P0174 with odd behavior

[CeodilEQ]

I have a 2005 Ford Ranger XLT 4.0L automatic, recently replaced timing and head gaskets due to the timing guide breaking on bank 1 on the drive home. I used a Cloyes timing kit replaced all gears guides chains and tensioners, I used the proper tool to hold the cam in place to time the motor and all went well. I finished everything up put everything back in and test drove the truck and it was fine I put 500 miles on it and then someone stole all 3 catalytic converters. I bought an aftermarket Y-pipe and new rear catalytic converter and since I was replacing everything new I went ahead and replaced the resonator pipe from the rear cat to the muffler, new muffler, new tail pipeand, 4 new oxygen sensors from Bosch. I put it all together and I could hear a slight exhaust leak between the passenger side exhaust manifold and the y-pipe I disconnected everything moved it around a bit till it fit better snugged it down and started it again and it sounded fine and was running fine, or so I thought. I took it for a short test drive of 10 miles and it ran fine seemed to be doing well I came home parked and it sat for the next 3 weeks while I was out of town. I came back and took it out with a friend to look around and the entire 45 minutes we were out I drove 55 mph on old country roads, it seemed to have a lack of power sometimes so I hooked up a scan tool and saw that my bank 1 fuel trim was around -1% up to +6% that seemed normal, but my bank 2 fuel trim was +18% - +56% going high only briefly and then going back down to the lower +18% - +25% range, I had my friend drive while I monitored it and saw that it would go down to +6% while going up hill and then go back up while on level roads and going down hill it would be in the same high 18-25 range. I decided we needed to get back so I could see what was wrong and as soon as we turned around and made the short 5 mile trip back to my house it started to show an active misfire by the blinking check engine light on the dash which would last for 30-45 seconds then stop for 2 minutes then suddenly start again during this the MAF was going crazy jumping from 12-36 G/S which I barely noticed because I usually don't look at the MAF because I forget about it a lot. I pulled the pending codes when I got stopped and I had pending P0300, P0301, P0302, P0303, P0174 I went and rented a smoke tester to try to find the bank 2 leak and smoked the intake begining right behind the MAF on the intake tube and saw no smoke after 15 minutes pulled the adapter and there was plenty in the system if I had a leak I should have saw it, I then plugged it into an evap port, again no leak, then I thought maybe it's not sealing on the driver's side exhaust manifold to Y-pipe connection I hooked the test up to the tail pipe and again no leak and no smoke anywhere. I waited till the next morning for the motor to be cold again started it up and unplugged the IAC valve to see if it would stumble and it almost immediately died, I let the motor get up to operating temp (my normal idle temp is 190) once it had sat at 190 for 5 minutes I unplugged the IAC again and this time no change in the rpm no stumbling didn't try to die at all. I have exhausted my ideas and knowledge and any help anyone can provide in figuring this out so I can get back to using my truck again without fear of it jumping time again or similar is greatly appreciated as I can't afford much more expenses and I can't afford the $200 diagnostic the local Ford dealership wants just to tell me what's wrong, again thank you all in advance.

 

[nesralyrrej]

welcome to the forum!

sounds more like a fueling issue to me, i would carefully inspect the wiring to each o2 sensor, as theyre usually not gentle while stealing, and could have de pinned the harness, stretched the copper internally, or completely severed some wiring.

the iac sounds like its acting normally for the most part to me. depending on the scan tool the maf will almost always be jumpy, unless the engine is only idling.

 

[CeodilEQ]

It's interesting you say that, last night I was doing some more digging and for the first time I noticed that the bank 2 upstream sensor shows a constant 0.1 volts with key on engine off while all the other 3 show 0.0 then once I start the motor that sensor switches faster than the other upstream sensor and always seems to be either at 0.8 or 0.1-0.2 I wonder if I got a bad sensor (I know from prior experience that new just means untested) bad part is I tossed the old Ford sensors I'll try switching bank 1 and 2 around tonight and inspecting the pins and wires when I get a chance this weekend and update the thread in case anyone else runs into a similar situation thank you for the reply

 

[Mechrick]

Did you get the upstream cats and all four O2 sensors back in the factory location?

 

[pentode]

Sounds like the computer thinks that bank is running lean and dumping a ton of fuel in to try to compensate, which would explain the misfires and the flashing CEL.
When you say that upstream sensor is switching faster, how much difference between the 2 is there? Are they both switching consistently, no dropouts?

 

[CeodilEQ]

Yes I was able to get the new exhaust system all back into the factory aligned position and held by the hangers and insulators like it was from the factory
The bank 1 sensor will show switching from 0.2 to 0.4 to 0.6 steady switching doesn't seem fast at all the bank 2 sensor on the other hand only shows 0.2 or 0.8 back and forth every 2 seconds it seems i've yet to see it read anywhere in-between, I thought it may be the PCM and I had a spare matching PCM available from a parts truck, I switched that PCM in and had the same behavior. I had a problem at one point right after replacing the timing where I was getting a crank sensor code and camshaft code I found the problem to be a small amount of dirt in the cam sensor connector on top of the bank 2 valve cover I pulled it cleaned it with CRC electronics cleaner and let it dry for an hour and those two codes never came back.

 

[Mechrick]

What's unusual is the lean code is for bank 2 (and fuel trims are adding fuel to bank 2) but the misfire codes are bank 1. Is it possible you got the O2 connectors swapped left to right?
If that's the case, the PCM is adding fuel to the wrong bank of cylinders.

The jumping MAF reading might indicate an intake valve sealing issue.

 

[CeodilEQ]

The O2 sensors are connected correctly made sure to check that because that was also something I thought of, as far as the valves I thought of that also since the original reason for replacing the timing kit was the guide breaking on the drive home and it jumped time so I took the heads off sent them to a shop to be serviced and make sure all the valves were good etc. knowing that it was an interference engine the shop told me all the valves were fine and none bent or not sealing so I dodged a large bullet there. The misfiring issue hasn't come back yet it was a one time thing but I also haven't driven the truck more than 15 miles at a time while I try to track down the cause and fix it

 

[Mechrick]

You won't get misfire codes until the misfire monitor relearns profile. When you clear codes on a Ford, it wipes out the learned misfire monitor profile. To relearn, run the vehicle through a series of decels in second gear. Run it up to 45 mph or so, then lift off the throttle. As the engine coasts down with no power pulses, the PCM learns the teeth position on the crankshaft reluctor.

Looking at O2 voltages won't help much. Let the PCM run it's own testing, either by driving it or doing a running test with a scanner. If there is a problem with the sensor switch speed or voltages, the PCM will catch it.

Clearly this is a bank-to-bank issue. Check simple stuff like harness connections, injector wirting, etc. The problem wasn't there before pulling the heads off, therefore it's unlikely to be something unrelated to the repair.

 

[CeodilEQ]

I made a small amount of progress this morning, I pulled the upstream bank 2 sensor and put in one I got from a salvage yard for testing purposes, the key on engine off voltage now showed 0.0 like the other 3 sensors. I started it up and now at idle the fuel trim on bank 2 is showing 10.4% - 19% I went for a test drive (before reading Mechrick's post) and allowed the for the adaptive relearn to try to relearn new trims by doing exactly what he said going up to 45 then letting off and coasting and gradually slowing down to to an almost stop) this was showing me fuel trims on both banks that almost matched, both banks stayed below +6% and above -4% until I came to a complete stop and idled with my foot on the brake or with the trans in park. I was showing trims on bank 1 of +5% to -1% and on bank 2 between +10% to +18% I think I may have a small vacuum/air leak still somewhere that is so small that I'm not seeing the smoke come out when I do a smoke test. The Y-pipe had the largest gap on the driver's side bank 2 connection right before the O2 sensor before I thought I got it to sit right so I'm wondering if it's still sucking in a small amount of air there and like I said I'm not seeing it with the smoke tester I rented from autozone.