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'72 K5 - BYT - 1 ton swap

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6p0swap219.jpg

This is what most of the last few days have looked like around here, but I hit another milestone this evening. I finally got all of the wiring finished and reinstalled! :woot:

I still have to hook up the radiator before I can try to start it but I did hook the battery back up and turn the key to "on" just to see what would happen. I heard what sounds like the alternator doing something and the speedo lite up with an odometer reading of 2. :rolleyes: I couldn't help myself and I did give it the tiniest kick of the starter just to see if it would turn over an it did do that at least. :waytogo:

A couple of concerns though. When I turned the key to "on" I expected to hear the fuel pump fire up and I didn't hear anything. Also, the check engine light was on. That might be normal with the key on and the engine not running though.

All in all another good day. It shouldn't take long to get the core support and radiator back in in the morning so that I can spend the rest of the day troubleshooting whatever comes up. :woot:
 
Yeah, check engine light should always be on with key on/not running.

Getting there!
 
I pulled the old 383 December 7th. Started the 6.0 today!


After chasing wires for a little while to make sure everything was hooked up correctly it occurred to me that The PCM was just sitting on the tire... Not grounded. :doah: Once I ran a wire to ground it everything came right on and it started without issue. :woot:

A couple of things I noticed while it was running. The tach isn't working and the check engine light is still on. More troubleshooting ahead, but I'm pumped it's running!
 
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AJs72K5 said:
Dammit!! Great job! That's gotta feel good.
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lol, does that mean I win? :haha:

Thanks guys. I was pretty pumped when it fired up so quickly. I'll have to chase down why the tach isn't working but for the most part I'm ready to start buttoning things up. I've only actually had it running for a couple of minutes, but the only issue I've seen so far is a few fuel leaks. All of those were easily fixed by either tightening fittings or switching to better hose clamps. Several of the oem style spring type clamps I used on my return line weren't up to the task. I switched them out for normal hose clamps and it was all good.

If the weather is decent tomorrow I'll pull the truck outside and let it run until it gets up to temp. One thing I've noticed already is just how much cleaner this engine burns than my last one. I've only had it running for a couple of minutes in the shop but with the last engine that would have been enough to make it unbearable in there. It smelled like exhaust and I did need to air it out but it wasn't nearly as bad.

Oh, and one other thing. In the video after I start it I go around to the engine like I always do on a fresh start up and my first instinct is to pull on the throttle cable and get video of the new engine going vroom, vroom. I was kinda at a loss there for a second when I realized there was no throttle cable anymore. :rolleyes: I had to go back into the cab to rev the engine. :doah:
 
Your tach issue may be PCM related. They are a 4cyl signal from the factory. Do you know if yours was flashed for a 8cyl sig when the rest of the flash was done?

Nice job on getting this going! I've been selling a lot of these swaps and harnesses. Have yet to do one for myself....
 
Thanks guys, I'm pretty excited!

POORBOYK5 said:
Your tach issue may be PCM related. They are a 4cyl signal from the factory. Do you know if yours was flashed for a 8cyl sig when the rest of the flash was done?

Nice job on getting this going! I've been selling a lot of these swaps and harnesses. Have yet to do one for myself....
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Bigblock72 did my PCM for me and I'm pretty sure he flashed it for 8cyl but I can check into it. Even if that was the case though, wouldn't it just be reading too slow or too fast or something? The fact that it wasn't moving at all makes me suspect it either isn't getting a signal or isn't getting power.

If I put a test light or multimeter on the input signal, what should I expect to see? pulses I assume. :dunno:

Another couple of issues came up that are somewhat frustrating. First, somehow I've broken the headlight switch. When I installed the new dash and went to insert the knob it wouldn't stay in. I guess the retainer piece inside must have broken. :doah: Looks like I'll have to source a new one.
Also, while fishing the wires over for the heater control I noticed that it was sitting at a funny angle so I pulled it out to see what the problem was.
Heater_controls1.jpg

Sorry for the fuzzy pic, but you should be able to see that the back has pulled free of the rivets that hold it to the face. Unfortunately, the rivets are molded into the face so there isn't any way to replace them. Gonna have to get a new one of these as well.
 
Why is your idle so hi and why was it slow to come back down to an idle after you blipped the throttle? ECM still "learning" I assume?
 
rjfguitar said:
Why is your idle so hi and why was it slow to come back down to an idle after you blipped the throttle? ECM still "learning" I assume?
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I'm assuming the same thing, but I do have a check engine light on so maybe something is up.
It does drop right as I get back into the cab before I touch anything so maybe it's just warming up a bit first. I did keep the crank wire connected and it is supposed to tell the PCM when the engine is cranking so maybe it sets the idle higher among other things to make it easier to start. Just a guess. :dunno:

I pushed the truck out of the garage and let it idle until it got up to temp. Everything seemed to work just fine although I don't have my fans hooked up yet so I guess I wasn't able to verify that they work.
I did learn a few things though. First off, I learned that I either need a SYE or I should reinstall the driveline before running it that long. Nice puddle on the driveway from the back of the transfer case. :doah:

The more useful bit of info was that when I hit the throttle the speedometer went nuts while the tach did nothing. My first thought was that I had maybe gotten the wires switched so that would have been an easy fix. Unfortunately I traced them both all the way back to the PCM and both are hooked up correctly. The white tach wire goes back to pin 10 and the green/white speedo wire goes to pin 50, both on the green connector.

According to my schems this is correct but maybe it's possible that the engine speed and vehicle speed signals were swapped in the program? I guess I'll have to investigate that further.

Another issue fixed is my headlight switch. The problem was that I forgot to push the little button up on the top before jamming the knob in. The switch works by pushing a little "shuttle" back and forth in a slot. When I jammed the knob in it pushed the shuttle back and out of the way of the button. With the switch out I was able to remove the metal cover and push the shuttle back forward and everything was good again. :waytogo: I probably should have gotten pics of the process but I forgot until it was back in.
 
Congrats on getting it running with no drama:waytogo::woot:.

It's normal for the idle to do weird things (especially DBW) until the PCM learns everything. I did bump the base idle up a little because the factory 550 rpm is a too low especially off road.

The tach and speedo signals are hard wired internally in the pcm for function and there is no way to switch them with software. The software settings are only for setting the number of pulses per revolution.

My guess is the transmission and transfer case are spinning since there is no rear drive shaft to stop it even though the trans is in neutral.

The tach problem is probably a wiring issue or possibly a bad tach.:confused::dunno::dunno:

Do you have a way to check codes?
 
That make sense on the speedo. I did notice the transmission output was spinning without the driveline attached.

I traced out the wiring on the tach and the signal line looks good. I can double check to see if it's getting power though. I guess it could be bad. That would suck.

I can't check codes yet. I'll have to wait until I finish putting it together so that I can drive the truck somewhere to get the codes.
 
OBDII reader came in today!

The good news, no fault codes are being stored on the PCM. :woot:

The bad news... the check engine light is on. :confused: I guess I messed up the wiring somewhere.

On a side note, I got the drivelines resized and reinstalled today.
 
If I don't find anything after checking the wiring again I'll contact autometer and see what they say.
 
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