Captain Obvious

Glad the shafts fit well. As for setting them up on the car, I think there are some great guides already posted in the carb sections of the site, but my words of advice would be to make sure: - The carbs are spotlessly clean. - The throttle plates are properly installed in the shafts and centered in the carb throat bores. In order to get them perfectly centered, you'll have to loosen up the stop screw on the linkage so the butterfly plates actually contact the carb throat. Remember to reset the screw after you've got the butterflies perfectly centered.. - The needle is properly centered in the nozzle and that the needle or nozzle isn't worn from contacting each other due to prior maladjustment. - The float bowl level is correct. - The nozzle enrichment function (choke) slides easily without any binding. - The oil level in the damper is at the correct level. - Set your nozzles two and a half turns down to start and make triple sure you don't have any vacuum leaks. Anywhere. At idle, the engine isn't sucking a lot of air and you need every last molecule going through the carb venturis, not around them. If all of the above works out as intended, the engine should run and then for the fine tuning, you can use one of the guides in the carb section. I think Blue has consolidated some good info.

Naa. It's not materials used or degradation. It's more the fact that these things were built as IC technology was in it's infancy and some of the standards that are ubiquitous today were not yet in effect yet. Things like "mmyy" date codes that are printed on almost all IC cases don't exist when you don't have IC's in cases. Prior to that standardization, there were other more cryptic methods employed. Usually three characters with coded info that is undistinguishable without the decoder ring that goes with it. Adding to the issue is that every manufacturer used their own Rosetta Stone for translation. For example, NEC's date code encoding wasn't the same as Hitachi's. So while I did find some three character markings on the transistors that are probably date codes, I don't have anyone's Rosetta Stone to do the translation into a date. The best chance for an easy to distinguish date code comes off markings from wheee's newer ECU with the DIP's. Oh, and we've gone full circle on the component markings as well... With the advent of tiny surface mount stuff, many manufacturers don't have room for full info on the parts anymore and have gone back to cryptic markings. More cryptic than ever before. In fact many times there isn't even room for a part number, let alone a date code. Full circle and beyond.

Shaft looks great, but you won't really know until you try it in a carb body. I use a little silicone grease on mine. It's supposed to be an interference fit of course. That's how the O-ring seals. Just a little interference, but there has to be some. Also, I can't tell from the pics, but make sure the groove corners are deburred. You don't want them chamfered, but make sure there aren't any brass burrs kicked up from the grooving operation. Some 600 grit sandpaper should take care of it. You just don't want any burrs that could damage the O-rings during installation.

Great. When you get a chance. On a related note... I popped the case on my spare ECU and went hunting for date codes on components and found nothing easily distinguishable. So remember when I said it would be likely that you could be able to closely estimate the dates of production by determining the manufacturing date of some of the parts used on the boards? Apparently not! I was planning to find a couple easy spots to guide you towards so you could do the same... That's not gonna happen.

Yes, there's no mystery there. It's not a version thing, it's a chronology thing. I've got one sitting in my driveway. An 83 ZX. The 83ZX has a later revision of the Bosch L-Jetronic that includes a Lamda sensor. The point wasn't that it was hard to find... the point is that the ECU they were tweaking in that HybridZ thread by changing the resistor values doesn't apply to us with the first gen Z's. wheeeeeeeeeeeee, Haha! I don't think yours is the holy grail of ECU's. It wouldn't have the same P/N on the outside if it were. I just think it's a newer produced version for the older cars. I'm thinking that in 1990 the factory still had to supply ECU's for people who needed them and there had been so many technological changes in electronics between 1975 and 1990 that the newer ECU's changed some with the times. Form, fit, and function identical to the old ones, but different inside. I'm just wondering if Hitachi decided to get away from the completely custom IC's used in previous versions for more readily available silicon. Or maybe they thought they could sell some of the components on the open market to other manufacturers and started offering them for sale outside Hitachi. I really doubt it, but it doesn't hurt to check into it.

Great, I'd love to have some better pics and some numbers from that newer ECU. No hurry... At your leisure. As for the Hellfire... I believe the only thing holding it up is available time. Lenny keeps fading in and out of consciousness. Maybe if I were to resurrect my somewhat similar project I was working on before he came along and seemingly made my project obsolete before it was ever completed. Maybe I should have never pulled the plug? Maybe if I just TOLD him I was going to resurrect it... ::

I've been through that EFI thread on HybridZ and I wouldn't put any credibility into the validity of the information as it pertains to the guts inside the Z's ECU. The discussion of things OUTSIDE the ECU case are valid, but all the stuff about changing resistor values and such inside the case are suspect. I've been through that info a couple times now and I believe he's working with a different ECU. Bosch L-Jetronic yes, but of a newer generation than what we're discussing here. Might even be a ZX, but I can tell you that it's not a first generation Z. If I remember correctly... The pics are wrong. The resistor designations are non-existent. And there's talk of a lamda sensor. All that spells different ECU. In other words, the overall system info by BRAPP is good stuff, but the resistor tweaking stuff inside the ECU case dug up by cygnusx1 doesn't apply to us. Unfortunately cygnusx1 didn't write it either, but dug it up somewhere else from what appears to be early internet days so it's very difficult to trace.

Hi Tamo, Great start. I got a couple comments: 1) The black/yellow wire to the starter connects to the solenoid pin on the starter, not the same place as the B+ connection. 2) You've got wire coloring mistakes on the 77 ignition relay. Also, this simplified diagram makes it clear how there's always some sort of current limiting device between the alternator and the battery. That's the point I was talking about in your other thread where you were talking about fuse and wire size upgrades. I didn't spend a lot of time on the 75 diagram. I've got a 77 so I'm much more familiar with that one. Hopefully someone with lots of 75 experience can chime in on that year?

Glad to help. Forgot to ask before, but to double check... What you were originally saying is that you've got three ECU's in your possession and all three of them outwardly appear to be identical. Same part number on the outside of the case and all three "should" work fine in your 76. But you took the case off and found significant differences inside (at least between two of them). And you're wondering "What the heck? I thought all three of these were supposed to be the same?" Did I get that right? I'm intrigued by the ECU you have there that has DIP (Dual Inline Package) components instead of the round ones with the finned heat sinks. The parts I'm talking about have sixteen pins each and have a big "1", "2", "3" on them. Can you take a closeup pic of one or more of those for me? I believe they are semi-custom (not available off the shelf) Hitachi parts, but it would be nice to have the numbers off the tops. If you get a chance?

The (C12-001 004 N) ECU with the larger rectangular multi-legged components is newer than the other one you have pictured. I wonder if it's aftermarket or a newer factory replacement. If it were me, I'd use the newest one you got that runs properly. The pics aren't clear enough for me to pick up any date codes, but it's likely that you could be able to closely estimate the dates of production by determining the manufacturing date of some of the parts used on the boards. Also, it's academic, but... The components loaded into that white holder are not resistors They're actually inductors. They use a L-C (inductor and capacitor) as a filter to try to prevent high frequency interference from entering the ECU circuitry. Each pair of little L's and C's is a filter on a pin that enters the case. I bet they decided that some of them were no longer necessary as time went on. Better filtering elsewhere in the car maybe? I wouldn't call the more heavily loaded filter section "overkill". Noise is a tough and difficult to pin down opponent. And sometimes when the schedule is looming there comes a time where sprinkling some insurance in the form of some cheap components is the right course of action.

Rolf, Don't apologize for the description. I don't consider it bad and I doubt anyone else did either. In any event, glad your shop fixed you up!

I can't claim independent invention for any of those stupid kid tricks. I partook in lots of them, but didn't invent any of them. I picked most of them up from the kids in the neighborhood or from school. I have no idea where those other kids got them from. But the propagation of these tricks is astounding. I never knew they traveled so well.

I bet the stickiness with the replacement injector was a result of two things: 1) The fact that it had sat for so long without actuation, and 2) The lower current supplying capability of the 9V battery that you were using to test it. I bet that if you would have connected it directly to your big honkin lead-acid car battery it would have opened right away first time. My brain fart moments now usually result in "$^!#. My back just went. I'll see you in a couple days. I gotta go lay down."

Excellent. This kind of info is invaluable when you need it. You don't need it often, but when you do, it's great to have it filed away. Thanks again for sharing!

We used to mix up that gasoline/Styrofoam stuff as well! Add it to the list of stupid kid tricks! If there's a list, I know I'm certainly on it. This kind of stuff would make a very interesting social study, How (back before the internet) did all of these tricks travel? Could only have been word of mouth, because nobody was writing this stuff down! I'm thrilled that there are other people who have experienced this kind of stuff. And lived.

Excellent. Glad you were able to confirm the leak. It's always nice to find the smoking gun.

Forgive me guys if I'm incorrect, but I think there might be some confusion about what is being asked for here... Rolf, You're looking for a dimensioned mechanical drawing (a "blueprint") for the radiator, right? If that's the case, I don't have what you're looking for, but it might help others understand what it is you are asking about.

Chas, That's a great method for checking the flow balance.

Nice! Now let's hope you can get at least a year out of it without any significant surprises!! I mean, there will always be surprises, but lets hope for no "big" surprises.

Hahaha!!! So you're going to take the entire car completely apart and go over everything with a fine tooth comb?

Sounds like a plan. Just don't leave the power connected to the injector for very long. The injectors aren't designed to stay open for long periods of time, regardless of what you're powering them with. It's not the voltage that's the problem. It's the amount of current. But the reason a 9V might be safer is that it just simply isn't capable of supplying the vast amount of current that you can pull out of your 12V lead acid car battery. But you're right about the leak... If you're looking for a leak, you won't even need to open the injector. 40 PSI air and dunk it in a container of water and look for bubbles. Of course, seeing the spray pattern is interesting too, but if you're focused on the leak, it might not matter. My prediction? It's an intermittent leak. Sometimes it will close completely, and other times it'll remain open a tiny bit resulting in a "seeping" kind of slow leak.

I'm not coming up with any real easy to fire them using the car as a test mule. I'd be wary of connecting wires to the pins on the ECU connector. That would work, but you have to be very sure that you don't make any sparks there, and if you're making and breaking connections with a wire, you run the risk of making sparks which will damage the connector pins. Order of connection and connection integrity are important. Have the rubber booties on the back of your injector connectors rotted and fallen off yet? If so, you could easily determine which wire goes to the dropping resistor and which wire goes to the ECU. Once you know that, you could stick a wire down into the back side of the injector connector on the ground side and intermittently connect the other end of that wire to ground. Turn the ignition to run, block the AFM open (to get the fuel pump to run), and when you ground the other end of the wire that injector will fire. In fact, three injectors will fire because of the way they are connected together inside the ECU. Two wires on two different injectors and you could get all six to fire. Sorry, not pretty, but that's the best I got.

Cool. I love background info like that. Even if I'm not going to do anything with it. Did you actually measure the taper, or did you determine the value empirically by verifying that the K6024's fit properly?

Thanks guys. I'm no woodworker, but I'm doing my best! The question about stain has an interesting answer... I'm still of the opinion that the original knobs may have been impregnated with a resin of some sort. I've cross-sectioned an original knob to get a good look at un-weathered grain in the middle, and on the inside, the grain and rays are clearly visible. There are no visible air cavities however. Seems completely and totally solid. Also, it's much harder than the rock maple that I'm working with, and when machining a factory knob, I get the distinct odor that you get when you machine most plastics. Thirdly, it's of a significantly higher density than the maple I'm working with. So... With all that in mind, what did I do? Well, I tried to impregnate the wood with resin, of course! I mixed up a concoction of polyurethane sealer and a custom wood stain blend as an attempt to replicate the factory coloring. Then I dunked the wood portion into a small jar and put the whole thing under vacuum to draw air out of the knob. That way, once returned to atmospheric pressure, it would draw the colored polyurethane into the wood to replace the air that was sucked out under vacuum. Poly and stain concoction mixed in small jar: Under vacuum inside my chamber drawing some of the air out of the wood. Bubbles out, poly in: So the answer to the question is that there is some finishing done to the knobs, but maybe not the kind of finish you were imagining?

A while ago I made a couple wooden shift knobs (http://www.classiczcars.com/topic/44856-making-a-wooden-shift-knob/) and while I think they turned out pretty well, I've always knew there was some room for improvement. They were "close" to the original design, but just different enough to bug me. So with that in mind, I set out to make couple more with the intent to see how close I could reproduce the original knob. After a completely unprofitable and unreasonable amount of time, effort, trial and error, and raw materials, this is what I've got. The knob I made from scratch is on the left and the original Datsun knob is on the right. Only catch is that since the shift map from the factory knob was crazed and cracked into multiple pieces, the shift maps in both knobs are reproduction pieces that I made: Here's a side view. Note that my base is real metal instead of metalized plastic: I was on a roll, so I also made another knob to accepy my red 5-speed emblem as well. Here's the happy family: I'm still working out some of the bugs, but I'm pretty happy so far. Under magnification, I can still see some remnants of the damage from the original shift map that I used as a pattern, but I'd challenge the casual viewer to discern the difference between mine and an original factory knob in excellent condition. I don't have an older style 5-speed knob, but if I had one to use as a guide (hint hint), I could probably go through the same process with it as well.