hello every one i own an automatic 280zx turbo here is the deal the motor is completely spankin new it has new everything and i mean new everything!!!!
while im boosting feel like i am running lean but i dont think that is the issue.. more like what is my boost doing??

the problem/new suspecttoday like all wekends i put my optima from my other z in and began on this head ache.i was adjusting the idle screw and brushed my hand against the vacuum modulator (located below the AFM )and noticed a drop in idle pushed the connection together and it improved. however, there are two connections and only one makes a difference when unplugged. i have cross refernced the hoses connected to the mod. with non runnin turbos and pics online that happen to snap it and not to mention the bible.
does any one have a turbo automatic that whants to help me diagnose ??
ill be on every 20 minutes and have laptop on me outside "im ambitious"
whats new on the z so no comments on these things
hosses, alternator(off 300zx), new fancy poly hosses(all hoses), new master brake and calipers, relays, fusses, no cracks in the inlet boots, cold air intake, carbon canister, all sensors (all sensors), motor has like 30 miles, the AFM has tested fine vs many different same part number ones, ecu also fine, injectors, FPR,all connectins polished to the copper, all harness wires and ground are good or repaired..

 

You need a WBO2 if you want to know if you are running rich or lean - it's the only way to know properly and in real time. Reading the plugs is not the way to do it anymore....

Cleaning your connectors to the copper is a bad idea. They are plated because the copper will quickly corrode and give you a bad connection. Copper is an excellent conductor (only silver is better) but is not suitable for a connection/contact. It's OK to polish up brass connectors like the ones on the stock injectors, etc but not the plug/harness side since they aren't brass/bronze.

 

I wouldn't say "don't read the plugs". Reading the plugs is the easiest and quickest way to see the general running condition of the engine. If one cylinder is having problems, you'll know. A WBO2 won't tell you "cyl #5 isn't firing".

So those two hoses on the vacuum module go to the AAC and EGR. Either one of those hoses will introduce a vacuum leak if disconnected. So... I'm not sure what your question is...

What psi is your boost set to? Are you running an aftermarket boost gauge?

 

Yes good point. I was refering to using the plugs in general to see if you are running rich or lean. Definately still a good indicator of something fouling on a single cylinder, etc.

Also wrt the module it's a simple system. Pull it out and it's just a solenoid on both sides. Check to see if it seals properly and you can activate the solenoid itself with 12V

 

"aww you 2 guys" i always take a gander at the new threads fric frac and nismopick have a post in ha ha

well no rust after a couple of months plus i put some spray that keeps errosion away..
its stock boost 7 psi need to figure out this issue so i can upgrade
plugs all look like they are buring fuel fine.. pressure guage confirms no loss in pressure
i wanted to know: if i unplug any one of the harness connecters from the vac mod. should i see a difference in idle ???
exacly what it does
while im driving, when i "floor it" , it down shifts fine and takes off, then when it feels like it should shifts(as i have driven many turbo automatics) i feel like its still trying to boost(spooling) even after reaching 7psi (guage stays just below 7) then a pop sound comes from the turbo like a backfire if i never release the gas.. ive never had this problem flooring my auto turbo z's
1st to second boost and shift fine when flooring
in 2nd, i floor it, dwn shifts fine then feels like it keeps boosting(or spooling) and wont up shift
third does same thing after dwn shifting
car runs great and shift fine if give it a good amount of throttle, not flooring it, but whats the fun in that
tranny or vacuum??
all my new parts$$ and hard work i wanna have fun too...

 

I'm still not sure what you are asking, or what the problem is...

After re-reading your posts several times, this is what I gather:
-It feels like it's still boosting at full throttle, at 7psi. What's the problem?
-It pops "like a backfire". Like a backfire, or ACTUALLY backfires? Have you removed or modified the stock POV (pop off - emergency release valve)? Have you checked the wastegate?

 

ok so i figured out my problem that has givin me grief for so long.
AUtomatic 82 280zxt

the issue
the car would not up shift after down shifting via the kick down switch after i floored the pedal
how this effected the car
since the car would not up shift the turbo continued to spool which built up back pressure and made a loud pop noise when the turbo could not handle the pressure and suddenly released the pressure
my solution
after many weekends of headachs i accedenty brushed agaiinst the vacuum modual (VCM) located below the AFM and noticed a change in idle.
i have always checked every connection on my ride before starting to diagnose. turns out the wires that run inside the VCM probably disconnected.
after jiggling the wires i went for a test drive and whalla it ran perfect and damn after a whole motor rebuild 2 years of costumizing the **** is stupid fast tons of aftermarket...
i remember my first 81 turbo with super rare 2 1/2 chrome trim where i have only seen people have black trim along the bottom of the door and fenders.."kept the trim after rolling the car..."