Won't start after engine swap
Thread Starter
Staging Lane
Joined: Apr 2016
Posts: 52
Likes: 0
Won't start after engine swap I swapped the engine in the truck and it won't start. Went from 5.3 to 6.0. 6.0 was completely rebuilt- crank, rods, pistions, heads, whole deal.
After it was all put back together hooked up the battery and turned the key to acc. Dash lit up and fuel pump primed. Turned key off and released air from fuel via the schrader valve on the rail. Turned key back to acc, dash lit and pump primed. Radio came on and fan blower in the cab spun up. Turned key to off, rechecked all the connections, and visible grounds. Turned key to start and everything went dead and now nothing will light up.
During reassmbly sanded all the gounds on the block and frame and the connectors. Reused all the sensors, cam, crank, temp, etc, they were all working before starting the swap. Pre oiled the motor, could turn by the crank bolt before plugs were in. Has to be electrical, checked all the fuses for ignition, none blown. Tried to jump it with the other car, cab light did not even come on.
What are the top five things to check next?
After it was all put back together hooked up the battery and turned the key to acc. Dash lit up and fuel pump primed. Turned key off and released air from fuel via the schrader valve on the rail. Turned key back to acc, dash lit and pump primed. Radio came on and fan blower in the cab spun up. Turned key to off, rechecked all the connections, and visible grounds. Turned key to start and everything went dead and now nothing will light up.
During reassmbly sanded all the gounds on the block and frame and the connectors. Reused all the sensors, cam, crank, temp, etc, they were all working before starting the swap. Pre oiled the motor, could turn by the crank bolt before plugs were in. Has to be electrical, checked all the fuses for ignition, none blown. Tried to jump it with the other car, cab light did not even come on.
What are the top five things to check next?
Not sure if the full-size trucks have them but I know some GM products have a huge 200 amp Maxi type fuse that protects just about everything. I would trace your positive cable and make sure you didn’t blow this fuse. If you blew the fuse STOP and figure out what happened because that fuse doesn’t blow just because, something had to be majorly shorted. Also check all your cable connections and grounds too. Sometimes when you twist a positive cable to get it out of the way sometimes loosens the cable on whatever it’s attached to so check the cable connections on the Maxi connector and on the fuse block.
It sounds like something is wrong with your battery and/or starter wiring. Did you connect the battery feed to the starter and the alternator correctly? You said you sanded the grounds, so I assume you properly connected the batter ground to the block and the block to chassis ground. Check all of your fuses (including the big ones) with a multimeter for continuity. Good luck.
I see this at the shop all the time. Pull your battery terminals and clean them with water and a wire brush and put back together. Bet it solves your issue.
I had this happen on the day I sold my SS lol. The guy looked at it several times and drove it. He handed me money and got in it to leave and it wouldn't start and did exactly what yours did.
When you have a bad battery connection it will allow enough power through for all the small stuff, but as soon as you ask for a lot of amps (starter) it completely breaks the connection. I test for it by grabbing the cable and turning it, if that brings the connection back I pull them off and clean them.
If it was the starter connection you'd only lose the starter, not everything.
I had this happen on the day I sold my SS lol. The guy looked at it several times and drove it. He handed me money and got in it to leave and it wouldn't start and did exactly what yours did.
When you have a bad battery connection it will allow enough power through for all the small stuff, but as soon as you ask for a lot of amps (starter) it completely breaks the connection. I test for it by grabbing the cable and turning it, if that brings the connection back I pull them off and clean them.
If it was the starter connection you'd only lose the starter, not everything.
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If the cleaning the battery terminals suggestion doesn't fix the problem try this...
A couple of times on high mile cars and trucks with automatic transmissions, I've seen folks not be able to start the vehicle because the gear selector looks like it's in PARK but actually isn't. Turning the key on and moving the gear selector through all positions then back to park usually takes care of the issue. It's almost like something didn't click or connect going into park so the PCM won't allow cranking because it thinks the car or truck is in reverse gear.
Depending on year sometimes the VATS ignition key won't read because it gets worn. Might try the other ignition key if the truck has VATS.
A couple of times on high mile cars and trucks with automatic transmissions, I've seen folks not be able to start the vehicle because the gear selector looks like it's in PARK but actually isn't. Turning the key on and moving the gear selector through all positions then back to park usually takes care of the issue. It's almost like something didn't click or connect going into park so the PCM won't allow cranking because it thinks the car or truck is in reverse gear.
Depending on year sometimes the VATS ignition key won't read because it gets worn. Might try the other ignition key if the truck has VATS.
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Staging Lane
Joined: Apr 2016
Posts: 52
Likes: 0
@00pooterSS
I rechecked all the grounds and cleaned the crap out of the ground strap to the firewall. Disconnected the battery and cleaned that like crazy. Cranked up on the first key turn!
You are a life saver!
It runs like crap, needs a tune badly, but it runs. Kept it running and varying the RPM between idle and 2500 until it got up to 210 coolant temp to seat the rings. Running lean so did not want to push the revs.
Thanks again.
I rechecked all the grounds and cleaned the crap out of the ground strap to the firewall. Disconnected the battery and cleaned that like crazy. Cranked up on the first key turn!
You are a life saver!It runs like crap, needs a tune badly, but it runs. Kept it running and varying the RPM between idle and 2500 until it got up to 210 coolant temp to seat the rings. Running lean so did not want to push the revs.
Thanks again.
@00pooterSS
I rechecked all the grounds and cleaned the crap out of the ground strap to the firewall. Disconnected the battery and cleaned that like crazy. Cranked up on the first key turn!
You are a life saver!
It runs like crap, needs a tune badly, but it runs. Kept it running and varying the RPM between idle and 2500 until it got up to 210 coolant temp to seat the rings. Running lean so did not want to push the revs.
Thanks again.
I rechecked all the grounds and cleaned the crap out of the ground strap to the firewall. Disconnected the battery and cleaned that like crazy. Cranked up on the first key turn!
You are a life saver!It runs like crap, needs a tune badly, but it runs. Kept it running and varying the RPM between idle and 2500 until it got up to 210 coolant temp to seat the rings. Running lean so did not want to push the revs.
Thanks again.