Hello, does anyone have any experience getting stock gauges work with a Holley Terminator X Max system. I have not been able to find a thread that talks about using that system with factory gauges. Unless I am not looking hard enough. Vehicle is a 1987 Trans AM GTA that is getting a 6.0 LS 6L90 swap. Any insight would be helpful.

 

I have been researching this topic since I picked up my most recent 3rd gen. From waht I have put together (and I might be wrong?) is that you need to get the wiring diagram pinout for your year, make, model, trim, engine and transmission then wire in the terminator x or whatever other ECU you use for the factory gauges you want to function like stock from the factory harness. It is something that sounds like it will take a good amount of time, patience and attention to detail. I wish you luck.

It would be nice if there was a website or somewhere you could just send in all your car info, the engine/trans combo, fuel system, and ECU you want to use and get a full harness made just for your application to make it plug and play.

 

When I first installed an HP system I had my Oil, Fuel, Coolant, and Tach working as it should. I plugged in all the sensors for the Holley and used factory sensors/adapters for the factory gauges. ICT Billet is gonna be your friend here. For the Speedo with that 6L80e you'll most likely need to get a VSS splitter harness. I run a Dominator ECU and Autometer gauges and the Speedo didn't enjoy the signal the ECU put out and a VSS splitter fixed that for me. Holley will die on that hill saying how a 2 wire VSS can't have the signal split but I proved that wrong

 

Thank you for your reply. Just so that I understand, you mean running two sets of sensors, one set using the modern sensors for the LS and the Holley and then the other set to use with part of the factory vehicle harness and PCM to get readings on the gauges? Do you know of any dash lights that will be on because of it? Such as there no longer being a MAF sensor on the vehicle. Thank you!

 

VOLTAGE. Volt gauge is tied into dash wiring, you don't need to do anything with it.

FUEL. Fuel gauge also is part of chassis wiring so don't need to do anything with it. If you swap fuel tank and sender then just make sure the sender has a resistance range of 0 - 90 Ohm.

OIL PRESSURE. Oil pressure gauge requires its own sender. Use a thread adapter to install the stock oil pressure sender on engine, or use a 2000 Camaro LS1 oil pressure sender. The LS1 sender has the wrong signal scaling for your stock gauge but it will work, just that the numbers won't be as accurate as when using a stock sender.

ECM does not require oil pressure signal. You can feed it a signal if you want but it will have to be its own dedicated pressure sensor compatible with the ECM.

COOLANT TEMP. Both ECM and dash gauge each will need their own coolant temp sensor. They have different signal and wiring requirements that are not compatible with each other. However, 1998 Camaro LS1 has a combination coolant temp sensor with both in one unit. It was just a one-year thing and are getting harder to find but it makes the swap easy. It's up to you... install two independent sensors in two locations, or install one sensor from a 1998 Camaro.

TACHOMETER. Holley ECM has an output to drive the tachometer directly. Just wire it directly to the factory tach input.

SPEEDOMETER. If you have a factory electronic speedometer (not cable drive) then it requires a 4000 PPM (pulse per mile) input signal. The Holley Terminator X Max with automatic transmission capability should have a speedometer output that can drive the stock speedometer.

I don't know what to do with cable drive speedo, somebody else can answer that.

 

Let me know if you figure anything extra out. I'd like to only run one set of sensors for the engine, but have not found much information on anyone getting factory gauges to work with an aftermarket ECU.

 

Thank you for your response, very helpful!

 

You would you happen to know anything about getting the factory cruise control working?

 

Sorry, I don't know how to get cruise control working. Hopefully somebody else can help with that.
All I know is the stock cruise control requires a 2000 PPM (pulse per mile) input. Not even sure it is adaptable to the new engine?

 

There's a guy on ls1tech that's used a Dakota digital box to get cruise working. I can't remember exactly what was involved but there was a bunch of trial and error

 

for the cable speedo both dakota digital and abbott industries sell a cable servo box for the vss signal. speed hut sells one as well.