Conversions & Swaps LSX Engines in Non-LSX Vehicles
Sponsored by:
Sponsored by:

Need help! Fuel pump trigger

Old May 27, 2020 | 10:20 PM
  #1  
Lightn95's Avatar
Thread Starter
Staging Lane
 
Joined: Feb 2020
Posts: 79
Likes: 1
Default Need help! Fuel pump trigger

I'm new to this but I did search and couldn't find exactly what I needed.

I have a 04 5.3 i swaped into a '53 Cadillac. I Did the LT1SWAP.COM wire harness conversion. We went to start it for the first time and I'm not getting a signal from the ecm (green #9) to trigger the fuel pump. I check continuity and there's no breaks in the wire. I sent the ecm to a local tuner to disable the VATS.
what kind of voltage should I be seeing from the wire when I turn the key? I'm not seeing anything.
what am I missing? Could the ECU be bad, could the VATS still be enabled?

I need help here, I'm so close......i think...... to cruising this thing.

thanks!
Reply
Old May 28, 2020 | 05:14 PM
  #2  
33willys's Avatar
TECH Enthusiast
10 Year Member
Photogenic
Photoriffic
Shutterbug
iTrader: (1)
 
Joined: Mar 2014
Posts: 699
Likes: 59
From: Alamogordo, NM
Default

Are you running the wire directly to the fuel pump or using a relay?
Reply
Old May 28, 2020 | 06:48 PM
  #3  
Lightn95's Avatar
Thread Starter
Staging Lane
 
Joined: Feb 2020
Posts: 79
Likes: 1
Default

I'm using a relay. I checked it with 3 relays and neither one activates.
I tried checking voltage on the the signal wire from the Ecu and I'm not getting any voltage.
I'm going to make sure the ECU is getting voltage tonight.
Reply
Old May 28, 2020 | 08:14 PM
  #4  
33willys's Avatar
TECH Enthusiast
10 Year Member
Photogenic
Photoriffic
Shutterbug
iTrader: (1)
 
Joined: Mar 2014
Posts: 699
Likes: 59
From: Alamogordo, NM
Default

Don't forget, when you turn the key on the pump will prime for about 2 seconds then shut off 'till it sees the engine cranking. So when checking the trigger, do it within the first 2 seconds or crank the engine while checking.
Reply
Old May 28, 2020 | 08:14 PM
  #5  
1964SS's Avatar
TECH Fanatic
10 Year Member
Liked
Loved
Community Favorite
iTrader: (1)
 
Joined: Aug 2012
Posts: 1,539
Likes: 84
From: Mesa, Arizona
Default

I would start by disconnecting pin 9 from relay coil. Apply 12v to relay coil and see if relay and fuel pump kick on. If that all works reconnect to pcm and check ALL pink pcm ignition hots to make sure they are all getting power. Also check ALL constant hot wires and all pcm grounds to make sure you didn't miss any.
Reply
Old May 28, 2020 | 10:19 PM
  #6  
Lightn95's Avatar
Thread Starter
Staging Lane
 
Joined: Feb 2020
Posts: 79
Likes: 1
Default

Found the issue. The thermal the fuel pump fuse plugs into wasn't clipped into the fuse block. So when the fuse was put in, it pushed the terminal down, instead of clipping into it.
it fired right up but now I have a CEL on and low oil pressure light on.
Reply


Thread Tools
Search this Thread

All times are GMT -5. The time now is 10:35 PM.

story-0
Topdon ONE vs. Artidiag 800 BT2: Which is the Diagnostic Tablet For You?

Slideshow: We take a close look at the ONE and Artidiag 800BT2 diagnostic tools from Topdon and the reasons to buy one over the other.

By Pouria Savadkouei | 2026-05-28 11:05:11


VIEW MORE
story-1
Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine

Slideshow: The controversial Ferrari F6 swaps its original flat-12 for a Corvette Z06-derived LT4 V8 and sends power to four rear wheels through a custom-built drivetrain.

By Verdad Gallardo | 2026-05-26 18:23:54


VIEW MORE
story-2
7 Most Reliable High-Performance Engines GM Has Ever Built

Slideshow:These GM engines didn't just make huge power, they survived abuse, boost, track days, and six-digit mileage with a reputation for refusing to quit.

By Verdad Gallardo | 2026-05-21 16:45:27


VIEW MORE
story-3
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin

Slideshow: This heavily modified 1971 Camaro mixes classic muscle car styling with a fifth-generation Camaro interior and modern LS3 power.

By Verdad Gallardo | 2026-05-12 18:06:42


VIEW MORE
story-4
6 Common C5 Corvette Failures and What's Involved In Repairing Them

Slideshow: From wobbling harmonic balancers to failed EBCMs, these are the issues that define long-term C5 ownership and what repairs typically involve.

By Pouria Savadkouei | 2026-05-07 18:44:57


VIEW MORE
story-5
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph

Slideshow: A modern Camaro transformed into a retro icon, this limited-run "Bandit" build blends nostalgia with brute force in a way few revivals manage.

By Verdad Gallardo | 2026-04-21 13:57:02


VIEW MORE
story-6
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked

Slideshow: Cadillac didn't just crash the high-performance luxury vehicle party, it showed up loud, supercharged, and occasionally a little unhinged...

By Pouria Savadkouei | 2026-04-16 10:05:15


VIEW MORE
story-7
Top 10 Most Powerful Chevy Trucks Ever Made!

Slideshow: Top ten most powerful Chevy trucks ever made

By | 2026-03-25 09:22:26


VIEW MORE
story-8
Hennessey's New Supercharged Silverado ZR2 Has 700 HP

Slideshow: Hennessey has turned the Silverado ZR2 into a 700-hp off-road monster with supercharged V8 power and a limited production run.

By Verdad Gallardo | 2026-03-24 18:57:52


VIEW MORE
story-9
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes

Slideshow: A one-off sports car that looks like a vintage Italian exotic-but hides a C6 Corvette underneath-just sold for the price of a new mid-engine Corvette.

By Verdad Gallardo | 2026-03-23 18:53:41


VIEW MORE