- Tuning CIS -using a wideband controller
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    1. Member
      Join Date
      Aug 15th, 2007
      G60 on CIS-E and a bunch of other VW's
      11-15-2012 05:37 PM #26
      That is because a signal to the lambda causes a lean duty cycle, as in IIRC, opening lower chamber flow, increasing the lower chamber pressure and restricting the flow that is allowed to be metered out the upper chamber ports.
      Did you try switching the voltage?
      That is what I am doing on the DPR, but in that the DPR is a magnetic coil that can accept positive and negative current, the lambda cannot as it is a valve that is switched on.
      G60 on CIS-E, Now Twin Screw on CIS-E

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    3. Member ps2375's Avatar
      Join Date
      Aug 13th, 2003
      Meridian, ID
      80 Rabbit(DEAD), 94 Golf, '69 Type1 Sedan
      11-15-2012 05:50 PM #27
      We had the WB set up to output a NB signal in place of the NB O2 sensor. And yes, once the Frequency valve was unplugged, the system goes lean, then you just adjust the mixture screw to set the mixture(AFR) and that is pretty much where it stayed. We did have the WUR mounted up where the battery used to be, so as not to change the system pressure and therefore the the mixture.

      The Lambda system has a controller (under the dash) along with the NB sensor along with the Frequency Valve on the Fuel Distributor.
      Last edited by ps2375; 11-15-2012 at 05:53 PM.
      Tradition is the art of making the same mistake repeatedly, on purpose.

    4. Member teknikALLEN's Avatar
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      Jul 14th, 2010
      Ithaca, NY 14850
      2001 VW Jetta; 1985 VW Cabriolet; 1993 VW Cabriolet; 1984 VW Gti
      03-07-2013 12:31 AM #28
      Quote Originally Posted by briano1234 View Post
      I would rather do a 3 rear cables than a passenger side motor mount.
      020ld for this stuff... a clutch and 5th gear conversation with Broke VW

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    5. Member
      Join Date
      Jan 12th, 2014
      1984 Rabbit GTI
      02-16-2015 06:24 PM #29
      So the consensus is that these gauges are a more useful tool than dwell tuning? For setting a basic tune/diagnostic work is there a large advantage to the gauge? Thanks in advance, I am trying to justify buying the whole wideband setup when I could just buy a dwell meter. Thanks

    6. 02-16-2015 09:07 PM #30
      Dwell meter can get you close to a good tune if you have a dyno or wide band read out. Other wide the dwell readings will get you factory AFR . Remember normal CIS -k jet (GTI) injection runs open look (not computer controlled) at wide open throttle not real fuel metering other than your basic dwell settings. With the wide band controller you are running closed loop all the time. (computer controlled all the time) The computer controls fairly accurately your AFR for WOT and non Wot driving.

    7. Member leecatd8209's Avatar
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      Jul 13th, 2010
      '86 Westy Golf, '09 335xi
      03-26-2015 07:34 AM #31
      Does anyone have a good write up, or link to one on how to do all this? Or know if Scientific Rabbit still sells the harness kit for it? I'm building a CIS turbo frankenturd, and this would be perfect.

    8. Member
      Join Date
      Jun 7th, 2001
      Nor Cal
      Now: 84 Gti Callaway. Then: 79 Rabbit; 83 Gti, 80 Scirocco S, 86 Gli, and a few flips.
      02-15-2016 10:33 PM #32
      Wow I like this thread and found it while researching WB's. NY you have a PM.

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    9. 09-26-2018 09:44 PM #33
      This is the guts of the cis lambda controller.
      As you can see the problem is the cis lambda controller is slow to react, I assume this is on purpose so it doesn't overshoot the mixture requirements. Because of the reaction time simply switching o2 signals may not be the best solution especially for quick on/off throttle situations. How about feeding both o2 signals to the two separate cis lambda controllers and just switching the input of the frequency valve between the two cis lambda controllers outputs using the wot switch? I forsee no lag this way and would cost only another cis lambda controller box

    10. Member TheRealEddie's Avatar
      Join Date
      May 8th, 2006
      Long Beach, CA
      2106 Golf R, mk2 GTI Group 2 Rally car, 1990 Corrado G60
      02-17-2019 01:43 AM #34
      Yeah, I had a friend who used the MTX-L out for CIS-E (KE Jetronic) and it didn't work all that well under WOT for reasons described above. We went a different path for CIS-E which I posted. Similar idea in terms of using an MTX-L but different in that we added some of our own electronics in there to control the DPR. I didn't think to see how to do that with plain CIS which might be simpler?


    11. 02-25-2019 01:55 AM #35
      Quote Originally Posted by TheRealEddie View Post
      Yeah, I had a friend who used the MTX-L out for CIS-E (KE Jetronic) and it didn't work all that well under WOT for reasons described above. We went a different path for CIS-E which I posted. Similar idea in terms of using an MTX-L but different in that we added some of our own electronics in there to control the DPR. I didn't think to see how to do that with plain CIS which might be simpler?

      Do you have any ideas for implementation on CIS-basic, with no frequency valve?

    12. 02-26-2019 09:41 AM #36
      CIS basic does not have any way to control the fuel delivery with electronics. The only electronics is the heater in the warm up regulator, cold start valve, and the fuel pump.

      What are you trying to do?

    13. 02-27-2019 01:54 PM #37
      hook a digital DC volt meter to the O2 sensor fat output wire. Adjust mixture for .75-.80 VDC at idle.
      reading will flutuate, center it around the .75-.80 V. Done

    14. 02-28-2019 10:41 AM #38
      But CIS basic does not have an O2 sensor. If you put an O2 sensor in the exhaust, adjusting it to that value does not really set the mixture right.

      Read how a narrow band O2 sensor works and you will see, it only helps in a really narrow band. Certainly not good enough to adjust a fuel mixture.

    15. 03-12-2019 10:52 PM #39
      CIS Basic you do by ear. Some thing with CIS Lambda with a big cam, Throw out the numbers and go with what runs best.

    16. Member
      Join Date
      Jun 17th, 1999
      West Michigan, USA
      1998 Jetta VR6 (bone stock daily driver), 1982 twin screw Cabriolet, 94 Mazda B3000 4x4
      08-09-2019 02:29 AM #40
      wow... i haven't been back to vortex in a while so its kind of interesting seeing this CIS section.

      My Lysholm supercharged Cabriolet has been in storage for years as well so i haven't played with CIS in a while and frankly am a bit rusty lol. Someday i'll get the new 2.0 8v with 42/35mm solid lifter valves in and have at it again.

      When i was dyno tuning my Volvo 240 turbo CIS setup on it... i found i could not get the fuel i needed using the Volvo warm up regulator. i ended up adding an additional fuel circuit to directly drain control pressure with a frequency valve controlled by my VSAM setup. VSAM had load and duty cycle map which could be accessed using a laptop and the special software. Normally this fuel circuit would be closed, but under boost would open according to the duty cycle lookup point on the map.

      i did a lot of injector testing... and was able to get top end fuel flow up to 420 cc per injector (per minute?). i think it was close to 100% more than the stockers.

      i also found that after doing this that my new Bosch fuel pump was not supplying enough fuel at the top end... things were going lean. Ended up having to add a Boost-A-Pump to fix that problem (this was triggered only under boost).

      The car ran perfectly well with CIS and the charger (and old video):

      i ended up tuning things under boost to run around 12:1 afr... and of course off boost with the stock lambda valve in control dithering around 14.7 (all measured with a wide band).

      Anyways just my $.02 now that i am back visiting the vortex.

    17. 08-29-2019 08:32 PM #41
      I’ve built a aba with cis basic top end and runs good. I welded in a 02 bung and tuned with a wide band which helped.
      What should be the max timing and at what rpm? Engines in a 82 Westy

    18. 08-29-2019 09:46 PM #42
      Depending on compression ratio, they will make best power around 28 total degrees advanced for below 10:1 CR.

      With the lower compression engines its possible to have more ignition advance than required to make the most power, and even to the point of loosing power, before signs of detonation.

      Its also important to look at the specs for the distributor you have to see when the advance comes in and at the max is.

    19. 08-30-2019 05:51 PM #43
      The compression spec for the ABA is 10:1. I used a mls head gasket with two extra .009” outer shims so I’m thinking I’ve lowered it maybe a point. I have to use Chevron 94 octane to avoid detonation which I don’t mind as it’s a seasonal vehicle.
      But when I checked with the timing light the full advance was 40* @ over 3000 rpm.
      It’s just a stock 1.8 cis distributor. I guess I’ll try and recurve it with lighter springs and limit the advance

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