Taurus Car Club of America : Ford Taurus Forum banner
1 - 14 of 14 Posts

·
Registered
Joined
·
76 Posts
Discussion Starter · #1 ·
Hey guys. 89 3.0 auto. I have a funky idle issue. When my car is cold (first morning start up) I have a funny "surging" idle issue. Happens more while in gear but it'll happen in park as well. I've been looking at receipts and this has been an issue since 1991. Car only has 65k. The issue goes away after a few minutes of driving. I've cleaned the iacv to no avail. I have no vacuum leaks or CEL and the air filter is clean. I am going to do a tune up and change the fuel filter and trans fluid and filter. This car is remarkably clean with no leaks at all. This idle doesn't affect driving it's just bothersome. What do you guys think? Thanks in advance.
 

·
Registered
Joined
·
23,476 Posts
When it does it in park, set e-brake, get out and tap iac with handle end of screwdriver. If idle normalizes, replace iac.
 

·
Registered
Joined
·
76 Posts
Discussion Starter · #3 ·
When it does it in park, set e-brake, get out and tap iac with handle end of screwdriver. If idle normalizes, replace iac.
I did that. Nothing happened. I will try it again though. Anything else that you think it would be? If it was anything else wouldn't I get a CEL?
 

·
Super Moderator
Joined
·
8,663 Posts
89 is EEC IV / OBDI, which in general only sets codes when something is really wacked, so no CEL might be expected.

I am wondering if you have a vac leak that closes up shortly after startup, or you have a weak injector. EEC IV doesnt allow you to look at STFT / LTFT bank to bank, so you are often shooting in the dark with a diagnosis compared to EEC V / OBDII
 

·
Registered
Joined
·
76 Posts
Discussion Starter · #5 ·
89 is EEC IV / OBDI, which in general only sets codes when something is really wacked, so no CEL might be expected.

I am wondering if you have a vac leak that closes up shortly after startup, or you have a weak injector. EEC IV doesnt allow you to look at STFT / LTFT bank to bank, so you are often shooting in the dark with a diagnosis compared to EEC V / OBDII
the idle isn't rough per-say. If I had a tack I'd say its goes between 600~1000 rpms and back and fourth. So It feels like it's an air metering problem to me. Maybe I'll see if the iacv on my bronco fits and try that? Or just drop the whole 30 bucks it costs for a new one? lol
 

·
Super Moderator
Joined
·
8,663 Posts
Try the Bronco one and see if the problem goes away or changes. Even though the IACs may look different, they are electrically nearly the same. Only difference is early ones had an inductive kickback diode mounded externally in the harness right at the valve, and later ones had the diode internal to the valve. Using an internal diode one with an external diode harness is fine, but using an external diode one on an internal diode harness (i.e., no diode at all) isnt a great idea.
 

·
Registered
Joined
·
76 Posts
Discussion Starter · #7 ·
Try the Bronco one and see if the problem goes away or changes. Even though the IACs may look different, they are electrically nearly the same. Only difference is early ones had an inductive kickback diode mounded externally in the harness right at the valve, and later ones had the diode internal to the valve. Using an internal diode one with an external diode harness is fine, but using an external diode one on an internal diode harness (i.e., no diode at all) isnt a great idea.
I don't know how to determine the difference? I am going to work on it this morning since I have the time. I'm going to tap on it and hopefully that will tell me something. It seems that having a bad iacv would be the only problem here, considering I haven't found a vacuum leak.
 

·
Registered
Joined
·
13 Posts
My '06 Taurus 3.0 12v has rough idle and is giving me fits with problems starting. Yes, I replaced the IAC valve and it did not help. About ready to bring it to the ............dealer.
 

·
Registered
Joined
·
76 Posts
Discussion Starter · #9 ·
So I've figured it out. I started my car and of course it's ideling funky. I tap on the IACV too see if it does anything. Of course nothing happens. So after fiddling with that for a minute I just un-plug the IACV, whoa! car is still running! So I started searching for the vacuum leak, little less than 5 minutes later i found the vacuum leak on the back of the intake manifold. I plug the IACV back in and then I plug the leak, car runs fine! Then I unplug the IACV and the car dies. Okay so I found my culprit, but what was plugged into this? I have no idea! I searched and searched and searched and could not find a single hose, fitting, or adapter. Nothing. It's the barbed fitting that is underneath the fitting for the MAP sensor. I will post a couple of photos for reference. I am going to cap this fitting for now, until I can figure out what plugged into it. Anyways, can you guys help me determine what plugs into this? Thanks.


In the first photo you can barely see the fitting I am talking about. Its directly underneath the fitting for the map sensor. The second photo is just a general photo of the area to help out.
 

Attachments

·
Registered
Joined
·
76 Posts
Discussion Starter · #10 ·
well I put a cap on the fitting. But now when I start the car there will be one moment where the car almost stalls,(actually did stall once) then it evens out. I'm going to let the car cool down a little bit to see if the surge comes back. FYI I unplugged the battery for 10 minutes to see if the computer resets or something like that.
 

·
Registered
Joined
·
76 Posts
Discussion Starter · #11 ·
well I figured out what was missing. The FPR attaches to that nipple. I suppose I overlooked that the first time. This thing hauls ass now. But how the hell did this thing run before? Its crazy. The car had a vacuum leak, and no FPR and it still ran fine (for the most part) and got 18ish mpg. Hopefully I'll be getting 20 mpg again :D Any suggestions? The car still has a weird, "stall" when first started, but it goes away quickly. Does it sound right to believe that the computer has to "re-learn" the idle position, or are these computers too dumb for that crap? Thanks again for the help
 

·
Registered
Joined
·
27 Posts
my 97 sho also has a rough idle well i notice it all the time i think it just needs a tune up ? when im sitting at red light i can notice the rpm gauge needle move up and down just to say i notice it could it mean i need a tune up or could it be something else ? anyone have any other ideas ?
 
1 - 14 of 14 Posts
Top