[Main 9000 Bulletin Board | BBFAQ | Prev by Date | Next by Date | Post Followup ] Member Login / Signup - Members see fewer ads. - Latest Member Gallery Photos Darn newfangled technology! Like This Post: - Subscribe to Daily Digest for this Bulletin Board Posted by Ari [Email] (#2847) [Profile/Gallery] (more from Ari) on Fri, 14 May 2004 05:50:08 In Reply to: Re: Ignition/mixture, Yaofeng, Thu, 13 May 2004 16:14:51 Alert me when someone posts in this thread: Members do not see ads below this line. - Help Keep This Site Online - Signup

I'll tell you, this digital stuff is just a passing fad.

Your NOx numbers aren't way out of line. Just far enough for you not to pass. It would be nice if the plugs looked bad, but sometimes we can't be that lucky (!?!)

Nevertheless, I'm going to assume that you're running on the lean side. Maybe not wickedly lean, but still lean enough to spike the NOx. Yeah, it could be the catalytic converter, but let's think happy thoughts for now.

I'd still go for a set of new plugs. Maybe go to one cooler heat range. Next, look for vacuum leaks. They probably won't be huge, but every little bit counts.

It would be great if you could stick a voltmeter on the O2 sensor output. See what it thinks. The voltage should be swinging back and forth around 0.5 volts. If the sensor thinks the engine is lean (more time less than 0.5 volts), then it's a vacuum leak, or maybe the fuel pressure is a little low. If the sensor thinks the engine is rich, then it could be the sensor - it's telling the ECU the engine is rich, so the ECU leans the mixture out. One crude way to test the O2 sensor - At idle, pull any vacuum line other than the one to the FPR off and leave it open - the O2 sensor output should go to lean. Replace hose. Now, pull the vacuum line from the throttle body to FPR off and plug it - the sensor output should go to rich.

That's a crude test. Where you might have a problem is a 'lazy' O2 sensor - namely, it responds, but slowly. This happens to some sensors as they age. Unfortunately, I don't know of a quick and dirty way to test that.



posted by 192.249....

• The joy of owning a 10 year old SAAB..., Yaofeng, Wed, 12 May 2004 20:21:13
  • For your headlight, Call Jim at Sabstory...., Bill U, Fri, 14 May 2004 08:07:25
  • Ignition/mixture, Ari , Thu, 13 May 2004 12:21:17
    • One mre try..., Yaofeng, Thu, 13 May 2004 16:17:54
      • Arrgh..., Yaofeng, Thu, 13 May 2004 16:19:27
    • Re: Ignition/mixture, Yaofeng, Thu, 13 May 2004 16:14:51
      • Darn newfangled technology!, Ari , Fri, 14 May 2004 05:50:08 <-- Viewing This Message
  • Anyone want to stop long enough to look at the PROBLEM?, Brady, Thu, 13 May 2004 07:28:52
    • no EGR, Adrian, Thu, 13 May 2004 08:56:37
      • Probably means EVAP canister??? n/m, David Ingram, Thu, 13 May 2004 11:13:35
  • Re: The joy of owning a 10 year old SAAB..., Andrew, Thu, 13 May 2004 07:11:13
  • Better to keep the NGK's fresh to help the DI live (nm), Lu, Thu, 13 May 2004 06:34:26
  • I've been through this..., Adrian, Wed, 12 May 2004 20:55:17

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