Here's the diagram so you can see things a little better.
Printable View
Here's the diagram so you can see things a little better.
Well that sucked! GasGuzzler is correct, I only glanced at the diagram earlier and the N/S switch does ground through the relay as you can tell in the diagram that's too small to read.
There is a neutral safety switch wire on the new computer/harness, right now its not connected to anything. Are you saying this wire needs to be grounded? If no, On the tranny there are two different harness connections, is there a particular wire that the neutral safety switch wire should be connected too? Be specific and if need be, draw pictures.
Any chance there is a LS guru in KY, willing to help, put their hands on this mess of a project?
Thanks
Is this a brand new harness or a reworked one? I don't know of anyone that tests harnesses out when they rework them. New harnesses are just that, new, and shouldn't need testing. The guy that did my first harness conversion swore he tested my harness and PCM out on a test engine on a stand, only he was full of crap since VATS was still in the PCM and would not let the engine start. Nelson removed the VATS and put a hotrod tune in the PCM and it started right up.
The wires that I recall at the pcm are the old ones. Hes using a harness from the guys that fixed yours.
I guess they just add the connections.
About the neutral safety switch wire at the PCM....does it need to be grounded, any ground work? if no, the neutral safety switch itself has two electrical connections, combined there probably ten wires, which wire should the neutral safety switch (at the PCM) be connected too on the neutral safety switch itself?
this is a reworked harness.
This is what I did to test for resistance through the wire, correct me if I'm wrong. Set the meter up on ohms hooked 1 end to the blue/white wire on crank sensor signal and then the blue/white wire to crank on pcm. I get 0.00. Which is what I get if I take just a scrap wire to test and make sure there is no breaks. I get this for both crank and cam sensor signals to pcm.
I keep asking if vats were taking off and he says yes. It just after going through this theres not much else it could be but the pcm.
may be a bad pcm or the tune didn't take
if you know someone that has the same year model truck as the year PCM tune you're running, you should be able to take your PCM and plug it into their truck and it should run. Do you know someone that would let you swap them to test the PCM?
nope. I know someone with a 19999, 2-2002's but not the 2003 of course.
No, do not ground the yellow N/S wire, it goes straight out of the C100 connector to the switch input. The output is a purple wire which goes to pin B9 on the relay which goes across to pin A7 which goes to the ground distibution. The pin A9 goes to a constant 12 volts and the other contact side pin B7 goes to the purple solenoid wire. Fip the relay upside down to see the pin locations. Hope this is what you were looking for.Quote:
Originally Posted by LSXmyford
What I stated above is for the 96 truck and the N/S switch didn't go to the VCM like the newer pcm, I think it actually coded off the circuit to the VCM. I'm going to go back through my data to see how I hooked mine up because I don't remember going through the pcm pin 34 orange/black wire, I can't remember.
VATS is really only specific to the systems that have chip keys.
You have a security issue I'd say. A noid would help a lot like said above. Sensors rarely gay out like this. Something else is wrong. Remember, there are more modules and "thinking" involved on the security system than just the PCM. Someone's not happy here and I'll bet it's the BCM, etc. 'cause I bet you can't read body codes, eh?
right now i'm not getting any codes back but the red light on the diagnostic is lit. I'm leaning towards the PCM also.
I have a feeling the VATS wasnt removed.
If we connect the crank solenoid wire from the new computer to the starter, nothing happens with the key in start position.
Will his pcm work in a 2000 model truck with a 5.3?
You need to search local car lots, take an 03 for a test drive...haha
Quote:
Originally Posted by GasGuzzler
What 468blazer forgot to mention, earlier he stated that pin 12 CKP, shown no voltage. It was expressed that this is one sensor that needs 12volts. He replaced the crank sensor, and cam sensor. Currently, there is positive voltage at this pin, so it seems to have been an issue.
Quote:
Originally Posted by LSXmyford
A DBW PCM will not work in a DBC vehicle, it needs the throttle pedal electronics.
gotchya.
He has a buddy that works at chevy as a tech, he should be able to test his PCM correct? Will he need the VIN or any other info from the donor vehicle?
He should be getting a noid test light too. What I realized, weve been cranking the starter directly from the yellow wire, bypassing the neutral safety switch. On the plus side, we found out that two sensors were bad (one crank one pedal position), but still no fire, hopefully, hopppppppppefully, once he reconnects the yellow wires, and connects the purple wire from the original harness to the starter solenoid, she'll fire...not really optomistic at this point as when we tried that before, the engine wouldnt rotate...which led to the whole VATS not removed theory....ever feel like your chasing your tail?
The VIN is stored in the PCM. Don't let him change or reload the tune. Just verify that the VATS function has been turned off.
There's really no way I know to bench test a PCM with exception of the aftermarket tuners. I think what was said earlier was the MAF is one of the only 12V sensors as most are 5V. The CMP and CKP are 12V also.
Here is where we are at now, its actually where we began.
the yellow wire has been reconnected to its other half. he then took the purple solenoid wire (from the old harness) and ran it to the starter, turn the key, nothing happens. which is odd, as his truck was running fine with the old engine installed, so this solenoid wire should activate the starter fine but it doesnt.
just for the hell of it, he tested the solenoid wire on the new pcm with his multimeter, to see if he would get 12v with the key in start position...nothing.
otherwise, he is getting power at the PCM where it should be and the fuel pump relay on the new harness is clicking, as it should.
this is with the new harness connected to the Neutral safety switch (NSW). for chits and giggles, we even attached the old NSW to the new harness connection, then we connected the old and new NSW to the old harness NSW connection...nothing.
after talking with Jon this morning there going to get another pcm loaded and sent out.
Good luck, It's hard to diagnose an electrical issue over the net, you really need someone looking at it with you. I doubt this is a BCM issue, it's more than likely wiring or PCM/tuning related.
:doofus:
I forgot the vehicle is older than the harness and engine. The BCM doesn't factor here AS LONG AS THE TUNE HAS THE SECURITY TURNED OFF.
I keep looking at description and operation for the donor harness/powertrain forgetting the vehicles are often different.
I still surmise it's a security issue which would still be PCM related.
I keep doing the same thing so don't feel bad. This kinda stuff happens when you combine different year models. :)Quote:
Originally Posted by GasGuzzler
Shouldnt be a wiring issue, Id be happy if it was though, then this would be over and done with. ;)
To take one more variable out of the equation, he asked them to turn the neutral safety switch off within the computer. Im fairly confident everything else is wired as suggested, and no stock wires were modified....cross our fingers and hope fer the best I reckon.
Programmer man said you cant turn the neutral safety switch off inside the pcm via tuning.
What do you do to bypass it, just not connect it?
Correct.Quote:
Originally Posted by LSXmyford
just to clarify, the neutral safety switch is the box on the side of the tranny correct, that has the gear selector going through it? there are two electrical connections? should he remove one or the other or both?
thanks
Just remove the N/S switch not the indicator wires. It's worth having that switch though so you don't start your truck in gear.
My bro piddled around some, tested more wires and seems the neutral switch is fine, SHE CRANKS WITH THE KEY NOW, through the old wiring harness purple wire....STILL NO FIRE.
This rules out the NSW I believe, as it doesnt make any difference anyway, according to nelsons and everyone else.
He has the fuel pump relay connected to the gray wire that goes to the fuel pump, the relay can audibly be heard switching, as its supposed too. Rules that out.
He still smells fuel when he cranks it, crank the engine, get a strong smell of gas, lingers for a couple minutes...further verify this....PLUGS ARE NEW and WET.
Nelsons says its not the VATS, said the symptoms are something else, what I do not know? Still taking suggestions...still not convinced its not the VATS....as based on my understanding VATS kills the starter if theft is detected...we are getting nothing at the purple starter solenoid wire on the new pcm....so??? Is it possible 1 + 1 would equal 2
At this point not sure if they are sending a newly programmed pcm or not....hope so...as that should rule that out.
ok don't want to confuse anybody with conflicting info.
Truck will crank with key. Have power when truck is cranking through purple wire which goes to solenoid through starter relay,etc.
Getting like 11.4 volts from crank signal and cam signal. Tested wires for breaks everything is coming out good showing good lines.
Fuel pump is working and smell it very strong after cranking.
No bad fuses and all grounds are grounded.
Only thing I can think of is VATS are not turned off or PCM is bad. Not getting any codes back with scanner on diagnostic port although the red light to tell you there are codes is lit.
Hopefully I'll hear from or get another PCM from nelson next week.
I believe the SES light being on is the default mode when the key is in the "on" position. It's supposed to turn off once the engine starts.
that makes sense.