Captain Obvious

If it revs fine with the choke on, but dies without it, that's a pretty clear indication that it wants more fuel. But if you've got a wet plug and others that are carbon fouled, that's an indication that it's getting too much. Can you post a couple good pics of the engine bay. Maybe someone can spot an issue up in the pics?

Haha! Excellent! Glad you got to the bottom of that and that it was such an easy fix. PS - I bet that would have showed up in a good pic of the engine bay.

That servo diaphragm is part of what they called the "throttle opener system", and it's an emissions control device that works in conjunction with the "control valve". What those two devices do together are hold the throttle open a tiny bit in the event of a very high manifold vacuum. For example, when coasting down a long hill with your foot completely off the gas. It doesn't matter if you were at full throttle to none. All that matters is that the manifold vacuum is higher then the threshold to open the control valve. When you are at idle with the hood open, that servo should not move. On pre-74 cars, you might be able to get the throttle opener to move a little if you goose the throttle as you described. The manual describes such a procedure, but I've not tried it myself, so I don't know how pronounced of a movement you would get. The jury is still out on whether the control valve and servo diaphragm are supposed to hold vacuum or not. And the A.B. valve might not really be a problem either depending on where it's leaking to. I'm thinking that you should have more than 15 in vacuum at idle though. This is at 800 RPM? I'm thinking that two turns down on your nozzles may not be enough. Without more info, I would suspect you are running lean. What do the plugs look like?

If you aren't planning to use the A/C, then another option is to switch to the non-A/C control head. It doesn't use vacuum at all. Everything is controlled by cables.

Somehow, I just figured you were going to say that... air-fuel ratio would be a bigger deal. It would require the installation of an O2 sensor, and it would require an additional A/D in the design. Not only that, but it changes a lot faster than the rest of the inputs, so it would have to be scanned more often which takes more processing time. And you also have to provide the data to the scanner with a real time data stream. The other sensors, with the possible exception of the AFM, change a lot slower which means stale data is still good data. Not saying you can't do it, but it's definitely on a different level of difficulty than the rest of the parameters. Haha! That's funny. You know what? We're old.

I don't think it would be a completely different can of worms. If the design includes a microcontroller and it had enough processing horsepower remaining after taking care of all of the required necessary tasks, then yes... OBD interface could be included. I'm not sure how much value you would get out of it though. Sure, you would be able to purchase a small cheap code reader to connect to it, but the vast majority of the typical parameters wouldn't apply. You could probably make it so you could read AFM position, WTS temp, ATS temp, TPS position, and injector pulse width out. Are you thinking more value than that?

Haha. It's just that troubleshooting is a whole lot easier if everyone involved is using the same language. I suggest standardizing on the terminology found in the factory service manual. I'm not suggesting that everyone pour over every last minute detail of the manual... Just download it, open it, and look at the pretty pictures in the EC (Emissions Control) and EF (Engine Fuel) section. That way when someone says "I can't tell from that pic what the red outlined thing is connected to." The OP can answer "It's connected to something called the 'servo diaphragm'. I don't know what it does, but I found a pic on EC-11." Then we can handle the rest... :bulb:

How many turns down are your nozzles? Have you downloaded a copy of the factory service manual yet? You can find them here: XenonS30 No. Tell you what... If you can provide the name that the service manual calls the round thing with the black tube attached to it that's above your red outlined rod, then I'll tell you all about what it does.

Bring it! I've already gotten started. I grabbed a mechanical pencil and sharpened it! You with your 20 turn pots and your capacitors... Yeah, they'll be stable. Stable until the temperature changes that is. Haha!!

Just wanted to let you know that I literally 'd. I know it sounds corny, but I really did!

Haha! Sounds like an integrating A/D where you're tweaking the de-integration reference voltage a little based on temperature and then opening the injectors during the de-integration phase. I'd be a lot more comfortable just digitizing the inputs and performing the calculations in a micro. Tell you what... Let's both start right now and design and build our different proposals and see who's is "working" first. And yes, neither of us ever finishing our respective projects is a completely realistic outcome. Probable even! :laugh:

Yeah, once you get used to Viton's oil and fuel resistance, it's easy to get lulled into thinking it's the cure-all for all automotive applications. I've thankfully not designed any obscure O-ring assemblies in my travels and I've not messed with brake fluids to date. That will probably change if I get energetic and split my front calipers though. And at that time I will require a reading from the book of Parker. BTW - A little off topic, but did you know that burning Viton is a really, really bad idea?

Thanks for putting on the snowshoes to get those pics. I think that's cool and I'm going to look into doing that on mine. Thanks again!

My pleasure guys. I've got other lock pictures that I took when I redid all mine. Someday I really mean to get around to documenting some of that. There's always just something else hotter on the list though. Hey E, if you do get a pair of those facecap removal pliers, I'd be interested in hearing how well they worked. That holding fixture I made isn't the easiest thing to use, but it was virtually free (other than my time investment) and the results were really good. I've popped maybe six facecaps off since I made it, and all of them have been in suitably re-usable condition. I'm sure the "right" tool works easier and maybe better results as well. I'd love to have a good pair. Being as how I'm not in the biz, I just couldn't justify the cost for the few times I expected to use it.

Haha! Nice. So you could either know how fast your miracle was going, or where it was located, but not both at the same time? Am I the only one here who completely wiped chem from their memory? My transcripts say I took some chem, but other than that, I can't prove it!

Most of the off the shelf O-rings you will find in the hardware store are Neoprene, or Buna-N (Nitrile). And I'm not so sure that I would jump on the Viton bandwagon so quickly... Viton (fluorocarbon) is not compatible with glycol based brake fluids. I have no idea what today's brake fluids are made from, but the incompatibility bore special mention in the application charts. Point I'm trying to make is do your research homework first. :bulb:

Haha. Partial credit for the chutzpah. That's awesome! The prepackaged MS option is certainly viable. I wonder if this is the kind of thing that the Diyautotune.com company in that other thread is planing to do. I was thinking KISS. Less programmability than MS, but more target specific. In other words, it wouldn't need to be as complicated as MS, but it wouldn't be as adaptable either. Just does what the original system does and maybe a little more?

Thanks E. I made that fixture a while ago and it's been so long that I don't remember if there were any gotchas in the fabrication. Maybe I'll make a second one and see if it's possible to make them cheap enough to offer. Haha. My own time is "free" in my shop, right? If you're thinking you're going to do a bunch of these things, they make tools specially designed for this job. There are several different brands, but here's one example from http://www.gatortools.com/FaceCapTool1.htm: I did a little looking around and saw that the prices for tools like the above seem to range ~70-200. The simple fixture I made is specifically sized for the Z door locks (and anything else the exact same size). The professional tools are adjustable and adaptable to other sizes. You know would work the best? My holding fixture in COMBINATION with one of those fancy facecap removal pliers. I bet that would be the shizz.

Tomohawk, I think you're getting your users a little confused... User "billyjarrell" is the guy who started this thread. He started this thread to announce that he had just gotten a new job working at a company that develops, builds, and sells the MegaSquirt brand of engine management systems. That company is called DiyAutotune.com. I don't know if he is still working at that same company, but if he is, he could probably be reached there. User "superlen" is a different guy who popped up about a third of the way down the thread announcing that he had been working on a digital based drop-in replacement for the original ECU. He (superlen) is the guy that seems to have evaporated. I suspect life got in the way and this project has stalled again on the bench. I've got a million of those projects...

JB, My first attempt at getting the facecap off was to use a small screwdriver and bend (or unbend) the crimped over portion all the way around, and while it did work, it's easy to mangle the facecap in the process. So it's nothing glamorous, but here's what I came up with. It's got an angled face that accepts and supports the front of the facecap and it's got a tight fit around the outside lip of the facecap so there's no wasted motion by the cap squirming around while you apply force. It concentrates the force in the bend area where you want it and keeps the rest of the facecap from distorting during the process. Here's where the facecap goes: Here's a lock face down in the fixture: I clamped the lock face down into the fixture in a vise and worked my way around with a couple different sized screwdrivers. Here's a close-up shot showing the facecap flange after it has been bent out of the way: And here's a facecap completely off:

Haha! No, I wasn't offering you the black box part. That's the big selling point of a design which is digital at the core and "reacts identically to input stimuli" when compared to the original analog design. The trick is that nobody needs to figure out HOW the black box parts work. You only need to experimentally determine WHAT it does, and that can be done on the test bench. You need a power supply, some input conditioning circuitry, a microcontroller with enough A/D's to handle the inputs, and an output stage. The rest is software. As Bones says, "A child could do it"...

Come to think of it, I just remembered that there is a user superlen who I believe had been working on such a device. He said he started it in 1993... Lenny doesn't post much, but here's some info in this thread: http://www.classiczcars.com/forums/fuel-injection-systems-s30/45620-long-time-member-new-job-diyautotune-com.html I'm surprised he hasn't poked into this thread and mentioned it. He should be long done by now. :classic:

Fastwoman, I think that's what Tomohawk suggested earlier, and I agree. I think that would be cool. I've got the output stage under control, and I'll take care of the power supply. What section do you want to do?

TomoHawk, I believe you underestimate the amount of effort required to reverse engineer the original schematic when there are custom undocumented IC's in the mix. There's no way I could fill in for the "little black boxes" without lots and lots and lots of effort. Maybe never... It might appear "simple" from the outside, but I bet there's a lot of black magic in that old analog L-Jet box. In fact, I think it would be a much easier job to build a new system using a digital core that "reacts identically to input stimuli" than trying to figure out how the original analog system does it.

Re-keying any of the locks is very easy except for the door locks. The ignition, glove box, and hatch locks are all cake. The door locks are a little tougher due to the chrome (stainless actually) facecap trim crimped onto the outside face. I built a fixture that makes it possible for me to get that trim off with little enough bending that it can be re-used, but even with my fixture, it's not an easy job. They make facecap removal tools, but I wasn't thinking I'd be doing mine ever again. You're getting quite good with the clothes hanger wire! :laugh: