GoodSpeed150

iTrader: (7)

Since the terminator x has a tach output. What would it take to work with the tach on the stock gauge cluster of a 99-02 fbody? Has anyone tried with a dakota digital box and actually gotten it to work?

LilJayV10

iTrader: (39)

That's a good question. I have never used that box so I don't know what tach inputs it will accept and what signals it can output. I think the factory tach is 4000ppm. Does that sound right?

I haven't ordered the Terminator yet. I've ordered a cam, sending the heads off to TEA to have some work done.

The two biggest obstacles I'm trying to figure out is
1. How to integrate the Holley wiring harness so it doesn't look like a snakes nest under the hood.
2. Where the hell to mount the Holley ECU at.

Since the Terminator ECU isn't potted like the HP and Dominator I think placement is more important

I can either throw the Holley on now and not worry about how the wiring looks for the time being or wait till this winter and completely mate the two harness' together.

Darth_V8r

iTrader: (4)

4000 ppm sounds right for the odometer. Not sure on the tach tbh.

LilJayV10

iTrader: (39)

I believe you are correct Sir.

PeteS160

I've been watching this thread wait to see what developed or what direction people were thinking about going but it doesn't look like its going anywhere so I'm going to get this moving along.

What exactly are you wanting to accomplish? Say you manage to piggy back the stock PCM into thinking the engine is running.

Now what about everything you'll loose by doing this?

1) For DBW you won't be able to use the pedal for the Holly AND still have it connected to the stock Pcm/Tac module
2)Now what about the VSS signal? With no VSS going to the stock PCM anything that was speed dependent will not work
3)The Stock Cruise Control isn't going to work unless it was drive by cable, if it was drive by cable it may work depending on how you do #2
4)Stock Traction control will no longer function, ABS may or may not still work depending on how you address #2
5)The SRS(Airbag) system may appear that its working but you won't know until the time comes when you smack something and the bags don't deploy.

What are you willing to give up in order to make the Holly EFI work?

Lets say your willing to loose everything listed above and making the factory cluster/gauges work correctly with the Holly ECU is your only goal. What would a plug and play solution to do this be worth to you?

If there are certain things your unwilling to give up to use the Holly EFI what would they be and how much would you be willing to pay to keep things?

I've built devices for piggybacking LS pcm's with just a couple of wires...... I've also built modules for data bus conversions. Each method has its strengths and weaknesses so there is no universal solution for what your wanting to accomplish but that doesn't mean something can't be made to do it if the expectations are reasonable.

LSx '73 Nova

I am thinking of using the terminator system for my 05 Silverado turbo build.My truck is a base model 4.3 that we have done a 5.3 swap gen 3, 12v crank/cam sensor, so no cruise, ABS is through the BCM. it is DBC. I live in Phx where we are required to emissions test every 2 years. Does anyone know how to get a piggy backed system to show enough info to pass emissions.

LilJayV10

iTrader: (39)

Pete,

I appreciate the post. The reason for wanting to go Holley EFI to control the engine is, IMO it's a lot easier to tune. WB02 correction, it will do progressive nitrous/timing control. The safetys you can have. For the amount of money it will take to buy HPT, timing control box and a progressive nitrous controller, the Holley is actually cheaper.

1. It's DBC
2. VSS it will be going to the stock PCM for speedo use and other functions
3. See #2
4. I "believe" ABS will work due to #2 but won't know till I do it. I'm not worried about TCS working.
5. With the stock PCM, BCM and ABS module intact, on this particular car I "believe" the air bag system should work. But you are correct I won't know for sure until I crash into something.

If this was a 2010 Vette or something like that. I probably wouldn't even consider it due to how many things are controlled over the CAN. IMO, this car has a pretty basic setup with each module actually controlling it's function and not relying on the CAN. If I try it it, who knows it may not work. However I do know that Franz at RPM Speed piggybacks Holley EFI onto C6 vettes. I don't know if he is using the Holley to exclusively control all of the engine fueling or if the Holley is just running a second set of injectors. There are quite a few shops doing that on the newer DI stuff, which is actually really freaking impressive.

Again I appreciate the post. I created this thread to get input from different people about their experiences and thoughts on it.

91 Z28

iTrader: (3)

This should be doable. My brother Piggy backed a Holley HP unit on his 94 mustang so all the functions like AC, speedo, electronic shifting etc all worked normally. I think the only issue is the check engine light is on all the time.

PeteS160

I'm not questing why you would want to go to the stand alone EFI, with the way it looks OE computers are going stand alone EFI may be the only real option in a few more years and then every one will be needing to move to it if they want to do anything to their car.

My questions are for a personal perspective on what you or others may be looking for or expecting to keep when going to stand alone EFI. If I had unlimited time and funding I could design an interface that would allow replacement of a stock pcm in a 2019 with something like the Holly ECU using as few as 4 wires between the Holly and the vehicles data bus. 10+ years from now something like that will almost certainly be required but no one is even come close to developing something with the level of precision that would be required. But the fact is I have far less time for development of my conversion modules then I would like to have so I have been picking my battles carefully. The E38 has been the ecu I've had at the top of my list for research and development with for some time now but the more I looked into them the more difficult they became due to variations between OS's, Years and even vehicle models. When the Holly Terminator X was released it really caught my attention since it drastically lowered the cost of stand alone EFI that would be user friendly and had support built in for OE DBW and auto trans(Sorry MS3).

Now were am I going with this? Right now I have developed something that would let you piggy back the stock pcm off the Holly(or any brand ECU) so the stock pcm would see the engine as running. The hardware design was crude at best and had some bugs that made it difficult to program and use for the first time, once the module worked once it was fine, there was just not enough interest at the time to justify further development of the design to sort out the initial first use bug that drove me insane. Now perhaps the need for this has changed with the release of the Holly EFI that is quickly gaining popularity. However it does not remove the need to reprogram the stock PCM. There are a TON of things that need to be turned off for the vehicle to work as if it was stock so the cost of tuning was not eliminated, although in cases where the car/truck used a P01/P59 LS Droid can take care of a good part of this issue. In the end your left with a stock PCM and a dozen or so wires running to it if you cleanly remove the harness from it that's no longer being used.

It does not solve a vehicle speed sensor input issue and with out that a number of things will still not work correctly such as the air bags, cruise control dash light(or cruise for that matter on DBW) and even the speed sensing in the vehicles radio. ABS is going to be hit or miss here and if the vehicle used traction control it'll probably flag an issue right off the bat and disable the ABS. If it didn't use traction control then you've got a 50/50 the ABS will still work. Getting the speed sensor working with the stock PCM and an aftermarket PCM isn't going to be as simple as it might seem(unless Holly really did their home work and went above and beyond). The Speedometer gets its signal from the PCM and the PCM gets its signal from the transmission. Now you might be thinking you can just output the holly speedometer signal into the stock pcm's VSS input but its not gonna work like you think(could be wrong if Holly though ahead on this) since the stock PCM read the VSS in the trans, calculates the tire size and gear ratio and then outputs it as a 4000 pulse per mile signal.The Holly will have already done the gear and tire size correction and will also be outputting a 4K ppm signal......and that's not the type of signal the PCM is looking for from the transmission. With out speed sensor input to the stock PCM its going to assume the vehicle is stationary, this means the PCM will be broadcasting a vehicle speed of 0 to all the other modules on the data bus(Abs, Air bag etc). The airbags relay on the vehicle speed for deployment calculations so in the event of a crash they know when to deploy each stage of the air bag.....and below a certain speed a lot of vehicles will never command airbag deployed. ABS is very similar here on 3 channel systems(with out traction control), the VSS is used as the rear axle speed sensor even though its reading off the trans. This signal is a much higher output then the speedometer signal, 128K ppm if I remember correctly and with out that signal being feed into the ABS its also not going to work correctly.....its going to assume the speed sensor is faulty or that the rear wheels are locked up. Now in some cases the VSS signal is sent to the ABS over the data bus rather then by a wire directly from the stock PCM but either way with out a VSS signal going into the stock PCM its not going to work(on 3 channel systems). Because the VSS is also used for ABS adding a second VSS external to drive the stock PCM's signal input ...say off the drive shaft.... is not likely going to be accurate enough to keep the ABS happy. External sensors are also really bad about getting metal dust and rust stuck to them since there is a magnet involved.


Now an alternative is eliminating the stock PCM altogether is converting the data from the Holly ECU into the data bus format/message structure the stock PCM would have used in the vehicle. The primary concern here is that since your reading data into the Holly ECU, sending it to a converter module, altering the data bus protocol and then transmitting the message to the cars data bus that you encounter a bit of delay from this process. When your talking about dash gauges the amount of delay created by the conversion process isn't enough to be noticeable, maybe 50-100ms depending on how much conversion is being done, however the ABS and Airbag systems are able to react to things with in a couple of milliseconds so the delay created by the conversion process does affect these system. Now is a 50ms delay enough to make a difference in real world situations? Thats one of those things you won't know how it works until it actually happens. I've been down this road a little ways with GM 3 channel ABS and generating a 128K ppm signal that does not have a noticeable delay effect on the ABS was extremely hard. Rather then rear tires only locking up for a split second the amount of time they actually spent locked up seemed like a LOT longer then what it really was, meaning the effect of the delay although it seems like a very small amount was in fact noticeable. If you were to "Pump" the brakes in this situation(of course you shouldn't) the apply and release time from the pumping action seemed to almost coincided with the delay. So you apply the brakes, the brakes lock up.....you take your foot off the pedal and hit the brakes again. As you apply the brakes for the second time the ABS forces the rear tires to unlock..... since your currently trying to apply the brake the ABS module see's that and prevents you from applying any more pressure and is actually bleeding pressure off the rear brakes that in reality are already unlocked.Its a rather unpleasant feeling, if you've ever experienced a front wheel speed sensor that drops out at low speed(usually while turning in a parking lot) on a vehicle and causes the ABS to apply while your trying to stop you will be able to understand what this is like. Now I can only imagine that the delay created during the conversion would have similar effects on the air bag system, meaning its possible that rather then deploying the air bag as your face is about to slam into the steering wheel it deploys moments AFTER you've already hit the steering wheel and are now forced backwards by the deployment.It would in essence become counter productive and the deployment would likely produce a similar effect to whiplash but much more severe.

I've done a great deal of research and tried all sorts of ways to remove as much delay as possible. I finally came to the conclusion that the only way to reduce the delay is to processor the data being converted faster, and I'm talking about code optimizations I mean the speed that the data is converted needs to just flat out be increased. I'm at the point now where I'm just throwing more processor power at the issue hoping it will be able to cure some of the "delay" that happens here but migrating this type of work between processor types has not been a simple process.

Now that the "safety" concerns are out of the way a conversion module does provide a very simple end user solution to integrating a stand alone ECU into a vehicle where it does not belong. Now that does not mean its simple to create, in fact its very time consuming and requires having every piece of hardware to be able to reverse engineer a module onto but is very doable for things like gauges and warning lights in the instrument cluster. In the situation of an F Body outside of the Airbag and ABS there isn't much else that needs to be dealt with other then the instrument cluster it self and they are a bit simpler then other vehicles from the same year.The biggest road block to designing something that worked in this situation would be to reverse engineer the Holly CAN bus protocol since its propriety and has zero documentation avaible even to Holly dealers. The Car side is a bit less involved but again the ABS/Airbag systems are unlikely to be safe to rely on. Warning lights are not hard to turn off in the cluster it's just knowing they won't be there if you needed them.

LilJayV10

iTrader: (39)

Thanks for the post Pete. Lot's of really good information in there. You brought up several things that I had not considered, mainly the air bag system.

I think the easiest way to get a speedo reading into the Holley is to you a drive shaft speed sensor. I don't believe it would be possible to get it from a speed sensor since they are(I believe) a normal AC sine wave and not a hall effect sensor. On the flip side of that, unless you are needing MPH in the Holley for some sort of progressive nitrous logic or transmission control, the Holley really doesn't need to see vehicle speed. We have done a lot of Sniper EFI installs which have no vehicle speed input and they work just fine.

You are right about Holley's Can Bus. That **** is locked down and as far as I know there is no information out there for it. We are a dealer and they won't say **** about it.

Thanks again for the post. It's given me some things to think about.

NicD

iTrader: (7)

Some of you guys are seriously complicating something that is relatively straight forward and has been done since the beginning of stand alones, "piggybacking". Tap into as many factory sensors as you can that will still work normally and remove the components from the factory PCM that are not needed anymore (like coils/injectors, etc) and then just add secondary sensors for the ones that won't work as a split setup, done. Factory PCM still runs the dash, interfaces with body control and other modules, OBDII, etc and the aftermarket ECM runs the rest you don't need any specialized hardware at all. Hell some systems even offer full piggyback wiring for their boxes on lots of platforms like Haltech and Motec and many even talk CAN to run the factory gauges. All depends on how much you want to spend.

soloman369

iTrader: (13)

Lol are you the same guy I comment on that you don't need the factory PCM to run the BCM?

Also the dash on a 99-02 uses the serial data wire from the pcm for the gauges.

For speedo you can use the front wheel speed sensor and configure it in the stock ECU so you can read mph.That what I used when I had a factory pcm and a th400 so my stock dash would show MPH.

Like the guy mentioned above basically just have to leave the pcm remove all the stuff the runs the motor double ur sensors that the pcm needs (rather add sensors than tap into the holley harness for simplicity sake) but only sensors are really just the oil psi and coolant. The crank sensor would need to be split so rpm could work to go to the stock ECU and then to the dash.The gas gauge should function as normal with the stock pcm in place as well as the batt gauge.

a-low

iTrader: (26)

Any updates on this?

Sail Hatan

Immmore interested in this so I can run the car off the termx, but still get an obd2 inspection. Any input on that?

n3mi5is

Very simple to do. My 02 ws6 runs on a ProEFI 128 ECU. All stock gauges work and it passes emissions.

NCDEERE

iTrader: (1)

Its doable you just have to keep digging through diagrams and make sure each system has what it needs. Its a different animal but I've got a 97 K1500 running the factory ECM that controls the truck and tranny but a built earlier 355 running Fitech and a HEI dizzy. Both systems are happy and work well.

Jbtex

Im also intrested in this I tried the P59 swap but still get a ses light because of some kind of incompatability, would love to keep my stock pcm so I can pass Texas emissions.

FAST4THGEN

piggy
I'm going to be installing a terminator Xmax set up in my 2000 Z28 and I am very interested in a way to make the factory gauges work. How do I go about getting something like this setup with you?