Sensors/devices that affect performance.....

[elwesso]

Surprising, I searched for an hour and I didnt see it..... Im sure you remember where you posted it..... Could you link me up???

[nuQ]

wes, where did you go to get the diagnostic ECU code done,,the dealer? or an independent.

my Q has the symptoms that heath was going through, looks like the KS. thanks, jeff

[elwesso]

I did it myself...... You take out the ECU, do this little thing with a screw, and the computer blinks the codes......

Search around the full procedure is there, but here is a crash-course......

The passenger side kick panel is where the ECU is located (its right next to the speaker on the car, not the door).... There is a nut holding it in place near the firewall, so undo that..... The panel comes right off...... next, there is are two screws holding it on, one on top and on the bottom, on the connector end of the ECU..... undo those, and it should come out..... I had to undo the connector... Just loosen the bolt (it doesnt come out), and pull out the connector, being careful to pull it out straight..... From there, you just pull out the ECU, and plug it back in...... The plastic screw is on the front, and turn it clockwise, wait at least 2 seconds, then counterclockwise.......

Then the red LED on the ECU should come on, end then you simply count the flashes..... There is about a 1/2 second in between codes, so have a pen and paper ready.....

The long flashes are the first digit, and the short ones are the second digit....

Knock sensors are code 34, so it would look like __ __ __ _ _ _ _

Then there is a slight pause, and then it goes to the next code.....

You can also check your o2 sensors from the ECU...... I can post that if you'd like......

[elwesso]

Ok..... I have a question......

Basically, I got VETOED by the higher authorites to purchase all the parts to do the plenum and knock sensors...... So, how vital are the knock sensors??? Am I hurting anything by driving with them bad......??

[sanman]

Wes,Try cleaning your engine grounding points and receck for codes.

Sanman

[elwesso]

Ill try that......... But i am still getting that "bucking" that heath has described....... I just figured it was normal, since some other cars had it.......

[elwesso]

If its hurting the car driving with bad knock sensors, its no biggie, I have access to another car.......

[nuQ]

where are the engine grounding points????

[sanman]

I have a 95Q and the 2 grounding points that effect the knock sensors are about 6inches behind the radiator cap and 3 inches twards the passinger side. This is in front of the plenum and a little hidden under the plastic.

I had a code for knock sensors, removed and cleaned these and it went away.

Sanman

[elwesso]

Ill tell you the weirdest thing.....

I went downstairs, and just for kicks I thought Id check the codes again...... Guess what!!! CODE 55!!! Nothing wrong!!!

Are you kidding??? Really!!!

So I guess no need for KS......

[Q45tech]

The knock sensors are grounded via their mounting bolt to the engine block. The harness cable has a shielded mesh wire grounded at ecu but floating at the knock sensor.

[DAEDALUS]

Ill tell you the weirdest thing.....

I went downstairs, and just for kicks I thought Id check the codes again...... Guess what!!! CODE 55!!! Nothing wrong!!!

Are you kidding??? Really!!!

So I guess no need for KS......

It's intermittent. They're probably still bad (or borderline), and eventually they'll likely trigger again. When you checked the code, you probably cleared it. The ECU stores the code for the most recent 50 starts, so any drives in the last n weeks could have seen the code go off. Check it again in a few weeks. I don't think a bad KS needs to throw a code to begin retarding the timing.

[elwesso]

Alright, I'll still check it..........

[Q45tech]

True as the KS CHANGES frequency response from heating and cooling cycles [miles of driving] it may become more or less sensitive to the frequency of the knock.....as engines wear the noise level increases .............why the knock sensor [microphone] is only opened every 90 degrees [for around 10 degrees] when knock could occur..........^.............^..............^.............etc.

Just because the KS passes the resistance test doesn't mean it's as new...............the ecu is not smart enough to tell many noises from knocks if they occur when a knock could occur.

[elwesso]

If there is no kncoking occuring, then I am safe to drive the car......

I am going to just put this little shindig on hold until i get a few more$$$.......

[Q451990]

Not a bad plan, you want to have the cash on hand to do the job right! The ECU will protect the engine by retarding the timing advance at the expense of power and smoothness, so the protection is maxed out as much as it can do even if the sensors were detecting knock. Just make sure you keep running good (premium) fuel and you should be fine long term.

Heath

[elwesso]

Hopefully Ill do it christmas break....... Ill have every tool known to man (minus 3 maybe, and a lift), a heated garage, and an arsenal of 4 torque wrenches to choose from :drooling:

See, I have the cash on hand, but I dont want to drop the 500 and then have something catastrophic happen.... it would kill me to have a beautiful Q in the drive undriveable!!!

Im getting my leather done, and maybe some tintage.....

[crubio]

Hey Heath, What did you pay for the new harness?

Thanks

crubio