Rewire knock / det sensor

M

matt0702

New Member
Right I have had the 34 code now since a bought the car, I bought a new knock sensor and when i went to fit it i found it at the front of the engine block on the left hand side.
Anyway after replacing it i still have the 34 code - Now the previous owner had rewired the knock sensor and i think this is where the problem is.

There is one wire which i believe is the earth which is a attached to a stud on the rocker cover the other goes back to the 27 pin on the ecu. There is then another purple wire attached which part of the wiring loom which deappears off????

Help me!!!

When i disconnected all the wire and left just the white coming from pin 27 only getting just under 5volts dc

Also with the knock sensor removed across both pins i have 550 ohms

Hope this makes sense to someone
 
antgtir

antgtir

New Member
The OE position is the best place to put the knock sensor, can you not just replace it in the correct position, you may find that in the new position the sensor is picking up noise from other than where it should hence the continual 34 reading from the ECU.

Ant.
 
T

turboloon

New Member
i have a similar problem i replaced my det sensor with a new one (cheers sumo!!)cleared the ecu had a couple of runs in it it was ok then i drove it home from sumos gaff and it was in that 'limp home' mode i.e only running .5 bar boost ...so checked the ecu again and the code 34 appered again(det sensor) any suggetions would be appreciated..
 
M

matt0702

New Member
Making progess kind of -
I have run a wire straight from pin 27 to the left connect of det senosr, then i have run a earth wire from the right pin of the det sensor to the one of the studs on the rocker cover. I have then left the det sensor hanging free not touching anything. With the ecu reset and engine running i am getting 55 finally.

However when i attach to the block i get 34 back - this is with and without the earth wire attached ?????

Not sure where to go next with this
 
E

EssexAaron

Member
is your car overly noisy? i.e Shims?

my car kept going into limp mode because the ecu thought it was picking up DET because of the shim Gap
 
M

matt0702

New Member
Car is not overly noisy - and even with the 34 code it does not seem to be going into limp mode.

I just want the 55 code

I am just usung a bolt to connect it to the block - Does anyone now how the they are attached in the orginal position should i have washers either side or not.
 
M

matt0702

New Member
I thought the 34 code was only to tell you the det sensor or wiring was knacked.

If it was detting it would not show up 34 code providing the sensor and wiring are ok?

Not sure if im right only going by what i read -

If I am only getting the 34 code when it touchs the block wouldn't thatmean it is shorting the circuit somehow.

Once again not really sure if am barking up the right tree- a little bit of knowledge can be dangerous
 
M

matt0702

New Member
I have tried eathing to the chassis but still no joy when touches the block

eerrrrrrrrrrr

I will get there even if i cause 100 other problems
 
Jonesy

Jonesy

Member
Touching it onto the block will be earthing it completing the circuit, i would imagine. So are you sure the sensor you have fitted is defintley working ok.
 
M

matt0702

New Member
Well when the sensor is not attached to the block just left hanging with 1 wire from pin 27 on the ecu and 1 wire to earth all - all works ok - so would i be right in thinking the sensor is ok ?????
 
Y

youngsyp

New Member
You need to check the resistance across the sensor, to get a better idea of its condition. Do a search and you'll find the reading it should give off.
Have you had a volt meter across the wires going to the sensor ? As people are saying, bolting it to the block will earth it so, the 'other' lead may not be an earth wire ?!

As for the 34 code, apparently, it will get thrown up, if it detects frequent knock from the engine.

Paul
 
M

matt0702

New Member
So lets say I dont attached the sensor to the block so that the 34 code goes -

If there is detting will i be able to pick it up using the blazt cable - what should should I be looking for ????

Is there other types of sensor's or safeguards i Sould take ???
 
Y

youngsyp

New Member
matt0702 said:
So lets say I dont attached the sensor to the block so that the 34 code goes -

If there is detting will i be able to pick it up using the blazt cable - what should should I be looking for ????

Is there other types of sensor's or safeguards i Sould take ???
Click to expand...
The Blatz cable and Datascan won't be of any use. On the GTIR's engine, the knock sensor and associated circuitry, is the only safe guard you have for DET, albeit one with very limited usage. Personally, I'd contact Ed (from Fusion Motorsport) as, he does interesting things with the knock map on the stock ecu.

The only other gauges that might be useful, is an EGT gauge. With that, you may be able to see rapid changes in exhaust gas temps that, signify you're running lean. Of course, you will need to be watching it 100% of the time so, it's still not a great solution.

I'd just suggest you keep the fuel and ignition system in top condition, use the right fuel and run sensible boost levels for your stage of ecu mapping. That's really as much as anyone can do.

Paul
 
M

matt0702

New Member
Wow

what a beast, i have still not cracked the problem yet - but i now have the det sensor in the passengers footwell and wired so i get the 55 code.

I then took her out for a spin that lasted a hour half - I can't beleive how much more she had in her. It's like i have a new car now -

I think i will give in and take her to rising sun performance and see if they can sort the problem for me


Thanks guys for your advice
 
CruiseGTi-R

CruiseGTi-R

Member
So with your det sensor on the floor your ecu has no idea whether your engine is detting or not - not the cleverest of ways to clear a 34 code...

Putting the det sensor on the back is grief, get someone else to do it. As a test though, you can use one of the bolts on the front of the block to position the det sensor on. You then then wire the det sensor straight back to the pin on the ecu. No earth needed.

Firstly, test the det sensor for resistance. From memory its something like 357 or 538 Ohms (milli Ohms??) Not sure - its on the forum somewhere. Search for it. Buy a voltmeter, they're about a tenner.

If the det sensor is fine, and it doesn't return a code 34 when placing the sensor on the front of the block then its most likely all ok.

If it returns a 34 with it on the front, and the sensor is fine, you're detting and something is wrong.

FFS, there really should be a sticky about the whole det sensor issue...admin??
 
You must log in or register to reply here.
Top