5.3 ls starting issues
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Joined: Jul 2023
Posts: 2
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From: Alberta Canada
5.3 ls starting issues I have a 66 c10 5.3 LS swap that has been giving me starting issues. It only happens when the truck is hot and it is a hot day, 25-30 degrees C (75-85F). In the mornings when everything is cold it starts fine with no issues. When the truck is hot the starter will try to engage but goes cluck against the flex plate. I have done the following and nothing has helped. I can make it start by grabbing the serpentine belt and rotate it slightly, I assume I am lining up the teeth on the flex plate so the starter will actually engage.
Changed the starter
Added a heat blanket around the starter
Changed the power wire from the starter to the battery
Added a ground from the frame to the engine
Replaced the ground from the battery to the engine
Replaced the battery
Hot wired the starter to eliminate the truck wiring (wire from the big terminal on the starter to a switch and then back to the solenoid)
Shimmed the starter (0.032)
My next possible steps
Shim the starter to 0.063
Drop the transmission to either confirm the flex plate is installed properly (could it be installed backwards?) or replace the flex plate
I don't know much of the history on the LS swap. I bought the truck with the swap already done. I believe it is a L33 engine as it is an aluminium block with 799 heads. It has shorty headers on it but there is lots of clearance between them and the starter and there is no exhaust leak.
I don't really want to drop the transmission but I'm not sure what else to do at this point. Any help would be much appreciated
Changed the starter
Added a heat blanket around the starter
Changed the power wire from the starter to the battery
Added a ground from the frame to the engine
Replaced the ground from the battery to the engine
Replaced the battery
Hot wired the starter to eliminate the truck wiring (wire from the big terminal on the starter to a switch and then back to the solenoid)
Shimmed the starter (0.032)
My next possible steps
Shim the starter to 0.063
Drop the transmission to either confirm the flex plate is installed properly (could it be installed backwards?) or replace the flex plate
I don't know much of the history on the LS swap. I bought the truck with the swap already done. I believe it is a L33 engine as it is an aluminium block with 799 heads. It has shorty headers on it but there is lots of clearance between them and the starter and there is no exhaust leak.
I don't really want to drop the transmission but I'm not sure what else to do at this point. Any help would be much appreciated
