Wanted to share what I used to make a Holley Terminator X Max system work on my original L98. 1987 L98 with mild cam, exhaust, and intake work. Also factory 700r4 for now. I do plan to wire the TCC lockup to the holley at a later point.

Items needed

• Terminator x system of your choosing, I went with the X Max #550-916 for later use of a 4L60/80E. This a 24x/1x system with EV1 injector connectors matching our factory injectors.
  
• 24x reluctor wheel from EFI Connection #120-00086. I choose to piece everything together but they do offer complete kits depending on engine.
  
• Cam sensor/distributor from 96-99 vortec #GM01 from rockauto, also this requires a different cam sensor connector. I bought mine from efi connection #100-01104
  
• Crank Sensor from a 96-99 vortec #s10107 rockauto
  
• If you have the KC4 oil cooler option from factory it will not work with the crank sensor location. I removed mine and replace it witch a separate unit. #DER-15720 adapter plate to a standalone oil cooler.
  
• Timing Cover with provision for crank sensor from any 96-99 vortec should work, I went with an aluminum one #21-153 Summit
  
• TPS & IAC connectors are difference and new ones can be spliced in. I went with an adapter harness for both which worked as the wiring is just long enough now. TPS #109053 Summit and IAC #108172 Summit
  
• Harmonic balancer is something EFI Connection states needs to be trimmed ~2.5 mm to adjust for reluctor wheel thickness. A balancer from a 96-99 vortec is shorter and will work however the tdc mark is in a different location than the factory balancer. I currently have a new stock replacement on and have yet to have any issues. #594-121 AutoZone is the one I have mocked up and will use if I have any issues with the factory balancer.
  
• Other Sensors needed include IAT #su176 AutoZone, MAP (I used the built in one on the holley), oil and fuel pressure # 7990150 LowDollar Motor Sports 0-150psi
  
• Coil packs and harness came from a junkyard 2000’s 5.3 label cylinder 1 & 2 to keep track of even and odd firing for the Holley.
  
• Spark plug wires, I mounted my coils off the engine and made custom plug wires using a builders set of wires for a sbc and a boot/terminal kit for lt1 & ls1 #46069 Summit
  
• CAN-USB #558-443 for laptop tuning
  
• O2 sensor bung if exhaust is lacking one #VPE-11105 Summit
  

Optional Items I upgraded during install

• Timing Chain Single roller (fits inside timing chain cover) #CLO9-1157 Summit
  
• Injectors Accel 30lbs #150830 Summit/Holley
  
• Adjustable Fuel Pressure Regulator #4021 Southbay Fuel Injectors
  
• Can-USB splitter #558-443-2 Current Performance. I use this so I can use laptop and lcd screen at same time
  

If you have A/C and want to retain it, Current Performance has an add on kit just for that. #TermX_AC

Wiring

I roughly followed pockets guide on cutting down a harness to retaining the factory gauges while removing anything not used. The factory oil pressure sender behind the manifold and the coolant temp sensor by #1 cylinder are reused. The Holley has a tach output wire I connected to the solid White wire in the C100 connector. The Holley requires 12v key on while cranking and I used the large solid Pink wire in the C100 also. I am by no means an expert at wiring but using this site and a voltage meter I made everything work like stock.

Using a vortec cam and crank sensor will work if the cam sensor connector is changed to the correct one listed above and both connectors are re-pinned.

Cam Sensor; A: Ground Black, B: Signal Purple, C: 12v Red

Crank Sensor; A: 12v Red B: Ground Black, C: Signal Purple

One website I used a lot was https://www.lsenginediy.com especially this page https://www.lsenginediy.com/sensors-inputs-guide For any wiring diagrams I used http://www.austinthirdgen.org/

Things to note on my install is the Holley harness for a ls1 is meant for the ecu to be in the engine bay. I however routed the Holley harness and ecu in the car to the factory location. This caused somethings to shift toward the passenger side engine bay creating a bundle of wires by the heater box that would normally be hide behind the intake on a ls1 car. Later on, I want to clean the wiring up but for now it works. If I missed anything or anyone has questions let me know. I can provide pictures if needed, I hope this helps anyone debating on upgrading the factory computer.

 

First Start

Once everything is wired and ready for first start, I recommend downloading the most recent software onto your computer and updating the ecu/handheld before you do anything. I followed this video
When everything is updated create a file using the wizard on the handheld, at this point I would not try to start the car. Unplug the injectors and confirm timing. I followed this video
If you are as lucky as me your timing won’t be close but this can be fixed. On your computer in the holley software go to system ICF then Ignition Parameters, under ign type select custom then configure. Under cam sensor select single pulse and digital falling. Crank sensor lsx 24 tooth, now the timing offset is an option. Using a timing light and the offset feature I was able to bring my tdc mark around. At this point plug your injectors in and go for a first start.

I do want to say I am not a tuner or very knowledgeable in Holley efi, I plan to have a shop dyno tune the car but this is good enough that I can run the car and heat cycle everything. I want my dyno to go as smooth as possible so this allows me to find any bugs or problems beforehand.

One last video this really helps is for setting up custom inputs and outputs. I used this to configure my fans to run only with key on and rpm signal at set temps.

 

I'd be curious to know the specifics of what you chose here, did you keep the TPI / long runner setup?

Thanks for posting, I'm interesting in going this route as well. Do you think it would be easier to start with a 96-99 Vortec 350? Also, it looks like there's a substantial time and configuration investment to get everything you need for sequential FI, did you consider the Hyperspark distributor? Coil packs obviously have their benefits, but I was under the impression that a distributor setup wouldn't really show it's disadvantages in the RPM range that TPI wants to live in.

 

Starting with a vortec block may be simpler if it came with everything but you still have to swap the reluctor wheel from a vortec 4x system to the efi connection 24x. Also I did all this with the motor in the car. Dropping the oil pan to change timing cover was the only real challenge but its do able.
The time invested for me was in wiring as this was my first big rewire. If you don't care about factory gauges, it can be even easier to install. The Holley only needs four wires to run. 12v battery, 12v cranking, battery ground, and chassis ground.

Everything from the stock computer is removed, a lot of wiring was making sure lengths were long enough or trimmed to fit and clean up of body wiring left like wipers and heater box for example.

I did keep the stock tpi unit and nothing crazy for cam or amount of intake work. I self "ported" the upper plenum and smooth out some spots on the base. I didn't open anything up past stock gasket size. As for cam I when went with a mild cam that would work with stock heads and rocker arms. I did call Comp cams tech line and they recommend the biggest cam they had for a tpi with way to much lift for my stock setup. So I kinda guessed based on my research. My biggest reason for a cam was a small bump in rpm range for running the 1/8th mile.

Edit forgot to mention from my understanding the hyperspark doesnt allow for computer base timing control and isnt sequential injection. Thats what I didnt use it.

 

My bad, I said Hyperspark but I meant Dual Sync. Not sure if the cap for those is small enough to fit behind the plenum.

I'd love to see some pictures / videos of your work. Definitely post your dyno results when you get them.

 

with this is the holley terminator wizard able to help dial in the car? The self learning

 

The car is currently running on the wizard created tune. Once I had the timing set correctly it started first try and has started every time since. I have adjusted a few things in that tune like AFR, timing, and some fuel percent at idle everything else is from the wizard tune made off the handheld lcd.

 

If anybody has any experience in hooking up the Holly Terminator x mpfi to digital dash with stock computer running gauges,I need some help. Please reach out, thanks

 

This is just my observation/opinion but the Terminator X systems are junk entry level systems that have more problems than single moms. I get that the price point is sweet but an HP should be the "base model" when going aftermarket EFI.

The HP/Dominator ECU is fully potted, can use more than one type of wb02, high or low impedance injectors. The just goes on

 

The motor runs great and my tuner suggested using Holly mpfi , the best bet is to go with what your tuner recommends and excels at ,my gauges are the only issue I'm having. At least I didn't buy fitech, lol

 

I install a bunch of holley systems and disagree with this statement

Out of 50-60 units, one ECM has given me trouble
Pretty good ratio for aftermarket electronics

As for the WB02s, terminator systems use a common production sensor. $50-75 on rock auto
HP/DOM have the option of two sensors depending on fuel type. Both are holley exclusive and bring the price tag along with

Back on topic, this is a pretty solid write up. My thread was more scratch built everything