1994-2002 [Subscribe to Daily Digest] |
Yes the ECU remembers lots of things, but that may not be the issue.
Sports exhaust on a V6? Must make a lot of noise?????????????
After running with a bad wire, perhaps that spark plug is fowled up and black. Is this one of the plugs that you cannot get to?
Was the wire cracked or broken enougth to create a large gap. Was the spark jumping out of the damage to ground. Can you confirm that the coil is now delivering a spark now. Hooking up its far end to a clean plug with its body grounded would be a good test. What I am thinking is that if the gap was small, it would jump that and the spark plug gap too. If it was too big of a combined gap, then the spark would have no where to go and the voltage would be much higher than that dictated by a proper plug gap. The open circuit spark voltage can create an internal failure in a coil as the voltages are more than it was designed to withstand. So there are two possibilities. Fowled plug, or damaged coil. And easy to test. Have an old serviceable wire left? Use that to confirm that you can get a good spark.
Back to the ECU remembering things. In general with some turbo issues.
The calibration of some sensors is quite loose. The ECU calibrates its operation to suit. The O2 sensor is quite accurate at its ideal operating point. The fuel properties, air temperatures, fuel temperatures and fuel pressures are all variable. The ECU varies the fueling with RPMs and manifold pressure. Corrections are made for changes in intake air temperature. The varabilities in the pressure regulator and absolute pressure sensor are accomodated by the fudge factors that are worked out in keeping the O2 sensor happy under steady state cruise conditions. If you replaced the air intake temp sensor, manifold pressure sensor, air mass meter if so equiped the ECU will simpley adapt without needing to be reset. The ECU adapts to changes in fuel energy content. Again the O2 sensor is the touch stone for this. The ECU also learns about knocking threasholds etc. Some of this can work against you but is most often to your advantage. Sometimes you can fake out an ECU's limited model of reality to your advantage. Some early turbo systems could be modified with a pressure activated switch to change the intake air thermistor resistance when on boost. The ECU would go into cold engine operation and run rich, this would provide overboost enrichment. This avoided variable rate fuel pressure regulators, auxillary injectors and other stuff. For many situations this was an excellent cheat for otherwise marginal situations. There are other ways to fake out the ECU by tinkering with its world view by hacking its sensor signals. The ECU can then be faked into doing something is would otherwise limit. The ECU when put into a stressed situation like this can struggle to adapt for some time but eventually calibrate it self and become a different beasty. Perhaps some real life details at a later date. There are 'boxes' designed for some vehicles which tweek the ECU inputs and sometimes outputs to get more power without modifying the stock ECU. ... none for Saab ...
posted by 207.43.19...
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