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Finally swaped ecm's


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Posted

I finally got an ecm for my 95 GP SE 3.1. All the gumbled codes are gone now, only two remained the first time i started it, IC 24x Signal and Knock sensor. I cleared the codes and the IC 24x Signal went away.

 

Now what i notice with the knock sensor code, when i clear the car and start it runs fine for about 5 seconds, then while im watching laptop the knock spikes to 14.94 and stays pinned there then it starts to kinda run rough, nothing terrible just a complete lack of power.

 

Could this be as simple as changing my knock sensor out? I could have sworn the previous owner swapped it out, ill shoot him a text and see whats up.

 

Some insight could be useful here, let me know whatcha thing guys :)

Posted

15* of knock retard is automatically applied when DTC43 (knock sensor) is set, so that's normal.

 

when this happened to me, it was due to the knock sensor connector itself being broken. wiggled it around, cleared the code, went away for a long time, came back, did it again...

 

eventually just got a new connector. could be the sensor itself though.

Posted

Interesting, ill have to give that a try, I got an update from PO, he said he swapped it out, but not a new one a used one, so in all likely hood thats probably whats wrong here.

Posted

..... new knock sensors are like $10..... why anyone would grab a used one, i'll never know. they tend to be "one time use" in that after they are removed, they don't like to work the way they should anymore.

Posted

Yeah thats what i figured... This guy was sort of lazy with the car, but other than knock he replaced every sensor under the hood, but it was just the ecm bad, and the knock sensor.. New IAC, new TPS, intake air temp, etc etc.. are all new

Posted

did you grab the knock filter out of the original PCM? did the new one come with one in it?

 

those little bastards are ~$100 new.

Posted

Im not sure where that is? Do you mean the memcal out of the original pcm?

 

I have a memcal with the original, my buddy sent me an extra one with the new pcm and the new one had it in there already.

 

right now its rocking the new pcm untouched, as it was in a car in the junkyard.

 

So the pcm was half the problem, because pcm swap removed around like 30-40 codes lol

Posted

it's under a little access cover, two torx screws IIRC.

 

with the older units, it was a MEMCAL since it contained the actual calibration(along with a knock filter and a couple of other functions), but with these PCMs, it's only used as a knock filter. there are actually ~5 or so versions that i can think of that will plug in and work.

 

3100

3400

3.4 RWD

LT1

LT4

 

the OBD2 versions may use a different filter than the OBD1 versions though, not something i've looked into.

Posted

Oh okay i know what your talking about, yeah it has a new one, and i have two extras, one original to my car kinda ( my pcm that was in the car when i got it was a delphi replacement, must have been replaced once already idk )

Posted

just making sure. a bad or missing knock filter will cause DTC43.

Posted

I took a log of it idling in my driveway, ill make a video of it to show you. Hang on.

Posted

as opposed to making a video, you could actually post the XDL file that is created, then anyone with the correct ADX file will be able to play it back.

 

interesting TPS% guage BTW, i've never thought of doing a guage like that near a corner before.

 

but yeah, there's something messed in the circuit, i can post the flowchart for DTC43 if you'd like.

Posted

That would be awesome, i can post up my ADX, well only thing different is my night dash, so it should work with the adx that i got from you in the first place, i can post up those XDL's too if you want.

Posted

I followed your charts, voltage at the wire is fine with 5.02v which is between the 4-6, As for reading ohms for the knock sensor, i was unable to read anything at all from either sensor, the one on the motor or the one that came on the car originally. So should i assume the sensor is bad?

Posted

starting to sound like it....

 

should read ~3900 ohms with the leads connected to the little pin on one side and the threaded portion on the other.

Posted

I cant get a single reading from the think, absolutely nothing, and i did it the way you just said.

 

Lol my pontiacs will be the death of me.

Posted (edited)

Okay so i just went out and bought a new knock sensor ($37 with tax) and a new connector since the parts stores around here dont sell the gm style connector ($9) and i am still having this issue. Exactly the same way, Runs fine for 10 seconds, and then throws the code for DTC43 Knock Sensor. I am so lost, I just want to drive my car! :(

 

Here's my log after the new knock sensor and connector:

 

https://www.dropbox.com/s/ij40vqk3fgcmxy3/newknocksensor.xdl

 

I have fixed some bad grounds i found, Fixed all the vac leaks i could find, and this is still happening.

 

From what i am reading in my haynes manual, there might be a bank 1 & 2 knock sensor, wires DRK Blue and LT Blue... I dont think there are two, can you confirm?

Edited by Silentkillzr
Posted

1 sensor.

 

did you test it before you put it in?

 

if not, you should still be able to test it now.

Posted (edited)

Which multimeter setting should i use to clarify?

 

This is the multimeter i have:

post-6792-143689113512_thumb.jpg

Edited by Silentkillzr
Posted

the 20K resistance setting, since the sensor SHOULD spec out to 3900 ohms. a 96-up sensor would read ~100K.

Posted (edited)

I get nothing out of any of the 3 knock sensors i now have lol. Went back to the store they have one coming for me tomorrow, The replacement i have is a BWD replacement, if the one they give me in replacement to this is bad too then i think i may just order the GM one. I was trying to avoid it because of $50 cost.

 

 

 

Here's the part i have new:

http://www.oreillyauto.com/site/c/detail/BWD0/S8003/02200.oap?year=1995&make=Pontiac&model=Grand%2BPrix&vi=1255957&ck=Search_knock+detonation+sensor_02200_1255957_3860&keyword=knock+detonation+sensor&pt=02200&ppt=C0033

Edited by Silentkillzr

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