Activa knock sensor problem.

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Pat
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Activa knock sensor problem.

Post by Pat »

I posted a question about a month ago regarding a dianostic check I had done which came up "knock sensor fault".
.On checking it to see where it was I noticed that the wire that comes out from it joined a connector that then went into the loom.
This wire just after the connector was trapped beneath the engine mounting bracket . I took it off and joined it up as best I could 2 wires inside and a kind of coax type metalloc mesh which I also joined up . I then tried it but it made no difference to the running.
A couple of questions
A. If that was the problem will the ecu automatically rest itself or do i have to disconnect the battery and reset it?
b. The engine warning light, orange on left of dash ,stays on for about 5 secs then turns off, Is this cause the knock sensor is actually broken or could it be another thing
The problem with the car is it has a flat spot at 3000 revs and drinks petrol 17-18 m.pg. around town and 22 on a run.
Thats a lot isnit it? What should i be getting around town?
Could any kindly soul help me ?
Thanks, Pat. North London. activa turbo 97 115,ooo miles
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Panjandrum
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Post by Panjandrum »

Pat,
Can't help with the techy stuff on the ecu and sensor, though I did have a bit of knocking a few months ago that went away by itself before I got around to checking the sensor.
My Activa does low 20's or worse mpg around town, high 20's on longer runs and has been known to get above 30mpg on long A-road, non-motorway, cruise so maybe your consumption is not unusual?
But no sign of a flatspot at 3k revs. In fact, that's well on the lift-off-enjoyed-that curve for me.
PJ
Stempy
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Post by Stempy »

You'd be better off taking it to someone with a diagnostic tester That can check the engine management in real time, that way you can view all the sensors outputs and be reasonably sure they are doing their job. They can also reset the logged fault codes.
The knock sensor is there to compensate for the various grades of fuel that could be put into the car. You should ideally be running 97 for best perfomance, but if you need to fill with 95, the knock sensor will sense this and back off the timing to compensate.There is a noticeable difference on my V6 between the two grades if I have to put 95 in.
You should check your intake tract for air leaks and make sure the air filter is clean.
DoubleChevron
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Post by DoubleChevron »

Hi Guys,
those cars seem to be using quite a bit of fuel. My CX2500GTi Turbo I would have thought would use much more petrol than your modern (2litre) turbos.
I'm getting about 34mpg on a trip, down to 24mpg if the car ambles to work & back where it barely gets upto operating temperature.
I would have thought a Xantia turbo would be getting 40+mpg on the highway and low 30's around town ??
seeya,
Shane L.
xantiav6
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Post by xantiav6 »

On the subject of knock sensors (but not 2l turbos), where is the knock sensor located on the es9j4 V6 engine?
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Panjandrum
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Post by Panjandrum »

Shane,
I'm afraid I've never been close to 40mpg and the only way I can get low 30's around my bit of town is in The Other Car (new model micra) - which averages 33mpg tootling through the traffic at an average 15mph.
PJ
Stempy
Posts: 1626
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Post by Stempy »

<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by xantiav6</i>

On the subject of knock sensors (but not 2l turbos), where is the knock sensor located on the es9j4 V6 engine?
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
It's hidden in between the V somewhere I think.
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