How low can you go?

Here's my idle... '90 GXL, unplugged the TPS and got this:

 

On hot humid nights with all lights on with my foot on the brake my idle will drop that low and bounce up to 800ish

 

Fix your BAC valve.

My lowest idle is 750 RPM. That's what the factory specs the as the proper idle, hence that is what my car is set to idle at. With the bridgeport, I expect it to be slightly higher.

 

somewhere between the 0 and 500

 

My BAC valve is quite silly. I've cleaned it, and I can hear it click open when I put on the A/C. Idle becomes rock solid. It doesn't seem to want to work any other time.

 

rock solid 750rpms and 900rpms with the A/C on

... but....

1) RPMS drop with electrical load (lights, brakes)

2) Anti-afterburn valve (the non-accessible diaphram sealed on on the ACV) won't hold vacuum, so my idle's all over the place when driving in stop & go traffic.

3) If the A/C's on and I decelerate in 1st gear from 6500-2000 rpms and push the clutch in while going downhill I can stall it. Same thing if the engine's not fully warmed up and the A/Cs on.

and that's with a tuneup, good BAC, 2 of 3 ACV diaphrams holding vacuum properly, and TPS properlly adjusted.

 

Once i am worm i idle @ 650-680


And i am rolling pretty stock

 

yupp mines been there before...& stayed there for along time.. before i knew anything about the car.. thats where it always was.. and always died too...fixed the tps, bac, and another little screw ..

 

Don't forget factory tachs are WAY off in the low rpm ranges. My Haltech verified the factory tach was ~200rpm optomistic at idle.

I usually ran a true 700 rpm idle, if I went below 500 it idled like a bridge port. It was a large streeport w/ 11# flywheel and 750cc primaries. When I ran a smaller exhaust system I could drop the idle more with this set-up.

On the stock ports, injectors and the 11# flywheel it would idle smoothly at 500rpm as indicated by the stock tach- so ~300rpms!?? I once drove in terrible traffic past Sears point at that idle speed and if it stalled the only way I could start was the anti-flood proceedure. Luckily It didn't stall there, but it did once in SF traffic

 

When I took my emissions test I lowered it as much as I could and leaned it out a bunch, on the dyno it was at 480rpm on the screen.

 

An acv anti afterburn portion of the acv can be blocked off using RTV and approx 2hr work/setting up time. Remove the valve. Block the two anti afterburn holes. Reinstall and let a couple of hrs go by for the RTV to set up. Done at little to no cost.

 

my car when i first start it in the morning will idle at about 100-200rpm and almost die then bounce up for a sec then go back down....

i hold my foot on the gas to make sure it doesent die, but 100-200rpm is my lowest....

 

With the initial set coupler jumpered OR the plug pulled off your bac and the engine fully warm, the idle should be approx 750. If not, then adjust til it is close to 750. THEN pull the initial set coupler and or reinstall the bac plug. After the engine settles down the idle should be VERY close to 750.

To do the above the timing has to be set on the marks and the tps set PROPERLY.

And BAC's wear out over fifteen years. Buy another if cleaning does not work. I've several bacs and 1 or 2 are outstanding compared to the others (which are not exactly dogs either). Stuff just wears out.

 

Mine hits 750 on the tach but on my afc it reads 740-760. That normal?

-Andrew

 

Yah thats normal, its pretty hard to see such a tiny variation on the stock tach, S-AFC is much more easy to see the changing rpms.

 

I've had the SAFC reporting a solid 750 RPM idle while the tach was reading ~900. It tends to wander a bit, for some reason (the tach).

-=Russ=-

 

Crap.... my rx will stall's when it drops below 900.... she sits on 1200...

 

Mine has been sitting idle in my garage for over a year...yey

 

mine idles at a nice 800 rpm... and that's with a tb mod and removed bac
...with lights/wipers/brakes on, it's at a 700~

 

my car idles at a cool 2.5k right now 2 if im lucky

ive got a little work to do =X

 

mine hangs out at 1.5k, so I know how ya feel

 

i finally ended up taking my car to mr mazda, and found out its a combination of
pulse damper
thermo wax
tps
and a leaking water pump
oh yeah, my u joints are going out too

 

How do you clean your bac valve, and dose it help?

 

It varies. Sometimes it's 750 and stays there, sometimes it hunts and can't find a happy spot.

It needs some work - TPS adjustment, BAC valve cleaning, and oh can't forget the bolts to hang the AC compressor back up. One's gone (who knows where it went?) and the other sheared off. That's going to be fun getting that out of the bracket.

 

on my 10thAE for 10 years every single emmisions test was 0-5 RPM withn each other at 750 rpm