[ttsgeb]

So, this is an integral part of my electric conversion project, but I figure it deserves its own topic because it's more generally applicable.

I do not have a stock (or any) ECM in my car for reasons that are probably obvious. I want to continue to use the stock gauge cluster and have power steering and maybe even air conditioning eventually.

I know Pegasus is a thing, but it's trying to do something different from me. I want the cluster to think it's got an engine hooked up to it, while Pegasus just wants to ignore what the cluster is trying to do and do its own thing (A very worthwhile goal)

I don't know if anyone has looked at power steering yet

So where am I so far?
It looks like to get power steering working, I just need to spoof the engine speed pulse, which it expects about 6v at idle, but that tells me nothing about while the vehicle is in motion.

The mission critical part of the cluster should be accomplishable with just hooking up the speed sensor, but it'd be nice to have other readouts.

Here are some wiring diagrams conveniently pulled from PDFs in a way that they'll be easier to find.
Gauge Cluster:

Power Steering:

I fully welcome any feedback or pointers on this. I don't have anything on the bench yet, so I can't quite start hacking at it, but that shouldn't be much longer.

 

[*sean*]

For the amount of work it will take, consider maybe going with a panel? I found an HDMI display that, with a bit of work and cutting in areas behind the faceplate would let you create a new instrument cluster. Connect it to a Raspberry Pi and use Mario's SVG template for the display if you want the old school look. If you make the display code modular you should be able to theme the display to whatever you want. Mario's SVG image file is here. You can then tweak it for other information you want to display or even have a switch that flips between different views. Ping me if you are interested and I'll dig up the info about the display and the potential mounting challenges. (I'm not trying to sell it, I'll just go hunt for the model number)

 

[Mario]

Here's a diagram with both of the cluster wiring pages:

http://imgur.com/CsogJBF

With an Arduino and some simple circuitry, it's not too hard to spoof most of the inputs to the cluster. If you google site:insightcentral.net [cluster signal name, like METSCI, MTRTW, ENGRDY, etc] then you can find info on what the signal is and what the cluster expects.

 

[Gasoline Fumes]

It looks like to get power steering working, I just need to spoof the engine speed pulse, which it expects about 6v at idle, but that tells me nothing about while the vehicle is in motion.

I see both engine speed and vehicle speed going to the EPS control unit. I'm not sure if both are necessary, but I know the EPS won't activate until a certain speed. Turning the key on and coasting out of a parking space results in no assist. Turning the key on after coasting at speed results in assist after a slight delay. So based on that, the VSS signal is required and engine speed isn't. You could spoof the VSS if you had to, but I think it's there to enable less assist at higher speeds. I vote for removing the EPS motor and worm gear for easier manual steering! It's on my to-do list.

 

[ttsgeb]

So part of the reason I'm going through all this effort is that for my application, I have someone interested in the vehicle when it's done. They want all the creature comforts and I want to provide as little support as possible. I feel like the best way to do this is to get as much out of what's already there as I can. I also feel like knowing how to use the parts that come with the car is important for general troubleshooting and repair of these vehicles as time goes on. Like I said in the first post: This is for a project, but all of it has more general applications.

I see both engine speed and vehicle speed going to the EPS control unit.

Oh, right Vehicle speed is involved, but I kinda glossed over that because I already need vehicle speed for the cluster, so the only one I need to spoof is engine speed.

Thanks, Mario. I don't know how I missed that (1 of 2) in the PDF. I'm going to update the first post as well just to have it all in one place.

 

[*sean*]

I get it now. Sounds like a fun project!!!

 

[Gasoline Fumes]

the only one I need to spoof is engine speed

I can try removing the engine speed input from my EPS. I'm kinda curious myself what it does with that signal. I haven't noticed any different in steering assist while coasting with the engine off.

 

[ttsgeb]

My glancing over the manual tells me that it requires certain engine speeds at certain vehicle speeds and if they don't behave for more than a few seconds it puts the power steering in error mode that has to be cleared with a special tool through the OBDII connector.

 

[benr]

Not sure if it helps but there's a good thread on the cluster here: Taking control of the Instrument Cluster