Glliw

I just ordered a car's worth of these last night to replace my crapped out stock ones. I'll post up on my experience after the fact. For $130 shipped even if they don't last that long I can't complain. He'll that's near the price of one corner for the better options out there.

That's a good point, Kurby. I think I'll buy an egr block off plate and rule that out entirely then. I haven't had a chance to look at it any this week and won't until the weekend most likely.

I will double verify this tomorrow, but I have done this already with no effect as I recall.

Wouldn't that show as a vacuum issue on the gauge that I just tested with though? I would have to be below -15 in. Hg to begin to think I had a strong enough vacuum leak to create this effect I think. That and the whole works fine at cold temps part pushes me away from thinking vacuum.

It sure does, but it also happens when my foot isn't on the brake so I don't see a correlation there. In the videos above, I am not on the brake at all. Just run it up in 2nd gear and put the clutch in. I just did the vacuum test. I tee'd in at the brake booster line, at the firewall mount to try and include as much of the system as possible. From my perspective, I look pretty solid from a vacuum stand point. It hold at -18in.Hq at idle with maybe a 1/4 to 1/2 in. Hg fluctuation towards positive values. When blipping the throttle, it spikes to 0-ish, and returns down to -20 and settles back in at -18, just as it should. If there are any vacuum leaks at all, they are very minute and I do not think they are a driving factor here. I also inspected the underside of the intake manifold. I did not see anything obvious under there.

It always is something simple. Only thing is that there are 30 simple things in the system. Thanks again for the help, I definitely appreciate it. How long roughly should it take the intake to leak down during yogurt cup testing? 5, 10, 30 seconds? I'll buy a cheapo vacuum gauge and a mirror here shortly and follow this write-up: http://www.atlanticz.ca/zclub/techtips/vacuum/

I would think the same except the issue isn't there at cold engine temps. Also, EGR is effectively non-existent since the vacuum source to it is blocked off via the BPT block off, unless a massive leak is at the gasket surface. I do not have a vacuum gauge handy. The a/c idle control is disconnected and can be seen as such in the pic above as I had the same thought. Doing so had no effect. A few days ago I did do the "yogurt cup test" by using a yogurt cup to block off the intake after the AFM, creating a closed system. I pulled off the brake booster hose and pressurized via that. During that, I could pressurize with my mouth to a point and could hear a leak, probably past the valves. It would hold the pressure for 5-10 seconds. I sprayed soapy water at each nipple connection on the intake manifold and did not see any bubbling. The AFM boot does not have any tears in it.

Thanks for the thoughts, Mark, as well as everyone else. Though i do not think that is it. While the 280z does come with a "rev cushion", that has long since been removed as that was the first item I thought to look at. To back up my statement on how the car performs when cold, please check out this video. The rpms act as one would think they should and return to idle in a reasonable period of time. Once the engine begins warming up, the issue will persist. I also popped the cover of the TPS and checked its function. I cleaned the contacts with a electric parts cleaner. Everything looked cherry in there though. Do you think one of the temp senders may be playing foul here? I didn't think any interact with the system like this, but with it only happening at warmed up and consistently then I don't know what else to think.

Seems to happen only when warm. I have not checked the AFM. Yes it has been an issue since Ive owned the car. I'm complaining now as I only drove it from purchase origin then to body shopwhere it sat all winter. That used to help. I cleaned up the space around the throttle plate and added the helper spring which helps it come down quicker initially but still slow at2.5k downward.

It did this before the deleting began.the deletes were part of troubleshooting.

Between left and center pin, resistance is infinite at closed throttle and goes to zero throughout the whole range. Between the center and right pins resistance Is zero at closed throttle and goes to infinite slightly off of closed and stays that way throughout the full range. Between left and right pins there is infinite resistance throughout the range except for a small window of approximately 5 degrees off of closed.

Yep, it is. I pulled the AFM boot off and watched it return. Comes to a shut nicely. When the engine is not fully warmed up, say, around 1/3 temp gauge and below, a throttle blip will result in a quick rev and return to idle. The problem is greatly pronounced once at operating temperature.

Here's an engine bay shot.

Yep, both the torsion spring and the linear spring are in place. I installed a secondary linear return spring to see if it was a worn spring issue but did not see to help.

I'll take one here in a bit. The car is in the first post. There isn't a mods list because there aren't any, except for the vaccum deletes whilst troubleshooting this unless you think the front air dam affected this.

Mgood, nope its not on the car.

Update from testing: Unplugging BCDD had no effect Unplugging TPS caused idle to hang the same throughout RPM range. ie, no hard drop to 2.5k followed by slow descent. Only slow descent the whole way. Car ran like poo with it unplugged, of course. I do not have the dashpot in place. That was the first thing I eliminated when I started looking into this.

I plugged that vac tap that runs up to the BPT. I'll check unplugging it, thanks.

So, I have a problem that has been plaguing me and have done a fair amount of googling and searching on here and other Z sites and haven't found the bucket to stick my problem into to troubleshoot. Please see the video below. Here is a description and some details: The car's idle speed will "hang" after acceleration. For instance, accelerate through a gear up to 3k,4k, etc rpm. Push in the clutch and you would expect rpms to rather expediently hit idle, but here it drops from the initial high to 2.5k rpm rather quick then takes 10-20 seconds to cover the next 1600 rpm back to idle. 1978 280z Deleted AAR and the coolant plate under it A/C idle increase arm nippled off EGR nippled off added helper spring to throttle body return with little effect. Helps come down from high speed but will not help under 2.5k rpm It seems to only do this when warm. Any ideas where to look?

SpeedHut will get you there for half the price. I believe they are a sponsor over on Hybridz. . Auto From Speedhut.

Clean find! Get it close enough to the fence there? Any idea on what suspension's on the car? Looks like its go either cut springs or coilovers to be that low into the fender wells.

Looks good Moelk!

I thought about going the Autozone route but wasn't quite sure how to ensure I got the correct calipers (S12,S12+8,S12+8W). I guess the good news is that they would most likely take them back if they aren't the version you were looking for.

Hey man, welcome to the forum! I bet that was a helluva drive. I dollied back a 260z when I was 17 from Tennessee to Florida in a round trip so I can only imagine what it's like to do your first drive as a long distance one. Share some pics!

That's a good point. I went out there last year for the vintage races and saw a few guys out there. That was a bit before when I had gotten my Z so didn't poke and prod too much.