LS3 ignition problems; no spark
Thread Starter
Racer
Joined: Sep 2010
Posts: 302
Likes: 14
From: Northern Ca.
LS3 ignition problems; no spark
No Spark on my LS swap. I have fuel to the rails, but can't get it to fire up. I think there are a few that have had similar issues. I only have two power options to hook to my harness; power to the cranking source( purple, key in the start/crank), and 12v switched ignition off the braided coil wire to my ECU. Wondering if I have it backwards. The purple runs through my neutral safety and the starter (cranking). The braided is hot with the key on; which I believe to be the ignition source. Are there any other ignition sources for power in the start/crank and run besides the braided coil wire? 70 harness up to LS harness.
Thanks.
Thanks.
Race Director
Joined: Sep 1999
Posts: 11,361
Likes: 383
From: Plano TX
The braided wire is a resistance wire that drops the voltage at the coil to 9V. That may not work for the LS3.
You need to remove the braided wire and run a new wire from the engine side of the fuse block.
You need to remove the braided wire and run a new wire from the engine side of the fuse block.
Tech Contributor
Joined: Jun 2004
Posts: 20,905
Likes: 962
From: I tend to be leery of any guy who doesn't own a chainsaw or a handgun.
No Spark on my LS swap. I have fuel to the rails, but can't get it to fire up. I think there are a few that have had similar issues. I only have two power options to hook to my harness; power to the cranking source( purple, key in the start/crank), and 12v switched ignition off the braided coil wire to my ECU. Wondering if I have it backwards. The purple runs through my neutral safety and the starter (cranking). The braided is hot with the key on; which I believe to be the ignition source. Are there any other ignition sources for power in the start/crank and run besides the braided coil wire? 70 harness up to LS harness.
Thanks.
Thanks.
Thread Starter
Racer
Joined: Sep 2010
Posts: 302
Likes: 14
From: Northern Ca.
Switched signal to run the ECM. Thanks.
Melting Slicks
Joined: Sep 2004
Posts: 2,655
Likes: 19
What he said. The old ignitions were not hot to the run wire with the key in crank position. Voltage was supplied to the coil off the starter solenoids ballast resistor bypass wire. Your LS starter wont have that capability.
Also VATS typically disables the fuel pump. But I've seen some TBSS motors that had ignition disable too.
Also VATS typically disables the fuel pump. But I've seen some TBSS motors that had ignition disable too.
Thread Starter
Racer
Joined: Sep 2010
Posts: 302
Likes: 14
From: Northern Ca.
Its not supposed to have any VATS. I had Current Performance clean it all out. I was reminded from Riggs that the pink on the switch side is probably where I need to run my ECM switched wire to; s canning the braided all together. I think I can either tap into the wire itself, or on the fuse box.
Last edited by DEEPSEA70; Jul 18, 2013 at 03:31 PM. Reason: No VATS
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Tech Contributor
Joined: Jun 2004
Posts: 20,905
Likes: 962
From: I tend to be leery of any guy who doesn't own a chainsaw or a handgun.
Its not supposed to have any VATS. I had Current Performance clean it all out. I was reminded from Riggs that the pink on the switch side is probably where I need to run my ECM switched wire to; s canning the braided all together. I think I can either tap into the wire itself, or on the fuse box.
Thread Starter
Racer
Joined: Sep 2010
Posts: 302
Likes: 14
From: Northern Ca.
Right now I have the braided coil wire hooked to the switched 12V for the ECM, but I have since figured based on my wiring diagram and input from others that this is wrong due to the voltage drop and inconsistent input. I am going to rewire the switched 12 V from the ECM to the dash side off the pink ignition switch wire; which should do the trick.
Oh by the way, I own a Glock .45
Thanks
Oh by the way, I own a Glock .45
Thanks
Thread Starter
Racer
Joined: Sep 2010
Posts: 302
Likes: 14
From: Northern Ca.
Still no spark
I hooked my ECM 12V switched wire to the IGN post in the fuse box since I had power there with the switch. Just a starting point since it was the easiest point to attach. But, it shares power with DIR SIG, Back up lights, and gauges. Would it be wrong to assume I can use the IGN post to power the ECM. My next; and I believe last option, is to connect directly to the pink switch wire. I have fuel pump, and fuel to the rails, and the throttle body clicks when powering up and I think good grounds. Any additional thoughts. Thanks.
Thread Starter
Racer
Joined: Sep 2010
Posts: 302
Likes: 14
From: Northern Ca.
Power to relays, still no spark at the plugs
I have the 12v switch directly from the pink ignition switch. Crank signal to the Purple start crank has power. It shows power at the relays and fuses. Grounds all look good. Still no spark at the plugs. I'm not sure if maybe my coil packs and injectors my be suspect, or something else wrong with my harness. I might have to send it back to Current Performance if maybe my ECM has problems after the programming. Running out of ideas. Need spark.
Instructor
Joined: Oct 2013
Posts: 181
Likes: 5
From: Ontario, Canada
Another thought .... assuming an E38 ECU (I dont know about other ECUs), the clutch failsafe has to be programmed out using HPtuners (in addition to VATS, etc). The E38 wont enable ignition otherwise ... even though its powered (by key "run") and is sensing the engine cranking (from the cam and crank pos sensors).
Regards
eboch
Regards
eboch