Brief history: 2003 X Type 141k mi. - Service every 7.5k, Mobil 1 5w/30

-performed an induction cleaning 600mi. ago; removed vacuum line from brake booster, put 1/2 can of seafoam through intake, let sit 20mi, blew out under heavy acceleration
-also have run the previous 2 tank of fuel (93oct) with techron fuel system cleaner
-CEL has been on for a few weeks, O2 sensore (bank 1 sensor1)

*yesturday noticed very slight roughness when at idle, this morning while commuting went to accelerate at highway speed - no acceleration responce, CEL started to flash, overall rough ride the remainder of the commute.
*this afternoon i replaced the spark plugs, being sure to check the intake o rings, PCV hose and all other vacuum hoses and connections.
***i did notice when pulling the plugs that 4 of the 6 had oil on the plug (??) also when putting the intake manifold back on oil leaked out (??)

certainly roughness is a misfire caused by the oil on the plugs, what would cause oil getting onto the plugs and into the intake manifold.

could it be meer bad timing or in relation to the induction cleaning. i have successfully performed induction cleanings on all of my vehicles for years, never with an issue similar to this.

what to look for now? would a bad coil (s) causing a misfire allow oil to enter the upper cylinder coating the plug and entering the intake?

not sure where to go from here, any help???

Thanks

 

I can not help you fix this problem, but I can help you get better answers. With these cars (in my experience,) you won't completely know what the problem with the car is until you get the code for the check engine light. Go to autozone or something similar and get the code read. If you post the code or codes, I'm sure you will get a more precise reply and be closer to tracking down your problem.

 

OK, I know the best place to start is reading the codes. However, my code reader (Innova 3150) is locked in some type of upgrade mode and is unusable.

I have attempted to isolate any possible cause by replacing the known weaknesses. I have replaced the spark plugs, lower & upper intake gaskets, IMT o-rings (both), brake booster vacuum line and inspected the PCV hose.

The motor still seems to idle rough. When taking it for a short drive, once I get to about 3k rpm's the motor seems to stumble (miss) and will not go beyond that rpm. I also can recreate this when the vehicle is in park.

The only thing left on the ignition side would be the coils to my knowledge. Might this be an ECM issue, the "limp home" mode or just a series of bad coils causeing a misfire.

I will try to get the codes read asap, just looking outside the box to see if this rings a bell with anybody.

Thanks

 

zerochills, there are o-rings that go between the valve covers and the plug wells. If you have a valve cover that isn't seated properly, it can cause the o-rings to leak, getting oil into the wells. Then you have a condition where the oil is conducting and bypassing part of the spark from the plug straight to the block of the engine. This reduces the strength of the spark, and therefore a misfire is caused since all the fuel is not getting burned in the cylinder.

I would start with replacing the seals on the valve covers and then go from there.

 

Thermo; thanks for the responce. The oil is not actually in the well itself, but coating the firing end of the plug noticable after removing it, might have been access fuel as well. Did not give it a very close inspection, may just pull the plugs again to give it a more detailed inspection. Guess I will go ahead and replace the plug o-rings while I'm in there.

Is there any way to test the coils?

Thanks

 

zerochills, if you have oil on the end of the plugs, then you have wear issues or a failed PCV valve. I would first do a compression check on a few cylinders (probably want to do 1, 3, and/or 5 as they are on the front side of the engine and easy to get to without too much disassembly). From there you can determine if you have a sealing issue with any cylinders. Good cylinder pressure is around 150-180 psi. If you are down around 120 psi or less, then you have a sealing issue. From there, you can rotate the engine to where both valves are closed and then using a source of compressed air, you can pressurize the cylinder with 90 psi of air. You can then listen to the intake, exhaust and oil fill area and hear where the air is going. From there, you can determine a fix.

 

As for testing coils, you can do a resistance check, but that doesn't tell you much other than if it is failed completely. The best checks I can recommend is to first look at the top of the COP and see if you spot any cracks (white lines) in the clear top. If you see cracks, then the COP is questionable at best and you need a new COP for that cylinder. After that, if you only have a single cylinder that is misfiring, swap that COP with one that is easy to get to. If the misfire moves to a different cylinder, then you know it is the COP. IF the misfire remains with that cylinder, then you have another issue.

 

ok, got the codes. P1314, P1316, P1646 and P1000

also, checked and cleaned the PCV valve (works fine) and cleaned the MAF sensor.

 

zerochills, P1314 and P1316 are random misfire codes for banks 1 and 2 (ie, front and rear sides of the engine). This is telling me that odds are your misfire problem is not related to the plugs, but more with the fuel system. I would say to get your hands on a fuel pressure gauge and see what your fuel rail pressure is. With the engine off, it should be 40-50 psi and with the engine running around 30-40 psi. Normally the fuel rail pressures run towards the high end of the scale. It is sounding like to me that your fuel pump is starting to go and you are getting lower than normal fuel pressures, leading to the misfires. have you noticed your car hard to start in the mornings after it has sat for a long time (ie, take a few seconds of cranking before the engine finally fires up)? If so, try this, turn the key to the RUN position (not to the crank position), wait a few seconds and then attempt to start the car. Does the car start much faster/easier? If so, this is leaning the problem towards the fuel pump vice an ignition issues.

 

I will do the fuel pressure test this evening. However, I can not recall a situation where it has been slow or slugish to start (even after sitting a week or more at a time)

I'll get back with the results

 

Tested the fuel pressure. Was not able to get a reading on the gauge (gauge starts at 10psi). Tried another tester thinking the first gauge was defective, still no reading. I took the gauge off the fuel rail test port and depressed the shradder valve while the ignition was in the on position with out the motor running. I was only able to get a blurp of fuel to come out of the valve.

I have no problem starting the motor (very little hesitation if any), I would think if there is no pressure on the rail the motor wouldn't even start. Just a thought, maybe I am wrong. Should I still persue a failing fuel pump, could it be a clogged fuel filter or fuel line???? Or is there something else to look for?

I feel the fuel pressure test is rather straight forward and can not imagine it was performed incorrectly to register no reading, but if someone can identify an error in the way it was performed please chime in. Also, with the application of the fuel system cleaner could there have been gunk dislodged and clogging a fuel passage?

Suggestion on the next path to follow?? Thanks

 

A new fuel filter is cheap and easy to install (about a 20 minute job). I would say to start there and see what the pressure is after the fact. From there you can figure things out. It may be that there is enough pressure for idle, but getting it much above that can lead to your problems. But, at minimum, it sounds like you have a low fuel pressure issue.

 

Got the fuel filter install complete. Immediate improvement in idle (no longer rough). Fuel pressure registered 18psi(??) with ignition in on position and 46psi with motor running (good!).

However, still seems to be in limp home mode. Took on a test drive and once I hit 3k rpm CEL started flashing and it started to stutter and would not respond with any additional acceleration. I also could get it to (stutter) at 3k rpm while in park. Tried to disconnect battery to see if that would clear codes, no luck still same limp home mode.

Is there still an excisting problem or is the ecu still operating in limp mode???? Can this be manually reset with out a diagnostics tool??? Or is there any additional issue caused by running the car in limp home mode to get the car home and tested (about 150mi.)

 

disconnected the battery for a couple of hours in effort to reset ecm, no luck. CEL still iluminated upon restart. Let motor warm some and while in park brought rpm's to 3k. CEL started to flash and limp home stutter. Fuel pressure seems fine while motor is running leading me to think fuel pump is o.k. with it idling much better, is it possible a limp home mode can only be cleared by a computer or will it reset itself once issue is resolved.

further looking for possible issue, ignition coil? clogged catalytic converter? other?

 

Still trying to isolate the issue, looked again this weekend. Pulled the plugs in bank two. Plug 2 & 4 looked lean but ok, plug 6 looked brand new (has never fired).

So now I think I have isolated to cylinder 6, thinking either injector or coil. Though thinking further if it was the coil the plug would at a minimum be covered in fuel, correct? Being the plu looked brand new I am leaning towards a clogged injector.

Any thoughts on this??

 

zero, I would say to move the injector and coil to say the #1 cylinder and see if your problem moves. if it does, then you can easily access these parts without having to pull the intake and whatnot. After that, normally it is a coil that has failed. While it is possible that the injector is clogged/failed, I have seen tons more bad coils than injectors.

 

Isn't bank 2 (2-4-6) on the side closest to the radiator?? The cylider with issue is the one closest to oil fill cap (I believe that is #6). I will move around to see if the issue follows these parts to the next cylinder. The reason I think its the injector is prior to all of this happening i had ran (2) consecutive tanks full with Techron fuel system cleaner. I believe that broke some gunk free in the fuel filter. I was unable to get a fuel pressure reading, you had recommened replacing the fuel filter which immediately improved idle and I was able to get 46psi on the feul rail with motor running. I am now thinking if there was that much crap broken loose to clog the fuel filter it has probably found its way down line to the injectors (hopeflly only this one we are talking about) Anyhow, if it was a bad coil wouldn't the inject still be spraying the plug with fuel? I would think that I would see at least some evidence of that, this plu looked as it did out of the box.

Anyways, thanks for your help Thermo, much appreciated. I will get these repairs done and report the results. Anything special to know when replacing (removing the injector????

 

Have you looked at your catalytic converter yet? I had basically the same issue but on bank one (1-3-5) side of the motor. I replaced everything you have PLUS spending nearly 2 grand before I figured out I had a clogged Cat on the bank one side of my motor. What happens is the cat can only flow so much and when you put the motor under a load the back pressure will build up and the your upstream 02 sensor will read this and cause your engine to misfire. The misfire codes area symptom in this case not the problem.

 

Yeah, thought quite a bit about that. Prob will be my next focus after addressing either the coil or injector on #6 (if that doesn't fix things)

 

Zerochills,

Any resolution to this issue?