Captain Obvious

I was never planning to make a bunch of these, but if you were, the device you need is called a duplicating attachment for your lathe. Such devices are relatively common in the woodworking realm. Not as common in metal working venues, but certainly any well tooled wood shop should have such an attachment available to be fitted to one or more of their lathes. If you had a wood lathe with a duplicating attachment you would use a template as your guide and you could crank out multiple copies of the wooden part of the knobs easily and quickly. The metal base would still be an issue, but the wood part would be easy. I am tooled more for metal working though, and have no such device. That's why all my stuff was made one-off by eye. So your school has a machine shop... Does they have a wood shop as well?

Wayne, It looks awesome. Thanks again for all the great work you've done on this! It's an amazing piece of work!

Or for people who are allowed to... Change to carbs. I've got a great set of flat tops sitting all lonely in a box in the garage,

Haha! Yeah, but the prototype for this one occurred in 1973 or 74. The mass production is already over and long gone. You're thinking there might be a market for analog replacements for the stock analog ECU? With the digital options available already, I think that would be a hard sell. I'm not sure what you mean with the comment about adjustability. Are you wishing for a way to tweak the original analog ECU?

I'm with ya. I wouldn't mind having a drop in replacement for the ECU that is digital at the core instead of the current analog design. From the outside, it would appear to work pretty much the same as stock, but just better tuned, and more consistent. Famous last words, but I don't think it would be that difficult. I haven't really thought about how many A/D's you would need, but I bet there's a micro available with enough on board. As for the cost of building an analog ECU from scratch using the TR-7 schematic... Wow. A one off? You don't want to know. You don't even want to think about it. :pirate: I would guess hundreds if you have contacts in the industry. Over a thousand if you don't? And then there's no way you would be able to tune it. You know why there are resistors soldered in parallel on the stock ECM's? Because that's how the factory characterized and tuned the behavior. They probed points on the board under power and then tweaked the resistor values until they got what they wanted.

Right. Sorry, I thought that was what you meant. If you're looking to reuse all the original inputs and outputs, then you don't need a schematic. All you need to know is how the ECU functions as a black box. You need fuel, temperature, and time maps. All you need to know is WHAT the box does, you don't need to know HOW it does it. For that, you don't need a schematic. Your PIC programmers could care less what's really inside the original box. They just want to know how the output should react to the inputs, right? A schematic won't tell you that.

I think there's a misunderstanding here... Nobody has suggested swapping a TR-7 ECU into the Z. The only reason we're even looking at it is because Blue turned up a schematic for the thing. I wouldn't try to get it to work in the Z, I was just interested in knowing more about what's inside the ECU and because they're both Bosch L-Jet systems, there are probably some similarities. Heh. Hasn't that pretty much been done already? They call that Megasquirt? Different form factor, but that's what you got, right? Well, I've got a schematic for our output section. You do the input section, and we'll trade, OK? Then we need other people to do some of the intermediate blocks, and we're done! (And I've already got a "Boost" button. I'll post about it sometime when I get energetic.)

That's got to be the most common sentence I've seen in Z car ads. I see that almost all the time! Has anyone ever seen an ad that says "Engine blew and it's been sitting since"? Congrats. She's a beauty! Bountiful suspension tree too. I planted one in my back yard, but it didn't take. Must like warmer weather. [ATTACH=CONFIG]60015[/ATTACH]

That TR-7 ECU is probably a couple generations newer than the one we have. I haven't seen any schematics for our ECU's, but I suspect there are sections that would be very similar despite the newer design. Not all of it, but sections maybe. However, I can attest that those similarities do not extend to the output stage. A while ago I drew up a schematic for the output stage of our ECU, and ours is very different than the TR-7.

I suspect it contains the exact same RTD design as the water temp sensor. The curves are identical. I bet it's the exact same guts repackaged differently mechanically. If you got desperate enough, you could probably physically modify a WTS and stuff it where the IAT sensor goes.

Excellent! Sorry I couldn't be of more assistance. Glad someone else knew what was going on!!

Far be it from me to cast aspersions on an easy fix that took care of the problem, but a clogged fuel filter doesn't really fit the symptoms. However, whatever works, right? If that fixed it, then more power to ya! So before you replaced the fuel filter... What did it do when you floored it? Did it have good power on the highway when you really put your foot into it?

Sounds like you were just expecting too much too quick. One hurdle at a time... If you have to use a little choke until it's up tp temp, then do so. Worry about fouling the plugs later. If you aren't billowing black clouds of eye burning fumes, then I wouldn't worry about it. If it dies when you hit the throttle it's probably running lean. However, if you aren't yet up to temp with the engine, then it will compound the issue. Think about it this way... The colder the engine, the richer it wants the mixture. Where do you have your nozzles set right now, and why did you put them where they are? As for the clear tube method, here's a description and a pic: a) Pull the black rubber fuel line off the bottom of the bowl and drain the bowl Replace the black rubber line with a clear tube that is long enough to loop back up against the bowl body without kinking. c) Fill the carb bowl back up again using a funnel and another piece of tube connected to the fuel inlet nipple. d) As you pour the fuel in, the float will start to rise. When the float rises far enough, it will close off the float valve, and the carb will stop accepting additional fuel. e) Measure the bowl level and compare to the specs on picture EF-46 of the FSM

Haha! Well I'm not ready to claim any progress towards determining what's really going on with z_ya's car. There are still lots and lots and lots of things that could be wrong. I'm just in brainstorm mode trying to come up with hairbrained ideas that fit the problem symptoms well. I think that a voltmeter and a fuel pressure gauge in the skilled hands of someone who has messed with L-jet in the past could shed a lot of light in a short period of time.

How long are you keeping the choke on for? Another way to ask the same question... How quickly are you thinking your car will run well without the choke? The reason I ask is that in my experience it has been "minutes" before the engine runs as desired with no choke at all. Are you thinking that you can start it and then immediately push the choke off and expect it to run with no choke? By the way, any performance issues with the carbs could potentially be traced back to problems with the float bowl level. Did you ever verify your float bowl level using the clear tube method?

Zed, That's a well thought out interesting idea. I don't know if that's what's going on in this case, but it's a neat thought. Move the key to ON - Fuel pump runs and builds up pressure in the rail. Move the key to START - Fuel pump stops - Cold start valve dumps fuel quickly into the intake until the fuel rail pressure is gone. Quick blast of fuel from the CSV is enough to get the car to start, but with no pressure in the rail, there's nothing to feed the injectors when the key is moved back to ON - Engine stalls. Maybe on the second start attempt there's just enough pressure in the system to get over the hump? Maybe on the second start attempt, the thermotime switch has opened and the CSV isn't activated which saves fuel for the injectors instead? Interesting... :bulb:

No. Measuring +12 volts on both sides of an injector is not necessarily a problem. The way the system works is this... One side of each injector is always connected to +12 through a "dropping resistor". You should always measure about +12 on that side of the injector. The other side of each injector is connected to the ECU. Inside is the ECU is a switch (a transistor) which, when closed, connects that side of the injector to ground. When the transistor switch is open, no current flows through the injector and you will measure +12 on both sides of the injector. When the transistor switch is closed, current flows through the injector (which causes the injector to open), and you will measure +12 on one side of the injector, and ground on the other. However... The amount of time that the transistor switch is closed is very short, and your typical voltmeter will not pick it up. Your typical voltmeter will average the signal in some way, and since the amount of time that the injector is connected to ground is such a small amount of time, it will essentially average out to +12. Does that help? Does that make any sense? I'm not sure that your mechanic is familiar with fuel injected systems.

Haha! This has been bugging you since we talked last, hasn't it? :classic: You are a fountain of information. If it's not already on your had disk, you seem to be able to dredge it up from somewhere. I can tell already that the schematic is very different in spots than the 280Z ECU, but I bet the basic concept is very similar. That's awesome! Merry Christmas to me! I am going to have fun with that!

This is a great thread. Koalia, Hope you don't mind all the plating discussion. Jerry, PM back to you.

Jerry, Glad you had enough moolah left after LaSalle to do the Z car parts. Thanks again for the details. Sounds just like what I usually hear. Want nice clean shiny smooth results out? Then provide nice clean shiny smooth results in. GIGO. OK, now for the (hopefully not) million dollar question... How much? What did you pay for that tangle of parts?

Thanks Jerry. I suspect my buddy is getting zinc and doesn't know it. How agressive was the wire brushing prep you had to do? Did you have to abrade off all the original plating, or just get the big chunks of grease and rust off?

I understand the out of the comfort zone comment. I'm a slow decision guy too and my recent snap purchase should be delivered today. Not as big or as expensive as a Z, but same sentiment. Here's to hoping that 2013 will be both of our years!

Thanks for the details Carl. I've got a buddy who does a lot with antique motorcycle stuff and he often gets parts "cad plated". At least that's what they're telling him... Next time he and I get together, I'll poke him a little and try to find out if it's truly cad or if it's really zinc. As you described, they come back dull silver, and not yellow. I've thought about including some parts with his orders, but the results don't look "right" for a Z car. Sounds like it may be a secondary process that could be split stream for his stuff and mine. At this point, my Z is pleasure drive only and shouldn't see any inclement weather. Corrosion resistance for things like hardware is still important, but not as important as it used to be. I had not previously been interested in zinc plating, but Jerry's parts look good enough for me and it sounds like the corrosion resistance would be good enough for my application as well.

So what's the little switch pod by your right knee? Is that an ejector seat? PS - Put a wood shift knob in that thing... :bulb:

If that's original, then I just say "wow". I thought they all turned yellow butterscotch by now! Hoe away!! That's awesome! Want to trade for black? :laugh: