[rtuey]

I've been posting on Rennlist and PorscheTalk with CIS problems with my '82 SC. My project help request is to find someone with a loaner/rental of a working CDI and O2 Computer (the one under the passenger seat). I want to see if I need to buy one at the Hershey Swap Meet.

This CIS problem should stump most people. Anyone who would like to help me with this I'll treat to a beer, soda and pizza. The symptoms are similar to multiple problems:

Warm or cold - I can't get the '82 SC with 204,000 miles to get into normal idle and not stall. I have to play with the throttle to keep it from stalling.
Here is the scenario:
It was working fine until several weeks ago when I drove it to work with 1/2 tank. It got very cold (below 35F). It would turn over easily, but wouldn't stay started or be in a very rough idle about to stall. If I floored the pedal - nothing would happen (initially). Sometimes after a delay it would go to high revs, but quickly try to stall if I let off the pedal. After a long period, I managed to get the oil warmed up above the 1st white hash mark, but it didn't solve the problem. I drove it home by keeping it at high rpms.

The following week with warmer weather, it was working fine, so I put in some DryGas (isopropyl alcohol type) and went to Sheetz Gas Station to fill the tank with Premium (I had used regular without knocking in the winter).

More snow and bad weather and I try to drive it, but it is bad again. I add a can of 44K additive to clean the injectors, but that doesn't help much, as the tank was full. I drive it to the Driver's Ed Tech Session with it running lousy - using high rpm's to keep from stalling. After I get there it runs just fine and goes through Tech. A mile down the road on the way home - it reverts to form and I have to use high rpm's to make it home.

Here is what it shouldn't be:
1) Replaced O2 Sensor and fuel filter Oct 02

2) Checked plug wires while car idling and didn't see any "fireworks"
(Replaced the wires with Magnecor KV85's and still having idle problems)

3) Checked to make sure plug wires firmly seated.
4) Checked the Warm-Up Regulator - it showed 25.7 ohms - not an open circuit.
(Used compressed air to blow out WUR several times without any
positive effect)
5) Cleaned the leads on the cold start switch, but haven't taken it out to check it.
6) Checked the Auxillary Regulator leads and measured 33 ohms across it.
7) Checked the distributor cap and sanded the contacts. They were a bit burned. The cap and rotor were replaced in Sept 01.
(Used Ohmeter to verify good connections on Dist cap to plug wires.)

8) I had used 44K on the system in Oct 02.
(I fully drained the fuel tank and replaced the fuel filter - didn't help.)

9) I checked the air-flor sensor plate for freedom of movement. It seems to move up with slight resistance and drop without problem. I couldn't see if there was a problem with the way it was seated. I have been experiencing lots of backfires.

10) During last year's autocross school, the fuel pump was making a very nasty humming noise. Right now it appears to just be a quiet whine. (It worked great when I drained my fuel tank.)
11) At the high rpm's, it doesn't feel like any cylinders are missing.
(But it idles VERY rough around 450 rpm and wants to stall.)
12) Air filter also replaced in Sept 01, and the air box straps seem tight.
(I put in a new air filter and that had no impact.)

13) The pop-off valve I installed in Sept 01 seems secure.
14) I bench tested the O2 relay (under the passenger seat), but I have a new one on order.

15) I noticed that when the car was running OK - I heard the frequency valve. When lousy - didn't seem to hear it. I can't find the thing to measure for an open circuit. The Bently pictures don't show where it is located.

16) I checked all of the fuses and they looked OK
17) I replaced all 6 fuel injectors and o-rings - didn't help.
18) I haven't tested the fuel pressure yet, but Matt DeMaria indicates that would only be a problem when accelerating, not the symptoms I currently have.
19) I am beginning to check the wire harnesses. I was metering the CDI connector harness and found that three connectors go to GROUND. I don't recall their pin numbers. All connection leads on the CDI seem tight, but I sprayed contact cleaner on them, anyways and made them tighter.
20) I previously shot carb cleaner on lots of hoses and found some minor loose connections. One was the hose connector into the air box. I did tighten up all the other hoses - this didn't help.
21) I checked the timing - it was right on the money at 5deg BTDC at 900 RPM.
22) I've cleaned and regapped all the Bosch platinum plugs (about 1.5yrs old)

Things seem to be pointing to an electrical problem. Possibly something to do with the Frequency Valve.

[rickc]

Sounds electrical. Did you say you checked the coil? My CDI box just went out, and i suspect due to arcing from a faulty coil. The CDI boxes themselves can exhibit some strange behaviour. Mine would start up fine and run until the engine got a little warm. After the warmup, the car would die until it cooled off again. In this particular type of failure, the heat caused enough resistance to shut down the cdi box.

It could still be a fuel delivery problem, either a faulty cold start valve that is leaking or a gummed up fuel distributor. Sometimes a lean runnig car will start and run initially since the cold start valve is supplying the engine with fuel. When the cold start valve shuts off, the car has a mismatched air/fuel ratio and cannot keep an idle.