Tomorrow I have a meeting with "The Car Guys Garage" to see about tuning the GM Crate HT383 engine with the Holly Terminator Stealth EFI Master (NOTE: This is the Holley Terminator Stealth BUT with the HP/Dominator ECU..  Starting v6 never upgrade ECU FW with handheld plugged in.  How can you tell if you have the HP/Dominator ECU?  Guy said the back of the ECU on the far right is a blue plug like the one shown here its HP/Dominator ECU.  The blue plug is where you plug your USB cable from laptop to)

Sounds like they have some good reviews and so figured let's give them a shot at figuring out how to get my truck running like it should. It has been very very difficult to find anyone that even wants to touch this Holly setup.  Apparently starting at $650 they are willing to give it a shot.  They said 2-3 days of tuning and running it on the dyno I'll have it back purring like a kitten.

I'm hoping the fuel economy gets a bit better.  Its worse now then ever before the new engine and the fuel conscious Holly EFI

Holly Terminator 550-441k - $3500 (on average)

Holley has you covered with the new Terminator Stealth Throttle Body Fuel injection System. Now you can have all of the benefits of EFI and maintain the traditional looks of a carburetor. Holley's Terminator Stealth EFI systems have the same great self-tuning features of our Terminator EFI in a new stealthy package! - Easy to install - No computer experience required - Handheld tuner included - Simple multiple choice set-up wizard - Self-tunes while you drive - Upgradable to complete laptop control without buying another ECU - Carburetor replacement EFI from the fuel systems experts!

Features:

• Carburetor looks with the drivability of EFI
• Trouble-free performance with today’s fuels - put an end to vapor lock and fuel varnish problems!
• Fits V8 engines from 250-600 horsepower
• 4150 style 4BBL mounting flange - Bolts on in place of carburetor
• Available in Polished, Classic Gold and Hard Core Gray™ finishes
• Fully self-tuning ECU - No laptop required
• Includes full color, 3.5” touch screen LCD for both basic and advanced tuning options
• Timing control option for GM Small Cap HEI and Ford TFI distributors
• Connections for Ford, GM TH350, 700R4 and other transmission linkages
• Optional free software upgrade for full laptop control
• Easy plug and play harnesses with minimal connections
• Virtually maintenance free - keeps your vehicle reliable and ready to drive
• Master Kits include complete fuel system: fuel pump, filters, 40ft of hose (feed & return), billet regulator and all fittings including fuel tank return line bulkhead fitting

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The Terminator X Stealth 4150 2x4 kit comes ready to install. All you need to have is a fuel system that can support EFI fuel pressures (43-58 PSI) and Holley recommends an ignition system that has timing control, such as the Sniper HyperSpark systems.

Specs:

• BrandHolley EFI
• CFM950
• Emission Code3
• FinishHard Core Gray
• Flange Size4150
• Fuel Pressure43 Psi
• Height3.25"
• Injector Size80Lb/Hr @ 43PSI
• Product TypeTerminator Stealth Kit
• Throttle Bore1.750 inch
• UPC090127732908
• Part Number550-441K

Manual included

 

 

holly_550-441k_manual.pdf

So I was driving around one day and something didn't feel right.  Like it was struggling to keep going.. like it was about to stall but it would recover and be fine for a bit. Then it started to get worse and I went home and parked it and now it won't start.

First thought was spark

Pulled a spark plug wire off and attached a spare spark plug to it, wrapped a wire around the threads and grounded it and turned the blazer over and I could very clearly see spark (no issue with spark)

Next though is fuel

I can see two fuel filters in the path

this filter (pictured above) is located in the engine bay

this filter (FF3504DL pictured above) is located along the frame rail on the passenger side

I changed them both and tried to start the blazer and same results.  It sounds like it wants to start and kinda does but it just struggles to stay running then dies.

**Not giving up on the idea it could be fuel pressure but need to get a fuel pressure gauge to make sure I'm getting whats required.

Next step is to upgrade the FW on the Holly Fuel Injection since thats my troubleshooting is go after what I don't understand since I am unable to troubleshoot it in order to verify its working.

Based on the above image, this is the initial Build (6.0 Build 110) which they are up to Build 300 which was released 2023.04.17

 

IMPORTANT NOTE: You will not be able to plug your laptop into the Holly EFI system without the Holly EFI System USB Cable 558-443

 

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On a holding pattern while I install parallels on my mac and then install windows and all the patches so I can install the windows tuning program necessary to update the firmware

 

 

 

Edited June 1, 20232 yr by wildweaselmi

Found out I caused issues because I did a code upgrade to v6 while having the handheld plugged and the only way you can upgrade the ECU is unplugging the handheld and using a laptop with USB cable.

Step by Step instructions Scott gave me are:

1. Disconnect handheld
2. Plug in USB Cable from laptop to ECU
3. Launch v6 Desktop software
4. click Cancel on the window that pops up
5. CLick on two half circles and then select ECU - Upgrade ECU FW
6. Browse to file

 

HEFI_05001400.eep

Edited June 4, 20232 yr by wildweaselmi