ZFuel

[superlen]

Hello All,

I thought I'd start a new thread to get some feedback on my ZFuel project. To recap, I began a tuneable LJet ECM replacement long long ago in the early 90s, stalled out due to life/growing business, and then rekindled it last year when my son was driving a 77 280. He went away (along with car) to college, so again I stalled on development. I'm glad to say that I have the car back now, and I'm excited about getting this unit off the drawing board and into the garage. I think at the rate that AFM's and ECMs are aging, it's long overdue. Here is a quick overview:

Standard Features

-100% drop in replacement for stock (should be a 10min install - pull kickplate, ecm, unplug old, plug new, hit the starter)

-Also can run in Speed-Denisty (MAP) if you wish. This would allow you to nuke the stock AFM. I think this will be handy for anyone who thinks their AFM is suspect with aging wipers)

- Realtime data monitoring via USB/Laptop (now you can check the status of those pesky sensors easily)

- Internal diagnostics/logging of sensors.

- You can of course tune it and adjust the map with the laptop interface.

- Run any size injectors you want to plumb in (within reason of course)

- Tune for aftermarket performance parts (cam, headers, porting, ect)

- Some general purpose I/O for shift lights, ect.

- Will have CAN bus output on an optional connector (thinking aftermarket gauges).

- Idle air control/quick warmup mode

- Support for O2 sensor and closed loop mode.

- Run any throttle body and TB sensor you wish. (analog position, or just off-idle/WOT)

- copy/save/email tunes back and forth between users.

The primary concept is to have it plug-n-play with a bone stock unit, yet still have some flexibility to accommodate other configurations. While one could run it alongside ALL the existing stock equipment, to me the following would be an ideal setup. I say ideal mostly because all the additional plumbing/wiring complexity of the L-Jet under the hood annoys me.

- Replace the AFM with a straight pipe and run with the Map sensor. Now, no worries about the aging AFM, no restriction for incoming airflow, no but ugly AFM in the engine compartment with it's 40year old connectors.

- Leaky cold start valve? Remove all of this nonsense & the accompanying plumbing/thermo-time switch/wiring.

- AAR would be replaced with more modern idle air control. (or just remove it completely if you are in a warmer climate).

Well, that's the concept/idea. I'm actively soliciting feedback as to likes/dislikes or things I might have not thought of. Ignition timing is also possible, although I'm going to ignore that aspect on the first pass.

Superlen

[SteveJ]

One of the functions of the AFM is to cut power to the coil on the fuel pump relay when the engine isn't running. If you replace the AFM, what are you going to do to compensate for that signal?

[Captain Obvious]

If I were doing a project like this, I would simply control the fuel pump with the new digital ECU.

After all, the signal required to control the fuel pump is already available at the ECU connector. The original ECU doesn't do anything with that signal, but it's available.

[Captain Obvious]

Superlen, Admirable task.

My advice would be to start small and just get something that will drop in and run. Add all the other stuff like the ability to tune and use MAP for later. Don't include data logging. Skip the CAN bus and don't mess with the AAR or cold start. Run open loop with no O2 feedback, and set it up for the stock throttle body.

Once you get to the point where you have one that drops in and works, then start adding features. And BTW... Personally, I would completely skip the "copy/save/email tunes back and forth between users" thing. Completely unnecessary complexity.

I actually started a project like this myself, and it's fate has been the same as your project to date, stalled due to life.

I know the OEM fuel injection system pretty well, and my car is running pretty well accordingly. I've unfortunately got other things on the car that are crying for more attention than a FI system that's working.

[Captain Obvious]

Superlen, Forgot something...

What about the mechanicals? What's your plan on where is that going to come from? Are you thinking you'll harvest and re-use the case and connectors from original ECU's or are you thinking that you'll buy new connectors and fabricate a new enclosure?

Have you priced the mechanical stuff? You won't be happy.

[SteveJ]

Superlen, Forgot something...

What about the mechanicals? What's your plan on where is that going to come from? Are you thinking you'll harvest and re-use the case and connectors from original ECU's or are you thinking that you'll buy new connectors and fabricate a new enclosure?

Have you priced the mechanical stuff? You won't be happy.

You can usually get price breaks when you buy in quantities of 10,000 or so.

[Captain Obvious]

Haha! Yeah, but after me, Len, and Fastwoman install them, what's Len going to do with the other 9997?

I recently rebuilt my FI harness with new connectors and while perusing catalogs, I saw the connector that mates with the ECU. I didn't quote it since I didn't need it, but maybe I'll look into the cost just for entertainment value.

[Captain Obvious]

Just took a quick look back, and I believe the Amp (TE) P/N is 825213-(color). 35-Pin "Junior Timer" series with 90 degree board mount.

Price wasn't as bad as I was imagining... At quick glance at a few suppliers, Digikey was the cheapest and says they have them for a little over ten bucks with a min purchase qty 0f 176.

[superlen]

Steve,

Great question on the fuel pump relay. Captain is spot on about it. I have control over it via the ECU, but one can always leave the AFM connected and operating the fuel pump if desired. The main reason I wanted to be able to run a MAP sensor in lieu of the AFM is that many AFMs are so old that the wiper for the potentiometer inside them is becoming suspect. I'm truly amazed that they still work as well as the do....or do they? (I have a feeling that many of these old systems are working, but far from as good as they worked in 1975) Running MAP (but leaving the AFM in) would allow someone with a flaky AFM to go ahead and use it, as opposed to pay for a replacement/refurb.

Even if someone chose to run Speed- Density because their AFM wiper was suspect, the fuel pump relay connection inside the AFM would still function the same. In that case you wouldn't be able to take advantage of removing the vane restriction out of the airflow. bit I'm not sure it's that a big problem in a stock configuration anyway.

Captain,

Great minds think alike....or at least yours and mine are. The first pass out the gate will just be the simple stock replacement, but most of the features are just software functions once the hardware has been tested. The load/save/copy tunes I already have from other projects. It's nothing more than a file save/load from the GUI. The GUI will allow you to suck the tune out and write to file, and of course do the opposite as well. I've got the GUI already as I've written it to test/debug the hardware and simulate the control algorithm. I'm traveling this week, but I'll clean it up a little and post a screen shot next week.

My thinking on this would be that if you had a tune that worked for your setup, you could post it /email it to someone else that wanted to test it on their similarly configured engine.

My mechanical plan is to re-use the stock case and ECU connector. I just assumed the ECU connector was custom for Bosch. (I'll check out the AMP part & have Digikey send me a sample- thanks for the pointer Capt.) I can either re-use existing/or try the AMP (fastest way to start) or tool up a replacement. I have contacts in the plastics molding industry and my company has designed/manufactured several products with multiple plastics, metal enclosures, electronics (our primary line) so tooling up won't be forbidding. It's another cost that I'd rather avoid, but at least not a deal breaker as I have multiple supplier relationships already qualified. That goes for sheet metal, aluminum extrusions, injection molded plastics, pcbs, cables, ect. We source all of these on a daily basis.

As for the cases, I'll stock a bunch and can send out on an core exchange basis. The customer won't get their exact case back with that program, but they will have the shortest down time. (Hopefully 10 min) If someone just really wants their own case back, they can send it in, I'll update it and send it back. There's very little machining that I will have to do to the stock case. Just a few holes & I'll laser cut them. The old stock circuit boards of course get scrapped (except for the connector which I'll pull for use on the new circuit boards)

Thanks for the interest and ideas.

And yes. After three units sold, sales will plummet. Maybe, I'll buy a few more Zs to keep sales going.

Superlen

[superlen]

Captain,

That connector certainly looks like it. I would have bet money that it wasn't still being produced. It's a non stock connector for them with 0 in stock. 176 is certainly the min/mult qty. (Amp probably ships them in 176 piece cases). The non stock stuff at DK is common now. Many years ago, pretty much EVERY item the DK catalog was in stock. Not so anymore, but for prototypes, they still rock.

This part could still be a pain to get in smaller quantities. I have an AMP rep that calls on us, I'll sick him on finding some of these. Hopefully, he'll turn them up. The stock connector on the ECM's I've inspected have all been in great shape, so worst case, I'll just pull them from the core exchanges.

Superlen

Edited July 19, 2013 by superlen

[FastWoman]

Hi Len,

Welcome back! I'm afraid I'm now in "life gets in the way" mode, but I can certainly find time for a 10 min PnP swap. My Z runs pretty well, but I recognize the ECU isn't entirely stable. I think it's needs tweaks every now and again, and I haven't stayed on top of that.

What I would eventually like to do is to hand over control of the ignition to the ECU, as I recognize the distributor advance mechanism is one of the weak links in these engines. Unfortunately rebuilds have spotty availability. I feel ECU control of the advance would give us quite a bit more efficiency in these engines, so that's a worthwhile goal. I would also love to run a MSD ignition system, but that mucks with the ECU, as the spark is used to trigger it. I suppose I'd need a Pertronix distributor that would put out a clean square wave that I could split between the ECU, the tach, and the MSD?

I can understand your not wanting to take on every bell and whistle up front, but it will be great if you can have forward compatibility to future ECU versions, such that the programming can be transferred forward and the new capabilities then invoked. I would suggest that your design also utilize an internal connector (inside the ECU box) that can be used to swap out boards. Perhaps you could use a card edge connector. That way it would not be necessary for someone to mail in their ECU and suffer down-time between upgrades. And I'm curious: Would it be advantageous to have heat sink capabilities, for instance for the power transistors that actuate the injectors? Maybe passive heat sinking to the body, where the ECU mounts? Maybe a cooling fan? Otherwise the box might become a bit of an oven.

Anyway, I think much of your market for this ECU will be from the "life gets in the way" crowd, and I'm currently one of them. I think the initial PnP aspect, with the ability to improve engine control incrementally (an IAC here, a MAP sensor there) will have very broad appeal.

So talking business here, what sort of arrangements are you proposing with your initial guinea pigs? We'll be contributing by helping you to debug your system. I presume you sell to us at a "not ready for prime time" discount? Also, I hate to trash any boards. I can send you an empty ECU box (my spare) with the connector. Does that work?

Edited July 19, 2013 by FastWoman

[superlen]

Fast,

I agree on the ignition being iffy sometimes, so I am designing the hardware to handle ignition as well, all the inputs/outputs will be there via an auxiliary non-stock connector. In fact, the hardware will be able to handle crank trigger and coil on plug if someone is crazy enough to want that (and I am. ) However, I'll wait on the software until the stock fuel program is working. You won't need any other distributer other than the stock unit. Zfuel can read the pulse from the reluctor, filter/square it up & then fire any aftermarket ignition box such as the MSD unit as well as the tach. Those inputs will be on the auxiliary connector.

I will be using the existing heatsinks in the ECM & possibly another extruded piece internal. No fans are planned as they are just a point of failure. I'll do a thermal analysis & then as is usually the case, throw it out the window once a real unit is on the bench/car and some actual case temps (Transistor cases, not ZCar ecm cases) are recorded.

Core exchange can be just an empty case and connector, or find a salvage unit to send in so you can keep your stock original one. I'll start building up a few in inventory as well. I have a few now as you can imagine, and I think most Z enthusiast that have been picking in bone yards probably have some stashed as well. And yes there will be a GPD (Guinea pig discount). Feedback early on will be important as I can tune the initial map to my bone stock 77 & it may work for most, but it's also likely that my bone stock 77 sensors are so old and have drifted so much that further tweaking with several other stock cars to average these out may be needed.

Superlen