It is very possible injectors are clogged if it was sitting for 2 years. When you say it ran for 2 seconds, did it just kind of hit and run rough...or was it running great in all its glory then nothing?

It should run great for two seconds then quit.

You can check you're injectors by unplugging the injectors and using small clips (or best a spare injector connector) hook one injector wire to 12v+, and then quickly tap the other wire to ground somewhere. You should hear a very audiable click each time you tap the wire to ground.

I built a circuit with a 555 timer and a few resistors and capacitors to pulse injectors just for this reason. Sometimes when they are pulsing you can tap on the injector body with a plastic hammer and free them up. Usually once freed up and you run some gas through them...they will be fine.


Good luck.

 

Thanks to everyone for all the advice. I finally got back to work this weekend and found the problem. Much thanks to jeepinpete for his diagnosis. The injectors were throughly cloged. I took his advice and tried soaking them in seafoam. Overnight the seafoam turned from clear to gas colored. After reinstalling all of them the engine started right up. I am planning to take her out for my first test drive later this week. Again, thanks for all of your help!

 

I also would like a copy of the wiring. My motor is a 2007 5.3

 

I would also like a copy of the wiring. My motor is a 2007 5.3

 

Glad to hear you got it fired up! That certainly puts a smile on your face, and new wind in the sails, so to speak...

 

If it is available, I'd appreciate a copy of this wiring as well.

-Thanks

 

So I dropped a 5.3L 2005 Tahoe engine into a 1993 Silverado. I followed the wiring instructions using the underhood fuse block. I located the fuel pump wire, grey in red connector. I located the ignition wire, pink in grey connect A9. And wired the fuse box to the battery. Using the factory Tahoe harness there is a ground wire behind the driver's side head, a second ground wire next to it closer to the passengers' side head, a third ground wire that goes to the driver's side block. I've grounded the battery to the front of the passenger side head, grounded the block to the frame, and grounded the block to the body. There are two orange wires going to the PCM that are always hot (+12V), and several pink wires that are always hot. The engine will not start. If I spray starter fluid into the intake the engine will stumble and almost start. That tells me, the plugs are sparking... right? I pulled the injectors off and turned the key. No fuel out of the injectors. However, if I leave the key in and allow the pump (which is working) to build pressure, I can trigger the injectors with two wires. One wire has ground and the other 12V. They do spray. The pink wires at the injectors all show +12V with the key in the run position, but never show anything on the ground wire (not even with the key in the crank position). I'm assuming the PCM is getting power because the engine kind of runs when I spray starter fluid in. However, is there more than one ignition wire I should be looking for? All my grounds seem to be in tact. I had previously sent my PCM to wait4me performance to have it reflashed. I'm stumped. Any help would be greatly appreciated. Thanks.

 

are injectors geting 12v+ during crank? some ignition sources are hot in run only, but not crank.

all pink wires will be KEY hot ....only the two orange wires are hot at all times.

 

Thanks, I'll check this out tomorrow. Anything else I can check while I'm at it?

 

The PCM grounds the injectors to fire them. If you use an analog DVM and backprobe the ground wire at the injector, you will see the needle dip slightly when the PCM grounds the injector. It isn't much needle movement, but you will see it. Or pick up a set of noid lights. As for spark, put a timing light (inductive style) on and see if it flashes.

Pete

 

busta9876 you were right. The ignition circuit on my truck opens when the key is in the crank position. I used a different circuit that stays hot in the run and crank position. The engine fired right up. jeepinpete thanks for the instructions on the harness. They work great and are very easy to set up. Engine sounds very strong. Now all I need is an exhaust. BTW, can I run a check engine light straight to the PCM? I'll have to find the pinouts of course. And finally, I want to wire up the OBDII diagnostic plug that came with the harness. Can I also tap the wires comming out of the PCM to wire this plug? Or is there a peripheral module between the plug and the PCM?

 

I just bought a 2006 5.3/4L60e from a tahoe that is drive by wire. I have the engine harness and ECM, I do not have the underhood fuse box or dash harness. woul it be easier to find the inputs and hook up my own relays for power or try to find the other two harness for this? I am very good with wiring if I could find out what wires need what. the plug above is where my harness stops
thanks

 

hey do u have DIAGRAM OF HOW I CAN USE THE STOCK 5.3 WIRING HARNESS IN MY 71 C10

 

https://ls1tech.com/forums/conversions-swaps/872006-misc-harness-info-i-ve-put-together.html

some info is here, shows where to hook 12v+ for injectors, coils, pcm, also has info for pin locations for stuff for obd2 port, ses light, speed signals, etc.

 

Okay, here is an excel file with the pinouts for the...

Underhood Connector - Big black connector with multiple rows of pins
C100 - black in color usually, 16 pins
C152 - blue in color, 12 pins
C153 - black, 3 pins (maybe only two installed)

Attached excel file, each year has its own page on this excel file, see the tabs at the bottom.

 

We have wired ours up this way but we have no power to these fuses: pcm1,ETC,inj1,inj2. The fuel pump relay is also not switching on.
We sent the pcm out to have the vats removed. But maybe it didnt get done?

 

bump. anybody know?

 

What year is your engine. I can only state that the info I posted is good for a '99. That being said, have you connected 12v from the battery to the terminal on the side of the fuse block?

 

this is for a 99



see circled pins on picture above
C1- B11 - RED this wire feeds 12v Battery+ to ignition switch, hot at all times.

C1 - A9 - PINK - this wire is FROM ignition switch, hot in RUN, START. This powers up fuses on block.

C3 - F1 - GRAY - Power feed to fuel pump.

You will also have to feed hot in RUN & START 12v+ down C100 pin C. This powers up PCM and auto trans. Protect it with 10 amp fuse. This wire Usually gets its power from IGN 0 fuse in the underdash fuse block.
This Help??

 

thanks! just want to make sure. on c100 pin c. do you mean pin c-1? is will it be an empty pin slot?