2006 GTO LS2 6.0 in a classic car

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08-16-2019
Holdensbizz

2006 GTO LS2 6.0 in a classic car

I built a wiring harness for a guy to put an LS2 6.0 E40 and T42 tcm in a classic Pontiac. for whatever reason he cant get the injectors to fire from the computer? He has 10 volts at the pink wire of the injector, I have already talked to him about making sure the injectors are all pined right and in the right spot, they are. Still will not start. They can jump the injectors with a power probe and the injectors will open and spray fuel. He has 58 psi on the rail. It will run if he sprays starting fluid in the throttle body. Sent me back the computer I tested the injector circuit with a node light, the computer is sending the signal. He hooked a TACH up to that wire and he is getting a signal, which tells me the crank sensor is working. Is there anything anybody can think of that would not let the injectors fire?
Thank you for any input.
08-16-2019
5FDP

Is VATS turned off?
08-16-2019
Holdensbizz

Ya vats are off in the OS and the codes. Would the TCM have separate vats? I flashed them both together the first time, but when he sent me just the computer back I flashed it again just to make sure.
08-16-2019
5FDP

Nah, the TCM doesn't have VATS.

Just the PCM has to be done with a write entire for the two VATS patches to make it stop.
08-16-2019
Holdensbizz

Ya i didn't think so. All the vats are gone just a matter if the injectors not firing. Like I say they can run it with starting fluid.
08-18-2019
Lakegoat

I think the computer sends a ground signal to fire the injectors. May be a ground wire is left off somewhere.
08-21-2019
Holdensbizz

1 Attachment(s)

After looking at the car, the injectors fade out as it cranks, down to nothing, have spark. I have a noide light one the #1 injector and it fades out as it cranks.
Are there any other vats then in the operating system, and the dtcs?
Please help anyone with ideas?

Edited the post and going to try and post the file.

Attachment 92556
08-23-2019
IARLLC

It would be interesting to see if it is the voltage fading during cranking or the ground. It could point you at the reason for the fading.
08-24-2019
Lakegoat

Does he still use the Maf ?
Does he have a GTO gas pedal ?
08-26-2019
Holdensbizz

Quote:

Originally Posted by IARLLC

It would be interesting to see if it is the voltage fading during cranking or the ground. It could point you at the reason for the fading.

I have checked that. The voltage remains 12-11 through cranking, so its defiantly on the ground side of the circuit.
08-26-2019
Holdensbizz

Quote:

Originally Posted by Lakegoat

Does he still use the Maf ?
Does he have a GTO gas pedal ?

He is using the MAF, I believe it is the one from the gto, I'm not sure on the pedal. I tried to start it with and without the pedal and the maf, hoping in would fall back onto the map tables.
Also the throttle body is not working, so that leads me to thing its not the right pedal. The car this engine came out of had an interior fire.
Thank you, for your help.

Also could doing a "write entire" cause the ecm to brick?
08-31-2019
Holdensbizz

is there anyway to make the engine run completly off the maf tables?
09-02-2019
89 Caprice 6.0L

Sounds like it might be wired wrong. The feed for the injectors needs to be powered ,run position and start position,sounds like its wired through a acc wire out of the switch,the power would go away in the start position but come back in the run position.
09-02-2019
Holdensbizz

Quote:

Originally Posted by 89 Caprice 6.0L

Sounds like it might be wired wrong. The feed for the injectors needs to be powered ,run position and start position,sounds like its wired through a acc wire out of the switch,the power would go away in the start position but come back in the run position.

Thanks for your input. Its not in the wiring, I wish it was . I have checked and rechecked the wiring, everything pins out and ohms out correctly to an all data E40 ecm pinout.
Is got to be something is not happy on the MAP sensor side of things. I get different 5-volt ref. readings at the MAP and the low ref, has ground through to the block. The MAP is not reading on the scanner as well. IF it dosen't see the MAP signal it wont start. That's why I was hoping to run off the MAF tables only
09-03-2019
blindsquirrel

2 Attachment(s)

Is it the correct Service Number ECM for a 2006 (12596679)? Do you know for sure it came from the donor car or was it just supplied by the scrapyard and claimed as such (they could have grabbed one from a pile)?

Alldata usually gets things pretty close but they're not 100% on everything.
09-03-2019
Holdensbizz

Quote:

Originally Posted by blindsquirrel

Is it the correct Service Number ECM for a 2006 (12596679)? Do you know for sure it came from the donor car or was it just supplied by the scrapyard and claimed as such (they could have grabbed one from a pile)?

Alldata usually gets things pretty close but they're not 100% on everything.

Thank you, for the input.
It is the correct service number. I do believe that the ECM and TCM came out of the same GTO, however the GTO had suffered a cabin fire. So the pedal is from a different car, and come to find out its not the same part number as the vin. With or without the pedal hooked up the engine should fire. It wont, I rechecked the harness to the pinout you gave me its the same as the alldata and also the wiring harness is correct to the pinout you attached.
Could the cabin fire brick the ECM some how?
09-03-2019
blindsquirrel

There are some throttle fault situations that will cause the ECM to disable the injectors, though the manual doesn't describe exactly under what conditions that happens.
09-03-2019
Holdensbizz

Would/could that also causes a strange grounding of the 5-volt ref. to the MAP? I have noticed it the diagrams that the 5-volt for the MAP and the APP share the same 5-volt.
09-03-2019
blindsquirrel

They do not share a 5v ref, look closer. MAP 5v is C2 #35, APP1 5v is C1 #35.
09-03-2019
Holdensbizz

yep your right. that makes since. Ive looked at diagrams so much my eyes are crossed. Plus I don't know if it silver/gold throttle bodys are also wired different, or a glitch I found in alldata. guess you have to eat crow when the diagrams your going off of are wrong.

now it starts after switching the throttle motor wires but it wont rev, yet... rechecking diagrams yet again...
09-03-2019
blindsquirrel

Yes. Getting the throttle working should be first priority. A no-start condition won't make the throttle not work, but a throttle condition can cause a no-start. There are lots of threads like this, too. So it's not just you.
09-03-2019
Holdensbizz

Quote:

Originally Posted by blindsquirrel

Yes. Getting the throttle working should be first priority. A no-start condition won't make the throttle not work, but a throttle condition can cause a no-start. There are lots of threads like this, too. So it's not just you.

Thank you for the help and the diagrams to go off of. I'm still battling the throttle body not opening, in relation to the APP. Getting a PO641 Code as well. As far as the two 5-volt ref. on the APP should they both be 5-volt? Ive heard and read that one is at 5-volt as the APP is pushed one 5-volt goes to around 1.5volts the other 5-volt starts low and does the opposite, is this true? I have 5-volts at the APP #2 and 1.5 volts on the APP #6.

Again thank you for your help and insight to this problem.
09-03-2019
blindsquirrel

Don't confuse the 5v ref lines with the sensor return lines - this is set up as two completely independent 3-wire sensors that just happen to be mounted in the same plastic box. Two independent 5-volt reference, two independent low references (grounds, provided inside the PCM itself), and two independent sensor outputs. The 5v refs should always be around 5 volts no matter what, the two low refs always ground, and the two sensor returns vary with pedal position. And the two sensors both increase as the pedal goes from idle to WOT, but they are NOT supposed to output identical voltages. Different platforms/PCMs/ECMs work different, some do sweep opposite directions, but this one does not.

With the APP unplugged and key-on, you should have ~5v at #2 and #6, ground at #1 & #7, and something similar to ground at #3 & #5 (there is a pull-down resistor on those lines inside the ECM, they will be low with the APP connector not plugged in to the pedal).

Quote:

DTC P0641
Circuit Description

The engine control module (ECM) provides 5 volts to the following sensors:
• The manifold absolute pressure (MAP) sensor
• The engine oil pressure (EOP) sensor
• The fuel tank pressure (FTP) sensor
• The air conditioning (A/C) refrigerant pressure sensor
• The accelerator pedal position (APP) sensor 2
• The camshaft position (CMP) sensor (2006 Corvette and Cadillac CTSv 6.0 only)

These 5-volt reference circuits are independent of each other outside the ECM, but are bussed together inside the ECM. Therefore a circuit condition on one sensor 5-volt reference circuit may affect the other sensor 5-volt reference circuits. The ECM monitors the voltage on the 5-volt reference circuit. If the ECM detects that the voltage is out of tolerance, DTC P0641 sets.

Hmmm... note that this particular 5v supply leg feeds APP2, but not APP1, which appears to be working. Something in that list is pulling the 5v line down and affecting your APP2 - and MAP sensor. Unplug those sensors one at a time and see which one it is.
09-04-2019
Holdensbizz

blindsquirrl, I cant thank you enough. Thank you so much for your help. I'm not exactly sure what I've done but it all works now. Its interesting how the APP system works, with the 5 volt and low refs. The problem was on the OPS sensor, I'm not sure why but i repined it a couple of times, ending up pinning it back to what it was, the throttle works and revs great.
Thank you again for your help.
Holden
09-04-2019
blindsquirrel

1 Attachment(s)

Just for future reference (reference? get it?), this list comes from the DTC descriptions for P0641 & P0651.

Quote:

5-Volt Reference 1 Circuit
? The manifold absolute pressure (MAP) sensor
? The engine oil pressure (EOP) sensor
? The fuel tank pressure (FTP) sensor
? The air conditioning (A/C) refrigerant pressure sensor
? The accelerator pedal position (APP) sensor 2
? The camshaft position (CMP) sensor (2006 Corvette and Cadillac CTSv 6.0 only)

5-Volt Reference 2 Circuit
? The accelerator pedal position (APP) sensor 1
? The throttle position (TP) sensor 1 and 2
? The cooling fan speed sensor (If equipped)
? The crankshaft position (CKP) sensor (If equipped)

Some other years/platforms call out which 5vref circuit is used for which sensors in the ECM pinout, and rarely if never in the individual diagrams.

And if it makes you feel any better, there are mistaeks in teh GM diagrams too. This particular one isn't fatal, just a little confusing because of the leftover label that shouldn't be there.

Attachment 92891
09-19-2019
Holdensbizz

blindsquirrel, After I got everything working properly, I sent the harness and computer to the guy working on the car and he cant get the throttle to work. So... Can I just build him a different harness and use a 0411 pcm and switch it over to drive by cable, and put the gen 3 knock sensors in the spot where the gen 4 knock sensors, are and have him take it to a tuner in Vegas and have it all tuned?
I guess my question is will an 0411 run the LS2 with the drive by cable throttle body?
09-20-2019
blindsquirrel

Gen3 specifics are outside my wheelhouse, but, as long as this is a 24x/1x LS2, any Gen3 computer will run it just fine once the Gen3 components are bolted on.