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mikefocke

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mikefocke last won the day on April 12 2023

mikefocke had the most liked content!

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  • Present cars
    '01 986 Boxster S TIP arctic silver
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    99 Boxster (totaled)
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  1. The P0140 and P0160 are "interruption of signal". Brett posted on PPBB: The O2 sensors do just that, sense the amount of O2 in the exhaust gas relative to the amount of O2 in ambient air. Perfect combustion of a perfect mixture of air and fuel (around 14.7/1 air/fuel ratio) leaves behind only CO2 and water as products of combustion. All the oxygen gets consumed in the combustion and combines with all the carbons and hydrogens. If there is not enough fuel (lean mixture), then all the fuel gets burned leaving some oxygen left over. Conversely, if there is too much fuel (rich mixture), then all the oxygen gets burned leaving behind extra hydrocarbons (fuel). Now an oxygen sensor outputs a voltage between 0 and about 1 V depending on the difference between the amount of oxygen in the exhaust and the amount of oxygen in normal air. If there is a lot of oxygen in the exhaust (lean mixture condition), the sensor outputs close to 0 volts. Conversely, if there is no oxygen in the mixture (rich condition), then the output is close to 1 V. These O2 sensor voltages are read by the computer. This is the feedback loop that tells the computer how the engine is performing with regard to air/fuel mixture. It's impossible for the computer to hold the exact perfect air/fuel mixture constantly, so the way mixture control is designed is for the computer to continually adjust the mixture from very slightly rich to very slightly lean and back again using feedback from the pre-cat O2 sensors. This means that the pre-cat O2 sensor signal will oscillate back and forth from high to low to high to low voltage as the computer adjusts the mixture. In a normal running engine at idle the signal goes from low to high voltage and vice versa about every 1 second, with a transit time from low to high (or vice versa) being about 200-300 milliseconds. This transit time is important because as an O2 sensor ages, the transit time gets longer, and eventually it can get too long such that the computer will call it a malfunction and signal a check engine light and fault code for a slow responding O2 sensor. O2 sensors need to respond to mixture changes quickly so that the computer can keep up with the proper mixture adjustments. So the bottom line is that the pre-cat O2 sensors should oscillate between about 0.2 to 0.8 volts regularly (about every 1 second at idle) in a healthy engine. The post-cat O2 sensors are identical to the pre-cat O2 sensors (same voltage outputs). They are there only to monitor the performance of the catalytic converters. So, as discussed, the pre-cat sensor signals are oscillating between 0.2-0.8 volts. Once the exhaust gasses pass through the catalytic converter, most (all, in theory) excess fuel (hydrocarbons) will be combusted thus reducing hydrocarbon emissions. The cat uses oxygen in the exhaust to combust the fuel. So what you end up with in the exhaust after passing through the cat is a gas mixture that is reduced in hydrocarbons and reduced in oxygen relative to the mixture entering the cat. The post-cat exhaust gas mixture should be CONSTANTLY low in oxygen if the cat is doing its job of burning excess fuel. Therefore, the post-cat O2 sensor signal should be a constant lower voltage reading (not oscillating). So, if the post-cat O2 sensor is seen to oscillate just like the pre-cat O2 sensor, that means that the post-cat sensor is seeing the same gas mixture as the pre-cat sensor meaning that the catalytic converter isn't doing its job of burning excess fuel. The computer monitors the post-cat sensor and compares it to the pre-cat sensor. If the signals are similar, it assumes the cat is bad. What I recall...it has been years ..... The connection to the actual sensor is crimped, not supposed to be soldered. The Porsche ones come with the pigtail. The pigtails are of different lengths for the pre and post cat sensors. Bosch makes em for Porsche. Buy the version with pigtail crimped at the factory. Sometimes people buy a bare sensor and use the old pigtail. Not good.
  2. There is boxa.net in the UK but I don't know any sources for info on the continent. https://www.9apart.co.uk/ in the UK www.douglasvalley.co.uk Lancashire in the UK steve strange on eBay boxsterbits on eBay https://www.jasmine-porschalink.co.uk/ and on eBay porscheheaven@yahoo.com or https://www.facebook.com/Porsche-Heaven-246901405365392/ in Doncaster https://prestigesalvage.co.uk/ in Leeds is the closest to you I have. Good luck.
  3. Post codes and someone will help you follow the diagnostic tree.
  4. Isn't the normal total current draw after being shut off for 31 minutes for a '97-'99 car 17/1000 to 30/1000 amps depending on accessories? Has the alternator side of the circuit been tested? I've read of the voltage regulator causing weird current draws.
  5. See if this helps toward the end of part 2 https://sites.google.com/site/mikefocke2/replacingthetop-adiy
  6. With the number stolen for their precious metals, are there many left on wrecks?
  7. Maybe cite the way you are measuring the voltage and the resultant number? Here are parts of a writeup by Brett on how the post cat is supposed to work that I found years back.: Now an oxygen sensor outputs a voltage between 0 and about 1 V depending on the difference between the amount of oxygen in the exhaust and the amount of oxygen in normal air. If there is a lot of oxygen in the exhaust (lean mixture condition), the sensor outputs close to 0 volts. Conversely, if there is no oxygen in the mixture (rich condition), then the output is close to 1 V. The post-cat O2 sensors are identical to the pre-cat O2 sensors (same voltage outputs). They are there only to monitor the performance of the catalytic converters. So, as discussed, the pre-cat sensor signals are oscillating between 0.2-0.8 volts. Once the exhaust gasses pass through the catalytic converter, most (all, in theory) excess fuel (hydrocarbons) will be combusted thus reducing hydrocarbon emissions. The cat uses oxygen in the exhaust to combust the fuel. So what you end up with in the exhaust after passing through the cat is a gas mixture that is reduced in hydrocarbons and reduced in oxygen relative to the mixture entering the cat. The post-cat exhaust gas mixture should be CONSTANTLY low in oxygen if the cat is doing its job of burning excess fuel. Therefore, the post-cat O2 sensor signal should be a constant lower voltage reading (not oscillating). So, if the post-cat O2 sensor is seen to oscillate just like the pre-cat O2 sensor, that means that the post-cat sensor is seeing the same gas mixture as the pre-cat sensor meaning that the catalytic converter isn't doing its job of burning excess fuel. The computer monitors the post-cat sensor and compares it to the pre-cat sensor. If the signals are similar, it assumes the cat is bad.
  8. JFP I have Maurices instructions for the later top to earlier swap as long at the later top and frame are together. You are right on just swapping the cover onto the old frame, of course you are.
  9. Didn't Porsche stop publishing maintenance documentation sometime before the 3.2 was introduced? So wouldn't the only access be through one of the Porsche diagnostic computers? Find someone with a PIWIS and PST2.
  10. Charging should be a lot higher than 12.7. A thread below this said 14.2 which I presume is at maybe 2500 RPM. New batteries can be bad. Batteries can be tested for free at most shops that sell batteries.
  11. Might want to pump the figures into Online Wheel and Tyre Fitment Calculator. Offset, Tyre Stretch and Speedo Error | Will They Fit WWW.WILLTHEYFIT.COM Wheel and tyre fitment calculator - it calculates inset, poke, speedo error, tyre stretch and loads more. tire has to be considered too.
  12. I presume you have solved this by now. In case you haven't, email me and I'll send you a 10 year old write up that may help. mike dot focke at gmail
  13. Google has forced many web pages to be rehosted over the years since these were posted originally. And many of the links have long since expired. Try starting here https://sites.google.com/site/mikefocke2/hacks
  14. Always good to hear a cheap win for the good guys.
  15. Years ago I wrote up all the options I had heard of. https://sites.google.com/site/mikefocke2/what-can-you-do-if-your-engine-is-blown Some of the prices may be out of date but their relative cost is probably in the right ballpark.
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