ok
first my idle is really steady ... no stumble or misse fires

so why am i complaining??

its too low!!!!!

when my super curent eating flex-a-lite fan kicks in the idle is way to low ... neer stalling

so i checked the tps -> perfect

checked variable resistance for mixture -> "screwed" at max if i "unscrew" it engine stalls

checked the idle screw -> "unscrewed" at max if i "screw" it engine stalls

and yes the little stupid green connector as a jumper wire in it and yes i remove it before driving the car

i cant idle higher im stuck to where its idling now

its idling at 700 725 rpms

and i got a brand new 875amps battery


thanks for the help guys

 

i knew it !!

its too weird
nobody got a damn idea of whats going on

 

Just seems to be a bac thats not working. If idling and you pull the bac plug off, does the idle drop? Have any effect at all? If you jumper 12v to the bac does it pull in and click? Any self respecting bac will adjust the idle up when you put a load on the engine, like turning the electric fan on or the air conditioner. Read this url whether or not you have a turbo. The part about the bac is relevant. http://www.teamfc3s.org/info/articles/idle.html about three quarters of the way thru this article it tells how to check out the bac. Also how to repair the ECU is that transistor is determined bad. I did that fix on a spare ECU I have and it works and cost only about a buck fifty. Yours is probably not broken, but if it is there is the fix. Also at http://www.iluvmyrx7.com if you download section 4a for a n/a or 4b for a turbo, there it tells one how to check out a bac. No, your problem is not unusual.P.S. the passing along the url to the free download of the factory service manual is not a cop out on my part. It just reads better than my post and is an official document so to speak, not heresay.

 

I have a '91 vert with 60,000 miles. It idled at 700 rpm when i bought it new in 91 and it idles at 700 rpm now. What year/type(GSL,GXL...) is yours? Does it actually sound like it is about to stall, or are you guessing that because it is so low it is about to stall. Also, has it ever stalled?
Did the idle change? example-it used to idle at 1250, now only at 725. Or always at 725, now at 725?

need more info!!
Kris

 

its running 700 rpm and it did stall once
now its just neer stalling

it stumble a lot when its droping below 700 rpms

 

well
its the damn bac valve

when i play with the connector the idle goes up

thanks guys

 

Just a note of warning. Try your best to make sure that the two wires to the bac don't touch each other or short to ground. Might take out the transistor in the ECU (which there is a cheap fix if it happens).

 

Hailers—GOD BLESS YOU! I ALWAYS blame the BAC or the transistor on the ECU for low idle problems under load! I don't think people want to hear that because you need to pull up the carpet, remove the ECU, remove the blown transistor, solder in the new transistor and hope the lame connector on the BAC does not short out again! I found that permanently connecting the BAC with new shielded connectors BEFORE you work on the ECU is the way to go. I know this because I shorted out my ECU about 5 times in one month with the stock connector on the ECU. I eventually had to replace my ECU—THANK GOD FOR EBAY! Seriously, if anyone needs help, send me a message!

B

 

The real people to thank are Paul Stoaks and TEAMFC3S. The repair cost under five bucks and is easy to do. I fixed a spare N332 that the bac was not resonding to by putting in a new transistor per the article. Works fine now. The article has a title dealing with turbos, but it applies to N/A also. The bac fix is at the bottom of the article. Should bookmark this article for future reference. Its http://www.teamfc3s.org/info/articles/idle.html Thanks again to Paul Stoaks and Mr. Gibon.

 

i have a '91 n/a and it idles between 500-600 when warm and never feels like it will stall. is this normal or is my idle too low also??

 

I believe the fsm says the idle is 750. Give or take. I understood the problem was that it idled at around 700-725 rpm but that when the electric fan was turned on , it would nearly stall. That should be a sign that the bac is not working. A properly operating ECU should see the load on the engine increasing and see the rpm droping and then send a signal to the bac to open up and maintain the 750rpm. If you set your idle at 500 and are pleased as punch with it , good for you. But if you put a load on the engine like turning an electric fan on or the air conditioning, and the engine wants to stall and not hold the 500rpm, then you have a defective bac or ECU or wiring to the ecu, most likely(covered my *** with that *most likely*). It looks like Gab88 found that if he wiggled the bac plug and wires, the idle picked up. Crummy connection. I'd say that if your idle is 500-600 and you are happy with it, then its not worth messing with, even if the fsm says idle should be 750. Rules are made to be broken.

 

hey jeff
im using an external tach
so maybe your car is idling at 750 but the the tach indicates less

 

Gab,

Here's the image you requested.

Brian

 

thanks Brian

 

Did the new connectors work?

B

 

#1 =)