ZFuel

[240260280z]

I think that once this is working, there is a huge market for retrofitting all the porsche and other german classic vehicles as well as other x-jetronic vehicles from the mid 70's to mid 80's. Great project and it can make a lot of $$$.

Edited August 12, 2013 by Blue

[superlen]

Captain,

You have done more investigating than I on the internals. My investigation was mostly just modeling up the enclosure in cad to make sure the new circuit board fits, & making the pinout match.

Blue,

I know the L-jet was in quite a few different vehicles, but I'm not sure how many still have enough followers to make any really huge market. Without any market analysis, my gut feel says I'll most likely break even after a year or so which is fine. If I start buying Porsches that may stretch to...forever.

Lenny

I

[superlen]

Update & Opinion solicited:

After quite a bit of work on the software, I've transitioned to finishing up the schematic and board layout. The software is taking shape nicely. I have the system responding to RPM, AFM, MAP, & Intake Air Temp and calculating pulse widths appropriately. I still need to add in the code to handle all the system enrichments, but the basic guts would now meter fuel correctly if I had hardware to test with. Thus the switch to schematic and layout.

Due to the mechanicals of the factory case and mounting locations, I'm having trouble locating the usb connector where I want it. The usb port will be for updates and/or any tuning the user wishes to do. In a simple stock setup, it doesn't even need to be there. However, if someone upgrades to a hotter cam, or adds other goodies, eliminates the AFM, ect... they will need to get to it at least once during setup.

My original plan was to have a panel mount connector in the housing & the user could plug into it. This connector was to be located in the top left of the case as there is already an access hole in the plastic toe kick panel that hides the ECU. For anyone familiar with looking at the ecus this is exactly where the model sticker is located. That's apparently what the hole in the toe kick is for, to allow someone to check the number without pulling the toe kick panel. This would be a really nice clean setup & the ideal spot for a usb bulkhead connector.... However, due to some other mechanical clearances, I don't know if I will be able to mount it there. I have some other options that I have considered.

1. Mount in in the bottom right of the ECU.. This would require the user to add another hole in their toe kick to get to the connector to plug in which I don't like at all.

2. Just have the usb cable itself come out of the box & dispense with the bulkhead connector altogether. This is better in that there is less cables/connectors. However, it has the downside that the cable is then attached to the ECU all the time & would need to be coiled up and hidden under the dash when not used. To tune, one would unroll the cable out and plug into the laptop. This is probably ok, but I'm not thrilled with it.

3. A modified approach to number 2. Use an extension cable that comes out of the ECU but has the bulkhead connector on the end. This connector could be then mounted under the dash much like an OBD connector is. The user would then connect the laptop via another typical USB A to B cable.

I'm open to any thoughts or other ideas that anyone has. I haven't completely give up on the top left location, I'm waiting for the panel mount connector to come in so I can test how well it fits, but I'm not confident there is enough room.

Lenny

[240260280z]

Just have a small tail cable with a usb female connector on it and let the user connect to it as they want during installation....such as running a standard USB cable to the undredash or to the center console or to the glove box or to a jack on the dash, etc.

Just give them something standard to connect to outside the box and let them deal with it.

[Captain Obvious]

Bluetooth?

IR?

Seriously though... I would just put the connector anywhere on the unit your board layout will allow. Anyone who knows enough to mess with their engine in depth enough that they need a custom tuning set-up better be able to take the kick panel off to get to the connector. Drive around for a little while until you get the tune just right? Seems like a small price to pay.

[rcb280z]

I'm with Blue....under the dash, inside glove box, inside center console, ash tray. I myself would make it easy to access the cable.

[superlen]

Blue,

If the bulkhead connector won't fit, I think that is the next best choice. I'll run a 6" pigtail out with a female usb a. It can still be right there where the current access hole is.

Capt.. I thought about BTooth right off the bat, but held off. I did decide on using an injector driver IC like you had brought up earlier in the thread though. They are more common now and availability is good. I chose a MC33810. There will be two on there & this will allow us to have enough outputs to also do ignition timing.

Lenny

[Captain Obvious]

Cool. I like the idea of the injector driver chip. Assuming the availability is stable, I think they'll make for a better end result.

So, if you would like another set of eyes on the schematic and/or board layout, I'd be happy to have a peek. I'm probably not previously familiar with any of the parts you're using, but that shouldn't stop me. PM me if you're interested.

[FastWoman]

Are there any unused pins on the ECU connector? If so, perhaps they could be used for the USB. Then a dongle could be soldered in to the appropriate pins on the vehicle side of the connector. Otherwise my vote would be for a SHORT USB pigtail that could be tucked neatly away when not in use.

[Captain Obvious]

FastWoman, Haha! I was thinking about the exact same potential solution, and the answer to your question is yes... There are plenty of unused ECU connections on the stock connector.

Problem is, however, that the receiving connector on the wiring harness shrouds all the connections whether they are used or not and you would have to chop an access hole into that connector or the rubber boot on the back side of it. IMHO that violates one of the prime "plug-n-play" directives of this endeavor.

[superlen]

Sarah,

As Captain said, there are several unused pins on the ECU. Not only do you run into the harness wiring issues, but there is another hidden one as well. On the stock ECU, many of the unused pins aren't actually loaded on the connector. I'm assuming to save money, they just didn't mold those pins in. So while they are available in location, there's no physical connection down to the pcb. This is only a problem if I re-use the stock connector on the new PCB which is undecided at this point, but I think it's a good backup plan if the supply of Connectors becomes problematic.

The missing pins aren't a problem for true plug-n-play, but one important pin is annoying. Pin 20 is a wire from the FI relay and +12V on this pin will fire the fuel pump. It's wired and ready to go in the harness so the ECU could control the fuel pump if it wanted to (and I want to). I have an option in the GUI to turn on a fuel pump prime pulse for 3-5sec (configurable) every time you turn the key on. This was to let those that have a leaky check valve (myself included) to ensure there is good pressure in the line before start. However, that pin isn't connected down to the pcb, so if we re-use the stock connector we have to move that wire in the harness. Not hard, but not plug-n-play if you want the new feature of Fuel Pump Prime. The same thing exists with the cold start valve. However, I don't care about controlling it.

There will also be an auxiliary harness option so extra pins could be in it. This would be a short 6" harness that comes out the back and has a free-hanging connector. It's primarily for ignition IO connections for tying to the disty or even a crank angle sensor if someone wants to add a ring & sensor. A few GPIO will be in there as well for fan relays, or ??? This connector isn't defined fully yet. Thoughts anyone? Also, I should note, that the two inputs will be duplicated on both the ignition connector AND two spares on the ECU. These are earmarked for inputs from the disty. All the ECM needs is a reluctor input from the disty to completely take over spark control. By adding those two locations in the ECM harness, someone who wants a really clean stock look can add just two wires to the stock harness and run them 4' over to the ignition module under the glove box & connect to that harness. They won't even have to penetrate the firewall. Now, the stock ignition module can be pitched, and the ECM takes over with programmable ignition maps. Woot Woot!

On the USB cable, I think the consensus is that a short pigtail (6" or so) that can hide no problem will work well. It will have a usb A female connector on it. That allows a common usb A-A extension cable to be used to connect to the laptop. I'll supply one with the unit, but they are common as dirt now so when the user loses it they can get another easily. If the user did want to get nifty, they could add their own extension cable with a nice plug in socket someplace else like glove box, console, ect.

Lenny

[superlen]

Just a quick update. Still working on finishing up schematics & layout.

- The USB cable is going to work well.

- Added accelerometer on board for future development.

- Have my inside Tyco source working on finding some of the stock connectors. (crossing fingers)

Lenny

Lenny