Oh God... tell me how bad this is...

[kentompkins]

Okay. I have that seemingly common issue of inconsistent, but frequent misses throughout my RPM range. It's most noticeable at idle probably due to less sound from the engine. Randomly, within the beautiful, typical glug, glug, glug of the exhaust there is a puuff..... puff.. puff........pufff.

While getting it dyno tuned, my tuner and others gave me the theory that I have a COP doing bad. Not bad enough to throw a code yet but bad enough to cause this.

So... I ordered two brand new Motorcraft OEM COPs. (Don't waste time telling me to buy GMS, MSD, Accel or any other COPs). I moved them around the entire engine and it had absolutely zero effect. I tried the test of unplugging each one by one while idling... all of them had the same effect. So, I eliminated the COPs as the cause in my mind.

Next I focus on the plugs. I took out all four on the passenger side bank. Three plugs looked exactly as I would have wanted. One did not. It was wet. I smelled it and it doesn't seem like gas. I tried to light it think it would just go right up if it was gas... it didn't. It's not antifreeze... Yes, I tasted it. I think it's oil.

Hoping that it wasn't I tried moving that wet plug to the next cylinder and running it again - hoping that the same plug would come out wet from a different cylinder (hoping a bad plug or something I guess). Well, now the formerly wet plug was dry in the new cylinder and a previously dry plug is now wet in the same cylinder from which I pulled the first wet plug.

This cylinder and I are not friends. It's the second one in from the front on the passenger side. It's the one that I BROKE ONE OF THOSE DAMN OEM plugs in back in my naturally aspirated days. It's the one into which I feared a small piece of ceramic from the broken OEM plug fell down into. I thought we got it all out. I fear that we didn't...

So, what exactly would be the symptoms of a piece of ceramic being down in that combustion chamber? I assume it would not be vaporized. How much damage would be caused? Am I now looking at a rebuild?

I'm all in favor of getting a new block with a forged internal setup but does this now mean I need new heads too?

Lay it on me... I can take it. Be honest.

 

[94tbird]

So... I ordered two brand new Motorcraft OEM COPs. (Don't waste time telling me to buy GMS, MSD, Accel or any other COPs)

No one here would ever recommend GMS. and most here still use the stock COPS as the aftermarket ones never work right for the masses.

I'm all in favor of getting a new block with a forged internal setup but does this now mean I need new heads too?

Lay it on me... I can take it. Be honest.

Do a compression and a leakdown test if your worried. Without actual data, being the internet mechanic is hard....

 

[kentompkins]

Just ordered a compression test kit with a 16mm adapter. I'll do that next week when I get back from a business trip.

 

[94tbird]

good man. get us some data to work with

 

[bigray327]

What gap do you have on your plugs?

 

[JeremyH]

Not sure the problem bit sounds like oil is making it into the chamber past the piston/rings. Junk in there can score the cyl walls, damage the rings, get stuck in a valve all kinds of bad stuff. Good luck!

 

[ZmanM3]

Not sure the problem bit sounds like oil is making it into the chamber past the piston/rings. Junk in there can score the cyl walls, damage the rings, get stuck in a valve all kinds of bad stuff. Good luck!

If that is the case, I wonder if something like slick 50 could be used to fill in the score with out having to tear down the SB and bore it out.

 

[kentompkins]

What gap do you have on your plugs?

They are all gapped at .031


On my way to Autozone, Oreilley's and AdvanceAuto to see if any of them loan out borescopes.

 

[chad05gt]

I had that issue, or at least similar... months later found that when I had brought the car in for synchro's to the dealer, they had pinched my driver side 02's. They were nice enough to unpinch, but not check the wires.

When following the wires, seemed ok.

New wires, no problem.

Just something extra to check.

Is your car new? EVER had anyone else drop/swap trans???

 

[kenneth]

Also are you running a catch can?
could be blowby if not.

 

[kentompkins]

No catch can yet. Had a Moroso in the NA setup but waiting for the new one from BMC performance. Could blow by affect one cylinder like that?

On the O2 front... it was only a few weeks ago (meaning one or two drive ago) that Meineke cut into my manifold and welded a bung for my wideband A/F sensor. Maybe they screwed up the O2 sensor? Wouldn't that throw a code though?

 

[MikeVistaBlue06]

No catch can yet. Had a Moroso in the NA setup but waiting for the new one from BMC performance. Could blow by affect one cylinder like that?

On the O2 front... it was only a few weeks ago (meaning one or two drive ago) that Meineke cut into my manifold and welded a bung for my wideband A/F sensor. Maybe they screwed up the O2 sensor? Wouldn't that throw a code though?

I'd check that cylinder for spark. Take the COP off the plug, put a plug into the COP (an extra plug if you have one laying around), put a ground wire on it, and then start the car and see if you get a spark.

If no spark, check the wires coming to that COP. They may have been damaged.

Now for the worst thing electrical, if they used an electric welder, and did not disconnect the negative battery cable while doing it, they may have thrown a spike through the electrical system that fried something in your ECU.

Good luck.

HTH

Mike

 

[kentompkins]

There is a God... I got to thinking... was this the cylinder that had the broken plug. Guess what? It wasn't. I found my original post from back in February 2009:

http://mustangforums.com/forum/4-6l...n/406051-scary-plug-change-7.html#post5916254

So.... now this goes back to being a friggin mystery BUT THANK GOD - I am not likely working with a ruined cylinder wall or valves or piston.

Here's what I've tried (Compression tester is still on its way from Summit Racing):

1) Interspersed two new COPs around every position. Nothing resulted in the infrequenty yet recurring puuff, pufff, pufff going away.

2) I tried individually unplugging all the COPs one by one while idling. Each one seemed to have the same effect on the engine.

3) Measured the Ohms on all the COPs. All were with a tight tolerance somewhere in the high 5.X range.

4) Put a little dielectric grease on all the COP connections.

After those four things I am pretty close to saying it's not the COPs.

I also:

5) Pulled every plug. Regapped them to 0.300. Cleaned the all off and reinserted.

After running the engine and pulling all the plugs again - every plug was perfectly worn except that same cylinder (2nd from the front on passenger side). HOWEVER, it seemed to have less liquid on it. The liquid is definitely not gas and not antifreeze. It has to be oil.

6) I swapped the injectors (39.5 lbs) between the front cylinder and the second cylinder on the passenger side thinking maybe I had a spray problem. No dice. It had no effect.

So, after all this tinkering, I might be fooling myself but I think the miss seems less frequent. It's probably my mind failing me after breathing in so many fumes while kneeling behind the exhaust to listen. I have noticed that it is much more noticeable when I apply just a tiny bit of gas. So, between idle around 800 - 850 and under 1,000 rpms - this seems to be when it's most noticeable.

Next week holds the following to do's when I get back on Wednesday:

1) Bought two new upstream O2 sensors (Bosch OEM replacements). I will replace the originals and run it for a while to see if that has any effect.

2) Compression test when I get the tool in from Summit.

3) Look around for someone who can loan me a leak-down tester kit.

4) Oil change - just for the hell of it.

5) Maybe put a fuel pressure gauge on the rail... although I can't believe that my GT500 fuel pump setup isn't delivering enough fuel. I mention this one because, in the last few months, I DID replace the original fuel filter with a new Puralator OEM replacement. Maybe it's defective???

6) Recalibrate the throttle position sensor.

I know that numbers help so I should say that I have the SCT Livewire tuner. I noticed that both Short Term Fuel Trims seem to bounce around between 1.02ish and 1.10ish. Bank 1 seems to usually be lower than bank 2. Is that trying to tell me something?

Maybe I'm making too much of this? It almost makes it sound like I have aftermarket cams.... and she did dyno at 453 rwhp last week....

Should I just accept this as part of her personality?

 

[MikeVistaBlue06]

There is a God... I got to thinking... was this the cylinder that had the broken plug. Guess what? It wasn't. I found my original post from back in February 2009:

http://mustangforums.com/forum/4-6l...n/406051-scary-plug-change-7.html#post5916254

So.... now this goes back to being a friggin mystery BUT THANK GOD - I am not likely working with a ruined cylinder wall or valves or piston.

Here's what I've tried (Compression tester is still on its way from Summit Racing):

1) Interspersed two new COPs around every position. Nothing resulted in the infrequenty yet recurring puuff, pufff, pufff going away.

2) I tried individually unplugging all the COPs one by one while idling. Each one seemed to have the same effect on the engine.

3) Measured the Ohms on all the COPs. All were with a tight tolerance somewhere in the high 5.X range.

4) Put a little dielectric grease on all the COP connections.

After those four things I am pretty close to saying it's not the COPs.

I also:

5) Pulled every plug. Regapped them to 0.300. Cleaned the all off and reinserted.

After running the engine and pulling all the plugs again - every plug was perfectly worn except that same cylinder (2nd from the front on passenger side). HOWEVER, it seemed to have less liquid on it. The liquid is definitely not gas and not antifreeze. It has to be oil.

6) I swapped the injectors (39.5 lbs) between the front cylinder and the second cylinder on the passenger side thinking maybe I had a spray problem. No dice. It had no effect.

So, after all this tinkering, I might be fooling myself but I think the miss seems less frequent. It's probably my mind failing me after breathing in so many fumes while kneeling behind the exhaust to listen. I have noticed that it is much more noticeable when I apply just a tiny bit of gas. So, between idle around 800 - 850 and under 1,000 rpms - this seems to be when it's most noticeable.

Next week holds the following to do's when I get back on Wednesday:

1) Bought two new upstream O2 sensors (Bosch OEM replacements). I will replace the originals and run it for a while to see if that has any effect.

2) Compression test when I get the tool in from Summit.

3) Look around for someone who can loan me a leak-down tester kit.

4) Oil change - just for the hell of it.

5) Maybe put a fuel pressure gauge on the rail... although I can't believe that my GT500 fuel pump setup isn't delivering enough fuel. I mention this one because, in the last few months, I DID replace the original fuel filter with a new Puralator OEM replacement. Maybe it's defective???

6) Recalibrate the throttle position sensor.

I know that numbers help so I should say that I have the SCT Livewire tuner. I noticed that both Short Term Fuel Trims seem to bounce around between 1.02ish and 1.10ish. Bank 1 seems to usually be lower than bank 2. Is that trying to tell me something?

Maybe I'm making too much of this? It almost makes it sound like I have aftermarket cams.... and she did dyno at 453 rwhp last week....

Should I just accept this as part of her personality?

Before you go and do all of this stuff, have you verified that you are getting a spark from that specific cylinder. Even changing the COPs out won't do a thing if you don't have electricity coming to that specific COP. If there is nothing coming to the primary side, you won't get anything on the secondary side.

Switching plugs around and having the "new" on get wet tells me you are misfiring on that cylinder. Change the COP and no better result. So you either have no electricity to the COP or no compression (bent valve, hole in piston, etc.) Personally, I'd check for the spark first before delving into anything else.

HTH

Mike

 

[kentompkins]

When I unplug the COP on that cylinder the engine seems to see the same loss of power/RPMs as when I unplug any other COP on the other cylinders? Does that suffice to test for spark?

If not, I was considering taking the COP and plug out of that cylinder hole and putting an old plug in their place. Then wrap a wire around the base of the plug that is still in the COP and grounding it - assuming that if I see a spark on that COP/plug then I am not having a spark problem.

Would that McGyver method be sufficient to test for spark? Visually seeing it...

 

[kentompkins]

Ok. So the Compression test told me nothing but it at least made me feel really good about the likely condition of the cylinders, rings, piston, etc...

Cylinder

1 = 190
2 = 190
3 = 188
4 = 190
5 = 191
6 = 190
7 = 190
8 = 189

I also verified that all of the spark plugs are sparking.... sooooo....

Next stops include:

2 new o2 sensors for the front. Already bought so I might as well try it.

1 new Motorcraft Fuel Filter to replace the Purolator filter. Already bought so I might as well try it.

After that I plan to:

Test fuel pressure at the rail.


If that shows me nothing the I plan to forget about it because I am not buying new cats to see if that's it.

 

[LuckyH]

Just a shot in the dark, could be the injector hanging open/leaking. That could explain fluid residue on the plugs. Try to run some of the lucas fuel treatment, i use it every oil change. I notice a drastic change in injector noise every time i use it, engine sounds almost silent afterwards. I usually get it at walmart for like $5. I figure for that price it's worth a shot.

 

[MikeVistaBlue06]

When I unplug the COP on that cylinder the engine seems to see the same loss of power/RPMs as when I unplug any other COP on the other cylinders? Does that suffice to test for spark?

If not, I was considering taking the COP and plug out of that cylinder hole and putting an old plug in their place. Then wrap a wire around the base of the plug that is still in the COP and grounding it - assuming that if I see a spark on that COP/plug then I am not having a spark problem.

Would that McGyver method be sufficient to test for spark? Visually seeing it...

Yes. Verify that you get a spark from the cylinder you suspect is having the trouble. If you get a spark then it isn't your COP or the wiring to it, it is something else.

As the last person replied, I'd check that fuel injector next. Look at the wiring and make sure it isn't damaged going to that specific injector.

HTH

Mike

 

[Bizzyb0nes]

Lucky for you...Advance Auto has those buy 1 get 1 free

 

[kentompkins]

The injectors are new (like less than 250 miles) since they came with the ProCharger.

I can definitely rule out the fuel filter. Changed the Purolator for the Motorcraft and it made no difference - although for a minute I thought it was better until it warmed up.

Maybe that's a sign? I actually took my wife out in the garage because I thought the miss had gone away. We stood there for a minute and it was back.

For a second, the RPMs even dropped a bit.

Could this be something as simple as bad gas? Maybe I stirred up some crap in the tank when I put in the GT500 pumps...

At some point, and soon, I will just cam it so I can't detect it.