interestingusername

Nah, that makes sense! I'm so used to modern ECU controlled idles that when my cars idle speed started going up, I thought it was unusual, so I suppose that's up to ignorance on my part. I'm glad to hear that's normal, though!

I got the chance to make a blockoff plate for this other piece of the BCDD, and the idle problem has been mostly resolved! With the air regulator disabled(I'll be reconnecting this when I button the car back up), the car starts cold at about 900-1000RPM. The car still has a little bit of a high idle when its warmed up, it sits at around 1300-1400RPM, but I'm hoping this can be lowered with a bit of tuning up. There's still the ECU issue, I haven't had the opportunity to check the timing and forgot to test out the vacuum advance like a genius. Of course, after messing around in that area so much, the rubber coolant hose going to the air regulator has sprung a leak, but that's how these things go. Thank you all again for the help!

The engine in my car may have been from an automatic, or the dashpot has been removed, because it doesn't appear I have one. If the engine was for an automatic, would the throttle body have provisions to add one? I'll give the video a look, thank you! And Atlanticz has actually been really helpful for me while I've been working on this car! Quite a few things on there have been lifesavers for me. If I have my way, I'll eventually re-attach the BCDD. I think the one I removed may be able to be cleaned up, even. It just seemed like removing it was the easiest place to start with eliminating my idle issue(go figure that removing it the way I did may have exasperated it, but you learn!) I believe I know where that particular vacuum device is, I'll give it and the vacuum advance a check next time I'm by the car. Thank you for the suggestions! Just for the sake of reference, I removed & shot some photos of the piece that connects to the manifold, and where it connects. There's also a gasket shaped like the manifold-side of this assembly. I think I'm going to try making a blockoff plate when I can(hopefully soon) for this piece, capping the leftover hose connection and seeing where that gets me. I'll give ya'll an update when I do so. Thank you guys for the help!

Sure thing! Uploading images elsewhere is just a habit I've grown used to, but I'll start attaching the images from now on. I'll definitely give that thread a read, thank you!

Return springs & linkages are free and going back into position the way they should. I'm fairly certain it's the original Z ECU, here is a photo of it so you can confirm: https://i.imgur.com/S9QH4wL.jpg I believe you're onto something. I did a simple block-off. From what I can tell, there's a piece that bolts onto the manifold(this is what that three-way hose is connecting to), and then the BCDD attaches to it. I took some photos of it, but they're not the greatest(please excuse this awful sealer work, this was an attempt to deal with a broken screw): https://i.imgur.com/6JtdOUY.jpg https://i.imgur.com/JLtHK4z.jpg https://i.imgur.com/4JrlKiy.jpg Worst of all, I managed to discover a hole in this plate I had no idea was there! https://i.imgur.com/Y67nTkt.jpg I must've had this covered from sealer and it failed after running the car some, I can't believe I would've missed this on reinstallation. Zed Head also mentioned this, but could you just remove the piece connecting to the manifold and make a block-off plate for that, or would it be more in-depth? Thank you all for the responses!

Thank you both! I did replace the PCV valve at one point, but haven't looked in-depth at the entire PCV system It's definitely a new place to look, so when I get a chance I'll definitely check them out. I checked that part of the AFM out, and (to my eye) its mostly clean inside. If it's of any use, here's a photo of it: https://i.imgur.com/IgkcaZR.jpg It may be worth noting the silicone around the cover. I assume someone has been in here before me, though I don't know if they were playing with the fuel mixture or anything else important. My cars throttle body was definitely dirty, but I'm not sure if it was dirty enough to cause a problem this extreme. I have cleaned it since inspecting it, but haven't had a chance to run the car yet. With my engine being from a 280ZX, the BCDD was located on the intake manifold, rather than the throttle body. Would there still be an extra port to plug? I appreciate the help, and look forward to any info/tips you can show me! I'll do what research for them I can, as well.

Hopefully this is the right board for this thread, my apologies if not(also, forgive me for making my first post a "help me" post!) I have a 1977 Z I have been working on getting running, I'm at the point where my focus is on the engine. Unfortunately, I've hit a wall because of an issue with a constantly high idle. Sometimes the engine will start at around 2000-2200rpm and slowly climb until it settles at around 2500-2600, other times its immediately at 2600rpm. The AFM and throttle body move smoothly, and nothing is clogged/sticking inside of either. Throttle response is pretty sharp for what its worth, even at this extreme idle. I have a few thoughts as to what it could be, but I feel like I need some fresh eyes on the problem before proceeding. I have removed and blocked off the BCDD(it was the smaller, later model one) and this, if anything, made the car idle HIGHER. There is a three way rubber hose going to the BCDD housing (picture: https://i.imgur.com/12SzCHs.jpg) that I didn't remove, would removing this make a difference? A bizarre issue I've noted is that, sometimes, if I tap on the ECU, the engine will idle down to around 1000RPM, but it will also run SUPER rich. I believe the car is running rich even while idling high, but it becomes very noticeable after tapping the ECU. Could an ECU fault cause the car to idle high? I haven't had the opportunity to check my cars fuel pressure, could a bad pressure regulator cause a high idle? One of the biggest issues I'm currently facing is that the engine is from a 280ZX(F54 Block, P79 Head). Unfortunately, I have no knowledge of if this engine ever idled correctly while in the car, and it appears as if the PO just threw the engine into the car without swapping any of the accessories from the original engine, as there are multiple sensors and such with nothing on the wiring harness to connect to them. It's made it difficult for me (at least psychologically) to reference the 280Z service manual due to differences between the two engines. I also believe that, due to the nature of this engine swap, a few vacuum lines may have been reattached in creative places. I've been having trouble finding a vacuum diagram for the engine to confirm this, however. To my (inexperienced) eye, many of the vacuum lines check out visually, and I can't hear a vacuum leak, but are there any lines in particular that could cause an idle like this that I should check more in-depth? For what its worth, if I disconnect/plug this line (picture: https://i.imgur.com/r1ow9Hi.jpg), the car will idle at about 1000rpm. However, I feel like this is probably more indicative of removing a huge source of vacuum from the engine, rather than it being evidence of the problem coming from this area. I'm really unsure of where to turn next in terms of repairing this idle, so any help is greatly appreciated! Thank you!