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And happened again today, just not taking 15-20 minutes. Went to library to reurn some books and cane home exverything fine. Left in garage for 20 minutes and started, within a minute was at limit and stayed as long as at idle. Note vacuum now in 18s. Hair tearing time. Drops down when revved but comes back up. O2 sensors are cycling. OY.
I get the secondary pump coming on briefly after driving the car and then coming to a stop at idle as a short shot of fresh cool (relative) air into the exhaust could help cool the manifold. But, wouldn't injecting air into the exhaust any longer than that cause the O2 sensor to signal a lean condition and increase fuel when it is not necessary? Padgett was idling for fifteen minutes. Could the secondary pump find the increase in exhaust temperature over that 15 minute time frame and think it is time to turn on for a couple seconds? or longer?
what it does (if i recall correctly) is start to richen the a/f ratio then turns on the air injection pump and watches for that a/f ratio to drop. if it does drop then it allows the ecu to verify the secondary injection system is working properly. as far as i can tell it only runs this system for testing purposes after the engine is warm. I'll have to go back and read through all my service studies from years ago if i can find them.things like this that are so specific i try not to remember cause if i don't remember even one thing exactly the way it is the whole testing procedure is not longer any good so i prefer to just go back and read data and perform tests word for word.
OK. Have almost thrown the kitchen since at it now, just switched the oil filler cap for a new one. Only time I have seein anything other than P0170/P0173 (2017/2086) has been an occasional "pending" P0410 that never sets.
Keep in mind this is an early '00 SLK320 (same driveline as Crossfire just prefer a retractable to a soft top) so the ECU progam may not do everything a later car can. I have checked out the whole SAI system and is good/clean but only see it active when cold, never when warmed up. That might be a later revision.
The sudden spike at the grocery store I have to wonder if part of a learning process since when back down and has not repeated.
Posting here because of my coupe (no problems or codes) and people here are more technical tham the MB forums. Dual was the first to mention the swapped sensors. Have not seen screwy clong term cycles since.
Photo is of momentary spike (enough to set both codes) at the grocery store within a minute of starting and in Park (slightly higher idle and better manifold vacuum). Bright sunlight is not good to photograph a display. but is legible.
that pending p0410 code might be what your after. i'll have to look everything up later like i said as far as secondary air injection system operation but i do believ once the engine is warm at times it will test the operation of the secondary air injection system by riching up the fuel mixture for a quick second then turning on the air pump and monitoring for the a/f to drop. if the a/f doesn't drop it sets that p0410 code. if i recall that p0410 code will not set at cold start.
looked real quick today, i know i'm missing critical info but here's a couple quick things i found.
Under some situations, the Task Manager will not run a monitor if the MIL is illuminated and a fault is stored from another monitor. In these situations, the Task Manager postpones monitors Pending resolution of the original fault. The Task Manager does not run the test until the problem is remedied.
For example, when the MIL is illuminated for an Oxygen Sensor fault, the Task Manager does not run the Catalyst Monitor until the Oxygen Sensor fault is remedied. Since the Catalyst Monitor is based on signals from the Oxygen Sensor, running the test would produce inaccurate results.
and this is for the p0410 code. FWIW i can hear my air pump run with the a/c on so that bit might be false.
When Monitored and Set Condition
When Monitored: Once per driving cycle with the engine at idle, air conditioning is off, barometric pressure is greater than 78 kPa (11 psi), engine coolant temperature is greater than 50°C (122°F) and no other DTC set.
Set Condition: When the test is enabled, the O2 Sensor must increase by at least 23% (rich).
OK just noticed something. In the garage I mostly had the top cover off and replaced to drive. Just noticed when the top cover is on, MAF tilts and pulls out of rear spring clip. Just replaced and lubed all airway seals and made sure all MAF clips were in place. Now have 20.4 in-hg at 700 rpm idle in Park...but when I turn the AC on it drops to 17-18 in-hg. Turn AC off and comes back up. Is this normal or do I need to start looking for a leak in the HVAC system ?
OK just noticed something. In the garage I mostly had the top cover off and replaced to drive. Just noticed when the top cover is on, MAF tilts and pulls out of rear spring clip. Just replaced and lubed all airway seals and made sure all MAF clips were in place. Now have 20.4 in-hg at 700 rpm idle in Park...but when I turn the AC on it drops to 17-18 in-hg. Turn AC off and comes back up. Is this normal or do I need to start looking for a leak in the HVAC system ?
AC on or off is same, 700 in Park, 550 in gear. Was kinda hot so did not do much other than reseal and make sure all the clips were in place. That is when I noticed the drop in vacuum when ac turned on.
Re: SLK320 P0170 Nightmare
