24x knock sensor voltage (UPDATE!!)
24x knock sensor voltage (UPDATE!!) According to Shoeboxs site, the wire going to the knock sensor should have 5 volts. Is this the same for the 24x swap?
Last edited by ascastil; Jan 25, 2014 at 12:59 PM.
I tested the voltage at the connector and it doesnt have any. I then tested for voltage at the pcm and its the same, although im not sure Im making a good connection. Im gonna try tomorrow when Im not so tired. I was starting to get nervous shoving a paper clip down into the pin next to the wire. With the key on engine off, shouldnt it show voltage?
Teching In
Joined: May 2009
Posts: 20
Likes: 0
From: Anchorage AK
LT1 24x I am trying to trouble shoot my 24x kit on my LT1 using a PSI built stand alone harness and a #411 PCM from an 02 Tahoe. I am beyond frustrated trying to get spark! Without an ocyilloscope, I don't know if I'm getting the right wave form, but, I do know I'm getting a 2V AC signal from the crank and 4V from the cam sensors. All other sensors are producing signals I can see live on my HP tuner, on an EFI live and on a snap on scanner with the exception of those two sensors. I've swapped pcm's for known good one and I get the same outcome. Signal into the PCM and nothing out to the coils. The pump runs continuously and I had all of the injectors dumping fuel. I pulled the pump relay and cleared the cyls. EFI connections has helped somewhat, but they have no answers.
Can you run a crank to start pid and tell me what you see from the crank and cam sensors? Your knock sensor isn't a 5v its a GND. I'll look at my charts to be sure though. Any help you might give would be appreciated! I have triple digit hours in this and the shop I sent it to has close to the same. It's rediculous!
Can you run a crank to start pid and tell me what you see from the crank and cam sensors? Your knock sensor isn't a 5v its a GND. I'll look at my charts to be sure though. Any help you might give would be appreciated! I have triple digit hours in this and the shop I sent it to has close to the same. It's rediculous!
So it shouldnt have 5v? Im getting a p0332. Took it in to have some work done and got it back with this code. I ohmed the sensor but it was CLOSE to being within spec so i ruled that out, i believe within thousandths.
I dont have any tools to scan the car with to help you btw. Im sorry. I think thats what youre asking.
I dont have any tools to scan the car with to help you btw. Im sorry. I think thats what youre asking.
Last edited by ascastil; Oct 1, 2013 at 05:07 PM.
I replaced the knock sensor with an Autozone one. The code went away for about 4-5 days then came back on Sunday. Even took it to emissions test on Friday and it passed. Ill give it another shot with my question, am I supposed to be having 5v going to the sensor? I traced the wire all the way back to the pcm and didnt see any damage to the wire, but there was no voltage going to the sensor iirc.
TECH Veteran
Joined: Dec 2008
Posts: 4,146
Likes: 62
From: Little Rock, AR
I would imagine it has to have some voltage on the wire from the PCM, but the info on my site is for the LT1 PCM. I am guessing that the PCM you are using requires 2 knock sensors, since the code you are getting is for the bank 2 sensor. Do you have 2 sensors installed and are you sure you are checking the correct wire(s) back to the PCM?
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Verdad Gallardo TECH Veteran
Joined: Dec 2008
Posts: 4,146
Likes: 62
From: Little Rock, AR
So, does your PCM use one knock sensor or two? Like I said, your code is for the bank two knock sensor (that means there is also a bank one sensor).
Well, 3 months later and its fixed. It was right in front of me and I just didnt put 2 and 2 together. I called EFI about the code Thursday morning. They asked if it was bank 1 or 2. I told them 2 so he said easy fix. Disable it in the tune, there is no bank 2 knock sensor. DUHHHHH! Took it to the tuner and all is well. Its been a good week for the old LT1. Fixed a loud rocker arm last weekend. Even took the for sale ad off Craigslist.
TECH Regular
Joined: Jan 2005
Posts: 456
Likes: 0
I am trying to trouble shoot my 24x kit on my LT1 using a PSI built stand alone harness and a #411 PCM from an 02 Tahoe. I am beyond frustrated trying to get spark! Without an ocyilloscope, I don't know if I'm getting the right wave form, but, I do know I'm getting a 2V AC signal from the crank and 4V from the cam sensors. All other sensors are producing signals I can see live on my HP tuner, on an EFI live and on a snap on scanner with the exception of those two sensors. I've swapped pcm's for known good one and I get the same outcome. Signal into the PCM and nothing out to the coils. The pump runs continuously and I had all of the injectors dumping fuel. I pulled the pump relay and cleared the cyls. EFI connections has helped somewhat, but they have no answers.
Can you run a crank to start pid and tell me what you see from the crank and cam sensors? Your knock sensor isn't a 5v its a GND. I'll look at my charts to be sure though. Any help you might give would be appreciated! I have triple digit hours in this and the shop I sent it to has close to the same. It's rediculous!
Can you run a crank to start pid and tell me what you see from the crank and cam sensors? Your knock sensor isn't a 5v its a GND. I'll look at my charts to be sure though. Any help you might give would be appreciated! I have triple digit hours in this and the shop I sent it to has close to the same. It's rediculous!
We sell at $20.00 test harness as EFI# 100-00642 that will not require cutting into your crank sensor wiring.
These two items will quickly and easily identify a crank signal problem and cost much less than a couple hours of shop time.
TECH Veteran
Joined: Dec 2008
Posts: 4,146
Likes: 62
From: Little Rock, AR
Well, 3 months later and its fixed. It was right in front of me and I just didnt put 2 and 2 together. I called EFI about the code Thursday morning. They asked if it was bank 1 or 2. I told them 2 so he said easy fix. Disable it in the tune, there is no bank 2 knock sensor. DUHHHHH! Took it to the tuner and all is well. Its been a good week for the old LT1. Fixed a loud rocker arm last weekend. Even took the for sale ad off Craigslist.
Glad you got it figured out and another satisfied 24x user. Seems EFI is getting alot of flack from alot of users that dont know all the ins and out and flame them when really its just user error "most" of the time.
My setup has been working a-1 since day one its just been the motor giving me issues but i got them all worked out so far.
My setup has been working a-1 since day one its just been the motor giving me issues but i got them all worked out so far.
Thanks, I shoulda just stepped back and looked at the whole OBVIOUS picture lol.
