If you are using a BP-Automotive stand alone engine harness, please chime in! - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Steve Cole · 04-10-2019, 03:11 PM

I have a question or two about how you routed everything.

Thanks,

**1971Stepside** · 04-10-2019, 04:07 PM

I have one. What do you want to know?

sprint_9 · 04-10-2019, 10:13 PM

Ive got one aswell.

Steve Cole · 04-11-2019, 01:24 PM

If you mounted your ECM in the cab, where did you drill your hole in the firewall?

I drilled mine dead center, directly behind the engine. When I went to route the harness, I noticed the harness didn't lay right, I.e. Some of the legs were too long and some were too short. When I asked BP about it, I was told the harness was designed to come in on the passenger side and wrap around the intake (front or rear) to the driver side. I didn't recall ever seeing that in print or I would have drilled the hole accordingly. I will be able to make it work just fine, but to do so, it has to make a joggle about 6-8" towards the passenger side as soon as it comes through the firewall.

My question is, is this common knowledge? Did you guys know it needed to come in on the passenger side? It is not mentioned in the installation guide, in fact it says "determine where you want to drill your hole in the firewall"
Like I said, I can make it work, but it would have been neater if I had drilled the hole on the passenger side. Other than that, I think it is top quality.

How did your install go?

sprint_9 · 04-11-2019, 02:03 PM

Mine routes down the back of the engine and ties to a couple spots on the transmission, it then comes up through the center of the floor under the seat. No holes in the firewall for my engine harness.

Before I drilled anything I laid the harness on the motor and figured out it would work best through the floor.

**1971Stepside** · 04-11-2019, 10:29 PM

I did the same thing as Sprint. I ran mine down the back of the engine and in the trans tunnel. Hole is just to the passenger side of center under the seat. I had to buy a longer wire set for the gas pedal, but it all fit nicely. Two things I would change about the harness. I wish you didn’t have to feed it from the cab out. Gonn be a pain to pull it all off for paint and put it all back on...a time or two. Second thing is the fuse holder being impossible to mount anywhere.

Steve Cole · 04-12-2019, 08:59 AM

yeah in hindsight, I wish I had run mine like you guys did. Oh well.

04-10-2019, 03:11 PM	#1
Steve Cole Registered User Join Date: May 2012 Location: Faith,NC Posts: 1,626	If you are using a BP-Automotive stand alone engine harness, please chime in! I have a question or two about how you routed everything. Thanks,

04-10-2019, 04:07 PM	#2
1971Stepside Almost Satisfied Join Date: Mar 2002 Location: Springfield, MO Posts: 2,932	Re: If you are using a BP-Automotive stand alone engine harness, please chime in! I have one. What do you want to know? __________________ 1971 C10 Stepside. LSx 6.0 with BTR Stage IV, Speed Engineering Headers, 4L80e transmission w/3200 Circle-D Stall. 3.73. Posi. Purchased this truck when I was 17. I started the rebuild (or take apart) in 1993. I have drug it around all over the country in pieces. Finally back on the road in 2021. "I can't complain, but sometimes I still do. Life's been good to me so far."

04-10-2019, 10:13 PM	#3
sprint_9 Registered User Join Date: Nov 2012 Location: 9 Posts: 862	Re: If you are using a BP-Automotive stand alone engine harness, please chime in! Ive got one aswell. Last edited by sprint_9; 04-10-2019 at 10:19 PM.

04-11-2019, 01:24 PM	#4
Steve Cole Registered User Join Date: May 2012 Location: Faith,NC Posts: 1,626	Re: If you are using a BP-Automotive stand alone engine harness, please chime in! If you mounted your ECM in the cab, where did you drill your hole in the firewall? I drilled mine dead center, directly behind the engine. When I went to route the harness, I noticed the harness didn't lay right, I.e. Some of the legs were too long and some were too short. When I asked BP about it, I was told the harness was designed to come in on the passenger side and wrap around the intake (front or rear) to the driver side. I didn't recall ever seeing that in print or I would have drilled the hole accordingly. I will be able to make it work just fine, but to do so, it has to make a joggle about 6-8" towards the passenger side as soon as it comes through the firewall. My question is, is this common knowledge? Did you guys know it needed to come in on the passenger side? It is not mentioned in the installation guide, in fact it says "determine where you want to drill your hole in the firewall" Like I said, I can make it work, but it would have been neater if I had drilled the hole on the passenger side. Other than that, I think it is top quality. How did your install go?

04-11-2019, 02:03 PM	#5
sprint_9 Registered User Join Date: Nov 2012 Location: 9 Posts: 862	Re: If you are using a BP-Automotive stand alone engine harness, please chime in! Mine routes down the back of the engine and ties to a couple spots on the transmission, it then comes up through the center of the floor under the seat. No holes in the firewall for my engine harness. Before I drilled anything I laid the harness on the motor and figured out it would work best through the floor.

04-11-2019, 10:29 PM	#6
1971Stepside Almost Satisfied Join Date: Mar 2002 Location: Springfield, MO Posts: 2,932	Re: If you are using a BP-Automotive stand alone engine harness, please chime in! I did the same thing as Sprint. I ran mine down the back of the engine and in the trans tunnel. Hole is just to the passenger side of center under the seat. I had to buy a longer wire set for the gas pedal, but it all fit nicely. Two things I would change about the harness. I wish you didn’t have to feed it from the cab out. Gonn be a pain to pull it all off for paint and put it all back on...a time or two. Second thing is the fuse holder being impossible to mount anywhere. __________________ 1971 C10 Stepside. LSx 6.0 with BTR Stage IV, Speed Engineering Headers, 4L80e transmission w/3200 Circle-D Stall. 3.73. Posi. Purchased this truck when I was 17. I started the rebuild (or take apart) in 1993. I have drug it around all over the country in pieces. Finally back on the road in 2021. "I can't complain, but sometimes I still do. Life's been good to me so far."

04-12-2019, 08:59 AM	#7
Steve Cole Registered User Join Date: May 2012 Location: Faith,NC Posts: 1,626	Re: If you are using a BP-Automotive stand alone engine harness, please chime in! yeah in hindsight, I wish I had run mine like you guys did. Oh well.

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