Fresh ls swap no start
07-21-2024, 12:40 PM
#43
TECH Fanatic
Is that the blue connector hole 75 that you are showing in the picture? That hole in the red connector I think is unused. If that is an empty Blue 75 hole, you can replace that wire with wires that you have already pulled when you de-pinned this harness or go to the junk yard and get another one.
Rick
Rick
Last edited by B52bombardier1; 07-21-2024 at 12:46 PM.
07-21-2024, 12:51 PM
#44
Is that the blue connector hole 75 that you are showing in the picture? That hole in the red connector I think is unused. If that is an empty Blue 75 hole, you can replace that wire with wires that you have already pulled when you de-pinned this harness or go to the junk yard and get another one.
Rick
Rick
07-21-2024, 01:40 PM
#45
TECH Fanatic
Blue 75 should be a pink wire routed to a 12 volt "ignition key on" power source and these pink PCM wires actually for PCM "boot up" and provide primary power to operate the PCM. Pink wires are ALWAYS an ignition key on 12 volt power source for GM vehicles. An orange wire is an ALWAYS on 12 volt power source in GM vehicles and in this case for the PCM, it is for "memory keep alive" power when the engine is off / not running. The memory is for retaining the learned parameters for making engine starting and idling easier and some say for learning your particular transmission shifting habits.
What power supply are you using to power up your bench programming harness? During PCM write operations, it's gonna take at least two amps at or above at least a steady and clean 12.1 volts DC to complete the write and commit it to memory. A cheap wall wart power supply often fails at this critical point and can brick your PCM.
But there is a relatively easy method for recovering a P01 or P59 PCM by grounding a certain pin on the printed circuit board during boot up of the PCM. There is an excellent You Tube video that demonstrates the procedure. Fear not, it is very unlikely that you have permanently damaged this PCM.
Rick
What power supply are you using to power up your bench programming harness? During PCM write operations, it's gonna take at least two amps at or above at least a steady and clean 12.1 volts DC to complete the write and commit it to memory. A cheap wall wart power supply often fails at this critical point and can brick your PCM.
But there is a relatively easy method for recovering a P01 or P59 PCM by grounding a certain pin on the printed circuit board during boot up of the PCM. There is an excellent You Tube video that demonstrates the procedure. Fear not, it is very unlikely that you have permanently damaged this PCM.
Rick
07-21-2024, 02:01 PM
#46
Blue 75 should be a pink wire routed to a 12 volt "ignition key on" power source and these pink PCM wires actually for PCM "boot up" and provide primary power to operate the PCM. Pink wires are ALWAYS an ignition key on 12 volt power source for GM vehicles. An orange wire is an ALWAYS on 12 volt power source in GM vehicles and in this case for the PCM, it is for "memory keep alive" power when the engine is off / not running. The memory is for retaining the learned parameters for making engine starting and idling easier and some say for learning your particular transmission shifting habits.
What power supply are you using to power up your bench programming harness? During PCM write operations, it's gonna take at least two amps at or above at least a steady and clean 12.1 volts DC to complete the write and commit it to memory. A cheap wall wart power supply often fails at this critical point and can brick your PCM.
But there is a relatively easy method for recovering a P01 or P59 PCM by grounding a certain pin on the printed circuit board during boot up of the PCM. There is an excellent You Tube video that demonstrates the procedure. Fear not, it is very unlikely that you have permanently damaged this PCM.
Rick
What power supply are you using to power up your bench programming harness? During PCM write operations, it's gonna take at least two amps at or above at least a steady and clean 12.1 volts DC to complete the write and commit it to memory. A cheap wall wart power supply often fails at this critical point and can brick your PCM.
But there is a relatively easy method for recovering a P01 or P59 PCM by grounding a certain pin on the printed circuit board during boot up of the PCM. There is an excellent You Tube video that demonstrates the procedure. Fear not, it is very unlikely that you have permanently damaged this PCM.
Rick
07-21-2024, 02:55 PM
#47
TECH Fanatic
Your battery might not be strong enough to deliver dependable power or you might have some voltage drop to the PCM along the wires from the battery. The use of a battery charger to maintain your battery's supply voltage might not be suitable depending on the charging profile used by the charger. I use a no kidding, iron-clad capable three amp power supply to read and write to my PCM's.
You previously said that your PCM was a P01 device. Have you ever seen a document such as the kind that I've attached? Yes, you must apply 12- volt ignition power to Blue pin 75.
Rick
You previously said that your PCM was a P01 device. Have you ever seen a document such as the kind that I've attached? Yes, you must apply 12- volt ignition power to Blue pin 75.
Rick
07-21-2024, 03:00 PM
#48
Your battery might not be strong enough to deliver dependable power or you might have some voltage drop to the PCM along the wires from the battery. The use of a battery charger to maintain your battery's supply voltage might not be suitable depending on the charging profile used by the charger. I use a no kidding, iron-clad capable three amp power supply to read and write to my PCM's.
You previously said that your PCM was a P01 device. Have you ever seen a document such as the kind that I've attached? Yes, you must apply 12- volt ignition power to Blue pin 75.
Rick
You previously said that your PCM was a P01 device. Have you ever seen a document such as the kind that I've attached? Yes, you must apply 12- volt ignition power to Blue pin 75.
Rick
07-21-2024, 04:27 PM
#50
TECH Fanatic
What is your source of ignition power? Is it a source of power that stays powered up DURING CRANKING? Some do, some don't. Strictly, strictly, strictly for testing purposes, you could put all pinks and all orange wires straight to the battery and see if it starts.
How many PSI of fuel pressure do you have at the fuel rails?
How is your fuel pump powered??
Rick
How many PSI of fuel pressure do you have at the fuel rails?
How is your fuel pump powered??
Rick
07-21-2024, 04:45 PM
#51
What is your source of ignition power? Is it a source of power that stays powered up DURING CRANKING? Some do, some don't. Strictly, strictly, strictly for testing purposes, you could put all pinks and all orange wires straight to the battery and see if it starts.
How many PSI of fuel pressure do you have at the fuel rails?
How is your fuel pump powered??
Rick
How many PSI of fuel pressure do you have at the fuel rails?
How is your fuel pump powered??
Rick
07-21-2024, 04:46 PM
#52
What is your source of ignition power? Is it a source of power that stays powered up DURING CRANKING? Some do, some don't. Strictly, strictly, strictly for testing purposes, you could put all pinks and all orange wires straight to the battery and see if it starts.
How many PSI of fuel pressure do you have at the fuel rails?
How is your fuel pump powered??
Rick
How many PSI of fuel pressure do you have at the fuel rails?
How is your fuel pump powered??
Rick
His Fuel Pump is hard wired straight to the Battery, I asked that one too.
Blue 75 goes to the same place as Blue 19. Key-on 12v source, also called Ignition 12v.
Fuel Pressure would be my next check at this point. Most don't know the LS stuff runs at 58psi minimum, and use 43psi Pumps.
07-21-2024, 04:50 PM
#53
I'll be the first to say it, your initial posting of "it's wired properly" I'm doing a good job of picking that one apart so there's that.
07-21-2024, 04:56 PM
#55
Well ofcourse it would, it's directly off the Battery. That's not the correct way to do it, you want your Key-on 12v to be that when the key comes on because that turns on the PCM. The constant 12v is the stuff that should be direct from the Battery on a fused circuit. Having both as constant is not the way.
There's people out there that consider 43psi as "high pressure" that are used to Carb'd stuff that runs at 7psi. As I mentioned the LS runs at 58psi.
I'll be the first to say it, your initial posting of "it's wired properly" I'm doing a good job of picking that one apart so there's that.
There's people out there that consider 43psi as "high pressure" that are used to Carb'd stuff that runs at 7psi. As I mentioned the LS runs at 58psi.
I'll be the first to say it, your initial posting of "it's wired properly" I'm doing a good job of picking that one apart so there's that.
07-21-2024, 04:58 PM
#56
Not wired right, not enough fuel pressure.
That's it.
Basic checks that you do initially before spending money on extra sensors, etc...
I have my fuel pressure gauge in the garage, do enough of these swaps you keep the tools on hand.
Why would you get a new pump when you don't know what the current one is doing?
That's it.
Basic checks that you do initially before spending money on extra sensors, etc...
I have my fuel pressure gauge in the garage, do enough of these swaps you keep the tools on hand.
I’ll get a new pump. And make sure it the right requirements. And I normally have it wired from bat to the fuel pump relay that is controlled by ecu to fuel pump. So the ecu kicks it on and off. While it is in the set up it still stays constant. I only temporarily hooked it up directly to bat to make sure it was getting the same readings. I’m reverting it back to the relay setup.
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Jimbo1367 (07-22-2024)
07-21-2024, 05:17 PM
#57
Not wired right, not enough fuel pressure.
That's it.
Basic checks that you do initially before spending money on extra sensors, etc...
I have my fuel pressure gauge in the garage, do enough of these swaps you keep the tools on hand.
Why would you get a new pump when you don't know what the current one is doing?
That's it.
Basic checks that you do initially before spending money on extra sensors, etc...
I have my fuel pressure gauge in the garage, do enough of these swaps you keep the tools on hand.
Why would you get a new pump when you don't know what the current one is doing?
I got laid off work during this whole thing and it would be cheaper for me to swap this pump with a known good one than spend the 125 on a tester. Sorry for being not to fluent with all of this I知 doing the best I can lol.
07-21-2024, 08:00 PM
#60
