Need help with 3.1 (3100 SFI) idle/air problems

[chicagogtz]

Hello all,  I haven't been on this website in a long time almost 8 years now, anyway, glad to see people still like berettas...  I am having a problem with a 94 corsica.  It is a 3.1 (3100 SFI V6)  Car has 66,000 original miles.  The problem is that the car had a rough idle at low rpms, or sitting still.  Almost as if it had a performance cam installed or something.  Anyway, I did put new plugs, wires, and also did the basic clean up of the throttle body/AIR valve, butterfly.. ect..  (Thanks, Rex!)  And reset the computer by dissconnecting the battery over night.  I know your all going to say, scan the car, well I have been to about 8 different autozones, Advanced auto, ect... They don't have obd1 scanenrs.  Now i know I can count the check engine light by jumping A and B, but the problem is I have a 16 pin obd1 port, and there are only 2 metal contacts available to jump,  but they are on top of each other and all the way to the right.  So it would be like this. ÂÂÂ

                                       [][][][][][][][X]
                    [][][][][][][][X]

Now can I jump these 2? or am i just out of luck?  Thanks!

[SuzukiGhostRider]

You check your fuel filter yet? Could be a clogged fuel filter or even a clogged air filter. Also, look into your TPS (Throttle Position Sensor) and IAC (Idle Air Control) sensors. Best of luck. Let us know.

[chicagogtz]

I changed the IAC Control valve with a new one, and the butterfly valve seems ok, air filter is new, and I even ran the car without the airbox or hose connected to engine to see if this made it "breathe" better....  the thing thats strange is that it is random, sometimes it runs fine, then it just starts acting like garbage as soon as you start it, more seems you have to give it gas, in order to get it started, then the idle goes real high, then to low, then dies out,  so you have to floor it for a little bit to get it to start going, then after that runs fine...  Im hoping its not the EGR valve, maybe an o2 sensor causing problem?  

Thanks

[SuzukiGhostRider]

Yea, that def sounds like a bad fuel filter to me bud. Pull it out and blow through it in the direction of flow. It should be fairly easy to do and you'll be able to feel the air out the other end. If not, or if it's real hard to blow through, it's no good, replace it. GL.
Of course it COULD be the cat is clogged. That would cause the same symptons. Check out this thread. I just had to replace my cat and resonator in my Olds Achieva Quad with an 18" glass pack and pipe and had similar symptons. Check your fuel filter first, it's easier to get to.

[n00b20]

all my signs are pointing to my cat now, thats great  

[chicagogtz]

LoL, now I know why you said GL.... Well, I checked the fuel filter, I pulled off the one side from the tank with the plastic clips, that was easy, and gas seem to flow easily, now the bad part is, the gas lines are rusted, along with the nut holding the other end of the fuel filter, the fuel filter was changed from stock, as its not as rusted as the rest, but Im afraid if I tourque it to much, I might snap the gas line with the fuel filter, as they are fused together by rust, and wd40 isnt doing much good...  Is there a way to blow something through the filter while on the line?  Like an air hose? or is that a bad idea?  Also, anyway Can't I just count the check engine light?  As that was I was trying to do...  ?  Thanks again for the help...

I mean if I can't fix it, its still very drivable, just have to use a little more gas sometimes then other, but at $4.00 a gallon, does it really even matter... LoL

[heavywoody]

You can't use the paper-clip trick on 94-96 L-bodies due to GM using those years as a wanna-be OBDII startup.

96 is full blown OBDII, while 94-95 are sorta half-assed OBDII. The only way to read codes is with a scanner.

For the rusted fuel filter nut, get some PB Blaster (available at Lowes or most Auto Parts stores) and let that soak into the nut.

Normally I'd suggest using a little bit of heat, but since it's with the fuel lines, that might not be such a good idea  

[chicagogtz]

Ok, I got the fuel filter off, it blew thru ok, but I changed it anyway, as it was a ***** to get off, anyway,  Still no difference in the car,  I also noticed a whining noice coming from the front pulley,  Im 99% sure the water pump is going, or already gone,  now since I can't scan the car since I don't have an OBD 1 scanner, and the repair shops want to charge me, Im not gonna scan it, as Im not pulling  a check engine light, now I guess my next question is, would the water pump have anything to do with my rough starts/idle problem?  I don't think it would but I don't know for a fact. Here is my problem more specifically:

1: first thing in the morning. turn the key it starts (right away, I am not holding the key cranking and cranking, its more like 1 crank and it fires., then dies out right away, turn the key again after about 2 full presses of gas pedal, the car will crank run at low idle/ almost about to die, so I give it some gas to idle it myself at about 3,000 rpms for about 30 secs..  sometimes it will regulate itself out, with the idle, and then other times it will idle rough, sometimes it will idle to where you have to mash the brake down at a light, because the car literally wants to take off at low idle, like I stated earlier, as if it had a performance cam in it.



2: Come out first thing in the morning: Turn the key one crank, car fires up, has really low idle almost about to die out, then the IAC kicks in or something in the car sets the idle real high, then after about a min the car balances itself out idles and purs like a kitten. you wouldn't even know there was a problem


the thing thats frusturating, is that its not a constant problem, its almost as if the car decides when it wants to run ok, and when to be a pain...  Specifically my only problem I care about is trying to get it started.  It starts with a turn of the key one day, then the next I have to crank it, then it dies, crank it with gas, give it gas while its started so the idle doesnt go so low it dies out...what I mean by that is, once the car is running after you start it, the idle sometimes is low, to where if I throw it in drive or reverse it dies out, then I have to put it in park, and crank it, give it gas myself for a min to rpm to about 3000 then hurry up and put it in drive and start to go, once the car moves, it runs find... no matter what happends during starting.  Once again I cleaned almost everything that has to do with the throttle and everything attached to it, also have a new fuel filter, air filter, IAC valve, and reset the computer.  New plugs and wires, I have read other posts on here, I think I might try to see if its a vaccum leak, as it seems like sometimes the car isn't getting enough air/fuel ratio or something... I know its got fuel, cuz after I floor it enough, the exhaust reaks of gasoline... lol  anyway, thanks for all your guys help, I know its hard to diagnose things without seeing it in front of you, but I am at a loss, and am not going to take it to a repair shop and get ripped off...

[SuzukiGhostRider]

You check your TPS sensor out yet? They won't always trigger a code when they go bad.
Also, the hard starts sound more like an electrical than fuel problem. Have you checked your ICM and Coils out yet?

[APACHE 64D]

what's and icm?lol, also where does one find a iddle control switch or circuit?Check your IAC again. Mine was doing the exactly samething as yours and it had to do with the IAC. I took it off and what do you know the spring had come off of it.

[SuzukiGhostRider]

(APACHE 64D @ May 18 2008,15:01)QUOTEwhat's and icm?lol, also where does one find a iddle control switch or circuit?Check your IAC again. Mine was doing the exactly samething as yours and it had to do with the IAC. I took it off and what do you know the spring had come off of it.
I'm hoping you were joking.....
ICM = Ignition Control Module. Located under and attached to your Coil Packs.
Idle control switch? Never heard of it.
IAC = Idle Air Control.
TPS = Throttle Position Sensor. Senses idle needs and adjusts accordingly.....
Again....  

[JeffD]

Yeah, the ICM could be bad but what about the coil towers? are they rusty? plug wires could be bad too. I hate how everyone always points the fuel filter, I mean, did you read his description? he says it's an intermittent problem, a clogged fuel filter would usually case a problem all the time.