Kia Soul Forums :: Kia Soul Owners banner
1 - 20 of 67 Posts

·
Registered
Joined
·
43 Posts
Discussion Starter · #1 ·
I will try to be as detailed as possible so please forgive the long post. 2012 Soul base with 140k miles. 1.6 engine with automatic transmission. Bought the car used a few years ago and noticed almost immediately that there was a "stumble" while accelerating. Like a surging or noticeable miss. No codes at that time and seemed to run fine otherwise. Was noticeably worse in ECO mode so I avoided using that. As time went on the "stumbling" got worse until one day the check engine light came on blinking and the car had no power. It would still rev up but it just had no power and would barely move. Got several 03XX codes for multiple cylinder misfires and specific cylinder misfires (all cylinders). Also got O2 S1B1 stuck rich which I assumed was from the misfires. I turned the car off and restarted and it seemed fine but the problem recurs randomly.

I've done extensive research and have replaced the crankshaft sensor, all plugs and coils, both oil control valves and both O2 sensors, the throttle body (TPS) and the knock sensor. It seemed to run good after replacing each part but the problem always returns and continues to worsen. Just recently I did a leak test and was unable to find any leak. What happens when it crashes is it goes open loop fault. The fuel rail pressure is good (anywhere from 570psi at idle to 1200psi or more during acceleration) but the fuel trims go to 0 and it seems to be starving for fuel. The upstream O2 sensor hovers around -1 to -3ma (which indicates rich) while the downstream sensor shows .01v (which indicates very lean) and doesn't move.

When it's running "normal" the LTFT is high (around +20) and the STFT bounces around 0 to +10 and it "surges" at idle. It also has a slight hesitation when accelerating hard. Yesterday I tried to test the O2 sensors by pulling a vacuum line (PCV) and by adding propane to the intake via the PCV hose. Idling normally the LTFT was high and the short term was bouncing, as described above. When I introduced a vacuum leak the LTFT shot up to around +15 and the STFT around +10. The upstream O2 sensor hovered around -1 to -4ma and the downstream fell to .01. When I introduced the propane to simulate a rich condition the STFT bounced around 0 (-4 to +4) and the LTFT went to about +4 and stayed consistent. The upstream O2 sensor stayed around -1 to -4ma but the downstream sensor went to .7v and sat steadily there. Also, the "surging" at idle went away and it purred like a kitten.

I forgot to mention that when it's running "normal" there are constant misfires on cylinders 3 and 4 that range from 3-4 misses a minute to 1 or 2 misses in five minutes. However, when I introduced the propane the misfires went away completely. Also, with the propane applied the MAP pressure went from 6.2-6.8psi DOWN to 5-5.8psi. How did the vacuum increase when the propane was introduced and lessen when I turned it off? When I shut off the propane the LTFT stayed around+4 but the STFT shot up to +24, the upstream sensor stayed around -1 to -4ma while the downstream sensor bounced wildly from .75v to .01v and the "surging" came back. Everything about this seems to say starving for fuel but I have never seen low fuel rail pressure during any of this.

Also, I've removed the injectors and cleaned them and swapped them around to see if the misfires would follow but they did not and remained on cylinders 3 and 4 with 4 being the worst and 3 having less followed by cyliinder 2 with almost none. It seemed to me the misfires might be caused by a leaking PCV valve since the PCV line goes into the intake right next to cylinder 4 but when I plug up the PCV hose the situation continues. I've also plugged the canister purge line and the brake booster line and the situation did not abate. During the leak test I pressurized the intake and sprayed soapy water all around the intake gasket and saw no evidence of a leak. Of course, I could not see the very bottom as my view was obstructed.

I'm stumped. It appears for the world to be a fuel delivery issue but how if my fuel rail pressures are within spect? An injector would only affect 1 cylinder, not 3. An air leak would affect multiple cylinders but why is the upstream sensor not showing lean and the MAP sensor showing higher PSI (closer to atmospheric 14.7)? When I pulled a vacuum line the MAP went from 6psi to 9-11psi. I know this is a lot to digest but any suggestions would be appreciated. The next step is to throw big money at it (high pressure pump and high pressure sensor) and I'm not there yet so I thought I would ask better minds than mine and see what happens. One last note; the fuel economy on this has never been great. In the 21 to 24mpg range and I drive conservatively which I again attribute to the engine running so lean that it misfires but I could be very wrong because the plugs did somewhat sooted when I removed the old ones and the O2 sensor also seemed sooty, indicative of a rich condition but that could be from the misfires so I don't know:(. Thanks to all who read this.
 

·
Registered
Joined
·
2,434 Posts
Catalytic converter would be my best guess. Do you have a vacuum gauge? You can test for a restriction by watching manifold vacuum, use the line from the purge valve as it will be the easiest to access.
How exactly did you clean the GDI injectors?
 

·
Registered
Joined
·
43 Posts
Discussion Starter · #4 ·
Thanks for the replies. I thought converter too but when it runs "normal" it really revs (6k+) and shows no problem with air flow. Also, could the blockage be intermittent? I do have a vacuum gauge. What would I look for when attaching the vacuum gauge to the purge line that would indicate restriction? As to the injectors. I removed them and fashioned an adapter from a hypodermic syringe that the injector would fit snugly into connected to a can of carb cleaner. I pressurized the contraption with the carb cleaner and then hit the injector with 12v intermittently until the spray pattern "cleaned up" and looked uniform for all injectors. I then moved the injectors to new homes to see if the misfire would follow, it did not. Also, I forgot to mention in the first post that I started getting a code for cylinder contribution balance on all cylinders (P02XX). I also have gotten a P0420 "catalyst system efficiency below threshold" but that code has not returned since I replaced the O2 sensors.

The old sensor heater circuit failed. Still though, when the car is running "normal" the downstream sensor bounces wildly from .01v to .8v (sawtooth on a graph) as if the input to the cat is very sporadic but the upstream sensor shows pretty consistent in the -1 to -4ma range. The cat temp ranges from around 950F at idle to over 1300F when revved high and then cools fairly quickly back to mid 900s when the throttle is released. As I said in the first post, when I introduced propane to simulate a rich condition the MAP pressure went from around 6psi to around 5, the downstream sensor went to around .7v and remained steady (straight line on the graph), the misfires went away completely, the fuel trims balanced out well within specs (STFT -3 to +3, LTFT +3.5 to +4) and the "sruging" at idle smoothed right out, steady as a rock. In other words, with the propane added all the "problems" went away. As soon as I turned the propane off, it all returned. I was going to pull the back seat today and see if the pump screen is blocked even though I've never seen low fuel rail pressure indicating a fuel restriction but kinda grasping at straws now.

The fuel screen makes sense as the "problem" seems to have occurred more at certain times, like when braking or turning right. As if there was trash in the tank that got sucked into the screen and then when you shut off the car the debris falls away from the screen and it runs okay until it gets blocked again. However, the steady fuel rail pressure seems to contradict that theory so......who knows. Anyway, thank you again for the response. If you can, please let me know what to look for with the vacuum gauge and I will try that asap.
 

·
Registered
Joined
·
43 Posts
Discussion Starter · #7 ·
So I pulled the fuel pump out and was hoping to see a lot of trash on the pickup screen or even a lot of water in the tank but alas, the screen was clean and I could not see any sign of water anywhere. Kind of expected that but was hoping against hope. Anyway, I could not find my vacuum gauge but I was looking at the live data and the MAP pressure dropped from around 6.5psi at idle to 3.96 at 2500rpm and held solid as a rock. However, I went to the back and felt the exhaust and it felt weak. It seems there should be more flow at 2500 and it was even less at idle, like just a whisper. And, every now and again there was a larger "puff" or surge that lasted only a split second.

Another thing I find curious is the ambient air temp is off by 10 to 12F. The instrument cluster reading shows spot on, 85F but the ambient air shows 73.4 on my scanner. I thought the reading from the dash came from the same sensor that reads ambient air but it must not. And, I unplugged the coolant temp sensor just for giggles and the coolant temp went to -40F but the ambient shot up to 419??? The idle also increased (TPS showed throttle opened slightly) and the cooling fan engaged, which I kind of expected the fan to come on but not the idle increase or the 419F ambient temp. Curious. If you have any additional thoughts please feel free to share. Thank you again.
 

·
Registered
Joined
·
2,434 Posts
How often did you perform carbon cleanings? The valves and your combustion chamber might be gummed up real bad. Pop the intake off, it is super easy on the 1.6 and have a peak at your intake valves
 

·
Registered
Joined
·
43 Posts
Discussion Starter · #9 ·
I had read about the intakes carboning up because of the GDI so about a year ago, when I suspected injectors, I had to pull the intake to access them. I looked at the intake valves then and saw quite a bit of carbon build up. I took a can of carburetor cleaner, a long screwdriver, an ice pick and a bunch of rags and spent over 4 hours spraying, chipping and mopping up. I tried to be very thorough and the difference was dramatic. I would say the valves were 85% cleaner when I finished. I then followed it up by using a can of CRC valve cleaner (that you inject through the throttle body while running) to hopefully get most of the last 15% and in case there was any on the valve seats that I could not get to. I did a compression test on all cylinders and they seem okay for 140K miles (around 140psi) with the number 4 cylinder, the one with the most misfires, being the highest at 143psi. I've always used "top tier" gas (for the combustion chamber) and full synthetic oil (for the intake valves). I've even toyed with the idea of installing a catch can.

Everything about this situation seems to be contradictory. It appears to be an air leak but how can a leak be intermittent? And how can a leak not cause the RPMs to rise? And why is the upstream O2 sensor showing on the rich side (0 to -1.5ma) and the downstream showing very lean? The ECU appears to be adding lots of fuel (STFT at +24) so why do all the numbers and the idle go perfect when I ADD MORE fuel (propane). Okay, if not an air leak then a fuel restriction but how can that be intermittent? Failing pump maybe? So why do I not see low fuel rail pressure even when it "acts up" so bad it almost stalls out? Bad injector(s) maybe? So how does the misfire not follow when I moved all the injectors to new homes? Water in the gas? How can that just clear up when you turn the car off and restart? Plus, I just pulled the in tank pump yesterday and the tank was shockingly clean. Maybe it's an ignition problem? About 2 months ago I put brand new iridium spark plugs (paying very close attention to gap) and coils in, no difference. Plus an ignition misfire would make the system see rich, not lean, correct?

This all leads me to ask this question. What are the odds the ECU itself is having issues? I used to troubleshoot electronics and this seems to be one of those ghosts I used to hate to chase. I keep coming back to how turning off the vehicle and restarting could clear a mechanical issue and I do realize that the sensors are electronic but I'm not seeing any failures. I have checked freeze frame data countless times and there are no anomalies. This has become personal, this vehicle and I are becoming mortal enemies. I jest but it is quite frustrating. I really do not know where to go next. Do you believe the odds are favorable that the ECU could be the culprit or is that rare? Again, I really appreciate your time and input.
 

·
Registered
Joined
·
2,434 Posts
So you might still have a ton of carbon on the piston and in the combustion chamber. CRC or BG run it by spraying it into the intake while car is running and bleep the throttle.
Another possibility is the variable intake flaps. Seen a few leak around the bushings in the shaft so intermittent could be depending on what position it's in, you can try propane around that area.
Also good idea to check valve clearance at that mileage but a steady vacuum gauge would tell you needn't bother.
 

·
Registered
Joined
·
43 Posts
Discussion Starter · #11 ·
Okay so here's the latest twist on my situation. I tried the propane around the bushing of the manifold flapper as suggested and got no change. So since I had the propane out, I decided to try the rich/lean thing again. While the engine was idling "normally" (surging and rough) I pulled each coil feed and noticed the difference. On cylinder 4 there was no difference, zero, nada. So I pulled off the PCV hose to introduce a vacuum leak and the RPMs shot up as did the intake psi (7 to 11). I pulled the #4 coil wire and again, no difference at all. So here is where the dream gets weird. I put the PCV hose on my propane nozzle and introduced propane into the manifold. The RPMs dropped to normal, the manifold vacuum INCREASED(???) and the engine smoothed right out. I then pulled the #4 coil wire and there was a big difference. HOW CAN THIS BE??? I did not bother swapping coils because I know there is no way in hell that the coil knows when I'm adding propane and decides only to fire when propane is introduced.

So somehow, which is currently beyond my ability to understand, cylinder #4 is contributing nothing and cylinder #3 contribution is diminished UNTIL you add propane at which time both cylinders behave normally AND my intake pressure goes from around 7psi DOWN to 5.3 which indicates an INCREASE in vacuum when ADDING volume (propane) to the intake???? Isn't this impossible? Unless maybe the throttle body is being commanded to close slightly when the propane is added. But that does not explain why cylinder #4 fires ONLY when propane is being added. It really seems to point to a bad injector but the injector that is on cylinder 4 was on cylinder 1 when this all started. Why didn't the problem move to cylinder 1 when I swapped injectors and why is cylinder 3 affected but to a much lesser extent? I've read that the ECU can shut off an injector(s). Under what conditions would it send such a command?

That seems like what is happening. It would explain the lean readings on both the O2 sensors. Oh yeah, I forgot to mention that when I did this today the upstream O2 sensor, which was reading-1 to-3ma (rich), started reading +2 to +4ma which now indicates a lean condition. It would also explain the fuel trims trying to add 20% more fuel. And obviously it would explain the engine running so poorly as it is starving for fuel and only running on 2-1/2 cylinders. I know life isn't meant to be easy but holy crap. Anyway, when I took the injectors out to clean them and swap them around last year the spray patterns all looked uniform and the solenoids all responded smoothly. What am I missing? Any thoughts are greatly appreciated.
 

·
Registered
Joined
·
2,434 Posts
I'm assuming you are not getting any injector circuit codes. Easiest thing you can do is pull the plugs out and crank the engine over and see if any fuel ends up on the #4 piston. That doesn't make the injector bad necessarily but it will let you know that fuel is 100% the issue. If you have an oscilloscope, I know most people don't, you can see if it is firing the injector as the injector harness is right there in front of the intake. Be careful if you borrow someone's scope as the injector coil firing can produce 70volts spike so if their scope can't handle it you will need an atenuator.
 

·
Registered
Joined
·
43 Posts
Discussion Starter · #13 ·
Okay, I know I titled my post very confusing but confusion has turned into disbelief. I was always taught that an internal combustion engine needed three things to fire off. Air fuel mixture, compression and spark. That appears not to be true. We took the car out last night and it has now reached the point that it simply is not driveable. We only had a mile to go to meet our daughter and it acted up the entire time there and back. At one point I could floor the accelerator and nothing would happen, it would just sit and idle (roughly).

This morning I took your advice and pulled the number 4 plug (and the number 1 plug for comparison) and turned the motor over not allowing it to start (pulled all the COP wires). I could see a mist coming out of the #1 plug hole and smell the gas. I then compared it to #4 and it was basically the same. I then put the plugs into the coils and laid them against the engine (for ground) and could see a clear spark on both 1 and 4??? So I have an air fuel mix, I have compression which I tested again today and got higher numbers than before (180+) with #4 again being the highest at around 200 and I have spark. What I don't have is ignition on #4?? And I also am still showing both O2 sensors as reading lean, the upstream at +.5 to 3.5ma and the downstream reading .01v. So if I have air fuel mix and I have compression and I have spark why does the cylinder not fire off? And not firing off why are my O2 readings lean?

It has come to the point now where cylinder 4 only fires when I add propane into the intake. I thought about timing but how would the cylinder know if it was running on gas or propane? If it will run fine with propane added then how could the time jump off as soon as I remove the propane? I also pulled the intake again today and there is more carbon on the valves again after just a year of low miles driving, thanks GDI. I inspected for any cracks or holes in the manifold and verified the flapper was free. There was some oil on the head air channels and the intake manifold air chalnnels and it was worse on #4, less on three, little on 2 and even less on one. This also corresponds to the misfires, most on 4 less on 3 little on 2 and none on 1. Coincidence? The oil appears to be coming from the PCV hose which happens to plug in to the manifold closest to the #4 cylinder. Coincidence? The spark on # 4 was sooty but not fouled and it did not appear to have any liquid on it (oil). I am still looking for a scope to test the injector firing command but seeing the mist makes me think it's being commanded to fire. I'm still racking my brain to make sense of all of this.....
 

·
Registered
Joined
·
43 Posts
Discussion Starter · #14 ·
So I just finished a little test run after reassembling the vehicle. It ran perfect.?.? No surging idle, no chugging/stumbling, good acceleration. I monitored the live data during the test and the cat temp varied from 1250F to 1500F depending on acceleration, the fuel trims still seemed high (like a small air leak) with the LTFT around +18 and the STFT bouncing from +5 to -4 or so. The coolant temp hovered around 180 but the ambient air temp started at 90F and then fell to 68. The B1S1 O2 sensor still showed a little rich (-.1 to -.5) and the B1S2 bounced from .1 to .75. Last night when it ran so badly the ambient air temp showed 55F and it was close to 80 outside. So why did it run so good just now? I did nothing except remove the intake and reinstall it. I did swap the spark plugs on cylinders 1 and 4 when I reassembled but that's it. It has always done this before whenever I work on it. When I switched out any sensor, cleaned the valves, cleaned the injectors, changed the coils and plugs or whatever, it runs good for a while and then starts acting up again. It is maddening. I know I asked before but what do you think the odds are that the ECM itself it squirrelly?

Normally, when it's running well the scanner shows fuel system condition as "closed loop O2 sensors controlling fuel mix" or something to that effect. Last night when it acted up the message my scanner gave on fuel system condition was "open loop because of system fault" but when I checked the fault codes there was only multiple cylinder misfires, misfires on cylinders 1,2,3,4. No other codes that would lead me to an actual cause. So again, do you think the ECM is just unstable?
 

·
Registered
Joined
·
2,434 Posts
So hard to say without being able to see the car. Wonder if you could try wiggling the connector on the coil, I have seen bad pin tension on the connector and it will be intermittent and sometimes when you rev it the vibration of the engine will actually make the pin contact. A pin tension gauge is around $15, it's a tool I can't go without as I work on brand new cars quite often so when something doesn't work right it too often comes down to bad pin tension in a connector.
 

·
Registered
Joined
·
43 Posts
Discussion Starter · #16 ·
So hard to say without being able to see the car. Wonder if you could try wiggling the connector on the coil, I have seen bad pin tension on the connector and it will be intermittent and sometimes when you rev it the vibration of the engine will actually make the pin contact. A pin tension gauge is around $15, it's a tool I can't go without as I work on brand new cars quite often so when something doesn't work right it too often comes down to bad pin tension in a connector.
Thanks for the reply. That would make sense that whenever I pull the "loose" plug and reinsert it it makes good contact for a while. The longest it has done well after working on it was when I replaced the coils and plugs. That time it ran for almost two weeks before acting up again. I actually thought I had found the problem and fixed it. But then, as it always does, it just started acting up again. I really want to love this car. I have a touchy back and getting in and out of this is easier than many cars I've owned before. It has ample room inside, is fun to drive and is even comfortable on a long trip. We took it to Alabama in October last year and except for a short time going through Atlanta it ran fine. When it acted up I pulled over to the shoulder, turned it off and restarted and it did well the rest of the trip. I'm telling you this thing is so frustrating and the fact that the ECM won't throw a specific code to at least point me in the right direction (or even a direction) is making me dislike this automobile. When my brother was looking for a new car he asked my opinion about KIA and I told him to be leary. I wanted to say they're great but I just couldn't after the trouble I've had with this. I am going to get a pin tension gauge to check that and I'll report back. When I am finally able to fix this problem, I hope my efforts will at least help some other poor Soul owner find quickly what has taken me about 18 months so far. Thank you again for your time and input.
 

·
Registered
Joined
·
2,434 Posts
The #4 coil and wire are in the worst position, it has the shortest wire that gets pulled on and the clip is a little harder to reach than the others. That is why if it is idling fine use that moment to wiggle the wires so slightly and the connector as well and see if you get a big hiccup.
 

·
Registered
Joined
·
43 Posts
Discussion Starter · #19 ·
Thanks to everyone for the encouragement. I am nothing if not stubborn. Usually I used logic to troubleshoot issues in my previous job and I am at a serious deficit when logic does not apply. This situation seems to defy logic. Most mechanical issues cannot "self repair" at random. A leaky valve cannot suddenly seal. A blown head gasket cannot be "unblown" at random times. A clogged converter cannot "unclog" sporadically. Electronics, on the other hand, are affected by so many variables that their behavior can seem contradictory. Temperature, humidity, corrosion, voltage, current, vibration and so on can affect their operation. Today I plan to warm the car up and go about "wiggling" various plugs in an effort to uncover a loose connection, which is one of the few mechanical issues that can randomly change. The problem is it is unlikely that a mechanical issue like a loose connection could be rectified by turning the car off and restarting, improbable but not impossible.

It still haunts me that the ambient air temp fluctuates so much. Yesterday it showed 90F when I reassembled the vehicle, which was very close to the temp here. By the time I had finished my test drive it had fallen to 68F. The night before when the car barely ran it showed 55F when it was close to 80 at the time. Once, just as an act of desperation, I unplugged the ECT (engine coolant temp) sensor to see what effect, if any, that would have. The ECT fell to -40F but the weird thing is the ambient temp shot up to 419F. Also in the past, the ambient air temp would coincide with the cat temp before starting the vehicle. For instance, one time as I prepared to do a test drive, the ambient air temp showed 68F and the cat temp showed the same while the ECT showed 85 and the IAT (intake air temp) also showed 85, which was very close to accurate. Once started, the cat temp rose rapidly but the AAT (ambient air temp) stayed 68. Where did 68 come from? The AAT is almost always wrong but yet the dash thermometer, which I thought got its signal from the AAT sensor, is always spot on.?.

I still suspect a small vacuum leak because of my MAP reading. It fluctuates from 6 psi to over 7.5 while idling but if you are driving and hold RPMs at around 1500 the pressure drops to mid 3s to 4. Okay, a couple of questions. During deceleration the ECM goes open loop, which I know is correct, the STFT goes to 0 but the LTFT goes to +40 or more. Is that normal? The other thing, always before when the car is cranked cold (after sitting all night) the RPMs would go to 14-1500 for a few seconds (15 to 20) and then settle to about 1000 before falling to about 650-700 once warm. Now when I do a cold crank the RPMs only go to about 1000 and then settle to around 650-700 once warm. Should I still be getting that initial 1500 at cold start up? If so, any idea why I'm not? And one last question. When you first switch on the key the throttle opening shows to be about 11-12% and bounces a little (+-1%) but then after about 5-10 seconds it goes to 16 and sits solid. If you hit the accelerator pedal, car still not started, the throttle goes up (but only to 85% at wide open throttle) and then when you let go settles back to a bouncy 11-12 but then 5-10 seconds later it goes back to 16 and sits solid. This repeats every time you hit the accelerator. Is that normal? I truly do not wish to be a pest but I am determined to find out what is wrong with this car. I truly appreciate all the assistance.
 
1 - 20 of 67 Posts
Top