Hi Bob,

You may already know all of the following, but here are some things to look at with CIS:

The mixture is tuned using a modulation valve which should be mounted near the driver's side of the radiator, with two wires and fuel lines to and from - if memory serves, in the absence of a signal from the ECU, it operates at a set frequency. If this valve is shot, or if the signal isn't getting to it form the ECU, mixture may be off. The valve should make an audible buzzing noise when the engine is running.

If the oxygen sensor is kaput, you will have a difficult time getting the mixture right - on my previous 99, the O2 sensor went bad, and it eventually fouled the plugs. You said you own 900s as well, right? SO similar setup, but without the preheater circuit.

Have you already pulled the injectors and made sure they're all spraying properly and consistently?

And last, you might want to make sure that the throttle switch and the vacuum switch which trigger the cold start injector aren't somehow stuck closed - 'cause thar could certainly do something to your mixture as well.

When I got my previous car, the exhaust had broken loose and fallen on the CIS wiring harness, and the heat had melted stuff all the way back to the fusebox - so the owner had disconnected the whole system and set the mix so the car would run, and had been running it that way for a couple of years. Lots of backfiring when accelerating. I got all new harness and wired it up and it made a world of difference.

Oh yeah, one other thing - at least on my '78 turbo, there was a system relay for the CIS setup which was under the fusebox, not on top. It's shown in the wiring schematics in the Haynes, but the don't tell you where it is.

Hope this helps some.
Rowan

posted by 66.170....

• Full MSS header and exhaust experiences? >>>>, BobD, Thu, 28 Apr 2005 09:17:35
  • Re: Full MSS header and exhaust experiences? >>>>, super99, Wed, 15 Jun 2005 15:50:26
  • Re: Full MSS header and exhaust experiences? >>>>, Kevin, Fri, 29 Apr 2005 03:46:26
  • CIS stuff, Rowan, Thu, 28 Apr 2005 22:17:57 <-- Viewing This Message
  • Re: Full MSS header and exhaust experiences? >>>>, JesseP, Thu, 28 Apr 2005 11:59:54
    • Re: Full MSS header and exhaust experiences? >>>>, JesseP, Thu, 28 Apr 2005 12:03:01
      • 30 thousandths overbore with new pistons >>>>, BobD, Thu, 28 Apr 2005 17:11:20
        • Re: 30 thousandths overbore with new pistons >>>>, JesseP, Sat, 30 Apr 2005 08:04:15

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