Yes. Who knows, maybe there is even a special diagnostic routine the ecu runs occasionally to check the catalyst health :) Unfortunately I don't know the details of how that part is monitored.
TurboTR
Re: a/f swing, FWIW, I do SCT tuning for late model Fords, and we generally have a wideband hooked up to the car as well. I generally see an a/f swing that fits what I posted above. Hope that helps some.
TurboTR
As far as the frequency and swing of the a/f modulation, roughly, at low speeds it could be in the range of 10-30+ or so per second say. At higher speeds maybe 40-60+ or so. Again, roughly; your mileage may vary :) The older GM scheme used a variable called O2 crosscounts that maintained a...
Hmm. So you say the primary O2 went bad? When did you replace the sensors? Does the car lose any coolant at all? Are the exh headers tubular low grade stainless? If so they can crack, and that might throw things off severely. The turbo Buicks were notorious for cracking the ps side.
TurboTR
I didn't see you mention- how is the health of your downstream O2(s)? Is it working correctly? OBD2 mandates that the catalyst function, and anything else that can affect emissions must be monitored. If the ds O2 is bad it might be false coding.
TurboTR
I agree, 1750 is probably getting high for SI. Our engine supplier stated clearly that 1800 was the limit on this engine. 3100 psi- wow!!! If we had say a 4" bore, that would be a peak force of over 38,000 lbs pushing down on the piston (!!) The equivalent of having 11 average weight cars...
PS we also ran pilot injection on some other project diesel engines. Really an amazing quieting effect available from it- we even had an on/off switch to dramatically demo the effect. I can't wait until it catches on with all the annoyingly loud, clattery diesel p/u trucks around here, lol...
IME the pressure traces for diesel can be higher, but not necessarily so in general. For example, I try to limit the 900+hp turbo v6 SI engine I have to about 1600-1700psi max. It shows no signs of undo duress at this pressure in a 1/4 mile drags application. Yes I do have cyl pressure gear for...
