I own a WRX Sti II with modified by PE. Sometime (about a month) after the PE phase1 upgrade and after a track day the car developed some detonation. The people from Power Engineering have repeatetly looked over the problem and their final decision is that the detonation sensor is peeking false detonation.

The people from PE assume that there is some other kind of noise coming from the engine, which confuses the detonation sensor.
This is because a number of different detonation sensors were tried (with the same result) and the sensors peek detonation even when the engine is cold while the engine seem to run perfectly OK.

Ofcourse as the det sensor peeks (false) detonation the ECU retards the timing and drops the boost having a significant effect to the performance of the car.

As I am a bit lost here I would really like to find out if there is anybody else who has experienced the same problems (det sensor peeking false detonation) and what can be the cause of it.

Regards,


Alex.

Did they check the car properly with det-cans? Mind you, they may not find any det on their rolling road anyway, they didn't on my car. http://bbs.scoobynet.co.uk/frown.gif

Moray

You definitely need the car looked at under normal driving conditions with det cans on, just to make sure it is a faulty sensor !!!

What is a det can ?


The people from power engineering told me that they checked if there was any oil coming out from the engine at a point which indicates if the engine is worn that usually suggest detonation. They also told me that there was no indication of the engine being worn at all.

Regards,


Alex.

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:<HR>Originally posted by Ian Cook:
<B>You definitely need the car looked at under normal driving conditions with det cans on, just to make sure it is a faulty sensor !!![/quote]

They are like headphones that are put onto the engine, so an engineer can listen for det while the car is being driven by somebody else, all tuning companies should know about and use them ?????

Don't assume that you will be able to hear any/all detonation when driving your car on the road, especially under high load conditions. Unless you are using det-cans or some other reliable detonation monitoring equipment there is no way you could hear slight detting over a scooby engine at full chat. By the time you could actually hear det at high load, the engine would be suffereng badly.

Moray

Hello Ian,

Is the result conclusive after this procedure (using a det can).

The people from PE told me that they tried that and they could hear the noise but they don't think that the engine has actually a problem. Mr David Power was under the impression that it could be a problem with the ECU where Mervyn (a PE employee) thought that another part inside the engine may generate a noise of a similar frequency that the detonation sensor peek.

Under normal driving conditions (on the road) I can not hear any detonation even when I push the car very hard. The car is still powerful but its response is quite different since the original PE ECU program has changed.

So my questions are:

1) Is the det can a 100% proof method to say if a car is really detting ?

2) Since the people at PE believe that the car is not really detting I may need to get a second opinion. Can you suggest a good garage where I can check if my car is really detting ???

Best Regards,


Alex.

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:<HR>Originally posted by Ian Cook:
<B>They are like headphones that are put onto the engine, so an engineer can listen for det while the car is being driven by somebody else, all tuning companies should know about and use them ?????[/quote]

Before I had my phase one conversion removed (long story), I ran it on the rolling road at Powerstation in Cheltenham a couple of times... this rolling road revealed weaknesses in the David Powers's mapping which caused detting to occur. I had to get the conversion remapped 3 times in total, because the car detted on the rollers at PS.

I don't really want to get into an argument over who's rolling road is better, but I will say that I am convinced that Powerstation's road is the safer option as David Power couldn't make my car det on his road.

When a car is mapped correctly, assuming correct fuel and healthy engine, it should not det, however much load you put on it.
My car detted with the phase one and doesn't with a standard ecu.

Moray

Moray/ It is not the rollers all rollers are the same they just go round and round. It is the west country air, it is much cooler and cleaner. http://bbs.scoobynet.co.uk/wink.gif
Alex/
This must be a worrying problem for you.
Give Bob Rawle a ring on Home: 01666824917
Mobile: 0385748713 or e-mail him at
E-mail:fs66@dial.pipex.com
Bob Live at Malmesbury but is very good at this type of thing.
He fitted a knocklink to mine. This give a warning and peace of mind.
Regards
Bob Iles

Bob,

The words "Beg", "I", "Differ" and "To" spring to mind... http://bbs.scoobynet.co.uk/rolleyes.gif http://bbs.scoobynet.co.uk/smile.gif

Funny, I am suprised that DP didn't try the fresher cooler air excuse with me...

Moray

If you are concerned, you can fit (or have it fitted for you) a knock sensor, See our website at

Mike/
As Alex STD sensor is picking up knock. Another sensors fitted and also picked up knock do you think a knocklink will also pick up knock?
Alex/
If I were in your shoes I would get someone to put the det cans on the car and give you a second opinion.
If you are anywhere near Scoobymania have a word with Mike I’m certain he would put you right.
After all we don’t want to see another PE Phase 1 go bang, do we lads.
Regards
A concerned Phase 1 owner.
Moray/
Will I get more BHP in the cooler air of Cheltenham? http://bbs.scoobynet.co.uk/wink.gif



[This message has been edited by bob (edited 20-04-2000).]

These things are pretty clever, if the std knock sensor is saying knock, it is likely that is what you have got!
The fact that other sensors have been tried with the same results, only adds more weight to the indication that you are getting detonation.

The knock Link is a more accurate than a std sensor, but a quick run with Det cans can clear any confusion easily.

Mike.

How easy is the knock link to fit? Will it work on any car or is it a Subaru only item?

Not difficult to fit, depends how mechanically minded you are?
Not vehicle relevant, will fit any car and detect the same thing.

1) Locate suitable point to mount the sensor.
2) Run the cable to the sensor & clip it on.
3) Pick up power (ignition live) in the cab.
4) Find suitable location to mount the box.

Mike. http://bbs.scoobynet.co.uk/smile.gif

Has anybody ever heard about a case where the engine does not have a problem but something from the electronics cause the detonation (while settings for fuel mapping, turbo pressure and ignition timing are set within the right limits).

Mr Power said that it is most likely a problem with the electronics (and probably the ECU) that may cause the detonation.

From my side I heard so many different opinions like:

The det sensor may peek false detonation
There may be a problem with the electrics of the car (eg ECU)

Before my last visit to PE every time I was accelerating hard with 4th - 5th gear I could hear the detonation but now I can not hear any detonation. The car ofcourse is not as powerful as it used to be but at least there are no obvious signs of detonation.

Do you still think that it is worth buying a a detonation monitor ? Is there anything that could fit nicely on my Subaru (not simply something that looks like a square box).


Regards,


Alex.

So Mr Power thinks it may be a problem with the electronics in the ecu... hmmm... and who was the last person to open the box up and make modifications to the normally extremely reliable ecu unit... oh... that would be Mr Power then! http://bbs.scoobynet.co.uk/eek.gif

Now, now Mr Mackenzie http://bbs.scoobynet.co.uk/wink.gif

The knock link sounds like the right thing for me but I have two concerns. Firstly, how do you calibrate it, i.e. set the sensitivity so that you are not sensing other engine noise, but also are not missing out on detonation when it occurs. I don't have access to det cans or data logging equipment to calibrate it.

Secondly, it looks very ugly. It's not really a concern for a useful tool, but couldn't they have designed it better. Has anyone taken out the LED part and put it into a smaller, neater box. How big is the box anyway. Anyone have a pic. of it mounted into the cabin?

Thanks.