1981 SC CIS - low idle - wrong WUR?

[wreckah]

Hi tony, yes i have, functions perfectly. I'm thinking something has gone wrong with lambda box or lambda enrichment box. I will keep updating this thread untill i find a good solution. I dont think it will be cis though...

[wreckah]

And for anyone interested: i tried running the 'trick' that the innovate guy posted here so many years ago: use the wot switch to power a set of relays which switch between output 1 and output 2 from the innovate wideband box. So you could run 14.2 afr at idle and cruising, and lers say 12.8 during wot...but somehow the system senses when the inputs change and i get weird results during dynamic tests...

[wreckah]

More so, on the whole internet, i have not found one person who managed to pull this trick off, or at least when they did, post some results afterwards.

[wreckah]

But theoretically it is a nice idea....i think the lamda box and enrichment box do more things than we know. They have some intermediate settings, when you go from one state (cruise) to another (wot), and god knows what happens to the o2 input at those times.

[wreckah]

...and although this is all very interesting, it is not future proof nor economically sound anymore, thats why i am considering biting the bullet and go full efi, with or without ignition control.

[boyt911sc]

Originally Posted by wreckah

Hi tony, yes i have, functions perfectly. I'm thinking something has gone wrong with lambda box or lambda enrichment box. I will keep updating this thread untill i find a good solution. I dont think it will be cis though...

Jan,

I know nothing about ECU for th SC's and currently doing some experimentation using an oscilloscope to understand a good ECU from a bad one.



These ECU's were tested and confirmed to be in good working condition (?). And saved them as my control. This is as far my knowledge with ECU starts and ends.

Tony

[wreckah]

ok, the first upgrade in my quest to have a properly reliable car in all weathers is the Classic Retrofit CDI+ box. I chose it because of the ease of install, the programmability at a later stage (locking the distributor) and the stock looks. It's pricey, sure, but i don't really care. It has double spark across the revband.

It's basically a plug and play replacement for the Bosch CDI. Just a little twist of the dizzy and all is well.
I went from 5° - 26° advance to 5° - 28° so already some difference in high rpm ignition.

Straight away, i notice more stable low rpm manners. It's easier to get away from the lights, less prone to stall. Low rpm power was already up with the SSI's, but i sense even more now. This is becoming a proper quick and fun car, even if you don't go above 4000 RPM.

I notice little bit leaner numbers on the wideband display, so better burning for sure.

Just went out in the cold, and did a 3-hour-cooldown-0°C semi-cold start, and it fired up on the key, without touching the throttle, that's new to me. Anxious to see what a proper cold start will do tomorrow morning.

A fun bonus is the sweeping tach when you start the car...that's 2010 feel in a 1981 car

I've ordered the bitzracing FI kit as well. This will arrive shortly. I chose it once again for easy of install, stock looks, and easy tuning. And it's relativily cheap. I don't need all the modern accessories that come with the more expensive and modern FI upgrades. This is perfect for amateur wrencher like me. It will get rid of the all the aeging CIS components apart from the AAR (cold start air thingie).

[tito911s]

Appreciate the update. Sounds like a very reasonable option if CIS becomes difficult to manage.

[Vereeken]

Originally Posted by wreckah

ok, the first upgrade in my quest to have a properly reliable car in all weathers is the Classic Retrofit CDI+ box. I chose it because of the ease of install, the programmability at a later stage (locking the distributor) and the stock looks. It's pricey, sure, but i don't really care. It has double spark across the revband.

It's basically a plug and play replacement for the Bosch CDI. Just a little twist of the dizzy and all is well.
I went from 5° - 26° advance to 5° - 28° so already some difference in high rpm ignition.

Straight away, i notice more stable low rpm manners. It's easier to get away from the lights, less prone to stall. Low rpm power was already up with the SSI's, but i sense even more now. This is becoming a proper quick and fun car, even if you don't go above 4000 RPM.

I notice little bit leaner numbers on the wideband display, so better burning for sure.

Just went out in the cold, and did a 3-hour-cooldown-0°C semi-cold start, and it fired up on the key, without touching the throttle, that's new to me. Anxious to see what a proper cold start will do tomorrow morning.

A fun bonus is the sweeping tach when you start the car...that's 2010 feel in a 1981 car

I've ordered the bitzracing FI kit as well. This will arrive shortly. I chose it once again for easy of install, stock looks, and easy tuning. And it's relativily cheap. I don't need all the modern accessories that come with the more expensive and modern FI upgrades. This is perfect for amateur wrencher like me. It will get rid of the all the aeging CIS components apart from the AAR (cold start air thingie).

Know that I will gladly take this aging CIS stuff off your hands ;o)

[wreckah]

A little bit delayed because i totalled my daily car, and had to use my 911 as daily driver the last month and a half (what a terrible punishment!),
but,
i've started installing the Tbitz kit 3 days ago, and i'm happy to say i'm all finished, the car is running, no fires, no meltdowns, no black clouds.
The box that contains the old stuff is big and heavy: Fuel distributor, Fuel accumulator, Frequency valve, decel valve, AAV, the little enrichment microswitch, throttle switch, the lambda box, the lambda enrichment relay, all the injectors with their metal lines, the aluminium spaghetti trombone vacuum line, the heater blower, and last but not least, the fecking WUR, ALL GONE. Hallelujah.

So, i've got it working together with the classic retrofit CDI+, and this is important to mention: the MS software from the tbitz kit reads the tachsignal to provide fuel. This tach signal is provided by the CDI+ box. Well, the CDI+ box does a tacho sweep when you turn the car on, very cool, BUT, the MS box is already alive at that point, and reads this signal as if the car is already running, and thus dumping ****loads of fuel in the engine, almost hydrolocking it after a couple of attempted starts. That's basically the only issue i've come across after my install.
Reprogrammed the CDI+ to get rid of the tacho sweep and all is well.

I'm combining the whole setup with the innovate LC2 wideband sensor, and everything is now nicely working together. You have to be quite clean in your install: good grounds, clean wiring, all very important.

Now i'm starting the car, letting it warm up (it still uses the AAR), and once warm, click 'autotune' and drive! The car tunes itself to a preset AFR table. I'm sure i'm already up 10MPG, and all the power from my 'cheaty-13-AFR-CIS-workaround' is there. It's fast. And it's only the first day of testing, so i'm basically just starting to alter Tony's base map.
I already feel alot crisper throttle respons too.

Tunerstudio is great, programming on the fly, lots of parameters to learn, but that also means lots of ways to get the engine starting and running perfectly in all conditions.

Big thanks to Tony Bitz and Jonny from Classic Retrofit for their great products and great support.
I'll update whenever i have more information.

cheers, Jan

[wreckah]

well, here is an update for you...insert huge swearword...after 1,5 years troubleshooting (okay, and also lots of fun with a fantastic car) i finally found the culprit of my low cold idle...

The frickin' CSV mounting flange is CLOSED. There is NO HOLE. Some PO or mechanic mounted the wrong flange probably because he had too many airleaks, or maybe because he was always driving in 100°F temps...who knows.
The reason i ddin't see this before is because:
- it is almost impossible to remove and check with original CIS in place
- whenever i took off the AAR hoses, i noticed small changes in engine behaviour, so i wrongly assumed the flange was open.

Now, with my removed AC unit, removed heater blower, and bitzracing kit, there is a lot of space and i finally got the balls to take it off and check it. The reason for this check was that i could not get a raised cold idle, even with bitzracing kit with full control of fueling and CDI+ with full control of ignition. No matter what i did, idle was 500 RPM cold...or worse.

so...i took out my drill, and drilled a hole in the csv mounting flange, not a very big one, maybe 8mm diameter (it is a fragile platic little thingie and i didn't want to break it), so i've got less air flowing through.
I also bought a brand new Nissan 300ZX AAR (50 bucks), which does exactly the same as the Porsche one, except that the ports are smaller (3/8" instead of 1/2") and it takes around 10 minutes to fully close. But it does FULLY close. The old Porsche AAR looks like it fully closes, but even when you can't see through it, you could still blow air through it. I'm betting the majority of these old AAR's are like this.
Yes, the bitz kit still uses the AAR, it's the only stock component that's left over.

So now, my cold start went up from 500 to 1000RPM.
Now i can fine tune it with the warm up tuning from the megasquirt.

Hallelujah.
hope this helps anybody out there...i've only seen one other guy on the forums with the exact same problem.

[tito911s]

I'm trying to understand the CSV part of this. So did the PO simply cap the entire place where the CSV usually sits?

I borrowed a picture I found. But are you saying that this entire piece was blocked off, meaning there was no injector there?'

[wreckah]

hiya,

no, everything was there: csv, aav, decel valve, aar, etc...including all the piping.

The only difference was the dark red part you see on the picture. That part (mounting flange) has an air port to which you attach all the mentioned components. On earlier CIS systems, that part is blocked offinternally because they had a fast idle lever and no need for AAR etc... On my car, it should have been open. (updated part) So the PO mounted the wrong part. It looks exactly the same from the outside.

here's a pic if you can see it:
https://scontent-amt2-1.xx.fbcdn.net/v/t31.0-8/17880159_10155244957682863_3508662787624301961_o.j pg?oh=ea7d919297d5cdf0ab356d8543358cb2&oe=5954F42B

i simply drilled a hole in there now, and it works.

[wreckah]

and this is the new AAR,
it looks exactly the same, but actually is 3/4 the size of the original AAR.

(okay, link does not work to competitor of pelican, i understand)
/ac366-intermotor-idle-air-control-valve-mpn-ac366

[Jonny H]

Originally Posted by wreckah

A little bit delayed because i totalled my daily car, and had to use my 911 as daily driver the last month and a half (what a terrible punishment!),
but,
i've started installing the Tbitz kit 3 days ago, and i'm happy to say i'm all finished, the car is running, no fires, no meltdowns, no black clouds.
The box that contains the old stuff is big and heavy: Fuel distributor, Fuel accumulator, Frequency valve, decel valve, AAV, the little enrichment microswitch, throttle switch, the lambda box, the lambda enrichment relay, all the injectors with their metal lines, the aluminium spaghetti trombone vacuum line, the heater blower, and last but not least, the fecking WUR, ALL GONE. Hallelujah.

So, i've got it working together with the classic retrofit CDI+, and this is important to mention: the MS software from the tbitz kit reads the tachsignal to provide fuel. This tach signal is provided by the CDI+ box. Well, the CDI+ box does a tacho sweep when you turn the car on, very cool, BUT, the MS box is already alive at that point, and reads this signal as if the car is already running, and thus dumping ****loads of fuel in the engine, almost hydrolocking it after a couple of attempted starts. That's basically the only issue i've come across after my install.
Reprogrammed the CDI+ to get rid of the tacho sweep and all is well.

I'm combining the whole setup with the innovate LC2 wideband sensor, and everything is now nicely working together. You have to be quite clean in your install: good grounds, clean wiring, all very important.

Now i'm starting the car, letting it warm up (it still uses the AAR), and once warm, click 'autotune' and drive! The car tunes itself to a preset AFR table. I'm sure i'm already up 10MPG, and all the power from my 'cheaty-13-AFR-CIS-workaround' is there. It's fast. And it's only the first day of testing, so i'm basically just starting to alter Tony's base map.
I already feel alot crisper throttle respons too.

Tunerstudio is great, programming on the fly, lots of parameters to learn, but that also means lots of ways to get the engine starting and running perfectly in all conditions.

Big thanks to Tony Bitz and Jonny from Classic Retrofit for their great products and great support.
I'll update whenever i have more information.

cheers, Jan

Sounds like everthing is playing together nicely for you now. Glad to be of assistance!

Any chance of posting some pictures?

[wreckah]

let's see if this works...

cabin with wideband and volt gauge:

[wreckah]

junk!

[wreckah]

finished engine compartment,

Classic Retrofit CDI+ on the left side, next to the fuel filter. Notice the absence of the fuel accumulator

[wreckah]

my daily 1988 BMW 325i touring (300.000 miles and going very strong), and my former daily 1981 911 SC . Just booked an appointment with the bodywork guy to put on an RS bumper in the back, get rid of that ugly foglight and painted reflector.

[wreckah]

i was playing with the CDI+ box yesterday to try and influence the cold idle, and it's nice to see the engine react to the inputs of the laptop, gives you a good understanding how everything works.

I don't think i'm going to need a lot of 'recurving', because these are the numbers on my stock car, without influence from the CDI+: (all numbers are total advance)
900 RPM 5° adv
1500 RPM 15° adv
3000 RPM 25° adv
4000-6000 RPM 30° adv

So it seems that this distributor gives around 5° more advance than what a stock 911 SC distributor should do...maybe it's recurved in the past, who knows? Anyway, it's no problem with controlled fueling and 98 octane juice over here.
I do notice a lot of movement in the higher rpm's...the advance is not very stable, it fluctuates easily 3° back and forward. So that would be a big plus of locking the weights and using the CDI+ to control the advance. Something for the near future.