Hey, I'm new here, I have been drooling over rx7's for a few years, and now I have one of my own, its a 1990 convertible. black interior/exterior

My problem is it idles really low and usually stalls when the ac is turned on, it also drops to a really low rpm after racing up to 7k rpm and releasing the throttle. Any ideas before I rip into it?
I think it's probably a vacuum hose or somethin, but I need a diagram before I touch it

 

bac valve man....... whats the miles

 

well it could also be that your BAC is not working or you just need to raise your idle. But a vac leak could do that too.

 

Try cleanign out the BAC valve with some carb cleaner, I believe their is a really good write up at www.1300cc.com ...

 

does it pop and back fire when ur driving at high rpm and let off or even rev it up

 

sorry for the ungodly amount of time it's taken me to reply. (my computer is broken)

Every once in a while it will pop/backfire when letting off after 8k rpms never happens in lower revs.

its got 100K miles on it. replaced spark plugs & wires recently b/c the original owner told me he never replaced them... ever

the idle is at the spec. range, I did raise it a tad just in case, yet I still end up with the same problem.

 

wierd, mine is just the opposite. Mine ruff idles unless the A/C is on. And mine pops/backfires at high RPM too.
Should i do the BAC thing too?

oh ya and car doesn't stall.

 

...

 

Ya mine does the same thing! I haven't had a chance to clean out my BAC yet but I'm hopping thats all thats wrong.

 

Been there done that.. go to the link Rx7nub recommended. Its your BAC valve.

 

alrighty... ripped off the bac valve, got some carbuerator cleaner, cleaned it out (wasn't very dirty in the first place) till it was shiny. Same problem with idle, but at least it doesn't die when I put the AC on, but it's almost winter, and I don't need it anymore!

Idle bounces between 650-900 with no acc. on. Almost dies when releasing throttle, usually the needly drops to the bottom of the gauge.

this isn't exactly a problem, just more of an annoyance, since it rarely dies, and tapping the throttle usually brings the engine back up to speed

 

I have the same problem, but I think it might be my TPS. Any solutions?

 

Hpram99
The BAC could just not be function, if it is that BAC at all.

Blue94
You should test the TPS before saying that is the problem.

 

Same problem. 90 vert w/ auto trans. Have cleaned BAC. Installed a different BAC. Checked TPS. replaced Vacuum lines. Complete tune up. Idle is just unstable. Idles within spec in drive, high in park also surges at about 1400 RPM. Problem seems to be that the idle doesn't increase when you apply the brakes or when you turn on the air. Have also checked the signal from the ECU to the BAC and the voltage increases some when the accessories are turned on but I don't know how much the volts should increase. Ideas appreciated.