Yet another MSD crank trigger wiring question - Page 2

Jeff Niceswanger · 02-13-2024, 10:58 AM

If your TB has the long old style ob-longed TPS plug get the Steathram harness which is # 558-101. If it has the small round TPS plug get the 558-104. Both will plug right into your 558-431Cam/Crank (Trigger) harness. The 431 will plug right into your new 118 crank trigger hall effect sensor.Yes, you can just tie off the cam sync plug if you are not using a cam sync. The white wire goes to the points input on your MSD box with both harnesses.Make absolutely sure you take both 12 gauge red and black supply lines directly to the positive and negative post on the battery.. DO NOT put the red wire on the Kill switch. I've seen this many times and it will give you all kinds of stupid random issues.

https://documents.holley.com/techlib...10555rev16.pdf

Rob Petrie E395 · 02-13-2024, 04:00 PM

Well I didn’t know the 558-104 harness existed until I just read this. So I have the 558-101 harness and just bought the correct connector for the Iac valve (I also have the adapter from square to flat connectors). But once I got it. I thought it would look bad so I ordered the right connector from Holley. I have the right connectors for the TPS too. But wish I had known this when I was ordering. Uuugghh. I took the first of the 3 Holley classes a while ago. And they really tried to drive the point home about connecting to the battery. I run a battery with top and side terminals. So it’s easier to charge between rounds. So my plan it to run the car off one set of posts. And the ECM main power harness off the other set by itself. One thing other thing told us. Is if you wire the main power harness to the kill switch or somewhere else. And someone hits the kill switch while the car is running or Key on engine off. It can delete the global file. Can you imagine the pain in the rear that could be?

Jeff Niceswanger · 02-13-2024, 07:11 PM

I've had a couple lose the tune. A real slow drain on the battery to where it goes completely dead will lose them. Like leaving the water pump on all night or such. Always keep your tune on your laptop or a flash drive. Or both.

02-13-2024, 10:58 AM	#11
Jeff Niceswanger Senior Member Join Date: Jul 2003 Posts: 771 Likes: 588 Liked 839 Times in 293 Posts	Re: Yet another MSD crank trigger wiring question If your TB has the long old style ob-longed TPS plug get the Steathram harness which is # 558-101. If it has the small round TPS plug get the 558-104. Both will plug right into your 558-431Cam/Crank (Trigger) harness. The 431 will plug right into your new 118 crank trigger hall effect sensor.Yes, you can just tie off the cam sync plug if you are not using a cam sync. The white wire goes to the points input on your MSD box with both harnesses.Make absolutely sure you take both 12 gauge red and black supply lines directly to the positive and negative post on the battery.. DO NOT put the red wire on the Kill switch. I've seen this many times and it will give you all kinds of stupid random issues. https://documents.holley.com/techlib...10555rev16.pdf __________________ Jeff Niceswanger 3740 SS Last edited by Jeff Niceswanger; 02-13-2024 at 11:22 AM.

02-13-2024, 04:00 PM	#12
Rob Petrie E395 VIP Member Join Date: Dec 2007 Location: Woodlawn IL Posts: 1,093 Likes: 162 Liked 220 Times in 79 Posts	Re: Yet another MSD crank trigger wiring question Well I didn’t know the 558-104 harness existed until I just read this. So I have the 558-101 harness and just bought the correct connector for the Iac valve (I also have the adapter from square to flat connectors). But once I got it. I thought it would look bad so I ordered the right connector from Holley. I have the right connectors for the TPS too. But wish I had known this when I was ordering. Uuugghh. I took the first of the 3 Holley classes a while ago. And they really tried to drive the point home about connecting to the battery. I run a battery with top and side terminals. So it’s easier to charge between rounds. So my plan it to run the car off one set of posts. And the ECM main power harness off the other set by itself. One thing other thing told us. Is if you wire the main power harness to the kill switch or somewhere else. And someone hits the kill switch while the car is running or Key on engine off. It can delete the global file. Can you imagine the pain in the rear that could be?

02-13-2024, 07:11 PM	#13
Jeff Niceswanger Senior Member Join Date: Jul 2003 Posts: 771 Likes: 588 Liked 839 Times in 293 Posts	Re: Yet another MSD crank trigger wiring question I've had a couple lose the tune. A real slow drain on the battery to where it goes completely dead will lose them. Like leaving the water pump on all night or such. Always keep your tune on your laptop or a flash drive. Or both. __________________ Jeff Niceswanger 3740 SS Last edited by Jeff Niceswanger; 02-13-2024 at 11:36 PM.