LS in 55 Chevy truck
Thread Starter
Teching In
Joined: Oct 2016
Posts: 22
Likes: 1
From: O'Fallon, MO
LS in 55 Chevy truck I started this 4 years ago. 55.2 Chevy Task Force truck with C4 suspension and an LQ4 4L80E transplant. I had this running and driving. While waiting forever for the body and paint guy after disassembling the truck for paint, I began to lose interest.
I sold the LQ4 and this sat for a couple years. Finally I figured I would restart this project. I found an LM7 and before installing in the truck I hooked all of the wiring (LS engine harness with DBW computer and the chassis harness that was on the truck (brand new 21 circuit wired to the LS engine harness) and started it on the engine stand to make sure the engine was good.
The only issue was the starter would not work with the ignition switch. The fuel pump primed and the throttle actuated. I jumped at the starter with a screwdriver and it fired right up.
I mounted the engine back in the frame and figured the start issue was because of not properly grounded etc. Now with it mounted in the truck the starter still will not function with the ignition switch.
What am I missing??
The battery is good and this was running and driving before but with the LQ4 that the ecm is programmed for.
Checked all fuses
The fuel pump primes and throttle actuates.
All of the wiring is hooked up as before
I am thinking I am missing a ground or something.
I sold the LQ4 and this sat for a couple years. Finally I figured I would restart this project. I found an LM7 and before installing in the truck I hooked all of the wiring (LS engine harness with DBW computer and the chassis harness that was on the truck (brand new 21 circuit wired to the LS engine harness) and started it on the engine stand to make sure the engine was good.
The only issue was the starter would not work with the ignition switch. The fuel pump primed and the throttle actuated. I jumped at the starter with a screwdriver and it fired right up.
I mounted the engine back in the frame and figured the start issue was because of not properly grounded etc. Now with it mounted in the truck the starter still will not function with the ignition switch.
What am I missing??
The battery is good and this was running and driving before but with the LQ4 that the ecm is programmed for.
Checked all fuses
The fuel pump primes and throttle actuates.
All of the wiring is hooked up as before
I am thinking I am missing a ground or something.
TECH Regular
Joined: Nov 2018
Posts: 467
Likes: 116
Did you just use the original starter wire from the factory ignition? If so make sure its hot when you turn the key, if not check back through its connections through the steering column until you find the break.
If it works on the stand with a screwdriver then it works. Make sure the engine is grounded to the battery and frame and body. There is only one wire in your case that it can really be. You can always use a jumper hooked to the solenoid and touch it straight to the positive terminal as well to rule out ground issues. If the engine sensors power up and the fuel pump kicks on then its in the key switch, column or wire from the column.
If it works on the stand with a screwdriver then it works. Make sure the engine is grounded to the battery and frame and body. There is only one wire in your case that it can really be. You can always use a jumper hooked to the solenoid and touch it straight to the positive terminal as well to rule out ground issues. If the engine sensors power up and the fuel pump kicks on then its in the key switch, column or wire from the column.
