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Discussion Starter · #1 ·
Hello everyone, I have a 2005 stang with JBA mufflers and custom tune. It's currently running rich, gas smell coming from the back and combustion smoke at WOT.
I have no OBD2 codes but at idle sometimes after WOT it tends to decrease to 500rpms. Also at idle is sounds like an electric switch sound and it starts running rich with gas smoke.
Replaced spark plugs with motorcraft sp-412, cleaned TB and MAF.
The only weird thing is that the torque app says open loop due to system failure almost all the time, even when the car is on temp.
Sometimes it reaches closed loop but it says "closed loop (using only one o2 sensor).
Yesterday when I was at a stop it said "closed loop" with no o2 sensor warning and the idle was perfect.
What could it be?, bought a new fuel filter that I'm planning to install this weekend...
If I have a bad o2 sensor the car would be running really bad, but it starts with no problem and it accelerates with good response.
 

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2014 GT, 1967 Fairlane GTA
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Hello everyone, I have a 2005 stang with JBA mufflers and custom tune. It's currently running rich, gas smell coming from the back and combustion smoke at WOT.
I have no OBD2 codes but at idle sometimes after WOT it tends to decrease to 500rpms. Also at idle is sounds like an electric switch sound and it starts running rich with gas smoke.
Replaced spark plugs with motorcraft sp-412, cleaned TB and MAF.
The only weird thing is that the torque app says open loop due to system failure almost all the time, even when the car is on temp.
Sometimes it reaches closed loop but it says "closed loop (using only one o2 sensor).
Yesterday when I was at a stop it said "closed loop" with no o2 sensor warning and the idle was perfect.
What could it be?, bought a new fuel filter that I'm planning to install this weekend...
If I have a bad o2 sensor the car would be running really bad, but it starts with no problem and it accelerates with good response.
How many miles on this engine? Have all 3 of the timing cassettes ever been changed?
I really don't see how you don't have any trouble codes with what you're describing. Maybe whatever tune you have disabled something in the PCM. Is it a Bama tune? They're known to be problematic. In any case return the factory program to the PCM, drive it for a while, and scan it for codes. If some or all of the problems clear up then you know it was a bad tune.
Other possibilities are worn timing parts, vacuum leak, bad O2 sensor or problem in the wiring, or damaged cats.
The electric switch sound you mentioned is concerning if it sounds anything like a rattle or occasional loose mechanical sound. That would almost certainly be the timing parts getting ready to fail and destroy your engine. That would be imperative to fix right away and it wouldn't be cheap to have done.
Vacuum leaks and especially PCV leaks are common on older engines. Rubber or plastic hoses and elbows dry rot or crack and cause a lean issue due to unmetered air being introduced into the engine. This makes the PCM richen up the fuel mixture to compensate. Driven for long enough like that it will destroy the cats.
A bad O2 sensor or a problem with the connection/wiring doesn't necessarily mean the engine will run very poorly. It might just make it so it doesn't run tip top but it can cause drivability issues and can manifest itself at certain times/conditions.
If your cats are damaged from too much gas in the exhaust and/or overheating then you will be spewing out unburnt fuel and black smoke. The O2 sensors will alter the fuel/air ratio in that case as well.
 

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Discussion Starter · #4 ·
How many miles on this engine? Have all 3 of the timing cassettes ever been changed? I really don't see how you don't have any trouble codes with what you're describing. Maybe whatever tune you have disabled something in the PCM. Is it a Bama tune? They're known to be problematic. In any case return the factory program to the PCM, drive it for a while, and scan it for codes. If some or all of the problems clear up then you know it was a bad tune. Other possibilities are worn timing parts, vacuum leak, bad O2 sensor or problem in the wiring, or damaged cats. The electric switch sound you mentioned is concerning if it sounds anything like a rattle or occasional loose mechanical sound. That would almost certainly be the timing parts getting ready to fail and destroy your engine. That would be imperative to fix right away and it wouldn't be cheap to have done. Vacuum leaks and especially PCV leaks are common on older engines. Rubber or plastic hoses and elbows dry rot or crack and cause a lean issue due to unmetered air being introduced into the engine. This makes the PCM richen up the fuel mixture to compensate. Driven for long enough like that it will destroy the cats. A bad O2 sensor or a problem with the connection/wiring doesn't necessarily mean the engine will run very poorly. It might just make it so it doesn't run tip top but it can cause drivability issues and can manifest itself at certain times/conditions. If your cats are damaged from too much gas in the exhaust and/or overheating then you will be spewing out unburnt fuel and black smoke. The O2 sensors will alter the fuel/air ratio in that case as well.
Hey, thank you for your quick response!, the car is 74k miles The noise is not a rattle, it is like something electronic like a relay activates and it start running rich The previous owner did the tune and I live in Chile, so there are not so many experts that can do a good tune, maybe the tune is very bad in terms of air/fuel ratio. As an update, I've checked for vacuum leaks and the only thing that I saw was a loose vacuum conection in the EVAP valve. Conected it propperly and the problem persist.
 

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Try to find out where the clicking is coming from exactly.
You might want to do a smoke test on the intake system to see if any smoke comes out of it where it shouldn't. This will expose any vacuum leaks.
EVAP leaks could make it run poorly.
Did you return the tune back to the factory program? If you don't have the tuning device that the previous owner should have given to you with the car then you can go to the dealer and have them put the correct original factory program on the car.
 

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Discussion Starter · #6 ·
Try to find out where the clicking is coming from exactly.
You might want to do a smoke test on the intake system to see if any smoke comes out of it where it shouldn't. This will expose any vacuum leaks.
EVAP leaks could make it run poorly.
Did you return the tune back to the factory program? If you don't have the tuning device that the previous owner should have given to you with the car then you can go to the dealer and have them put the correct original factory program on the car.
Will try to find where the click soun comes from...
I don't have the tune device so I will try to find a place to go back to the original tune.
As a guide, here is my o2 sensors readings, the 1x2 sensor seems to have a weird reading ... sometimes the 1x2 and 2x2 have equal reading and other cases they are different. 1x1 and 2x1 almost all the time have the same value.
As I said before, sometimes torque have this warning "using 1 o2 sensor", sometimes it says "closed loop due to feedback fault" even when the car is warmed up and sometimes it says "closed loop" without any fault, so my guess is that something like electronics is affecting the fuel loop, but can't figure out what it is... forgot to say that due to rich condition the spark plugs builds up carbon very fast :(
The rich smoke is not a lot but enough to smell gas whe I accelerate over 3k rpm or at a stop
 

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2014 GT, 1967 Fairlane GTA
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You probably have a bad tune in the car and with it running that rich it will destroy your cats as well as make it run poorly. I'd get to a Ford dealer soon to have them restore the original program. Does this car have any other modifications other than the tune?
 

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Discussion Starter · #8 ·
You probably have a bad tune in the car and with it running that rich it will destroy your cats as well as make it run poorly. I'd get to a Ford dealer soon to have them restore the original program. Does this car have any other modifications other than the tune?
The only major mod is the JBA mufflers and paintjob, no headers, no CAI... Looking at the air filter it seems like a K&N red oiled air filter, I removed it and it seems a little bit dirty, but not enough to make the engine running rich.
The MAF sensor looked clean, but I also cleaned it with isopropyl alcohol. The throttle body seems clean, but I also cleaned it from the outside.
It's weird, maybe the tune is really bad or it got corrupted, but it's almost impossible to have problem with the tune after it runs ok, so my guess is that the tune is very bad in terms of air/fuel ratio.
My other guess is that it could be a wiring problem due to the paint job or a bad ground connection or bad fuse, but I doubt it.
The car runs ok and I don't feel a power restriction. The idle fluctuation is not very high, but enough to notice a little movement inside the car. Also the temp gauge when the car is warm after WOT reaches the upper mid portion and I've read that it could be in the middle all the time even at WOT.
Thank you for your replies!
 

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The only major mod is the JBA mufflers and paintjob, no headers, no CAI... Looking at the air filter it seems like a K&N red oiled air filter, I removed it and it seems a little bit dirty, but not enough to make the engine running rich.
The MAF sensor looked clean, but I also cleaned it with isopropyl alcohol. The throttle body seems clean, but I also cleaned it from the outside.
It's weird, maybe the tune is really bad or it got corrupted, but it's almost impossible to have problem with the tune after it runs ok, so my guess is that the tune is very bad in terms of air/fuel ratio.
My other guess is that it could be a wiring problem due to the paint job or a bad ground connection or bad fuse, but I doubt it.
The car runs ok and I don't feel a power restriction. The idle fluctuation is not very high, but enough to notice a little movement inside the car. Also the temp gauge when the car is warm after WOT reaches the upper mid portion and I've read that it could be in the middle all the time even at WOT.
Thank you for your replies!
That's good that there's nothing else done to it. That will ensure that the car should run well with factory program.
Those K&N filters always look dirty soon after they're installed and even when you clean them they have a brownish color to them instead of red. It should be fine as long as it wasn't overoiled.
How did you clean the MAF sensor? You should only use dedicated MAF spray cleaners on them. If you touched the wire with any physical object even a rag then there's a good chance that you damaged the extremely delicate wire sensor.
Painting the outside of the car won't affect how it runs.
If you have access to a code scanner that shows live data then you can see what temp the computer is reading from the temp sensor. Maybe your temp sensor is no good. That can lead to issues with how it runs.
 

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Discussion Starter · #10 ·
That's good that there's nothing else done to it. That will ensure that the car should run well with factory program.
Those K&N filters always look dirty soon after they're installed and even when you clean them they have a brownish color to them instead of red. It should be fine as long as it wasn't overoiled.
How did you clean the MAF sensor? You should only use dedicated MAF spray cleaners on them. If you touched the wire with any physical object even a rag then there's a good chance that you damaged the extremely delicate wire sensor.
Painting the outside of the car won't affect how it runs.
If you have access to a code scanner that shows live data then you can see what temp the computer is reading from the temp sensor. Maybe your temp sensor is no good. That can lead to issues with how it runs.
Did some research and its ok to clean the MAF with isopropyl alcohol, it is the most pure form of alcohol to clean electronics.
With the engine running as a test I've disconnected the MAF and the engine stopped running. The MAF seems to have good readings with the live data from the torque app, at idle it start with 14g/s so I think it in between tolerance. With the idle small fluctuations the MAF readings have variations but never goes to zero or a weird value...
The temp sensor in torque app shows stable readings, maybe the thermostat housing is leaking a little, 1 month ago I saw a small amount of coolant over the thermostat housing, but it stopped leaking and I refilled the reservoir.
I discard a timing chain issue due to car mileage and no rattle or stable behavior at WOT.
So as a final approach it could be the tunning and if I go back to the factory tunning maybe it will throw a code if it is a bad o2 sensor, EGR or PCV.
 

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Alcohol is perfectly fine as a cleaner but it would have to be sprayed on the MAF sensor wire. You can't touch that wire with anything. It can easily get damaged by even the slightest physical contact.
The thermostat housing on the 4.0 v6 is only plastic. They're actually well known to crack but you can buy an aluminum replacement. You would need to have low coolant and/or air in the system for the engine to read high or overheat.
Yes, your mileage is pretty low so even though you can't completely rule out the timing cassettes they're probably unlikely to be the cause of the problem. As I mentioned a few times before it's likely just the bad aftermarket tune in it.
 

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Discussion Starter · #12 ·
Alcohol is perfectly fine as a cleaner but it would have to be sprayed on the MAF sensor wire. You can't touch that wire with anything. It can easily get damaged by even the slightest physical contact.
The thermostat housing on the 4.0 v6 is only plastic. They're actually well known to crack but you can buy an aluminum replacement. You would need to have low coolant and/or air in the system for the engine to read high or overheat.
Yes, your mileage is pretty low so even though you can't completely rule out the timing cassettes they're probably unlikely to be the cause of the problem. As I mentioned a few times before it's likely just the bad aftermarket tune in it.
Still searching for a good place to retune it...
Still no codes, and reading 12.5 mpg avg :(
Filled with coolant to the top, no leaks
Here are some videos showing the problem:


Again thank you very much for your help!
 
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