Setting aside reasons for doing so, how dumb it is to get rid of the awesome fueling system, etc., if one were to run an LS on propane, could the factory ECM be made to run JUST the ignition system WITHOUT the fuel system? Why or why not?

I would think one could simply disable all fuel-related error codes (except lean / rich), reduce any fueling in the software to zero, and clean up the unnecessary wiring. Would this then cause the ECM to go crazy and explode? Would it be like an amputee with phantom pains? Or would it even care?

I ask this in this section because I am interested in the ECM / tuning aspect of doing such a thing, the actual propane conversion is simple and I have done it before on other non-computer-controlled engines.

Yes, I am aware that MSD makes a stand alone ignition controller. But why when the factory ECM probably does a better job?

Yes, I am aware that someone makes a distributor housing for them. But that seems even dumber than a stand alone controller.

The factory setup has all the necessary components to control ignition to a high degree of accuracy, probably moreso than any aftermarket manufacturer. So why not just retain them?

 

look into the 8.1 powered schwan trucks. I have looked into running 'pane on a LS a while ago but only found one guy who did it and he switched to a carb manifold and ran a impco 425 mixer instead of injectors. The 8.1's in schwan trucks ran injectors.

 

http://www.ecofuel.com/default.aspx

http://www.tinleytech.co.uk/lpgprices.html

are just 2 of the many places that allow you to run lpg with the stock ecu

 

HSV cars have LPI

 

I think about using propane in my Camaro Carbed Ls2, will it work carbed?

 

From a learning stand point what would the point in switching to propane injection?

 

The OP has a rock buggy, IDK why he is wanting propane over a EFI setup but to each his own.

Jeff-Yes, it is easiest to set up with propane on a carb'd motor. You just have to figure out if you need 1 425 impco mixer or 2. Depending on CFM your looking to pull. One advantage to propane is that turbos go perfect with propane because they just pull as much fuel as what is needed so with a turbo you don't really have to tune the fuel side of things.

Its a very easy tuneable system with a octane rating of around 105ish. However you will lose some power with it, but on a higher compression motor you can advance the timing more than you could with pump fuel and not detonate/ping.

 

First, sorry I didn't see all these replies before. I subscribed to this topic but am not receiving the emails for some reason. Thank you for the interest.

My goal in POSSIBLY switching is to simplify my fuel system by eliminating systems.

Right now I run gas with an in-tank fuel pump, a supply line, a return line, a fuel cooler with 2 fans, a fuel pump relay and fuse, injectors, and a whole bunch of wiring. So far I have had injector problems, fuel pump failures, suction issues, vaporization issues, and a couple other fuel related things that have put a major dampener on my out of town wheeling trips. I tow this rock boggy hundreds of miles and spend hundreds on diesel doing so every trip and spending that time working in the dirt on the fuel system is not why I go. With propane I could eliminate the pump, all associated wiring, the low pressure return line that is prone to vaporization, the cooler and fans, a bunch of wiring, and the injectors. I have run carbureted propane in the past and loved it, never had any issues. I long for that reliability and simplicity again.

That being said, I do own HPTuners and do love the precision computer control of the fuel system that the stock ECM gives me. I would have to run some sort of computer to deal with timing anyway, so why not just switch to propane and let the stock ECM still control fueling? Not something I'd recommend for the average daily driver. But for me, driving my rig on the streets is illegal and I wouldn't want to anyway. I only drive it offroad on the weekends and when I do it is way back in the woods on some mountain somewhere that I don't have access to a bunch of tools and diagnostic equipment. If my fuel pump dies and I don't carry a spare I have to look for someone to tow my dead buggy back to camp, which is normally just a dirt / mud lot that is pretty far away from a parts store. My steering is hydraulic with 44" tires, so the rig doesn't steer very easily without the engine running, which makes the tow back to camp a major work-out. I'm a big guy, very strong, but a 15-minute dead-tow back to camp normally leaves my arms and back spasming.

There are two ways to run propane with the ECM. One is liquid propane injection. It requires an in-tank pump and all the complexities of a normal gasoline fuel system though.

The other is vapor injection. This does not require a pump and all the related complexities. Its basically the same setup as carbed propane but with an injector for each cylinder instead of a carb on an intake. And the injectors are stupid-simple compared to a gas injector. Also low pressure.

It is vapor injection that I am primarily interested in now. I have tons of experience with propane and I could design my own system esily. The only thing standing in my way is knowledge of the injectors and where to get them, so I am honing in on those at the moment if anyone knows anything ...

 

Thanks for this suggestion but I am 90% certain that that system is liquid injection.

GM has a factory CNG / LPG system that was available on 8.1's and 6.0's, but it also was liquid injection.

 

http://www.rasoenterprises.com/index...kits?showall=1

Here what about this? Its demo picture is shown on an ls intake and also talks about going with a carb setup if you'd wanna do that instead.

 

Yes, I've seen and read some tech info on that system, its basically what I want. It is made by Technocarb, a big name in alternative fuels.

BUT that system is a bi-fuel setup, meaning you can switch back and forth between gas and propane. As such, it uses a piggy-back ECM that intercepts the stock ECM's injector pulses and modifies them for the propane injectors, blocking them to the stock injectors and sending the new signal to the propane injectors. The stock ECM maintains control of the fuel trim and timing weather it is running gas or propane at the time though. This gives me promise because I have no desire to keep the gas. It makes me think that I could run dedicated propane in conjunction with modified timing and fuel trims via. HPTuners without adding the additional ECM and just let the stock ECM control the propane injectors instead of the OEM's. If the propane injectors can be controlled by the ECM then basically all I need ARE the injectors.

I would run the carbureted propane system before I added another control module though.

I intend to call Technocarb on Mon.

 

I think you could do exactly that. Delete all gas component from the system and only run the minimum for what it takes to run propane injection. But wouldn't that only really get rid of the fuel pump and tank? Or is that all you wanted to get rid of?

 

Oh scratch that, I didn't see what you said at the end. Yeah I'd run carb for ultimate simplicity

 

It would eliminate:

- fuel pump, relay, fuse, wiring
- return low pressure fuel line (low pressure = prone to vaporization = bad for the pump)
- fuel cooler
- 2 cooler fans, wiring
- failiure-prone gas injectors

These are virtually all the things that I have had issues with, so I would be perfectly happy with that.

 

No, I think you're on to something. Technocarb's website says they can design a dedicated propane system upon request, so I am hoping they will be willing to discuss some technical details on that with me tomorrow.

In an ideal world they would say, "Yes, the stock ECM can control our injectors. If you can program your own ECM then we can send you some injectors tomorrow."

I can source the rest of the propane components myself.

 

Yeah when I wrote that I was thinking you still wanted to go efi. That'd be perfect for what you want. Good luck on your build.

 

It's already built and running. I'm just wanting to make it more reliable. But thanks.

I guess we never did answer my original question though. Say I went with the carbed option, at that point the stock ECM wouldn't have anything to do with fueling. Is there any reason I couldn't retain it just for ignition in that case?

 

Use the correct search terms and answer ye shall find:

https://ls1tech.com/forums/pcm-diagn...g-control.html

 

I have a file pulled from a 2004 6.0 cng vehicle its a goofy OS i dont think any software will edit the file maybe you could get hptuners to add support i tried tunercats and efi live and couldnt open it. I did open it in a hex editor and it was a goofy looking calibration. pm me you email and ill send it to your if you want

 

I have an 8.1 CNG file that was pulled using HPT. But I'll see what I can do with yours, thanks. PM incoming.