Dan's #495 build (2006 SS/SC)
- Thread starter TheAnesthetist
- Start date
TheAnesthetist
Active Member
Ok now the "power steering" message is gone from the dash. Progress! Unfortunately I'm still not getting crank. I guess I'll pull the starter and bench test it.
Robinjo
Goblin Guru
Check the small purple wire to ensure you are getting voltage when turning the key. Have you plugged in the big 50A fuse. Have you connected the big wire from the battery to the starter and the wire that runs from the starter to the B+ terminal of the fuse block?
Have you checked all the grounds?
Have you checked all the grounds?
Ross
Goblin Guru
It's probably not the starter. Jump it to test the starter... but make sure it is in not in gear.
My guess: data isn't flowing on the GM high speed LAN.
Evidence:
No voltage at the little post on the starter when the key is turned. No response from the butterfly when throttle is pushed.
My guess: data isn't flowing on the GM high speed LAN.
Evidence:
No voltage at the little post on the starter when the key is turned. No response from the butterfly when throttle is pushed.
Robinjo
Goblin Guru
Possibly but checking the items with evidence given. Plus the big main one, grounds. Isn’t it like 82% of electrical issues are grounds.
Ross
Goblin Guru
Another common issue (besides grounds) is the electrical connectors... dirty connections under the fusebox... loosen those 7mm bolts, push the bolt which will push the connector off a little, them retighten the 7mm bolts, and snug the connector back on. Hopefully reseating them allows electricity to flow.
TheAnesthetist
Active Member
Verified it is not the starter. Jumped it again and the motor turned over.
I ran a die over the ground lug just in case, but the lugs were taped up during powdercoating so I doubt that's the problem. I tried clipping all three ground wires in the back to a jumper cable and ran it to the battery ground.
Everything clicks and whines when I turn the key but the fuel pump no longer primes. Still says I have 5v at the connector and there's continuity in the ground.
I'm fearing it's those dang twisted data wires
I ran a die over the ground lug just in case, but the lugs were taped up during powdercoating so I doubt that's the problem. I tried clipping all three ground wires in the back to a jumper cable and ran it to the battery ground.
Everything clicks and whines when I turn the key but the fuel pump no longer primes. Still says I have 5v at the connector and there's continuity in the ground.
I'm fearing it's those dang twisted data wires
TheAnesthetist
Active Member
I have 2.4v and 2.5v at the twisted tan wires in the OBDii. Around 116 ohms, if I'm doing this correctly
Ross
Goblin Guru
The 116 ohms is telling us that only one 120 ohm resistor is in the circuit. There should be two 120 ohm resistors in parallel, giving us 60 ohms. I think one is in the ECU the other is in the power steering?
I think the twisted wire numbers have the right voltages. One is canbus high and one is canbus low.
I think the twisted wire numbers have the right voltages. One is canbus high and one is canbus low.
TheAnesthetist
Active Member
I think I need to remove and reevaluate the wiring harness. After looking over Ross's GMLAN table, I may have screwed up the data wires. My tan and tan/blk wires bypass the BCM and go straight from EPS to PCM. Would an error in the data wires cause a no-start situation?
Ross
Goblin Guru
If all 4 items (OBDii port, power steering, BCM, PCM) are in the high speed LAN then you would be getting 60 ohms.
The 120 ohm resistors are suppose to be at the two ends of the high speed LAN wiring chain. Since the OBDii port isn't a computer, it doesn't count. So there are 3 computers in our goblin, power steering (has a 120 ohm resistor, and is at one end of the chain), the BCM doesn't have a resistor, so it goes in the middle of the chain, and a PCM, which has a resistor, and is the other end of the chain.
In your goblin, it is only measuring one 120 ohm resistor, so the high speed LAN isn't seeing both the EPS and the PCM.
If you disconnect the PCM, does it still measure 120 ohms?
The 120 ohm resistors are suppose to be at the two ends of the high speed LAN wiring chain. Since the OBDii port isn't a computer, it doesn't count. So there are 3 computers in our goblin, power steering (has a 120 ohm resistor, and is at one end of the chain), the BCM doesn't have a resistor, so it goes in the middle of the chain, and a PCM, which has a resistor, and is the other end of the chain.
In your goblin, it is only measuring one 120 ohm resistor, so the high speed LAN isn't seeing both the EPS and the PCM.
If you disconnect the PCM, does it still measure 120 ohms?
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TheAnesthetist
Active Member
Still 120
ah.b.normal
Goblin Guru
That is power to EPS, it should plug in somewhere? If P/S is not powered I'd bet the high speed LAN is confused.
ah.b.normal
Goblin Guru
That is unusual but how are you jumping the starter?; jump 12V to the connection for the purple wire. The big battery wire to the starter should test 12V all the time. If there is not 12V there all the time we have other probs.
ah.b.normal
Goblin Guru
Do your Hi speed LAN wires still by pass the BCM?, that ain't right. LAN is a chain and every computer who belongs ought to be in it. Also, Recheck: 5V at the fuel pump? Odd?, it should read 12V. It might read 5V if there is resistance at it's ground point? or maybe you are looking at/testing the wrong wire? I'm no EE but if all the parts aren't connected fix that stuff first. 5V is also the voltage for most senders, I suspect that is the gauge wire?
ALSO! Hi speed Can Bus testing is NOT as scary as it might sound. Go to that YouTube post, hook your 2 meter leads to the ADL port and read. Basic, it must read 60 ohms; 120 or 0, no bueno.(Dang! wishin' I was back in town, I'd drive from Columbus to Athens just to see and diagnose in person. So much easier!)
All of this worked before and will work again, but it's going to be a test of wiring and patience.
ALSO! Hi speed Can Bus testing is NOT as scary as it might sound. Go to that YouTube post, hook your 2 meter leads to the ADL port and read. Basic, it must read 60 ohms; 120 or 0, no bueno.(Dang! wishin' I was back in town, I'd drive from Columbus to Athens just to see and diagnose in person. So much easier!)
All of this worked before and will work again, but it's going to be a test of wiring and patience.
TheAnesthetist
Active Member
I'm leaning toward a missing ground. Verified I have no power to the fuel pump. I have 5v at the sending wire, like Thad said but no voltage at the hot wire. It looks like the fuel pump relay and the crank relay are on the same circuit.
In an earlier post, I was confused when the wiring video said to combine the "fuse box ground" with the fuel pump wires. I never found any kind of fuse box ground, but according to the schematic, there does appear to be a ground (or does the "X3" mean three wires?) at the F2 pin. Anyone know where F2 might be? I've opened up every multiplug and don't see any pins with 3 ground wires.
In an earlier post, I was confused when the wiring video said to combine the "fuse box ground" with the fuel pump wires. I never found any kind of fuse box ground, but according to the schematic, there does appear to be a ground (or does the "X3" mean three wires?) at the F2 pin. Anyone know where F2 might be? I've opened up every multiplug and don't see any pins with 3 ground wires.
