didn't, I got "lambda sender".

06-08-11, 06:30 PM	#13
missfire making wooden things Classic Audi Club Member Join Date: Dec 2009 Location: cow land Posts: 8,156	i know you said you replaced the lambda already. sounds more like a mixture 'thing' than a timing 'thing'. is all i meant.

07-08-11, 06:14 PM	#20
msh 4 ring whore! Join Date: Jun 2008 Location: Rucava, Latvija Posts: 3,816	B4 probably. One connector has +12v from separate fuse and ground [I guess that's your black one], another should have two wires in it, if your ECU supports fast data, or one if it don't. But in any case any fault codes should be taken with caution. For example, my 3A had glitchy lambda, when it worked, I got "too lean mixture", when it didn't, I got "lambda sender".