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Please help! LS2 swap first start-- let the Gremlins begin
Background:
Just got everything squared away and finally started my ls2/ 64 Cutlass swap... We have some issues.
Engine too to bottom, pcm, tcm, trans are all from the same donor vehicle -- 2006 TBSS.
Pedal was snagged second hand from supposedly a 2006 tbss
The issue:
Zero movement in the throttle body from the pedal.
What I've come to this far:
The throttle body moves a tad bit when I go from key off to key on
I tested continuity of the wires from the pedal to throttle body and there doesn't seem to be a short or break anywhere
With key on or run, the yellow wire at the throttle body ( TAC motor control 1) is not getting power per a test light
C2-60 and C2-63 are both pinned correctly in the E40 pcm
I got the following codes
p0122- Throttle/Pedal Position Sensor/Switch A Circuit Low Input
p0123- Throttle/Pedal Position Sensor/Switch A Circuit High Input
B2AAA- Body
p0223- Throttle/Pedal Position Sensor/Switch B Circuit High Input
p2127- Throttle/Pedal Position Sensor/Switch E Circuit low Input
help.me!!!!!!!!!
Last edited by Fst_Byrd; Sep 18, 2019 at 08:14 AM.
Hmm,Your voltage readings look funny, let's see what we can figure out.
There are 2 parts here, the motor wring, and the throttle position sensor.
The throttle position sensor is a part of opposing potentiometers. So, variable resistors, with one end hooked to ground (Low reference), and one end hooked to 5 volts (5 volt reference). The two signals out will be opposites, and will be between 0 and 5 volts, but never quite all way to one end or the other. SO all of these voltage readings look incorrect. But, also, you won't get any usable reading on the two signal wires, if the harness isn't plugged into the TB.
The other two wires are your two motor leads. This thread details it pretty well
Are you in a position that you can read if there are any fault codes? I don't know the particulars on the TB control, but its not uncommon to disable voltage outputs if a fault is detected.
LOL, at it happens, If you live in Oxford as it says, I live there too. I have some leftover parts from building a 2007 TBSS motor. I have the throttle body on the bench, if you needed to try a spare.
Hmm,Your voltage readings look funny, let's see what we can figure out.
There are 2 parts here, the motor wring, and the throttle position sensor.
The throttle position sensor is a part of opposing potentiometers. So, variable resistors, with one end hooked to ground (Low reference), and one end hooked to 5 volts (5 volt reference). The two signals out will be opposites, and will be between 0 and 5 volts, but never quite all way to one end or the other. SO all of these voltage readings look incorrect. But, also, you won't get any usable reading on the two signal wires, if the harness isn't plugged into the TB.
The other two wires are your two motor leads. This thread details it pretty well
Are you in a position that you can read if there are any fault codes? I don't know the particulars on the TB control, but its not uncommon to disable voltage outputs if a fault is detected.
LOL, at it happens, If you live in Oxford as it says, I live there too. I have some leftover parts from building a 2007 TBSS motor. I have the throttle body on the bench, if you needed to try a spare.
Grew up in Oxford, but I'm in Clarkston now. Still just a good and skip away! If it gets to that point, I might use your TB just to rule that out (thank you)
Yes I have a handful of codes ( see #5 in original post). I also pulled some throttle readings from my freeze frame data when codes we're set.
Relative Throttle Position
FREEZE
FRAME 86.67 %
WWW Absolute Throttle Position B
FREEZE
FRAME 100 %
Accelerator Pedal Position D
FREEZE
FRAME 19.61 %
Accelerator Pedal Position E
FREEZE
FRAME 98.43%
Since the codes seem to be APP related, I did some testing on that today. Again, I don't fully understand if these are good results or not but here's what I've done...
1. Tested PCM grounds doing a voltage drop test
Both grounds tested 1.7v
2. Resistance tested Accelerator Pedal Position (APP)
Sensors 1&2
Sensor 1 was 3.48ohm at rest and was a smooth sweep to .608ohm at WOT
Sensor 2 was .926ohm at rest and smooth to 3.62ohm at WOT
3. Checked the 5 Volt Reference signals
Both sensors were at 5.04v
4. Checked and confirmed that sensors are getting ground
Sensor 2 reads good at 11.56v
Sensor 1....I could not get it to read steady. It would start around 50V then climb up to 145V. I tried retesting this one several times since there's no way 145V are running through anything on this car, but I got the same results each time 🤯
Trying to rule out this being an ECM ground issue...
I tested from the ground wire at the block to the ground pin in C2 and then also did from ground on block to the ECM case and get .2ohms for both.
This shows that the ECM ground is good, correct? Earth ground is 0.0, just making sure that's what I'm looking for here.
ALSO, using Torque App Pro I can watch Absolute Throttle position B, and accelerator pedal positions D, E &F, Throttle position and APP. These are all in percentages, so not sure how these translate to voltage readings.
D and E increase as the pedal does.
Absolute B, TPS, and throttle stay the same.
APP and F never give a reading.
The first image is pedal at rest, second is pedal WOT
At rest WOT
Last edited by Fst_Byrd; Sep 21, 2019 at 08:03 AM.
How old is your harness to the Throttle Body? How old is your TB? What shape is the connector to the TB. It might look OK but it might not unless it is new. Once these connectors get worn your done. You are probably (codes) in the reduced power mode which the TB hardly moves at all. Get a new pigtail there is a reason they sell so many of them. Now if you wiring is new then another story.
Last edited by Double06; Sep 26, 2019 at 06:27 PM.
Reason: adding stuff
Hey all, I haven't had time to work on the car at all lately, but I spoke to my pcm tuner and they checked their file and its all correct.
They've sent me a loooong list of additional tests to perform on the app and tps which I'll try to get to this week and I'll update the thread with my findings.
Hate to bring up an older thread, but I'm having a similar issue and I couldn't see what the outcome was....
I have a LS2 swapped into a gen 2 camaro. I sort of inheritted the swap part way so there are some challenges. When I started it was always going into limp mode if you held wide open any length of time. That turned out to be someone had the wrong throttle body. They had the gold one that is less expensive and good for about everything else. Swapped back to the correct silver one and problem solved. Fixed other issues and drove it another 6 months and all seemed to be good so the car went to paint.
A year later, car comes out of paint and all is well drive it home and probably have 20 miles on it checking everything out and all of sudden back to limp mode, rough idle, throwing P0123 & P0223 codes. Reset the codes and it comes back.
So where do I start.... is this likely on the TB side or the Pedal side?
Check all connections for intermittent shorts or circuit interruptions.
ok. I did swap the TBD and still barely idles. I’m going to start chasing wires from the pedal as I recall something there a couple of years ago when we started this. Is there a particular color wire on the pedal that should be ground and/or +12v?
Yeah, that's sort of what I was asking here ; ) Swapped back the throttle body since that didn't make a difference. unplugged and re plugged cables connected between the pedal > computer > and TB just to look for anything weird or a bad wire. Put it all back and cleared the codes and it works again. Strange... seems like there might be a short or something between the cables. I'll have to look at finding replacements just to avoid the problems maybe. Any good sources for them? thx
Probably junkyard for just those bits of harness you're talking about. But if reliability/works like it should is what you're after, I'd probably source the connectors new and make my own partial-harness. I bought an entire harness from PSI Conversions. My experience with those folks was fantastic. You might give them a call and see if they'll sell you the bits that go to the pedal and the throttle body. Good luck.
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Please help! LS2 swap first start-- let the Gremlins begin 
