Captain Obvious

Ummmm... Not even close.

Don't leave it the back of your hatch in the sun. The black fabric isn't very UV resistant. Kinda turns to dust after a year and tears when you look at it sideways... YMMV

Zedyone, I'm not a suspension guy, so my explanations come from the point of view of a non-expert who hasn't known this stuff forever. I apologize in advance if I'm telling you stuff that you already know. That said... Hard to press down is not necessarily an indication of damping. But neither is a slow or non-existent rise after being compressed. So when you say "there is little to nothing left in the way of gas pressure left. NO damping to be had in them", you're mixing somewhat unrelated functions together. The only thing that you can glean from a slow or non-existent rise after compression is that the gas has leaked out. You can't make any claims about the damping functions from that test. The gas pressure inside the shock has nothing (directly) to do with the damping. The only reason the gas is in there at all is to increase the static pressure on the hydraulic fluid which reduces the tendency of the oil to foam as it passes rapidly through the damping valve orifices under strenuous use. It's the oil that provides the damping, not the gas. Under non-strenuous conditions, the shock would work just fine with NO gas pressure in it at all (just like they did in the good old days). In fact, until or unless the oil starts to foam, there will be no difference in damping performance between a brand new gas-charged shock and one that's identical inside, but they forgot to put in the gas. Here's some good info from KYB that talks about the difference between the twin-tube (low pressure) and monotube (high pressure) designs and how the damping is accomplished: http://www.kyb.com/kyb-tv/the-differences-between-monotube-twin-tube-shocks/ http://www.kyb.com/knowledge-center/shock-tech-for-pros/monotube-vs-twintube/ http://www.kyb.com/kyb-tv/how-shocks-struts-wear/ Don't equate "hard to compress because it's got gas in it" with high damping. Don't equate "slow or won't rise after being compressed" with low damping. Those tests don't tell you anything about the damping, they just tell you how much gas you have left. Yes, if your shock is supposed to be gas charged and all of the gas has leaked out, it's not healthy like a new one, but assuming it's not worn out inside, it will still damp like a new one until you foam the oil. So, I'm certainly not telling you that you weren't due to change your strut inserts, but your old ones might still provide reasonable damping despite not being gas-charged anymore. Please forgive if you knew this stuff already. I worked on cars for many years and didn't... Here's hoping I wasn't the only one.

I second the mylar transparency suggestion. You should be able to find something at the craft store. I wouldn't cut it into strips though. I would try to find a sheet large enough such that you could wrap the whole thing into a full cone shape and stuff it down into the speedo hole to use as your ramp. This approach hasn't worked for me in the past, but it's been so long that I don't remember why. YMMV. And as for pulling the speedo out through the back... It's a hard "No". Doesn't come out that way.

No, and no. Sorry.

I have found the same thing. And that high of a gas pressure damps the spirits of those around me. Shocking, huh?

Back when I had my first Z, the fuel injection used to scare me. It doesn't scare me anymore. The only things that bothers me now are 1) The lack of visibility into what is going on inside the black box, and 2) the ability to do anything to change it. In my limited Z experience, I've found the performance of the carbs (once up to operating temp) to be about the same as the FI. The FI seems to be a lot more stable when cold, but other than that, I've not noticed a huge difference. I've found the fuel economy about the same as well. I don't have any insight into HC, NO, and CO though. The published belief was that the FI systems were put into operation as a result of continuing stringency of the emissions standards and even the open loop EFI systems we have might be better in that regard. I don't know... I do know that neither system work right unless you do it right and pay attention to all the little details. Personally, I'd love to have my Z on a dyno with the original EFI and then swap to SUs and run it again to see what happens. Of course, I'd also to toss on a pair of flat tops and run it a third time!

At the risk of being pedantic... Just because you can't press the shock down by hand doesn't really mean it'll be stiffer in application. Most of what you're doing by pressing it down on the bench is fighting the internal gas charge. You might not even be collapsing it quickly enough to get a real sense of the hydraulic valve damping. It's not the gas charge that does the damping, it's the oil. I'm no suspension guy, but it sounds like you're equating a high amount of gas pressure with a high amount of damping function, and I don't think you can legally do that.

So you're switching to carbs for this next engine build? Did you mention that before, or is this a new revelation? I've considered the same... I find beauty in the simplicity of operation.

Haha! It was for me! We can sure keep each other entertained! Worst part about it though is that Labatt's keeps all the better stuff for themselves up north. We get the Americanized versions.

I see what you did there.

Cool. That makes sense. Thanks for filling in the blanks.

Man, that sucks. I'll keep my eyes and ears open.

As mentioned above, the FI get's it's trigger off the negative side of the coil. Since we're talking about this kind of stuff though... I've always wondered about the possibility that the multiple spark discharge systems screw with the fuel injection? Isn't there a risk that the ECU will misinterpret the multiple discharges and pulse the injectors more often than is desired. I'm assuming it doesn't cause a problem since you're not the first to pair an ignition system like that with the stock fuel injection, but just wondering if anyone has had issues with that.

What I want to know is... Was it YOU who was doing donuts in that parking lot, or where those marks there before you got there? Supposedly.

Last time I talked to Superlen, he had completed his home built flow bench and had poked around with a couple AFMs. I betcha he knows. And if we're lucky, he'll be able to come up for air sometime soon!

Absolutely. Cross drilling and plugging that way would work great too. I was gonna mention that, but I thought for some reason that you didn't want the modification to show. I was reading too much into it, and even so, you could always do the plugging from the underside and that way it'll be invisible after installation. I'm not sure you're going to want pipe threads though for the job though. You're need to drill and tap deep enough that you'll completely eclipse the cross hole and I'm thinking that straight threads would be better for the application. Another cross plug option would be to drill (without tapping) and shrink fit an aluminum plug into the hole. Size the hole and the plug such that with a little heat on the manifold and a little cool on the plug... Press the plug in, grind off the excess, and it'll be pretty much invisible when done. Just make sure you use aluminum for the plug so the thermal expansions are matched.

So here's a question. When was the last time you had the car at a more typical altitude? Did you still have the same problem when you were down off the peak? And I'm not sure that really even has anything to do with it... I could see running at altitude would make you run richer than necessary because the air is so thin, but how could it drop the gas mileage to an unreasonably low value. Think about it this way. Your car runs great at 1000 feet. Gas mileage is 20 mpg. Then you drive up to 10000 feet and the car runs rich. But the gas mileage should still be the same since the injector pulses are still the same width. In other words, the altitude increase won't make the pulses wider, they'll be the same width but are now wider than necessary. (Haha! Did I say that right? ) Just tossing out ideas...

Maybe it's just me, but I'd be skittish about using any type of plastic or rubber to plug that hole. I'd want something with a positive retention feature of some sort. If a chunk of something comes off or out of that hole, it's going straight into your intake valve. I'd want to use some sort of metal and I'd want it welded into place or retained with threads of some sort. I know I'm conservative when it comes to that kind of stuff, but I'd sleep easier. Some ideas? Drill out the end plug and tap the hole as you already suggested. Find or make a tap short enough to be able to stick it into the hole and tap it with quarter turns right through the circular runner opening. That way you won't have to drill out the end plug? Then use a set screw to plug the hole (with thread locker) and grind off any excess. Make a two piece tapered plug contraption, one with a male thread and one with a female. Put one in runner 1 side and the other in runner 2 side and then thread them together (with thread lock) from one side to the other? Grind off any excess. And of course, the obvious of weld one side shut. Someone trained in the art of aluminum welding ought to be able to make easy work out of that. Wonder why they only connected 1 and 2...

I'm more confused by the blanket statements from post #4. That's what started all the discussion: I'm guessing what you really meant to say was: The AFM only provides mixture measurement and correction until it maxes out full open. And if the Z is like a lot of other cars, a full open maxed out AFM could occur as low as 4500 RPM if the throttle is full open. And if the AFM maxes out full open, beyond that point the ECU calculates IDC entirely based on RPM, TPS signal and CTS. Note that I've not tested this for confirmation, so I cannot attest as to the accuracy of the statement, but it sure makes more sense to me and I'm thinking it's at least a lot closer to what you really meant?

BCDD should have no effect on mixture at all. All it does is provide a path around the throttle plate. Think of it as an idle speed control. I'm not going to rule anything out at this point, but the BCDD shouldn't have anything to do with this. As for an altitude switch, I looked through the manuals as well and I don't see any mention of the altitude switch prior to 77. I'm thinking they added that for the 77 year and beyond. I agree with FW in that I wouldn't go shorting pins on the ECU. Probably wouldn't cause any problem, but not worth the risk. So unless you're triple positive sure you've got the right injectors in there, you need to address that. Where (and when) did you get your replacement injectors? Did they come with the car or did you put them in?

10 MPG ought to be easier to find than this... Those plugs don't look all black and sooty as I would have expected. At 10 MPG, I would have expected loose fluffy.

I've not gotten to that part of the circuitry yet, and I may never get there. but I'm not buying the 4500 RPM limit either. It takes much more air and fuel to run WOT up a steep hill at 4500 RPM than it does sitting still no load in neutral at 4500 RPM in the driveway. There's no way you would want the same amount of fuel injected under both of those conditions. I won't deny it if someone shows me the circuitry or the test results, but until then... I'm not buying it.

Great! Repair looks good and it sounds like you're back to reasonable numbers for where to put the screws. Glad you found someone who had the welding skills to do the repair!

I'm traveling so my resources are very spotty, but I can tell you that pin 6 Is a ground line. It's an analog ground for the sensor, so yes, those two parts ARE in series, but not in the usual sense. Yes, if the temp sensor in the AFM has gone open circuit, you will run rich.