Please help... PCM not getting power
Thread Starter
On The Tree
Joined: Jul 2009
Posts: 122
Likes: 1
From: Richmond, VA
Please help... PCM not getting power Background: I have a 2000 camaro LS1 with factory harness and ECU (both are 2000 also)
Problem: I cannot figure out why my ECU is not getting 12 volts. I checked the four grounds (pins 1 and 40 on red and blue connectors) and they are good. I know that I have 12 volts at the ECU fuse, but when I connect the wires for IG+ to the ECU (there are four) I am reading zero volts. It seems like I have an open circuit somewhere, but I am not sure what to check first.
I am sorry if this is a common question and I am retarded for not being able to find an answer by searching (I did try). Thank you in advance for your advice.
Problem: I cannot figure out why my ECU is not getting 12 volts. I checked the four grounds (pins 1 and 40 on red and blue connectors) and they are good. I know that I have 12 volts at the ECU fuse, but when I connect the wires for IG+ to the ECU (there are four) I am reading zero volts. It seems like I have an open circuit somewhere, but I am not sure what to check first.
I am sorry if this is a common question and I am retarded for not being able to find an answer by searching (I did try). Thank you in advance for your advice.
Staging Lane
Joined: Sep 2008
Posts: 92
Likes: 1
Checked my notes: Computer plug C1 (blue) should have ignition switched 12v power to pin #19 (pink wire) and constant battery 12v power to pin #20 and #57 (orange wires). Do you have the ign switch in "on" position when checking for voltage at #19? I think there may be two fuses feeding the ecu, one for ign hot and one for batt hot. Did you check both? Use a continuity tester to test your fuses. Use the continuity tester to check the wiring between the fuse locations and the ecu pins. If still not fixed, post again or pm me and I'll try to help.
Thread Starter
On The Tree
Joined: Jul 2009
Posts: 122
Likes: 1
From: Richmond, VA
I have 12V switched and 12V constant going to the ECU. I have verified this situation.
I also have 12V switched to three other wires (left bank inj/coils, right bank inj/coils, and O2 sensors).
I am now able to get the fuel pump to kick on, but the fuel injectors are still not firing. I know this because the spark plugs are bone dry.
I have not checked for spark yet due to no one to crank while I check. I am going to check that, double check electrical connections, and try to confirm fuel pressure tomorrow.
PS. VATS is still not disabled, but from what I understand the car should still turn over and run for a couple seconds.
I also have 12V switched to three other wires (left bank inj/coils, right bank inj/coils, and O2 sensors).
I am now able to get the fuel pump to kick on, but the fuel injectors are still not firing. I know this because the spark plugs are bone dry.
I have not checked for spark yet due to no one to crank while I check. I am going to check that, double check electrical connections, and try to confirm fuel pressure tomorrow.
PS. VATS is still not disabled, but from what I understand the car should still turn over and run for a couple seconds.
Do you have power at the injector plugs? Should have power on one side of the connector with the key in the run position. If you do, and it sounds like you do, the injectors are probably stuck from sitting. How long has it been since the engine ran? This is a very common problem on many people's first start up.
Thread Starter
On The Tree
Joined: Jul 2009
Posts: 122
Likes: 1
From: Richmond, VA
Thanks for all of your responses.
Last night I checked a few things. I know that I have spark (saw and felt it...), I know that I have fuel under pressure at the fuel rail. I know that I have 12v at the fuel injectors.
I have heard that the injectors can stick, but it seems strange to me that all 8 would be stuck. I have had the engine for a year without firing it; I am not sure how long it sat before that. If they are stuck, is there a way to free them?
Thanks for the suggestion, yellowbrother, I will check tonight to see if they are getting 12v during cranking.
Can anyone comment on my thoughts about VATS and it still running for a couple seconds if it is enabled?
Last night I checked a few things. I know that I have spark (saw and felt it...), I know that I have fuel under pressure at the fuel rail. I know that I have 12v at the fuel injectors.
I have heard that the injectors can stick, but it seems strange to me that all 8 would be stuck. I have had the engine for a year without firing it; I am not sure how long it sat before that. If they are stuck, is there a way to free them?
Thanks for the suggestion, yellowbrother, I will check tonight to see if they are getting 12v during cranking.
Can anyone comment on my thoughts about VATS and it still running for a couple seconds if it is enabled?
Do you see an rpm sig when cranking? No sig, no inj pulse.
Use a noid on the inj's..Should blink if they are firing.
I see the clogged/stuck shut injs frequently, on the j/y engines I clean injs for. [usually the first thing the j/y owner does is send me the injs when he has a complaint.]
Use a noid on the inj's..Should blink if they are firing.
I see the clogged/stuck shut injs frequently, on the j/y engines I clean injs for. [usually the first thing the j/y owner does is send me the injs when he has a complaint.]
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I've seen all eight stick more often than you might think. I soaked mine in some sea foam over night, seemed to work good.
And you are correct, the engine should fire and die with the vats still enabled. Sometimes they will run for a few seconds, others will just fire then shut off immediatly.
And you are correct, the engine should fire and die with the vats still enabled. Sometimes they will run for a few seconds, others will just fire then shut off immediatly.
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Verdad Gallardo Thread Starter
On The Tree
Joined: Jul 2009
Posts: 122
Likes: 1
From: Richmond, VA
more electrical gremlins Thanks for everyone's help so far. I am still having trouble, but here is an update.
I figured out why the ECU was not getting power and rewired some things to fix that. I got the car to start very briefly, but at the time everything but the starter had power even without the key in the ignition. I determined the reason for this was that I had the IG2 pin on the key switch was getting 12V, so I unhooked that. Since I did that the starter no long runs, and it is shorting out through the ECU grounds (they get very hot). So far this has not caused an ECU failure because the fuel pump is still coming on. I thought that perhaps the starter had gone bad, so I replaced it with no luck.
To recap...
-ECU comes on
-starter will not turn
-electrical system is shorting out through the ECU ground wires.
I understand that this is probably a problem with the wiring that I did, but I would appreciate suggestions on where to investigate next.
I figured out why the ECU was not getting power and rewired some things to fix that. I got the car to start very briefly, but at the time everything but the starter had power even without the key in the ignition. I determined the reason for this was that I had the IG2 pin on the key switch was getting 12V, so I unhooked that. Since I did that the starter no long runs, and it is shorting out through the ECU grounds (they get very hot). So far this has not caused an ECU failure because the fuel pump is still coming on. I thought that perhaps the starter had gone bad, so I replaced it with no luck.
To recap...
-ECU comes on
-starter will not turn
-electrical system is shorting out through the ECU ground wires.
I understand that this is probably a problem with the wiring that I did, but I would appreciate suggestions on where to investigate next.
Thanks for everyone's help so far. I am still having trouble, but here is an update.
I figured out why the ECU was not getting power and rewired some things to fix that. I got the car to start very briefly, but at the time everything but the starter had power even without the key in the ignition. I determined the reason for this was that I had the IG2 pin on the key switch was getting 12V, so I unhooked that. Since I did that the starter no long runs, and it is shorting out through the ECU grounds (they get very hot). So far this has not caused an ECU failure because the fuel pump is still coming on. I thought that perhaps the starter had gone bad, so I replaced it with no luck.
To recap...
-ECU comes on
-starter will not turn
-electrical system is shorting out through the ECU ground wires.
I understand that this is probably a problem with the wiring that I did, but I would appreciate suggestions on where to investigate next.
I figured out why the ECU was not getting power and rewired some things to fix that. I got the car to start very briefly, but at the time everything but the starter had power even without the key in the ignition. I determined the reason for this was that I had the IG2 pin on the key switch was getting 12V, so I unhooked that. Since I did that the starter no long runs, and it is shorting out through the ECU grounds (they get very hot). So far this has not caused an ECU failure because the fuel pump is still coming on. I thought that perhaps the starter had gone bad, so I replaced it with no luck.
To recap...
-ECU comes on
-starter will not turn
-electrical system is shorting out through the ECU ground wires.
I understand that this is probably a problem with the wiring that I did, but I would appreciate suggestions on where to investigate next.
