TJP55 Posted October 11, 2013 Report Share Posted October 11, 2013 It's smog check time for my 1986 Peugeot 505 Gas Turbo in California. Although it has always passed smog check before, this time I'm a little worried. I've gone through my usual tune up routine of cleaning and regapping spark plugs, replacing the oil and oil filter, checking the timing, etc. However, I've recently discovered wire 22 on the inner right fender. The manual says it should measure 7.2 volts plus or minus 0.2 volts. Mine measures 5 volts? This means I'm running rich? What would cause this? The car runs fine. However the rpm at idle goes up and down a little. In California, I'm not allowed to adjust the richness screw as any tampering would cause it to fail smog check. Quote Link to comment Share on other sites More sharing options...
Bean Posted October 11, 2013 Report Share Posted October 11, 2013 Welcome to the forum! How new is the O2 sensor itself? Injectors ever been cleaned / flow tested? These are old cars now, so things like the O2 sensors and the injectors will need to be looked at as well to ensure they're functioning. Heck - even the air filter can be an issue if its not clean. Rabin Quote Link to comment Share on other sites More sharing options...
TJP55 Posted October 11, 2013 Author Report Share Posted October 11, 2013 The O2 sensor is original. It's never been changed. The injectors are original and have never been cleaned or flow tested. The fuel pressure regulator was replaced 10 years ago. The air filter is old, but is still clean. Quote Link to comment Share on other sites More sharing options...
Bean Posted October 11, 2013 Report Share Posted October 11, 2013 How many miles on the car? Have you noticed a decrease in fuel economy? Cap and rotor? Plug wires? Rabin Quote Link to comment Share on other sites More sharing options...
TJP55 Posted October 14, 2013 Author Report Share Posted October 14, 2013 The car has 156,000 miles on it. No drop in fuel economy, still averages 25 mpg. The cap, rotor and plug wires were replaced 13 years ago. They still appear to be in pretty good shape though. Quote Link to comment Share on other sites More sharing options...
Bean Posted October 14, 2013 Report Share Posted October 14, 2013 I'd bet money the O2 sensor was no longer functioning... As for the cap, rotor and plugs, wires - miles on then is a better indicator of wear on them. Rabin Quote Link to comment Share on other sites More sharing options...
TJP55 Posted October 15, 2013 Author Report Share Posted October 15, 2013 Is the Bosch 13004 the right O2 sensor for 1986 Peugeot 505 Turbo N9TE? Quote Link to comment Share on other sites More sharing options...
andrethx Posted October 15, 2013 Report Share Posted October 15, 2013 yes. aka peugeot part number 1628.A4 andré Quote Link to comment Share on other sites More sharing options...
Bean Posted October 19, 2013 Report Share Posted October 19, 2013 If you're handy and have some time you might want to consider installing a 4 wire O2 sensor... 4 wire sensors are heated so that they come up to temp faster and the ECU can go into closed loop sooner. If you google "4 wire oxygen sensor upgrade" or something similar there's lots of info online. Might not be worth the effort, but its something on my todo list... Rabin Quote Link to comment Share on other sites More sharing options...
TJP55 Posted October 22, 2013 Author Report Share Posted October 22, 2013 I replaced the O2 sensor, but the problem remains. When I first start the car with the engine cold, I get 7.9 volts. It stays at 7.9 volts as the engine warms up. Then something kicks in and the reading drops to around 3.5 to 4 volts and stays in that range. Quote Link to comment Share on other sites More sharing options...
andrethx Posted October 23, 2013 Report Share Posted October 23, 2013 not a turbo owner so just spitballin' here...is it possible that there is some problem with the ecu, like a broken solder lead that only acts up when heated up? that might be a level 2 or level 3 thing to check out... andré Quote Link to comment Share on other sites More sharing options...
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