Captain Obvious

African or European?

Hey Zed, I'm sure you know this, but just wanted to make sure it was clear to everyone else. The fuel cut function kicks in anytime the RPM's are above 3200 and the idle switch portion of the TPS is closed. This can occur at 3200, 4000, 5500... Anything above 3200. And once the fuel cut function HAS kicked in there is some hysteresis such that it will not kick out until either a) the idle switch is opened or the RPM's drop below 2800. Maybe it's just me, but I found your description misleading. Made it sound like the fuel cut was only active in the band between 3200 and 2800, and that's not the case. It's anywhere above 3200.

I didn't say anything about coasting in neutral, and neither did the FSM. In the FSM, when they say "The Boost Controlled Deceleration Device (B.C.D.D.) is employed to reduce HC emissions during coasting." They aren't talking about coasting in neutral. By "coasting" what they mean is "moving down the road with your foot not on the gas pedal". In other words, "Letting the wheels drive the engine instead of vice-versa." Question - What's the difference between "coasting in neutral" and "idle"? Answer - Nothing. No Duh, you don't get the problem coasting in neutral. That's because you're "idling". You happen to be "idling while your car is moving", but your engine doesn't know it's moving... As far as it's concerned, it's at idle. I've got an idea... How about you vigorously investigate the suggestions that have been made so far and let us know what you find.

Anyone else going to the Sport Import show next weekend at Carlisle? I was thinking that this would be a good opportunity to sell/swap parts which would normally be a pain in the butt because of shipping. Now, I'm not going to throw an engine block in the back of my Z, and I'm not bringing anything that doesn't have a recipient at the other end, but I've got some other cumbersome parts that could make the trip if necessary. For example, I've got a: a) Full dash cap. Center consoles (2) for fuel injected cars without the choke lever slot. Neither is perfect, but both usable. c) Parts off an early ZX motor - N47 head, N42 block. I'm not going to put the block in my car, but if there's anything else you want, maybe I could pull it off and bring it? Crank? Pistons? A grind cam? Valve train? Valve cover? d) Rear window interior surround trims. I've got a pair of black early styles and a pair of cream late style. e) Snowflake wheels with virtually new rubber: As for parts I would like to have that would be a pain to ship: Windshield and rear window chrome trim strips. Late style heater box to experiment with. Anyone else?

A reading from the book of FSM: "The Boost Controlled Deceleration Device (B.C.D.D.) is employed to reduce HC emissions during coasting." EC-5 - 1977 As for the smoke... When you are coasting at high RPM, the cylinder vacuum is much higher than it is under other conditions because you are pulling high RPM against a closed throttle plate. Under these intermittently very high vacuum conditions, you'll pull more oil into the cylinders, but you won't see smoke because you're not burning it. You're pumping it out the exhaust without burning it. I'm just applying theory here trying to help. You asked for it.

77 still has a ballast resistor. I don't think 78 gets one, but 77 definitely does.

Thanks guys. I'll poke around a little more for other options, but if nothing interesting turns up, I'll just buy from MSA.

Leon, it's worse than that. The gap spec for 1977-78 is .039-.043 for the US cars but Canada retained the .028-.031 spec. For some reason, the US got a wider gap in 77 and 78 while Canada didn't?? I'm no spark engineer either, and I have no idea why...

I wonder why Nissan decided that it was a good idea to make the two ends of the tube different diameters in the first place. That's a neat idea you got going there with tapping the block. I've not tried finding a replacement at a Nissan dealer. Finding a stock replacement is easy... I was hoping for something better.

Thanks for the info. Years ago I bought the whole silicone PCV kit for my ZX. Included formed tubes where some of the tubes were formed with different diameter ends. Kinda surprised someone isn't making something similar for the first gens.

I'm sorry, but I've lost the pea. Can you put together a refresh of what's currently on the engine in terms of carbs and ignition? You're running round tops, right? What about ignition... What are you currently running? Points or something electronic?

In 75 they switched away from the projected tip to a non-projected tip plug. (They switched from the projected tipped BP6ES to the non-projected tipped B6ES.) That was in 75. Then they switched back to the projected tip in 1980. Here is a little non-conclusional discussion about it: http://www.classiczcars.com/forums/electrical-s30/47495-spark-plugs-projected-tips-vs-standard.html

Done. I'm registered. They said they were not mailing any more stickers out, so I will have to stop at the office to pick mine up, but other than that everything went smooth. Let's hope for good weather!! I think if it rains, my Z might melt (just like so many others before...)

Forgot to ask... Do you remember where you saw the reducer hose in silicone?

I started my search at Black Dragon and MSA. I couldn't find anything at BD, but I did find one at MSA: But there's no mention about composition. My assumption is that it would not be silicone. Nobody offers a silicone version?

Anyone got a recommendation for a good replacement PCV hose? (The one that runs from the front of the block under the intake manifold to the PCV valve.) Does anyone make this in silicone?

I just remembered about the upcoming Carlisle show and I've missed the cut-off for pre-reg. Is there a way that I can I still bring my car to the display field, or is it too late?

Well it sounds like you run very, very rich when you coast at high RPM. So rich, in fact, that you're beyond a mixture that will ignite and you're pushing clouds of atomized gasoline mixed with motor oil out the tailpipe. So you should look for things that would add fuel or oil to the party. Worn rings, valve seals, and maybe a specific kind of head gasket failure could all offer oil. Non-functioning or improperly adjusted BCDD or AFM could encourage extra fuel. So could a faulty FPR, leaky cold start valve, or injectors. But of all the items listed above, the BCDD is the one that is supposed to help with exactly that kind of "extra rich mixture at high manifold vacuum" emissions, so that's where I would start. You familiar with the carbs used on the earlier Z's? If so, think of the BCDD as the fuel injection equivalent of the older throttle opener servo that pulled the throttle open when you coasted. The BCDD essentially does the same thing.

Yup. We're on the same page now... Comes down to the tradeoff between originality and functionality and that's your call. So the OD of the original fuel line is larger than what you find today in the parts stores? So much so that you're thinking the original clamps might not fit well? You don't need it for the application, but the hose rated for fuel injection is usually a little larger than the stuff not rated for it. I think they might use an additional layer on the FI stuff due to the pressure and permeability. In other words, you don't need the FI line for performance, but maybe you could simply use it for the OD? :bulb:

Occurs when you have high manifold vacuum. That's why it only happens when decelerating in gear. Higher the RPM the worse it is, right? How's your compression? Do you use oil? Is your BCDD working properly?

I'm not far from Pottstown. I'm no Z car expert, but I'll do what I can if you get stuck.

Gotcha. But to be honest, the original clamps that you have out for plating weren't what I was suggesting you use. The clamps that I was recommending are the ones Nissan used on the later fuel injected cars (and are still using today). They have a solid band (like the ones you are currently using) and don't cut into the fuel hose like the typical American style "hose clamp" with the slots in the band for the worm gear. They look very similar to what you have on there now, but they are made from stainless instead of zinc plated carbon steel. In other words, I was recommending the solid band clamps, but just from a different vendor. However... It sounds like any clamp that isn't year correct is temporary, right? I didn't know you were aiming that closely at originality. Sounds like originality trumps functionality here, and that's great too! And BTW - Please don't let all this talk about something as mundane as a few tiny hose clamps take away from the beauty of the big picture!

It's conceivable that if the ambient air temp is low enough that the AAR wouldn't be able to maintain enough internal heat to keep itself closed. But I don't think that should be happening at 80+ air temp day. If your AAR is opening and raising your idle while you are driving on an 80 degree day, then I think there's something wrong inside your AAR. Have you tried other AAR's to see if you get the same reaction? I'm with siteunseen... I don't have the heat plate under my AAR and mine doesn't do that.

Hi Wayne, Awesome. Thanks for the help! Out of curiosity while I got you here... There is a device on the dwg called the "Timer Unit Belt Warning". It is located to the left of the fuseblock and is near the new ground you just added. You have all the connections to it listed as US only, but the 77 FSM that I have makes no distinction for that module based on vehicle destination location. So, is there another document somewhere that lists that module as USA only? Thanks again!!

Haha! Yeah, and so are two resistors used as a voltage divider