Looking forward to hearing your results. I have been thinking about my "22" open loop number. Isn't that 50% duty cycle default?

If my 3mm screw is set in close to the right place and pressures are ok with the WUR, maybe 22-ish is normal?

I doubt it as there is so much extra fuel and extra air on cold start (even when 80F ambient) it cannot be rock solid.

There is a table that was posted in a Tim (Tirwin) thread last year that shows what the Lambda box tells the freq valve to do across all the operating ranges. I think it is broken down by year (edit: not 1980). Let me find that and report back.

Edit: See post #37. Explains why touching my throttle linkage sent my numbers higher. Phew.

http://forums.pelicanparts.com/porsche-911-technical-forum/787542-low-power-low-rpms-after-reconnecting-o2-sensor-2.html

Confirmed....my Fecklar FV es KAPUT! And the search goes on..................

Crap. That is a chunk of change. Keep searching. Any alternatives? I have never checked.

I know the Ferrari 512 Berlinetta Boxer had CIS. Any of those "Pull-a-Part" or "Pick a Part" yards in the foothills of CA? They have to be littered with tattered carcasses like the 512.

Found a used one at a Pcar place in the bay area. Buck and a quarter plus shipping. If this doesn't do it I'm selling the car in Ohio!

Yikes. Good luck with that. I wanted to do my test this evening but I got a huge electrical storm coming through the Atlanta area. Will try again tomorrow Bob.

I see that on weather.com. Ouch.

OK update: I tried when cold and got a goose egg! Then I found something. The switch on the Actron in the middle dwell position is a bit dicey with no real detent. When I played with it some the needle shot right up to 21 or so then dropped back to 7 quite quickly but the engine had got quite warm by the time I had figured out what was going on. I'll try again tonight once it cools down again.

On another note. I measured the resistance on my WUR when cold and it was only 10.1 ohms. Quite warm ambients in the 80's though. I think I'll pull it and send to Tony for a test after I measure some fuel pressures. Once warm the car runs like a champ though so I don't think there is really too much wrong with it.

The key is our friends at the EPA want our car to start in open loop with the 3MM screw set as close to 14.7:1 as possible but with the recognition that rich is required for cold engines.

If you set the 3mm screw to where it reads 50% duty cycle at warm idle and all of the cold start goodies are working right, the car will not blow out excess hydrocarbons while warming up. Lambda box should take care of the rest post the 90 seconds or so warm up.

My WUR resistance is in the higher twenties. But it's an 090.

Tony has the scoop on the 80 WUR. Sounds low but I am not into the full range of tech info as he is. Thy guy is amazing.

Just a side note. If you read that Tirwin had issues with the Mighty Actron not working properly, that is cool.

However, note that it is not to be used as an engine/car support when coupled with a 15" piece of wooden 4X4. It may "spread the load" as Tim says, but can perhaps impact functionality.

http://forums.pelicanparts.com/uploa...1437092403.jpg

Thanks very much for that Bob.

Ha yes I'll use it as a chock to stop the Mrs driving her car into the wall at the end of the garage. :).

Mine's an '82. I'm pretty sure that's the 090 WUR. It should be in the ~22 ohm range when it's "cold" like you said. I'll ask Tony if he'll check it for me once I can run a pressure test on it and check the timing. I verified it's got 12V+ at the plug.

The car's never had the elevated idle when it's cold. I can see that the AAV is open when it's cold so that's confusing. My injector seals are leaky so between that and the possible dodgy WUR I'd say that's at least part of the warm up issues. Once she's warm she flies so there's not too much wrong with it.

These are good little projects for a noob like me. I just need to find some time to myself to do them :).

Bob, what would happen to that meter/car stand if you set one of yer ham-hocks on it?!?!?

You have to put it face DOWN when using it to jack the car by the sump plate. :D

So, here's been my experience... I was having trouble with the Mighty Actron. Jim Williams said he tested a few of them against the Almighty Oscilloscope and there was a good deal of variation. Bob must've got the good one in the batch. Some guys have all the luck, you know?

The signal is a square wave. There are a few multimeters that have the ability to read the square wave. You have to know whether the reference for the meter is "on" or "off". 60% on and 60% off are different things.

I invested in a wideband O2 sensor gauge a while back. When I dropped the engine last year I finally got to take care of all the nagging vac leaks. When I started the car the first time I had AFR in the 10 range. Using the gauge and the AFR<->exhaust gas CO table I got it dialed in perfectly to what psalt recommends. I think I'm at 13.2-13.5 range at idle. The car has never run better since I've owned it. We also used it a couple of months ago to dial in garrett490's car after a fresh engine rebuild. He was set way lean before. Definitely more money than the Actron, but it is something worthwhile in the long run for CIS cars. The thing I like best is the data logging. If you pay attention it will tell you if something is starting to change over time.

I'm not going to be home for a couple of weeks, but when I get back I could try to hook up the Mighty Actron and the multimeter again for comparison against a known good baseline.

And it was JR (javadog) that posted the excellent reference for what the ECU does in various conditions, not me.

Thanks tirwin will be interesting to see what you get on the old Mighty Actron :). I've read all your threads on the subject. I've learned a tremendous amount. I'm over in Suwanee so we're not far from each other.

Just wanted to clarify something. You might have seen the old post where I tried the PLX gauge. I did not have good luck with it. For one, the gauge itself just quit working. I also learned (the hard way) that the narrowband output from the PLX was NOT compatible with the ECU. That was also another insight from Jim Williams. Failures are still learning experiences. :)

Right now I'm using the LC-2 from Innovate Motorsports with a gauge. I haven't done a permanent install yet. One day I will take my test pipe to a muffler shop and have them weld in another bung so I can run the narrowband and wideband in parallel. The narrowband still feeds the ECU and the wideband is for the gauge and data logging.

Jason,

The voltage on the O2 sensor goes from .1 - 1V. Since it's a narrowband sensor, you can think of it's output as either lean, stoichiometric, or rich. It can't really tell you how lean or how rich. If you really want to dial in the ideal idle AFR you need either an exhaust gas analyzer or a wideband O2 sensor.

The surging could be because the ECU is trying to find a happy place and can't. It might be detecting rich, then leaning, going too lean, then richening the mixture, going too rich... rinse and repeat.

I think ossiblue, psalt and javadog have all noted that this is why some people have disconnected their O2 sensors -- they were trying to solve a surging idle. The disadvantage is poor fuel economy and it's not really necessary.

Assuming your fuel pressures are good, no vacuum leaks, idle and timing are set correctly and the O2 sensor is good, you should be able to dial in a good idle mixture and not have surging.

Has anyone tweaked the 3mm screw to see if the dwell changes away from the low readings?

WUR tests and evaluation.......
 

gazzerr,

Do you know the number on the WUR? Your USA model '82 SC should have the -090. And don't expect to get a good and nice cold idle with an out of spec. WUR. When it is warm that would not be a problem. Your erratic cold idle will not go away unless you solve your cold fuel pressure. If you want the WUR tested and evaluated, send it ASAP because I will be going to Europe mid August and won't be available till first week of September. Or I could lend you a WUR to use or test on your car and see if it solves your problem. PM me if you need help.

Tony

Hi

Hi Tony,

In post #50 gazzerr mentions he thinks he has an -090.

Hi Guys,

Thanks so much for the info. I still haven't plugged the Mighty Actron back in. Work's been conspiring against me. Thankfully it's Friday :).

Tirwin I think I did read that post! Jim did quite a science experiment on that one from what I can remember from it. Thanks for the warning appreciate it. Once I get everything sorted nagging vac leak wise I'll find a shop that will stick a gas analyzer up it's rear and have them sort the CO for me.
I might be able to borrow one too. See how I go.

Tony & Bob -> I do have the -090. No worries I can wait until September, there's no rush. I'd love you to check the WUR out for me when you get back and settled from your trip! I'll send you a PM when the time comes. Thanks so much.

Bob, I haven't tried to play with the 3mm screw. I don't actually have a 3mm allen key that will fit. Keeps me from temptation :).

Once I get a day to myself I'm going to check those fuel pressures and post here.

Maybe for the best.

I do have a pic of a 3MM tool I made that helps with the metal lines. I may wait for Tony to let me know when it's ok to post. :D