need help fast guys, please help

[broncobuckinaround]

i need to know the computer voiltage to the knock sensor wires. im getting 2.5 volts. is that good or bad.

 

[PetesPonies]

KS doesn't work that way. Most input sensors work with a reference voltage of 5V. Then "how much" of the 5 volts is returned after the sensor is how the computer reads them. However, similar to a O2 sensor, a knock sensor develops their own electricity. However, it is extremely small in the KS because it is only generated by oscillations. I cannot see anything even remotely close to 2.5V being generated. Its in the millivolts I believe and only when a sound triggers the oscillations.

 

[broncobuckinaround]

thx pete. but im not talking about coming from the sensor it self. im saying the wires coming from the pcm.

im only concered about this because i got a code 25. which is knock not sensed in. so im tring to figure this out.

if you know how to solve this, that would be awesome. lol truck is lagging power and it is pinging

 

[PetesPonies]

There is no voltage coming from, the sensor generates the voltage. It goes to the ECM only. There should be nothing there otherwise . . . I think Just like an O2 sensor. The pin that carries the voltage from the sensor has nothing until the O2 sensor generates it. There is no reference voltage.

 

[broncobuckinaround]

lol not to argue but tring to get the whole picture. even if it has two wires with my knock does. shouldnt it have a ref voltage of some sort. if not ill drop it.

but how do you diag this 25 code

 

[PetesPonies]

MOst info you read will tell you to ignore the KS code is there is no pinging Problem with that is it happens before you can hear it. BUt . . . what is your issue? not just the code. And which test brings this up??

 

[broncobuckinaround]

im not going to lie its a crappy test. just me and my multimeter. i tested for voltage and the connector to the computer by probing both wires and got the 2.5 volts. then tested the knock by probing the those two wires. once by hitting the block and sec by running the engine. it didnt do much when it was running but when i struck it, it moved.

my issue is pinging under a load and lack of power. ive done a lot to this b2. and now im going after the codes. all maintanace has been addressed.

 

[PetesPonies]

well pinging, or lack there of, is effected greatly on these engines by a properly functioning EGR valve system. I would check that closely..

 

[broncobuckinaround]

i have, its good. i cleaned it very well. at first the valve wouldnt open. it was stuck shut. so i soaked it in diesel fuel over night. it didnt ruin the diaphram. it help vacuum pressure. also i cleaned the port, it was completely block.

i do have a question about the green plastic hose. that would be vacuum, why does it go through a lil black part attached to the fender wall. and then a red plastic hose to the intake. is that some sort of pump.

other than that the egr is clean and in working condition

 

[PetesPonies]

That is why I carefully selected the phrase "egr valve system". It's more than just the valve. The vacuum to the valve is directed by a relay. That relay is controlled by the computer. Then there is a erg position sensor mounted right on the valve. Thats tells the computer when and if it is open. No vacuum will come if the rlay is bad . . and they do go bad. So just having a egr valve that moves and HOLDs vacuum is not enough.

 

[broncobuckinaround]

which relay is it, i can go check to see it if working. and i know i hear a strange noise when i shut the truck off. a small humming noise. and when i listen it sounds like its coming there and i can feel it vibrating.

 

[PetesPonies]

its the one that the vacuum line come from.

 

[broncobuckinaround]

lol i didnt know that was a relay. i thought that was a pump. lol i knew that i was just seein if you knew. lol ill go check to see i can blow air through it. and ill connect power to hear a click to see if i can air throught it. ill write back when i have some answers

 

[PetesPonies]

You can't test it that way. It has two vacuum lines. One has vacuum from the engine. The other goes to the EGR. When the computer turns on the relay, vacuum can travel through. You can't blow through it.

 

[broncobuckinaround]

i am able to get air back and forth through that replay. is that a problem.