NEED HELP Wont start after engine swap

[dvs.dave.03ltz]

Was the relay physically damaged, like burnt or melted? Or just tested bad as in no longer making the connections correctly when commanded?

You could possibly have damaged traces on the underside of the fuse block, if the relay showed physical damage

no physical damage to the relay, just stopped functioning as it was supposed to....

 

[mrrsm]

IIANM... With your Ignition Key set to the Run/Start Position... by by-passing the Starter Solenoid... The Engine Starts and Runs until you set the Ignition Key to the Off Position? ...and you are using an Insulated Crow Bar to make the Jump across the High Amperage Starter Poles each time? This sounds like your Starter Solenoid could be the Bad Guy in this matter. Did this Starter Motor come with the Swap Motor and if so, can you use your Old Starter as a Temp Replacement? And ...In lieu of the Crowbar... Perhaps you can get one of these well made and useful Remote Wire Clip Button Starters:

https://www.amazon.com/Performance-Tool-W80586-Remote-Starter/dp/B00OPVYHZ4/ref=sr_1_1?ie=UTF8&qid=1529510273&sr=8-1&keywords=remote+starter+switch&dpID=41cFZ2HF%2BZL&preST=_SY300_QL70_&dpSrc=srch

 

[dvs.dave.03ltz]

Thanks for the post/link @MRRSM, to answer your question I have ruled out the starter and solenoid, as both have been replaced since the donor motor was installed. I have since abandoned the crow bar method (or starting stick as my son calls it) for a much less dramatic start up procedure involving the relay and pins 87 and 30 lol, but this push button is a definite 1up from jumping the relay... Now if only I could get the transmission to cooperate lol.

 

[dvs.dave.03ltz]

**UPDATE**​

OK I'm completely at a loss and stumped. I figured out that im not getting a ground signal from the pcm to the starter relay so the tb still no crank no start from the key, but it'll run if I jump the relay pin 87 and 30 and leave the key in the run position.
The service engine soon light is on, but its dimly lit and flickers in tempo with the vibrations of the motor.

Gremlin #2: I've already poured over the service manuals and troubleshot the tranny but it still does nothing in any of the gears. I've disconnected one of the trans cooler lines to verify that the fluid is moving and it is. When adding fluid back to the tranny I used a hand pump and pushed it in thru the tranny cooler line and not thru the dip stick tube. Now when jumping the relay to start the tb I can start it in any "gear", it doesn't matter what position the shifter is in at all.

So are these issues I'm having coming from the same root problem? Or are they their own entities with individual root issues that need to be addressed one by one...

 

[Mooseman]

Check the schematics and find which wire sends the signal from the ignition switch to the PCM and see if it does in fact send that signal.

Is the PCM possibly defective? What about the cluster? The dim CEL is weird. The PCM sends a signal to the cluster to light the CEL when needed. With these problems, you'd need someone with a Tech 2 to give all this stuff a good going through to find what is going on.

 

[I_Shoot_Back]

Personally I think the cut transmission harness is suspect. 2 wires got crossed? If pcm doesn't get the message that tranny is in park or neutral it won't allow the starter to engage. Flickering cell light voltage feedback into cluster perhaps from said harness? When you move gear selector,do you see the proper gear marked on the cluster ?

 

[mrrsm]

+1 --^-- ... and if the actual Wiring Repairs are NOT FUBARed... there is always the issue of perfecting the variable position of the ADJUSTMENT TO THE PARK NEUTRAL SWITCH WHERE IT ORBITS ABOUT THE 4L60E SHIFT ARMATURE. As it is depicted in the attached diagram... the entire switch can be rotated very slightly up and down like a Teeter-Totter by loosening the two 13 MM (15 ?) Fasteners again... and by careful Trial and Error... Keep checking the Park and Neutral positions with the Transmission Shifter in the Cab...and try to Start the Engine. Once you locate that "Sweet Spot"... then Tighten down those Two 13 MM (15?) Fasteners:

 

[mntegra01]

I know this is kinda far from topic, and the flickering maybe related to something else, but did you use original alternator or one that came with donor engine, and have you checked voltage from alternator? Can you still not communicate with the PCM via OBD port?

 

[dvs.dave.03ltz]

I know this is kinda far from topic, and the flickering maybe related to something else, but did you use original alternator or one that came with donor engine, and have you checked voltage from alternator? Can you still not communicate with the PCM via OBD port?

I used the original alternator as it was purchased and installed 3 weeks before the motor grenaded itself, and it was a brand new unit purchased via the interwebs. And no, i still dont have any communications via the obd port.

What do you think the flickering may be related to?

 

[mrrsm]

Start by downloading and viewing and following the instructions shown on this attached image to perform some Basic Tests on your Female OBD2 Connector under your Dash Knee Bolster using a Volt Meter to check for problems with the Common Network Grounds and for any Short to 12 VDC Conditions:



This information might seem a little obscure at first... but the outline shown in the attached PDF... and the Diagnostic Link especially towards the end of both read(s)... will provide you with some more insight into how the GM Network at play inside of your vehicle functions and what can go wrong. In the basic design of the PCM/Body Control Module... it is possible to lose communication with the PCM is the Ground Splice connectors are damaged... such as if the system is "shorted to ground" and if the system is shorted directly to 12 (+)Volts.

It is also possible to lose or fail to make this connection and communicate with the PCM if the 12(+) Volt connection from the Cigarette Lighter is malfunctioning as the independent source for power leading to your OBD2 Diagnostic Device:

Post #38 in this GMTN Link covers lot of this data as an Italicized group of paragraphs...with images of the GM Common Ground Splice Pack:

https://gmtnation.com/forums/thread...ng-of-a-gm-repaired-instrument-cluster.18272/

This link covers the Basic Background and History of the GM Automotive Network Designs:

http://tomboynton.com/GMnetworks.pdf

This link echoes the issues of GM Network System Problem Diagnosis:

https://www.autoserviceworld.com/ca...neral-motors-communications-network-problems/

 

[mntegra01]

also recheck your Trans range switch, sounds like you have some weird voltage backfeeding or grounded out wire somewhere. If you aren't confident in the wiring of the range switch, I would just replace the whole pigtail and start over. P/N for the 7 pin for my 2003 2WD is 15305887 or PT1031

 

[dvs.dave.03ltz]

Start by downloading and viewing and following the instructions shown on this attached image to perform some Basic Tests on your Female OBD2 Connector under your Dash Knee Bolster using a Volt Meter to check for problems with the Common Network Grounds and for any Short to 12 VDC Conditions:

View attachment 85160

This information might seem a little obscure at first... but the outline shown in the attached PDF... and the Diagnostic Link especially towards the end of both read(s)... will provide you with some more insight into how the GM Network at play inside of your vehicle functions and what can go wrong. In the basic design of the PCM/Body Control Module... it is possible to lose communication with the PCM is the Ground Splice connectors are damaged... such as if the system is "shorted to ground" and if the system is shorted directly to 12 (+)Volts.

It is also possible to lose or fail to make this connection and communicate with the PCM if the 12(+) Volt connection from the Cigarette Lighter is malfunctioning as the independent source for power leading to your OBD2 Diagnostic Device:

Post #38 in this GMTN Link covers lot of this data as an Italicized group of paragraphs...with images of the GM Common Ground Splice Pack:

https://gmtnation.com/forums/thread...ng-of-a-gm-repaired-instrument-cluster.18272/

This link covers the Basic Background and History of the GM Automotive Network Designs:

http://tomboynton.com/GMnetworks.pdf

This link echoes the issues of GM Network System Problem Diagnosis:

https://www.autoserviceworld.com/ca...neral-motors-communications-network-problems/

OK so I went to check the female obd2 underneath the steering column and there is no wire or pin in slots 6 or 14. From what I can tell I have wires or pins at #2, 4,5, and 16. The rest are empty or unused...

 

[mrrsm]

This confusion falls upon my interest in showing the (-) and (+) probing for possible shorts and the use of the DMM to investigate it. Please visit THIS link to get a more precise set of GM OBD2 Diagrams to see which Pins to apply the DMM Probes inside of. Please ensure that your orientation on reading these Pins is in the proper facing ....as when the wires are introduced from the backside of the Connector... if you have to either replace or re-insert any missing Pin-Wires into the Female OBD2 Port Connector... they will have a Backwards arrangement. Be careful when doing this.

I also wanted to point out that your 2003 SUV seems to have some additional After-Market JVC Radio and Amplifier Gear that might need to be disconnected until you can re-establish functional OBD2 Communication. There has been at LEAST one instance where the 12 Volt (+) short was actually accidentally traced to the presence of a Dime that had been dropped into the CD Feeder on the Radio/CD Panel ...that once removed... immediately allowed for renewed OBD2 Comms :

http://pinoutguide.com/CarElectronics/gm_car_obd_ii_pinout.shtml

Ordinarily... I would not recommend your having to wade through any of my complicated "tomes" on any particular subject... but since you are an Electrician by Profession ... THIS Thread involves an investigation of how I created a "Bench-Top OBD2 Harness" for the purpose of powering up a PCM and other OBD2 Modules on the Bench and allowing for connecting up to a GM Tech2 "GYMKO" Clone OBD2 Scanner. I used the very same Female OBD2 Port that you are concerned with and If you will examine this Thread ...you should find the images of how the OBD2 Female Port and Wiring communicates directly to a PCM helpful. You will KNOW which Pins carry 12 (+) Volts (Pin 16), which Pins are Ground(s) (Pins 4 &5) and which of the remaining Pins carry the 0-7 Volt Class 2 Comm Signals to and from the PCM and all other Modules in the SUV:

https://gmtnation.com/forums/thread...ng-of-a-gm-repaired-instrument-cluster.18272/

 

[dvs.dave.03ltz]

**!!UPDATE/SOLVED!!**​

Before we get to the meat and potatoes, i want to thank everyone here at gmtnation that offered their advice and guidance, without yalls help there's no way in hades i would've ever been able to get the trail-bastard back on the road, so THANK YOU THANK YOU THANK YOU. Yall prevented a trailblazer bonfire and saved me from getting an arson charge on my record lolol.

Yep, you are reading that right, the no crank no start, no drive in any gear, no communication via obd2 port, ARE ALL SOLVED and the trailblazer will be back on the road come Tuesday when the parts come in from ebay. So I'll cut to the chase cause i know a lot of yall gave me amazing advice and helped me keep the course and walked me thru some painstaking procedures and processes and are dying to know wtf the culprit(s) were, so here goes:

Remember the original mechanic I hired to do the engine swap couldn't get the transmission harness unplugged and he cut the damn thing; well he neglected to disconnect my capacitors that feed my amps when he disconnected the batteries and shorted out the pcm,and the transmission park safety switch. Not only that, but he also installed the torque converter incorrectly and when the engine was started for the first time when the tc went to start spinning it broke the trans oil pump rotor, and the vanes that sit in the rotor slots...

So now the pump slide and rotor rebuild kit is on its way from ohio, and I've already gotten the tpss, and a pcm and itll be a matter of days before my tb back on the road. Tuesday cant get here soon enough....

 

[mntegra01]

Amazing how much someone can F stuff up that they really don't have any idea what they are doing. Glad to here it will be back up and running soon.

 

[Mooseman]

For the PCM, is it a used one from the same year and gearing? Otherwise, it will need reprogramming. It will for sure need a security relearn.

 

[dvs.dave.03ltz]

For the PCM, is it a used one from the same year and gearing? Otherwise, it will need reprogramming. It will for sure need a security relearn.

Yes it is from the same model year as mine with all of the same options. I slapped that joker onto the side of the motor, put the harness on it, reconnected the battery, turned the key and she roared to life without having to do a security relearn!! I have no idea why it didnt need the relearn and at this juncture am gonna leave well enough alone and blame it on the universe, lol. Even though the tb started normally with the key in the ignition, i opted to keep the hidden toggle switch as the hot-to-start my tb. I mean hell why not, i already had the wires ran from the ignition relay spot in the fuse block to the dashboard and already had the switch installed..

Amazing how much someone can F stuff up that they really don't have any idea what they are doing. Glad to here it will be back up and running soon.

that aint no lie bro. my "mechanic" did a bang up job of turning my engine swap into a giant soup sandwich. Thank goodness i brought an appetite and a huge straw lolol.