FC idle issues... help me out please!
 

Hey everyone,

I'm the happy owner of a '91 NA FC, but "the weird one", it's the Middle-East spec.

Only 65k miles. No mods really, just a cone air filter.

Here's the details on what makes it "special":

- S4 Engine on S5 body
- Distributor-controlled Ignition
- No AWS (All-Wheel Steering)
- No cats
- Ports 5 and 6 are operated by a solenoid
- Ports 5 and 6 are butterfly valves in the LIM
- N368 ECU

And here you have the 3 unique FSM sections for this specific car, most of the content is divided in "Australia" and "Except Australia" sections -- my car falls under the "Except Australia" category:

http://starc.com.ar/FC/FSM/

So... I am having some issues with my car, they are the following:

- Bouncy, cycling idle

When the car is at normal operation temperature, the idle is bouncy and cycles. It doesn't cycle in the exact same way all the time, it varies. Other than that, the car runs pretty smooth and nice... other than some bucking on decel sometimes.

I also notice that this bouncy cycle gets worse with time, after getting to normal operating temps -- it starts very subtle, but gets worse and more prononced as I keep driving... as if rising engine bay temperatures would somehow be related. The temperature gauge has never gone over 50% of the scale though, ever.

Other detail, when I start the car cold, the dash's voltmeter reads slightly over 12 volts, and slightly goes down as I keep driving... exactly the same way the bouncy cycle gets worse, after about 40 minutes of normal driving, this is what I get:

http://starc.com.ar/FC/DSC00709.JPG

-- I haven't checked the battery with a multimeter though, for a better reading. I know I should.

Here are some videos of how it idles, all recorded the same evening (ignore the audio, just cars passing by):

http://www.youtube.com/watch?v=NDgKRvgP0IU

So, after searching and reading a lot, I adjust the TPS to about 1k ohm, and thought about adjusting the idle screw, the one on top of the Dynamic Chamber.

I read that I have to jump the Initial Set Coupler... problem is that... I cannot find the damn thing... I check the FSM (Fuel & Emissions Control Systems, Page 8), and I find that there isn't one... why!? In my FSM there's only a "Digital Code Checker Coupler". Found it in my car, check:

http://starc.com.ar/FC/DSC00711.JPG

http://starc.com.ar/FC/DSC00712.JPG

Looks a lot like the Check Connector, doesn't it? But according to the FSM, it's not.

So... as far as I know, the Initial Set Coupler modifies the operation of the BAC valve, and checking near it, I find this:

http://starc.com.ar/FC/DSC00718.jpg

It looks a lot like the Initial Set Coupler (and many other service points...), and it's connected to the BAC valve, 2 solenoids in the solenoid rack, and... well, stuff

http://starc.com.ar/FC/DSC00717.jpg

Would that be the Initial Set Coupler? Or it is something else?

Any help, recommendations or anything I might not be considering?

Oh, by the way... I am having issues with my oil pressure gauge... it reads zero most of the time, and randomly goes up slightly... should I be worried? Should I check the oil pressure sender/cable? Where is it, and what should I do/check for?


Thank you for your time!

-Dan

The other video I was talking about... forgot to post it:

http://www.youtube.com/watch?v=XhZdaM5c5Vk

that looks to be the initial set coupler yes.

pics of the engine bay please, i've never seen a photo of a middle east spec car

Sure, there you go -- 2 pictures, one with the stock air box, and without it

http://i26.photobucket.com/albums/c1...DSC01257-1.jpg

http://i26.photobucket.com/albums/c1...i/DSC00267.jpg

Some of those FCs came with dizzys instead of Crank Angle sensors...

And your Initial set coupler will be a yellow connector on the other side of the engine bay. Look around your intake piping, air pump, etc...

Yup, dizzy here, as you can see on both pictures.

So it's the yellow connector on the passenger's side?

You can see it in the second picture, it's a very pale yellow one, between the variable resistor and the black intake elbow.

^ that's normally a fuel pump check connector to pressurize the system. I suppose it could be an initial set coupler on a middle east car.

Sooo... which one? The one near the BAC valve or the one near the variable resistor?

why don't you give both a shot? jumper the yellow one with the engine off and the key in the on position, and if you hear your fuel pump running continuously then you know it is not the initial set coupler.

So I set the idle speed, adjust the TPS to 1k ohm... and nothing... actually, I had to set the idle speed to about 950rpm, because the whole bouncy idle thing meant that setting it lower, to about 750rpm would potentially stall it, you know... when the rpms go down for a second.

Now... I checked my battery with a voltmeter.

With the engine hot, the key set in "ON" (engine off), I get about 12.05 volts.

With the engine effectively running, I get about 12.95~13 volts.

Could this be the cause of my problems? Is my battery about to die? Or maybe my alternator? Help :(