hopefully you find it.. I've not had to work on mine to this level but it's always interesting to have a look around at the diagrams and trouble codes. so if I do need to i should be more familiar with how the system works.
looking a bit more today, it seems gm calls the communication lines high speed GMLAN serial data circuit. it could be helpful to try and use the scanner to communicate with the modules called out buy the dtc codes. stuff like turn on the cooling fan in the battery control module, or see if the tranny will react to gear selections thru the bi directional scanner. if so, it would rule out those GMLAN wires and could narrow it down to what they call the wake up signal. seems like the ecm sends a wake up call at key on to some modules first and it might not be getting a reply back. if it doesn't let the scanner talk to them, there's some tests listed to see if the lines are open, shorted to ground or shorter to B+. there's also a terminating resistor in the circuit that needs to be there.
these trucks fall under this tsb as well, I doubt fully because yours worked correctly before the motor swap, so I'd guess it's something related to that, but there's some pics and info in there that might help
hopefully you find it.. I've not had to work on mine to this level but it's always interesting to have a look around at the diagrams and trouble codes. so if I do need to i should be more familiar with how the system works.
looking a bit more today, it seems gm calls the communication lines high speed GMLAN serial data circuit. it could be helpful to try and use the scanner to communicate with the modules called out buy the dtc codes. stuff like turn on the cooling fan in the battery control module, or see if the tranny will react to gear selections thru the bi directional scanner. if so, it would rule out those GMLAN wires and could narrow it down to what they call the wake up signal. seems like the ecm sends a wake up call at key on to some modules first and it might not be getting a reply back. if it doesn't let the scanner talk to them, there's some tests listed to see if the lines are open, shorted to ground or shorter to B+. there's also a terminating resistor in the circuit that needs to be there.
these trucks fall under this tsb as well, I doubt fully because yours worked correctly before the motor swap, so I'd guess it's something related to that, but there's some pics and info in there that might help
So I Believe I've solved the no crank issue. apparently it's a great time for the battery to decide to crap out. if I toss the battery charger on it she will start. when its running its running exactly like the other motor. P0300 code. With now the addition to the brake light and service traction light on. I'm not sure why or how the misfire could of followed to the replacement motor.
I used the scanner and under the balance engine section I found where I could turn off each individual cylinders fuel injectors.
when I would turn off any of the injectors the truck would start to run rough.
hopefully you find it.. I've not had to work on mine to this level but it's always interesting to have a look around at the diagrams and trouble codes. so if I do need to i should be more familiar with how the system works.
looking a bit more today, it seems gm calls the communication lines high speed GMLAN serial data circuit. it could be helpful to try and use the scanner to communicate with the modules called out buy the dtc codes. stuff like turn on the cooling fan in the battery control module, or see if the tranny will react to gear selections thru the bi directional scanner. if so, it would rule out those GMLAN wires and could narrow it down to what they call the wake up signal. seems like the ecm sends a wake up call at key on to some modules first and it might not be getting a reply back. if it doesn't let the scanner talk to them, there's some tests listed to see if the lines are open, shorted to ground or shorter to B+. there's also a terminating resistor in the circuit that needs to be there.
these trucks fall under this tsb as well, I doubt fully because yours worked correctly before the motor swap, so I'd guess it's something related to that, but there's some pics and info in there that might help
do you happen to have a diagram of the main harness? where it foes where it grounds etc?
ahh so you had the misfire with the other engine too? these do seem to be picky about their 12v battery. which is weird since it doesn't start the engine. I'm half tempted to put a deep cyl Optima battery in mine haha
so the p0300 is an over all missfire code, 301-308 is the individual cyl. so something causing the whole engine to shake not just one cycle not firing. under fixes it says outside source can cause it, example a bad tire. that sounds crazy lol.
how much did you use off the old engine?
but under real fixes it lists throttle body replacement as the most common fix for misfire. I don't know how they are linked but that's what it says.
if the miss fire is on one of the 4 afm cyl that would make more sense. I wouldn't be surprised to see 2 engines with bad lifters. the quick check for that seems to be pull a valve cover and watch the rockers while cranking over, your scan tool might be able to crank without starting. starting would work, but make a mess of shooting oil out. there's a whole thing I've seen about how much oil comes out of the push rod on the bad lifters but probably not your issue.
grounds I'll up load pics, but basically the coil packs are grounded to the engine block under the header. #1 in that pic. odly it doesn't show behind the drivers cyl head ground on my stuff but I know it's there because I missed putting it back and it wasn't happy. threw a 4wd code if I remember right.
since you did swap an engine, your scanner should be able to do a crank Relearn. but since you had the miss before, probably won't fix it. but couldn't hurt.
ahh so you had the misfire with the other engine too? these do seem to be picky about their 12v battery. which is weird since it doesn't start the engine. I'm half tempted to put a deep cyl Optima battery in mine haha
so the p0300 is an over all missfire code, 301-308 is the individual cyl. so something causing the whole engine to shake not just one cycle not firing. under fixes it says outside source can cause it, example a bad tire. that sounds crazy lol.
how much did you use off the old engine?
but under real fixes it lists throttle body replacement as the most common fix for misfire. I don't know how they are linked but that's what it says.
if the miss fire is on one of the 4 afm cyl that would make more sense. I wouldn't be surprised to see 2 engines with bad lifters. the quick check for that seems to be pull a valve cover and watch the rockers while cranking over, your scan tool might be able to crank without starting. starting would work, but make a mess of shooting oil out. there's a whole thing I've seen about how much oil comes out of the push rod on the bad lifters but probably not your issue.
grounds I'll up load pics, but basically the coil packs are grounded to the engine block under the header. #1 in that pic. odly it doesn't show behind the drivers cyl head ground on my stuff but I know it's there because I missed putting it back and it wasn't happy. threw a 4wd code if I remember right.
since you did swap an engine, your scanner should be able to do a crank Relearn. but since you had the miss before, probably won't fix it. but couldn't hurt.
a friend of mine said its ecu. I have another. but how do i flash it using a autel scan tool?
it was just a link to a very long thread where guys talk about what it takes to flash modules when replaces. like say you found a used ecm for your truck, it will need to be programed to your truck. I haven't been thru the whole thread but figured there might be some useful info in there for you if you swapped ecm.
as for the injector circuit tests, I've not seen that before myself. I looked it up and took some pics. let me know if you can read them. this software is such a hassle. it won't let you down load save anything but I can try a different way if you can't read it. there's all I got from it.
1st one just explains the 3 options for the test results pass, fault or not run.
did list a check for the injector circuit, but it's basically a noid light test. checker led in a plug. you unplug the injector, plug in the light and see if it flashes. it should. any parts store should have them or just use a test light.
and the other is what resistance the injectors should be. which injectors did you use? maybe they need cleaned from this crappy e10 gas clogging them up? there's some eazy tests on YouTube for injectors with a 12v battery and some brake clean can to check the spray pattern too. I've done that to clean up some 42lbhr injectors I had on a shelf for a few years. they would bearly flow anything but some brake clean flowed thru got them going.
it is a bit weird you're not getting miss fires on the cyl that show fault in the test.
it was just a link to a very long thread where guys talk about what it takes to flash modules when replaces. like say you found a used ecm for your truck, it will need to be programed to your truck. I haven't been thru the whole thread but figured there might be some useful info in there for you if you swapped ecm.
as for the injector circuit tests, I've not seen that before myself. I looked it up and took some pics. let me know if you can read them. this software is such a hassle. it won't let you down load save anything but I can try a different way if you can't read it. there's all I got from it.
1st one just explains the 3 options for the test results pass, fault or not run.
did list a check for the injector circuit, but it's basically a noid light test. checker led in a plug. you unplug the injector, plug in the light and see if it flashes. it should. any parts store should have them or just use a test light.
and the other is what resistance the injectors should be. which injectors did you use? maybe they need cleaned from this crappy e10 gas clogging them up? there's some eazy tests on YouTube for injectors with a 12v battery and some brake clean can to check the spray pattern too. I've done that to clean up some 42lbhr injectors I had on a shelf for a few years. they would bearly flow anything but some brake clean flowed thru got them going.
it is a bit weird you're not getting miss fires on the cyl that show fault in the test.
WELL I THINK I JUST SOLVED MY ISSUE.... WHATS THIS MISSING PINS FUNCTION? I Almost guarantee it provides power to the ecm....
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09-30-2022, 12:01 PM
Re: HELP! No crank after engine swap.
