I know it is a lot of reading, but I put everything out onto the table here in hopes that somebody could help me out. I have tried almost everything.
The car starts and runs fine, however it runs extremely rich. My live data scanner shows that bank A is running closed loop, while bank B is always running open loop due to unmet conditions.
Bank B stays in open loop due to unmet conditions. The only time it switches to anything else is when I press the gas and the live scanner shows both Bank A and B in open loop due to driving conditions, however when the rpm's settle bank A goes closed loop, and bank B is back to open loop due to unmet conditions.
Work done prior to problem occurring:
All vacuum lines replaced.
Intake, valve cover, and throttle body gaskets replaced.
all 4 o2 sensors replaced.
Spark plug wires replaced.
Spark Plugs replaced.
timing set perfectly to 10 degrees btdc
idle at 650 +- 50 rpm's (set accurately via live data).
Throttle position sensor perfectly set to 0% at idle.
After all of this work was done the car started and the live data scanner showed that both banks where in closed loop, the car sounded great and idled perfectly around 650 rpm's for a while.
I was playing some music, and letting the car idle for a while (twenty to thirty minutes) testing things out, and suddenly I felt the idle get really rough, and I could hear some misfiring going on little pops here and there, and when I would press the gas pedal there would be missing and it wouldn't be very smooth.
I immediately pulled out my live data scanner and I was seeing.
BankA: Closed loop.
BankB: Open loop due to unmet conditions.
Coolant temperature: (around 200 degrees F at the time).
Throttle position: 0% ( no dead zones all the way to 100%).
O2 Bank 1 sensor 1: swinging back and fourth between 0 and 1v
O2 Bank 2 sensor 1: swinging back and fourth between 0 and 1v
For whatever reason o2 bank 1 sensor 2 and 3 ( pre and post cat o2 on my car) are intermittent, they seem to only show up when the car is in closed loop, or diagnostic mode is triggered sometimes. The pre and post cat O2 sensors are the four wire sensors with the fourth wire being a ground, I tested the ground points, and everything looks good. Also, considering in closed loop, the sensors go between 0 and 1 volt fine I do not think they are an issue either. I have replaced them for good measure though.
O2 operation on this car (from what I have witnessed prior to this issue).
Bank A and B closed loop: all 4 sensors work
Bank A or B Open loop: only upstream sensors work (b1s1 b2s1).
Diagnostic mode bridged: all four sensors kick on and work.
Currently both upstream o2 sensors are working fine, and with diagnostic mode jumped all sensors show up just fine.
Diagnostic mode not jumped = working front o2 sensors with intermittent pre and post cat o2 sensors.
Vane airflow stats:
The intake air temperature was around 108 which made sense being that it was taking in air straight after the radiator fans, and the car was not exactly cool.
The airflow rate seems to match up with what it should be doing, as the rpm's go up the intake air speed numbers rise, and fall with engine speed.
The idle is less steady it does not hold a perfect 650 very well with half of the engine running open loop. It bounces a lot between 600 and 700, but stays within those boundaries.
Worst of all is that the car is running super rich now.
I noticed a map sensor problem as well, if I have the map sensor hooked up the fuel trims spike, and keep climbing past 35%. There is so much fuel being added that raw fuel vapor is exiting the pipe (not water), the ECU would then attempt to make some sort of correction and the fuel trims would go back to 0 then the idle would drop quickly and sometimes stall the engine. So I put a new-used map sensor on ($140.00 plus from Ford or Mazda new). The new-used one seems to work intermittently, the short term fuel trims spike and drop, the ECU does not seem to know how to correct and the car starts misfiring, idle increasing, decreasing, and things get really rough, and sometimes the car simply stalls out.
When I disconnect the map sensor the car runs with a nice more-less smooth idle, (as smooth as it gets running half open loop) and there is no random bogging of the engine as the ECU over compensates.
Basically with the map sensor totally disconnected the car runs with long term fuel trims around 10% +- a few percents. On both banks.
I have tested the live data of the car prior to this problem with the map sensor removed, as the random bogging at idle happened in the past, and the car ran in perfect closed loop with the map sensor totally removed from the system. So I do not personally believe that the map sensor is related to this whole mess, and I am unsure if its my map sensors that are bad, or something else that is bad.
I tried to get the long term fuel trims to come down to 0% to try to reduce the rich smell of the exhaust.
I found that unhooking the vacuum line to the fuel pressure regulator causes the long term fuel trims to hover around 0-2% on each bank, +- a few percents on the short term, which I would imagine is a good number.
The exhaust is still quite rich, however with this setup it is not pushing as much raw fuel out of the exhaust pipe.
I have tried swapping bank A and B o2 sensors.
Same error on bank B.
I have replaced all of the injectors with known working injectors. (Tried all different injectors, and tried the bank A injectors from two different sets and still have Bank B running open loop due to unmet conditions.
I have compression tested the engine, and made sure to test for head gasket leaks, absolutely no sign of a head gasket leak ( if there was a blown head gasket it would have randomly occurred sitting at idle for twenty to thirty minutes ).
I cannot remember the numbers, but I remember checking the workshop manual and the numbers where indicative of a very healthy engine.
At this point I am at a loss as to what is causing my Bank B open loop issue.
Bank A always goes into closed loop no problem.
Bank B always goes open loop due to unmet conditions as soon as bank A is in closed loop now.
I have a spare ECU, and it gives the exact same errors so I do not believe this is an ECU related problem.
Also, I do not have a vacuum gauge, but the vacuum to the map sensor location feels very strong.
A few things to keep in mind:
I happened to test this in the past, and my car runs closed loop just fine with the map sensor disconnected prior to this current issue.
The error occurs with map sensor plugged in or unplugged.
My car has a small pinhole fuel tank leak at the top of the tank ( it drips when I top off the tank ) - this never caused an open loop issue in the past, and has not thrown any codes.
When this happened the car was idling twenty to thirty minutes with music playing, and the AC turned on. I know it is bad for the compressor to do this, but I was messing around with equalizer effects and this was one of those few exceptions.
The car being the age it is, has very little rust on the underside, it is in pretty good shape. It has been kept in southern states most of its life.
When the fuel trims drop down (map sensor disconnected along with fuel pressure regulator vacuum line disconnected), there is little to no visible vapor coming from the exhaust. The trims stay within 10% all the way to full throttle with this setup, and still smells rich.
Diagnostic mode is something on this car that disables the IAC operation, and prevents ECU from changing timing so one is able to adjust idle, and timing accurately, and help diagnose various issues linked to diagnostic mode.
I do not know what else to say, I just want closed loop to come back so my car does not stink, and I have some decent gas mileage.
I am sitting here with a trunk full of extra injectors, fuel rails, fuel pump, map sensor, vacuum lines, and various distributor parts, I do not know what caused the issue to start, and I do not know how to fix something that is not throwing any codes, or giving me any real indications of where to look first.
These are currently the only screenshots I have of the current O2 sensors working. In these screenshots I had the post catalytic converter o2 sensor disconnected, however I had proper readings across the board from all sensors. The fuel trims are about what I get with the fuel pressure regulator correctly connected to vacuum, the trims drop down around five or less when the vacuum line is removed from the fuel pressure regulator.
All of the spark plugs are identical in appearance. (See spark plug images)
I cannot seem to remove the pictures that all posted in duplicates. This is a tad frustrating and misleading. There are only three pictures I was expecting to post.
have the same problem?
Friday, October 20th, 2017 AT 9:04 PM