toofer

I have a 80S Euro w/CIS. Up untill afew days ago it started and was ready to get up and go. Now apon starting the engine idel is very rough for a mintue or 2 until engine warms up and once warm runs fine. I`m thinking there is something wrong with the warmup regulator. If the cold start valve is not doing its job could it cause the rough idel when the engine is cold?? Possibly take the regulator apart and clean it?? As I said once the engine is warm it purrs like a cat, a very large cat. Toofer

Mrmerlin

Try putting a can of techron in the fuel tank use a can in a half full tank, stop and start driving is the best for this treatment to work. Might have a clogged injector, let us know what you find

Lizard928

I think that the cold weather may have found a mal adjusted aux air valve, or a cold start injector that is not recieving power, verify that your AAV is open when the engine is cold, and check for power to the cold start injector when cranking.

toofer

Mrmerlin, Would the engine run smooth if I had a clogged injector?? This is only a problem when it`s sets for a day or two and the engine hasn`t been started. Once the motor warms up it`s not a problem the rest of the day, motor starts and idles properly.

toofer

Lizard931, From what I have read the cold start injector is only used when temp is below 30F degrees. I live in south florida and haven`t seen that yet this year. But I will check it while cranking anyhow. About the AAV, how do I check to see if it is open when engine is cold, I have a CD showing all parts and most repairs but have not found any info on AAV adjustment. Thanks in advance for any info you give me and taking the time to help.

Mrmerlin

Try a can of cleaner first, its the easiest thing to do and the cold start injector may be leaking you could remove it from the intake and see if its wet but dont adjust anything yet ,try the can of cleaner first

Lizard928

you have to remove the AAV and look through it, you can also put it in a freezer and see if it is fully open when it comes out.
I will have to find the info for you regarding adjusting it.

toofer

OK, thanks guys I`ll dump some cleaner in and drive it around town if that doesn`t help I`ll pull the AAV and see if it is staying open. Put in freezer for short while and see if it is open. Then warm it up and see if it closes.Right?

Lizard928

that is the basic idea, yes.

the info you want regarding the AAV is on the 924board.org just do a search on there for AAV adjust.
Though from your screen name you may already be familiar with the 9toofer

jpitman2

Mine slowly degraded cold idle until it got rough. It had never had a cold idle over 1000rpm anyway. The fact that it cought ok stone cold told me it wasnt cold start injector. Try removing the air hose going into the aux air valve (front face), and looking in there cold - it should be 80% open under 55F IIRC - mine was < 50% open. I removed the unit, drilled the rivets off and opened it up. I put it in the freezer for 10mins and checked how far open it got, looking for 100%. There is a spring pulling the blade shut - stretch it carefully and refreeze and repeat until its near 100% open at 0C or 32F. Also check that it gets close to closing fully if you put it over boiling water....or hit it with a hair dryer. The rivets can be replaced with 3/16 bolts, or whatever fits in the holes. Worked for me.
jp 83 Euro S AT 51k

nlneilson

I have a '79 928 that is hard to start cold, otherwise it runs fine.
Looking at the wiring diagram for the '79 the power to the cold start valve is connected to the wire that goes to the starter solenoid. T14, #14, that would indicate the cold start valve would only squirt fuel when the engine is cranking and the temp switch makes the ground connection, which it does.
My aux. air valve is fine, open when cold and closes when it warms up.
No power to the cold start valve even when cranking, will track that down, probably at the 14 pin connector T14.
My question is:
Does the cold start valve only squirt fuel while the engine is cranking, seems like it should until the temp switch warms up and breaks the connection to ground??

928ntslow

A timely thread...my 82 Euro is having the same issues. I am narrowing it down to the CSV or the AVV. I have 6v running the the CSV when cranking so it might be the valve itself. I hope to hear what happens with you guys.

As for mine, the car sits outside and gets down to the 30's in temp. I turn the key, engine cranks but it takes several tries to get the engine to run. It is as if I have to get gas into the system, so I pump the throttle a few times. The engine will do several quick "try to starts" where it runs by itself for a rev or so and then dies. Eventually, it will catch and run, but giving it throttle will kill it. I have to let it idle and warm up to a point to where it will rev higher. This is a 5 or 10 minute procedure. Once warmed up, it idles and runs fine. Turn it off and wait a bit and she still fires right up.

BTW nlneilson, the CSV only has voltage when the starter is turning/key is turned to the #3 position. As soon as engine runs, the starter quits and so does the CSV because the key is back to the #2 position.

JP Rodkey

Good advice, JP.

The cold start valve for fuel on the front of the air housing works to provide a shot of fuel at startup and warmup. It is energized when you turn the key to the start position, remains on, and is controlled by the thermo time switch which means it's supposed to shut off at 35C (95F). Air volume through the cold start valve is controlled by the aux air valve, which is the CIS version of a carburetor choke plate. Cold start valve failures seem to be rare, but aux air valve malfunctions are relatively common.
Hope that helps.

928ntslow

As I said, this thread was a timely one. I took some time this afternoon to delve into this issue, especially since the car wouldn't start this afternoon and I wore out the battery in the process.

I did as suggested with the Auxiliary Air Valve. It was easy, but didn't know what to expect inside, so I opened it carefully. Nothing jumped out, but the upon pulling the pieces apart, the door slammed shut from the spring. That immediately told me that the lip on the door has to be set on the metal bar of the body before putting it back together(see the photo...explains it better). I pulled out the Cold Start Switch too and to the best of my knowledge, it was plugged. I soaked it for a bit in some Berryman's before I added it to the gas tank.

I took compressed air and ran it through the injector and blew out the crap. As you will see in the photo, I used a 9v battery to open the valve. You will here a Click* when you connect the battery. This means the valve it open and you can run air through it. Otherwise, with it closed, you won't accomplish a thing.

I stretched the spring a bit on the AAV, reattached the two pieces together and stuck it in the freezer. It opened from the original 20 or 30% to about 50%. I stretched to the point the door would barely close. I didn't check too closely to see if it needed any lubrication, but from what I could see, the opening and closing action was pretty smooth. I screwed it all back together and reinstalled.

It all seemed to work OK, but the true test will be tomorrow when I try to start it from sitting overnight.

Incidentally, I am not real certain how the AAV actually functions. I see the two leads inside and I don't know if there is a magnetic process or a heating process to move the long flat bar that the spring loaded door sits on. Maybe someone else can explain it.

928ntslow

Reporting back here on my fix. It seemed easier to start today, but I still had trouble. I am narrowing this down to a possible fault with the fuel pump OR the AAV. Not sure the AAV is really the problem ,but I do need someone to explain how this works to begin with. When should that electrical connector be live...when the car is cranking or all the time? I would really like to know how this unit works.

It just seems like there is no gas immediately getting to the cylinders. I crank several times before the enigne tries to catch and run by itself. After many tries, it finally catches enough to stay running. No way can I rev until it warms up either or it will just be starved and die. Ideas?