Help with Engine knock - rod bearing/hydaulic lifter/fuel injector, which one?

[abhusa]

Hi all,
2007 Ford Territory RWD SY, Barra 4 190KW inline 6 engine with VVT, DOHC. , Petrol, 245k kms.
VIDEO of the noise

Dropbox

www.dropbox.com

Hoping someone experienced can help me identify the cause of the noise. Car vibrates only on idle when in D or R, slight vibration when in Park. As soon as touch accelerator or driving at constant speed (any speed with foot on peddle or in cruise) the vibration and noise go away instantaneously, whether staring from cold or hot. If I start the car and let the car just drive on its own without touching the peddle, sometimes the vibration is there, sometimes not. RPM stable btw 750-850 at park, about 550-650rpm in drive and brake pressed. A mechanic who inspected the car had told me partial misfire only in one cylinder. No misfire codes in history or present, or any codes for that matter.
A little Background
Was getting very lean condition , +VE LTFT , 15-16 %, did smoke test, Oring at injector to head interface leaking air- replaced O ring cyl 1, then get high -ve LTFT ~-23% in park, -12.5% in D and brake pressed, -14.5% when driving at constant speed, any speed, STFT normal , varies btw -5 to 5 in all scenarios, but mostly close to 0. I did replace a faulty precat 02 sensor, but made no difference to the idle. The new sensor works fines, voltage varies btw about 0.3 to 0.9V. The LTFT does not follow the STFT, it just jumps to the constant numbers mentioned above straightaway.

Suspected an internally leaking fuel injector, again at cylinder 1, as could smell a bit of gas at the cyl location + inside the cabin when recirculation mode off, and when stepping out of car, but no visible signs of leak.

Replaced injector with another used one from a known good engine, exact part # OEM. MY LTFT went straight to zero for a day, however rough idle as described above did not go away, and next day LTFT jumps back to high negative. Have checked the injectors with a stethoscope, always give me the constant clicks, incl. cyl 1.

Things to note, as soon as I touch the accelerator even slightly, LTFT - hovers btw -ve 3 to 0 , else goes straight to exact -12.5% in D and brake pressed, about ~ - 23% in P, and -14.5 % when driving at constant speed. STFT stays mostly close to 0. Also just a tiny tinge of gas smell (hardly noticable) when recirculation is off and after a long time like 20 mins or longer, can still smell gas at cyl 1 injector area at the head interface not fuel rail, but not strong or unbearable. My fuel economy is a bit low, e.g for pure city driving I should be getting about min. 5.333km/liter. Am currently getting about 5km/liter. Get much better fuel economy with highway driving ~8km/liter.

The car drives like a knife on butter other than the rough idle. Can someone help identify the cause of the noise. Could it still be a leaking fuel injector. Car occasionally needs 2-3 cranks, but it is random, not necessarily on a cold or hot start. Somedays I will leave the car overnight on warm or cold days and it starts straight up, and 'sometimes' leave it in the parking lot for a few hours or even few minutes and may need multiple cranks - this is occasional , I haven't deduced any pattern.

Car has not stalled even once, acceleration is superb. I step on the gas and it zooms. I race past commodores and sedans at the stop light.

I have run 4 bottles of injector cleaner including redline si-1 and a catalytic & EGR cleaner- no black smoke came out, added 1000k since. Have run liqui moly engine flush, but to be honest the oil didnt look that sludgy and I didnt see any metal shavings in it. changed the engine oil for full synthetic per spec. Have added antifriction additive PTFE, engine runs colder, but it never overheated to begin with. No smell of gas in the dipstick anytime. Dipstick level never rose. Occasionally get white smoke for maybe 30 seconds when I start the engine, but might just be the weather, but it isnt huge and goes away and in no one affects driving performance, no blue or black smoke anytime, and no smoke at all when the engine is hot either driving or idle. Replaced spark plugs with iridium as per spec. No fouling either on the old ones, or new ones, have checked multiple occasions. Car has never stalled or even felt like stalling even once.

One thing I have noticed after changing the oil and adding the PTFE, that ON OCCASION once the engine is hot, the rough idle is greatly reduced, but it is random, sometimes it is still there. However, the intensity of the sound at start up is the same as day 1 and will more than not, return even when engine hot and say if stopped at a signal or starting car after a few hours or days.

I havent done a compression or leak test as there has been no loss in performance, not even a hint. So I dont suspect stuck valves, or piston rings. I did want to do a fuel pressure test, but no schraeder valve on the fuel rail and too chicken to go under and disconnect the fuel lines. Mechanic was adamant (on several occasions) that it was a partial misfire in only one cyl and my mounts were absolutely fine.

Thanx for reading. Any help would be appreciated. This problem has been driving me nuts.

 

[kschachn]

Not all knocks are the same. Please post a video of the sound. That will help with diagnosis.

And don’t ever use PTFE in the oil. DuPont has unequivocally stated that it has no place in motor oil.

 

[abhusa]

Not all knocks are the same. Please post a video of the sound. That will help with diagnosis.

And don’t ever use PTFE in the oil. DuPont has unequivocally stated that it has no place in motor oil.

Hi, thanx for your quick reply. I was having difficulty posting the video. It should be on there now. Might have to turn up the vol. a bit.

 

[kschachn]

I am unable to distinguish what you are describing. Perhaps someone else will be better at it.

 

[DriveHard]

Pull the plugs and see if there is one that stands out.
Pull plugs one at a time and see if there is one of them that still keeps the rough idle when not firing.

 

[abhusa]

Pull the plugs and see if there is one that stands out.
Pull plugs one at a time and see if there is one of them that still keeps the rough idle when not firing.

Hi, will give it a try, but pretty sure it's cyl 1. What do I do after narrowing down the cyl. How would I deduce what is causing the noise in the video I posted?

 

[DriveHard]

Steps I might take...

Check compression on that cylinder
replace spark plug on that cylinder
check valve clearances on that cylinder if they are adjustable (too tight would lead to open valve and idle misfire) - compression check should find this
swap coils with another cylinder to see if it follows
swap injectors with another cylinder to see if it follows

 

[twX]

Have you monitored for misfires again since doing the injector work? Fixing a lean condition in one cylinder would cause the remaining cylinders to run richer, which might expose another unrelated problem. If there's no single problem cylinder, the MAF sensor could be bad, or all injectors could just be worn out and flowing too much.

The MAF sensor on a 4.0L engine should show around 4-5 g/s at warm idle. If you're unsure if it's bad, try cleaning it, or just replace it.

White smoke could mean that coolant is leaking into a cylinder. You might want to pressure test the cooling system. Coolant can cause a misfire in the affected cylinder, and can also affect oxygen sensors readings.

 

[abhusa]

Have you monitored for misfires again since doing the injector work? Fixing a lean condition in one cylinder would cause the remaining cylinders to run richer, which might expose another unrelated problem. If there's no single problem cylinder, the MAF sensor could be bad, or all injectors could just be worn out and flowing too much.

The MAF sensor on a 4.0L engine should show around 4-5 g/s at warm idle. If you're unsure if it's bad, try cleaning it, or just replace it.

White smoke could mean that coolant is leaking into a cylinder. You might want to pressure test the cooling system. Coolant can cause a misfire in the affected cylinder, and can also affect oxygen sensors readings.

Hi, I had the same thought. Considering replacing all my injectors, but would help to be sure what the exact issue is before throwing money at it. No misfires after injector work. Reason I suspect it's cyl 1 is cause I don't smell gas from the other ports. But I'd have thought replacing it would have made some difference. Car has a MAP sensor in the intake mani, which is reading fine, about 4.56-5.04psi at idle park. I have been regularly checking coolant, and oil cap. No discoloration, or drop in level. No milkiness at all even in the oil change. I use 91 , will try 98 tomorrow to see if that stops the rough idle. If it does I suspect it's just bad injectors . If it doesn't I will put hydraulic lifter additive to see if it makes any difference at all. I don't think it is a rod bearing as the noise goes away instantly moment I touch the accelerator, even a small tap, whether engine is hot or cold, each and everytime. I also dont drive the car hard. Am leaning towards a bad lifter that probably doesnt have enough oil pressure at idle or in drive with brake pressed, and then starts to work moment i touch the accelerator or bad injectors flow patterns or both as I cant imagine a bad lifter causing a rich condition even when driving smoothly. Along with the noise, it feels like the car is sighing and heaving at idle, like it is short of breath. But most likely fuel injectors as I get a high negative LTFT, and that may be the reason it hasnt affected my engine performance, as I would imagine even if the cylinders are getting more than required fuel, acceleration and power wouldn't be affected by the rich condition. My car doesnt jerk or hestitate when changing speeds or driving or starting. I can hear the gears shift smoothly.

 

[abhusa]

Hi all,
2007 Ford Territory RWD SY, Barra 4 190KW inline 6 engine with VVT, DOHC. , Petrol, 245k kms.
VIDEO of the noise

Dropbox

www.dropbox.com

Hoping someone experienced can help me identify the cause of the noise. Car vibrates only on idle when in D or R, slight vibration when in Park. As soon as touch accelerator or driving at constant speed (any speed with foot on peddle or in cruise) the vibration and noise go away instantaneously, whether staring from cold or hot. If I start the car and let the car just drive on its own without touching the peddle, sometimes the vibration is there, sometimes not. RPM stable btw 750-850 at park, about 550-650rpm in drive and brake pressed. A mechanic who inspected the car had told me partial misfire only in one cylinder. No misfire codes in history or present, or any codes for that matter.
A little Background
Was getting very lean condition , +VE LTFT , 15-16 %, did smoke test, Oring at injector to head interface leaking air- replaced O ring cyl 1, then get high -ve LTFT ~-23% in park, -12.5% in D and brake pressed, -14.5% when driving at constant speed, any speed, STFT normal , varies btw -5 to 5 in all scenarios, but mostly close to 0. I did replace a faulty precat 02 sensor, but made no difference to the idle. The new sensor works fines, voltage varies btw about 0.3 to 0.9V. The LTFT does not follow the STFT, it just jumps to the constant numbers mentioned above straightaway.

Suspected an internally leaking fuel injector, again at cylinder 1, as could smell a bit of gas at the cyl location + inside the cabin when recirculation mode off, and when stepping out of car, but no visible signs of leak.

Replaced injector with another used one from a known good engine, exact part # OEM. MY LTFT went straight to zero for a day, however rough idle as described above did not go away, and next day LTFT jumps back to high negative. Have checked the injectors with a stethoscope, always give me the constant clicks, incl. cyl 1.

Things to note, as soon as I touch the accelerator even slightly, LTFT - hovers btw -ve 3 to 0 , else goes straight to exact -12.5% in D and brake pressed, about ~ - 23% in P, and -14.5 % when driving at constant speed. STFT stays mostly close to 0. Also just a tiny tinge of gas smell (hardly noticable) when recirculation is off and after a long time like 20 mins or longer, can still smell gas at cyl 1 injector area at the head interface not fuel rail, but not strong or unbearable. My fuel economy is a bit low, e.g for pure city driving I should be getting about min. 5.333km/liter. Am currently getting about 5km/liter. Get much better fuel economy with highway driving ~8km/liter.

The car drives like a knife on butter other than the rough idle. Can someone help identify the cause of the noise. Could it still be a leaking fuel injector. Car occasionally needs 2-3 cranks, but it is random, not necessarily on a cold or hot start. Somedays I will leave the car overnight on warm or cold days and it starts straight up, and 'sometimes' leave it in the parking lot for a few hours or even few minutes and may need multiple cranks - this is occasional , I haven't deduced any pattern.

Car has not stalled even once, acceleration is superb. I step on the gas and it zooms. I race past commodores and sedans at the stop light.

I have run 4 bottles of injector cleaner including redline si-1 and a catalytic & EGR cleaner- no black smoke came out, added 1000k since. Have run liqui moly engine flush, but to be honest the oil didnt look that sludgy and I didnt see any metal shavings in it. changed the engine oil for full synthetic per spec. Have added antifriction additive PTFE, engine runs colder, but it never overheated to begin with. No smell of gas in the dipstick anytime. Dipstick level never rose. Occasionally get white smoke for maybe 30 seconds when I start the engine, but might just be the weather, but it isnt huge and goes away and in no one affects driving performance, no blue or black smoke anytime, and no smoke at all when the engine is hot either driving or idle. Replaced spark plugs with iridium as per spec. No fouling either on the old ones, or new ones, have checked multiple occasions. Car has never stalled or even felt like stalling even once.

One thing I have noticed after changing the oil and adding the PTFE, that ON OCCASION once the engine is hot, the rough idle is greatly reduced, but it is random, sometimes it is still there. However, the intensity of the sound at start up is the same as day 1 and will more than not, return even when engine hot and say if stopped at a signal or starting car after a few hours or days.

I havent done a compression or leak test as there has been no loss in performance, not even a hint. So I dont suspect stuck valves, or piston rings. I did want to do a fuel pressure test, but no schraeder valve on the fuel rail and too chicken to go under and disconnect the fuel lines. Mechanic was adamant (on several occasions) that it was a partial misfire in only one cyl and my mounts were absolutely fine.

Thanx for reading. Any help would be appreciated. This problem has been driving me nuts.

As an addition to the above steps.
I also cleaned my electronic TB with carby, but it was clean to begin with. (MY car doesnt have an IAC ). I thought maybe the TB doesnt open at idle, but the scanner reading shows it to be partially open. MY PCV works fine as well. Airfilter is replaced.

 

[ElectroMechanoMan]

If #1 is missing all of the time, keep your efforts there. Replace the spark plug. No change, replace the coil. No change, compression test. Look for a leak in the intake….hoses, gaskets, cracks in runners if plastic. If this doesn’t resolve the problem, then I would try an OEM injector in that position only. Any information you can get with a good scan tool is always helpful. Check the ignition and injector wiring for problems too.

 

[abhusa]

Hi, I had the same thought. Considering replacing all my injectors, but would help to be sure what the exact issue is before throwing money at it. No misfires after injector work. Reason I suspect it's cyl 1 is cause I don't smell gas from the other ports. But I'd have thought replacing it would have made some difference. Car has a MAP sensor in the intake mani, which is reading fine, about 4.56-5.04psi at idle park. I have been regularly checking coolant, and oil cap. No discoloration, or drop in level. No milkiness at all even in the oil change. I use 91 , will try 98 tomorrow to see if that stops the rough idle. If it does I suspect it's just bad injectors . If it doesn't I will put hydraulic lifter additive to see if it makes any difference at all. I don't think it is a rod bearing as the noise goes away instantly moment I touch the accelerator, even a small tap, whether engine is hot or cold, each and everytime. I also dont drive the car hard. Am leaning towards a bad lifter that probably doesnt have enough oil pressure at idle or in drive with brake pressed, and then starts to work moment i touch the accelerator or bad injectors flow patterns or both as I cant imagine a bad lifter causing a rich condition even when driving smoothly. Along with the noise, it feels like the car is sighing and heaving at idle, like it is short of breath. But most likely fuel injectors as I get a high negative LTFT, and that may be the reason it hasnt affected my engine performance, as I would imagine even if the cylinders are getting more than required fuel, acceleration and power wouldn't be affected by the rich condition. My car doesnt jerk or hestitate when changing speeds or driving or starting. I can hear the gears shift smoothly.

Added 98, didn't help, my fuel economy grew worse. Added about 200ml hydraulic lifter additive, so far no help, but might take some time to work. I have noticed 2 things different now. My LTFt doesn't stay stuck at 14.5% while driving, it fluctuates, and more often than not , combined with STFt at driving stays within +-10%, combined, but LTFt is negative, but does go to zero while fluctuating. At times combined goes to -20% e.g STFt -3:51, LTFt -16.5 ,but it's momentary.. Also, the vibrations reduce more often when temp, goes to the quarter mark, but sometimes they are still there.

 

[Propflux01]

Have you done anything to the ignition portion? I would pull and replace plugs and/or coil packs. If it is misfiring, the knock could very well be a result of it. You have alot of mileage on the engine, coil packs get weak, spark plugs go bad.

 

[abhusa]

Have you done anything to the ignition portion? I would pull and replace plugs and/or coil packs. If it is misfiring, the knock could very well be a result of it. You have alot of mileage on the engine, coil packs get weak, spark plugs go bad.

I have put in new ngk platinum spark plugs, made no diff. I used aftermarket coils for testing, made no diff, out the original back. In any case if it were the coils or plugs , I wouldn't have smooth acceleration n driving. Other than the rough shaking at idle I wouldn't even know there was something wrong with the car. My rpms don't fluctuate either. I can feel the engine shaking at idle, likely due to firing imbalance, but no misfire codes

 

[Propflux01]

I have put in new ngk platinum spark plugs, made no diff. I used aftermarket coils for testing, made no diff, out the original back. In any case if it were the coils or plugs , I wouldn't have smooth acceleration n driving. Other than the rough shaking at idle I wouldn't even know there was something wrong with the car. My rpms don't fluctuate either. I can feel the engine shaking at idle, likely due to firing imbalance, but no misfire codes

OK good. you are incorrect about the smooth acceleration. Many a time have had bad idle and good acceleration with a bad plug or coil. Have you done a leak down or compression test?

 

[abhusa]

OK good. you are incorrect about the smooth acceleration. Many a time have had bad idle and good acceleration with a bad plug or coil. Have you done a leak down or compression test?

Hi, haven't done a leak down or compression test. From all that I have read online, if they were ever required the car would exhibit symptoms of poor driving performance. I did want to do a fuel pressure test, but no schrader valve on my fuel rail, and I dont really have the guts to get under and disconnect the fuel lines, and monitoring the gauge would be cumbersome. To be honest, I thought someone experienced would be able to deduce the cause from the engine noise I have posted. Seems pretty distinctive to me, but I dont have the experience to know what is making the noise. I dont think it is a rod bearing as it should get worse as the oil warms up. I feel it is a hydraulic lifter, but cant imagine that causing a rich condition, and definitely not allowing smooth acceleration. Unless, the oil pressure kicks in as soon as I press the accelerator and makes the lifter work.

 

[Propflux01]

Hi, haven't done a leak down or compression test. From all that I have read online, if they were ever required the car would exhibit symptoms of poor driving performance. I did want to do a fuel pressure test, but no schrader valve on my fuel rail, and I dont really have the guts to get under and disconnect the fuel lines, and monitoring the gauge would be cumbersome. To be honest, I thought someone experienced would be able to deduce the cause from the engine noise I have posted. Seems pretty distinctive to me, but I dont have the experience to know what is making the noise. I dont think it is a rod bearing as it should get worse as the oil warms up. I feel it is a hydraulic lifter, but cant imagine that causing a rich condition, and definitely not allowing smooth acceleration. Unless, the oil pressure kicks in as soon as I press the accelerator and makes the lifter work.

A small valve leak will cause the exact symptoms you describe. The noise is a symptom of a problem, not the cause. Do a leak down. Or at minimum a hot compression test.

 

[kschachn]

Hi, haven't done a leak down or compression test. From all that I have read online, if they were ever required the car would exhibit symptoms of poor driving performance. I did want to do a fuel pressure test, but no schrader valve on my fuel rail, and I dont really have the guts to get under and disconnect the fuel lines, and monitoring the gauge would be cumbersome. To be honest, I thought someone experienced would be able to deduce the cause from the engine noise I have posted. Seems pretty distinctive to me, but I dont have the experience to know what is making the noise. I dont think it is a rod bearing as it should get worse as the oil warms up. I feel it is a hydraulic lifter, but cant imagine that causing a rich condition, and definitely not allowing smooth acceleration. Unless, the oil pressure kicks in as soon as I press the accelerator and makes the lifter work.

You threw parts at it and did other maintenance items, but without any diagnostic information you're only going to get guesses.

 

[abhusa]

You threw parts at it and did other maintenance items, but without any diagnostic information you're only going to get guesses.

Hi, for the most part you are right, but from all that I have thrown at it, my inner Sherlock Holmes and pink panther ( mostly pink panther) have deduced that it is a very (hoping) slightly stuck open exhaust valve only at idle due to a likely faulty lifter or some connected component in cyl 1. And I will be doing a leak test to confirm ,once I get my hands on an air compressor and figure out how to crank it with a wrench, as the crankbolt is in the front and btw that and the radiator fan hardly any place to barely even squeeze my hand. Anywho, reasons I have come to the conclusion it is a slightly open exhaust valve due to a faulty lifter are:

1) adding four bottles of fuel injector cleaner made no diff at least to the shaking at idle.
2) changing the cyl1 fuel injector with a used OEM one, albeit from a trusted mechanic who vouched for the injector did not change the fuel trims noted in my original post. I found that the most puzzling.
3) adding 98 did nothing or so it seems, might have helped clean off some carbon from the valves
4) adding about 150 ml of lifter additive didn't seem to do anything. Only added 150ml as already few ml past the full mark. It didn't seem to quiet the rough idle, but when I checked my fuel trims after, I found my long term fuel trim while driving, not static anymore and it was actually fluctuating.
5) I just added the remaining 150 ml of lifter additive and hoping against hope overfilling will not create more problems. Car isn't heating more than normal so far and haven't seen bubbles on the dipstick but let's see. Anywho I digress. So after adding the remaining bottle my rough idle seems to have quieted by about 25%. Now the bottle just mentioned it cleans lifters and not valves. So assuming it's actually a lifter causing the exhaust valve to stay open.

Still leads me to believe it is an open exhaust at idle which seems to fix itself when stepping on the gas. The reason I think it's only slightly open is that my engine is still running smoothly, unless the clattering noise I hear in the video is the exhaust banging against the cylinder.

6) reason I think it's exhaust and not intake is the constant negative LTFt. I believe LTFt is measured by the post cat O2. So I suspect the fuel is leaking from the open exhaust valve for me to get such consistent LTFt readings at idle

 

[ripcord]

I think you are barking up the wrong tree with the lifter additive. Defective lifters usually get lose, not tighter. A slightly burned valve will cause your symptoms. You need a compression and preferably a leak down test to rule out mechanical issues.

I'm not super familiar with the Barra engines except that they have a very good reputation in general. Is 2007 one of the years where some of them had valve spring breakage?