Everything posted by Captain Obvious
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Dropping 83 ZX Motor Into My 77 Z
Nothing? All these people building engines and nobody has any ideas? Wrong forum? Is this a hybrid Z kind of question?
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ZFuel
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.
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Dropping 83 ZX Motor Into My 77 Z
I'm going to replace the motor in my 77 Z with one from from an 83 ZX and I'm trying to figure out what parts I should use from the 77 and which parts I should use from the 83. Two of the specific areas of decision making are the intake and exhaust manifolds... The 83 intake manifold is webbed while my 77 is not. Anyone know why Datsun started webbing the intake manifolds? Is that for heat? Strength? Something else? Given a choice, which is better? The 83 exhaust manifold has an O2 sensor while my 77 does not. Are there performance gains to be had by switching over to the ZX fuel injection controller that uses the O2 sensor or does it not really matter? Basically I'm trying to build the best motor from the two and I would like to keep it looking like a 77, but if there are compelling reasons to use 83 specific parts beyond block, head, timing cover and oil pan, then I'd like to hear about it.
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Dropping 83 ZX Motor Into My 77 Z
I'm going to replace the motor in my 77 Z with one from from an 83 ZX and I'm trying to figure out what parts I should use from the 77 and which parts I should use from the 83. Two of the specific areas of decision making are the intake and exhaust manifolds... The 83 intake manifold is webbed while my 77 is not. Anyone know why Datsun started webbing the intake manifolds? Is that for heat? Strength? Something else? Given a choice, which is better? The 83 exhaust manifold has an O2 sensor while my 77 does not. Are there performance gains to be had by switching over to the ZX fuel injection controller that uses the O2 sensor or does it not really matter? Basically I'm trying to build the best motor from the two and I would like to keep it looking like a 77, but if there are compelling reasons to use 83 specific parts beyond block, head, timing cover and oil pan, then I'd like to hear about it. Should I be asking these questions in the first gen or second gen forums? Maybe I should post in both...
- fluid specs and capacities for 78 280z
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Ignition swapping
I don't know if the whole assy's swap, but I do believe there was a design change to the electrical switch part of the assy that resulted in two non-interchangeable versions of the electrical switch. Are you trying to fix an electrical issue, or a mechanical issue? (Or both?)
- fluid specs and capacities for 78 280z
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mechanical throttle linkage, what's the problem ?
Check out the venturis on that beauty!! :kiss:
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plumbing
The nipple on the top of the float bowls is a vent, not an overflow. Yes, in the event of a float valve malfunction, a properly connected tube would direct overflow gas into the air cleaner box instead of spouting straight up making a dangerous flammable mess, but that's not the intent. The intent is that the float valves do not malfunction. However, there is still a need to vent the upper part of the float bowl even when the float valves are working properly and venting it to the clean side of the air cleaner is the proper location for it. Problem is (as you have discovered) that the 260 air cleaner backing plate doesn't have nipples specifically for those vent tubes like the 240 base does. There should be a smallish nipple about middle top of the 260 backing plate. Used to go to the throttle opener. Use a "T" there and port to both carbs. If you aren't using the throttle opener deceleration system anymore, that port is surplus. Question though... The 260 air cleaner doesn't naturally even bolt up to the round top carbs... Are you using adapters?
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Big Cottonwood Canyon Photoshoot and Near Disaster
Haha!! Finally!! That took way longer than it should have! (It was 38 by the way... :laugh: )
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Big Cottonwood Canyon Photoshoot and Near Disaster
How many drops is this for you, Lieutenant? Me too. And I don't use the clutch to take it out of gear. Once you slow down to the point where the gear train is unloaded it slips out easily.
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A/F Monitoring Points Info
That's neat stuff. I've wondered about that. I like your conclusions as well. Makes sense for some small amount of additional mixing and smoothing of transients by the time gasses reach the light of day, but it should still be FIFO for the most part. Cool!
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Source for a 1994 Maxima Chime
I found the first generation Integra (85-89) headlight chime to be quite polite. Not the key in the lock warning, but the headlight chime. The key left in lock is your ubiquitous "beep-beep-beep-beep", but the headlights are this very polite "bing-bong" thing. Sounded like they even used mechanical bells struck by a clapper of some sort instead of it being electrically generated. Don't know if you can buy the module aftermarket, but if you're junkyard hopping, it might give you another alternative to try. Might also be on later modules as well, but I don't know for sure.
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ZFuel
Yeah, the original ECU is a highly trimmed black box full magic and voodoo. I didn't do a lot of reverse engineering either, but I did get through the output stage and the "After Start" enrichment section. Tough part is there are three IC's in there and I have no visibility into what's inside the cans. They predate DIP packages, and there's no discernible standard like "opposite corners are power and ground". So for the sensor inputs, I've traced the circuits up to the IC's, but once they connect to one of the IC's, I hit a wall. I hooked the ECU up on the bench with a scope and a sig-gen and tried to get it to speak, but no luck. I just stuck in fixed resistors for the sensors, but I must have missed something because I couldn't get any injector pulses. Then I ran out of time on that project and moved on to something more pressing. My car runs well so it was an academic investigation only. But think about this... All analog. Instantaneous continuous response. Smooth transfer function. And has been bulletproof reliable since 1977.
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please help really bad day
All that stuff I said about big current not flowing through the fusible links? Forget all that... I bet one or more of your fusible links fried. You should double check them to be sure. (Glad you found it!!)
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ZFuel
I don't know anything about the supply side as I'm jut datasheet shopping. Never actually tried to buy any of the injector drivers. From fuel injection to industrial chicken skinner... You'll have to walk me through that one over drinks sometime. FYI, the original ECU used a pair of NPN Darlington BJT's to drive the injectors. Three injectors per driver pulled to ground. They segregated the ground for these drivers from the rest of the circuitry so the switching currents didn't mess with the analog front end. Separate analog and digital grounds inside the ECU.
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please help really bad day
In theory, shorting the battery post right to ground through the hold-down bracket should not have put any current through any of the fuses or fusible links at all. The loop would be: positive battery post to the body through the hold down bracket body into the harnesses through all the ground wires connected to the body the ground wires back to the battery negative post through the negative batt cable and/or the FI ground connection Of the two ways to get back to the battery negative post the negative FI connection is clearly the weaker link. I'd start there and at the body to block ground tie connections. I bet you burned up a ground wire or one of your FI components that connects to ground. If stuff got hot enough that you got smoke, there should be visible damage somewhere. Look at the smaller ground wire off the battery that goes to the FI system. If it's not there, you should probably seek the assistance of someone in your area who really really knows the FI system because it's probably gonna be a tricky hunt. I didn't look hard, but quick scan shows the FI main relay, thermotime, fuel pump relay, fuel pump control relay all connect to ground. On edit... I see that lenny types faster than I do!
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ZFuel
Haha! If you weren't so far away, I'd put em back on for ya. I bet I could convert you to the dark side...
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Potentiometer and timing question
Wow... The temp was at "E"??? You must have been really flying!! :laugh:
- ZFuel
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ZFuel
Makes sense. Moore's Law historically has been as accurate as Murphy's Law, and if memory space and processor cycles are cheap enough to burn off, then why not, right? However, for this application my plan for all assy wasn't driven so much by cost or speed, but for reliability and predictability. I wanted to know exactly what was in all the registers at all times. I'm out of touch and I'm comfortable with that. I always wrote the low level interface code for the stuff I designed, but I've never been a software jockey. I've done just enough to be dangerous. You're clearly going a lot more complex than I had planned to do. I was thinking just model the transfer function of the original ECU and that's it. Let's see... Of your vars above, the only things I need to know are AFM, IAT, CLT, TPS, and Pulse_Width. Everything else was for phase II. So I don't want to hear about it when your interrupts hiccup once every few days and you can't track it down. Are you sure you main loop will be able to keep up at 100ms worst case update at redline? You got a pulse width module timer in that beast so you don't have to babysit digital output pins to drive the injectors? About the battery voltage... The original ECU tweaks the injector pulsewidth WRT battery voltage. Higher voltage opens injectors faster and all that. However, if I were doing this, I would probably switch to one of the pre-canned injector driver IC's that has the voltage correction built in. That would be one less thing to worry about and would be much more consistent than the stock system or trying to make that adjustment yourself. If you use something that has the fast opening peak/hold current control as well, then you can get rid of the injector resistors and run Vbatt right to the high side of the injectors. The PIC stuff was intriguing. I did maybe three projects with them, and it sure was a paradigm shift from the Motorola stuff. It took a little sideways thinking to figure out that branching stuff, but once I got a handle on it, I really liked it. It's like Whaaaat? Skip the next instruction? What the crap is that? You have to use goto's? I was always taught that goto's were evil. You need to embrace the goto. But guess what... The newer bigger PIC stuff has conditional branches just like Mot. Feels like home.
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ZFuel
Haha! No kidding. Our controls were used prominently in petrochemical, waste water treatment, food processing, steel and other metals... Oh, and Jack Daniels. :laugh: And almost everything was Motorola based. So everything embedded you wrote everything yourself in C. I'm feeling better. I've got a software engineer buddy who scoffed at me the last time I mentioned assembly. He says I'm out of touch and that the compilers of today are so much better than they were even ten years ago. He says there's really no reason to write in assembly anymore. My back of napkin sketch included something from the Microchip PIC24 family. The smallest and simplest part I could get that had at least a 12 bit A/D and enough channels to digitize the analog stuff. Then I had a beer and used my napkin to catch the condensation, and I haven't seen it since...
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ZFuel
BTW - I'm not poo-pooing what you've done. I think it's awesome. I'm just telling you what I would do.
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ZFuel
Nice update Lenny. If I were doing something like this, I would write everything in assembly and do it without a pre-packaged operating system. For reliability (and liability) I would want to know exactly what that processor was doing at all times. No RTOS, No high level languages. No optimizing compiler. Nothing open source. Nothing fuzzy... I would want complete control over the horizontal and the vertical.
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EGR System - Theory Behing BPT Valve?
I'm no expert on the subject, but my thinking behind the concept is: The position of the AFM vain is directly proportional to the volume of air in. The volume of air in is directly proportional to the volume of air out. The volume of air out is directly proportional to the pressure in the exhaust manifold. Therefore: The position of the AFM vain is directly proportional to the pressure in the exhaust manifold. That's why I was thinking that the AFM position could be used as an indicator of engine load. Seems like it should be proportional to backpressure. I know the backpressure measurement is available and doesn't require any translation, but the thing is... What about exhaust system changes? What happens when you put on a free flowing low backpressure exhaust system? The air in doesn't change, but the pressure in the manifold does. My PO put on a huge diameter exhaust and a free flow muffler. I don't know if I even generate enough backpressure to close off the BPT.