Cylinder #3 down - Heads coming off!

The suspect cylinder has good compression????? If so that would suggest mechanically things are okay, a leakdown would tell more perhaps. Can you swap coil pack #3 to another cylinder and see if the misfire follows? Any smoke out the tail pipes at cold start up?

 

+1

I wouldn't jump into a teardown until you check a few more things first.

 

Start exchanging the wires. See if you move the wires (not just the coil) if the problem moves with it. If not that probably the computer.

Art

 

Leakdown time.

 

Have you hooked it up to a SDII? The miss may be ECU related.

 

Was the plug you pulled glossy/smooth on the porcelin section? (Asking that which would indicate
fouling...........and contrary to popular belief its hosed and should be replaced). And when you say
that CP#3 is taken off and not change........... is it possible to swap and see if the issue moves
to another cyinder?


BobR

 

Sounds like ECU or coil wiring related. This hasn't happened to my 360, but other vehicles. When replacing and exchanging all those parts doesn't work, it usually ends up being the ECU. I've even tried running new wires from the ECU to the coil before changing the ECU.

 

I agree, Had a missfire in my 355, replaced the ecu, replaced the plugs, did compression test, dealer wanted to pull apart said it was most likely valve guide problem. Took to another dealer/mechanic and it was as simple as some build up in the spark plug chanel and once cleaned out with steel wool and a new spark plug and rubber seal were added it was never better.
If the compression is ok seems to me it will only be electical.

 

Carbon on a spark plug usually is an indication that the plug/cylinder isn't firing completely. Think of when you have a fire in your fire place. When the fire is roaring hot, everything burns up pretty clean. But if you stick some wood on there after the fire has largely gone out, that wood will smoke and smolder all night and give off a lot of black (carbon) smoke. Sort of the same idea with spark plugs when they aren't igniting the air/fuel mixture effectively. If the cylinder is getting a very weak spark or isn't firing properly, the spark plug can end up being coated in carbon as a result. This will lead to the plug shorting out internally. Have you replaced the plug during these tests? I would not just assume the plug is okay.

From how you describe things, it sounds electrical to me. I remember a similar situation years ago on my little sister's car. I was sleeping in and the phone rang. It was my sister, Carol, in a panic at the Toyota Dealer... "Big brother, I'm at the Toyota dealer and they are telling me I need a valve job and a new cylinder head and it's going to cost $3500, but the car is only worth $800 - I need your advice". WTF? I asked her "Wasn't your car running fine just last week?". My sister, "Yeah, it was". Me, "Tell those clowns not to touch your car and get the F out of there. Go home right now and call me when you get there". Her, "But, but, but, they said it needs a valve job and I shouldn't even risk driving it home!". Me, "Oh my god, who are you going to trust, some flunky at Toyota or your brother who has been working on cars and motors his whole life? Go home immediately and call me when you get there and if you aren't out of that dealership in 10 minutes then we are no longer related".. click

So I get up and take a shower, get dressed and my sister calls. "Are you at home?" Her, "yes". Me, "With your car?". Her, "yes". Me, "Okay, we are still related". I told her I would be over in a bit. So I drive over there and she tells me the whole story. How Toyota checked the car and told her they are 99% sure it needed a valve job and new cylinder head, blah, blah, blah.

I told her there was no way the car would run last week fine and now suddenly need a $3500 valve job. I fired the car up in her drive way and it ran horrible (4 cylinder Toyota with a zillion miles on it). While it was idling, I reached down and pulled off each plug wire one by one. The RPM's fell on all cylinders when I did this, except #2, which had no change at all.

Okay, so cylinder #2 wasn't firing. How the people at Toyota couldn't diagnose this in like 10 seconds is beyond me. Anyway, so I took the plug wire and stuck a nail in it, then held the nail about 1/8 inch away from the spark plug and had her fire up the car. Nada. So I took the plug wire off and did the same basic thing with the coil. Ah, spark at the coil. Okay, so I go in the house and get a safety pin and stick it into the plug wire about 3 inches from the plug end - no spark. 6 inches up, no spark. 10 inches up, spark. Hmm.. broken plug wire.

So I went in the house and told my sister we could fix the car for $5, maybe $10. She said "Are you positive it doesn't need a valve job?". I was like "Carol, I have two questions for you: 1) do you want to be related to me? 2) do you even know what a valve job is?" Let's go to the store. We made a quick trip to the local auto parts store and bought some carb cleaner (just for good measure), some new plugs, a new cap, rotor and wires of course. I did a quick tune up for her and her car ran like a top. All in I think we spent $25 or so. It ran great until my brother-in-law got a hold of it. That's another story in itself!

Anyway, back to your car. If the compression is within about 5% plus/minus across the cylinders, then that pretty much rules out any major issues in the motor. Sure, you can do a leak down test, but I doubt very much if that will show anything different. The motor only has 35K miles on it. I know that panics the average Ferrari owner who doesn't know "for sure" where the cams are located on the motor, but in the big scheme of things, I'll bet the average 360 motor will go 100K miles without so much as blinking.

Have you changed the spark plug itself? It could have an internal short which is resulting in a partial ground when installed in the block. I would put a new plug in if you haven't already. Also, I would be less concerned with the coil itself as the wire that runs from the ignition control unit to the coil pack. There could be a short in that wire or a crack or something - hard to say. Additionally, the ignition control unit itself could have a problem. If you can get access to it (I don't know off hand where it is on the car) you might try cleaning the connectors where the harness attaches to the ignition control unit. Has anyone sprayed down the motor compartment with water or steam or anything? Or have you been driving through huge puddles or anything like that? Could be some moister has gotten into a connector some place.

Just for the fun of it, have you tried clearing the ECU's by cutting the power? You'd be surprised how many times I've seen that have a positive effect on cars.

A bit of advice... before you start tearing the motor apart and/or start replacing everything on the car, try very hard to actually track down the source of the problem if you can. In my experience, a lot of times the ultimate cause of the problem and solution to the problem is a lot different than what you think it is when you start looking.

It will be interesting to hear what the outcome of this is, that's for sure

good luck!

Ray

 

It only takes 3 things to make a cylinder fire. Compression, ignition and fuel.

Figure out which one is missing before you tear the engine apart.

 

Well said. This is why Brian is one of the few people in the world that I would trust working on my Ferrari.

Ray

 

You need to do a leakdown check. You need to hook the car up to SD2 to check the coil pack is working. A fuel pressure test would be useful. Don't just start removing the head. It's a lot of work and you might later find there's a problem with the coil wiring/e.c.u or many other things......

 

It probably has something to do with overheating the chamber while you ran it with out the intake on.. remember the cats glowing??? THat glowing red heat was in the cylinder also.

Change the injector. Id say you melted the tip of the injector or just damaged it from the high temp heat from the very very lean condition.

You have not mentioned changeing the injectors. Swap the injector from a good cylinder. Also, maybe rifledriver can help but the computer may have cut the injector of due to the cats getting hot. What does the dash say? any check engine lights? Does it say slow down by any chance?


BTW, Considering the luck you are having I would not take the head off of this car yourself. Take it somewhere plz.

 

compression test means very little without leakdown.
you can prevent combustion even with spark and fuel if you got no air. you can have no or reduced airflow if your glowing cat is so fried it prevents combustion by not allowing air flow changing the A/F mixture in something not burnable.

 

a leak down test is usually used to isolate worn valve guides or perhaps a worn seat or burnt valve. It can also disclose broken or very badly worn rings and/or broken ring lands. Think of a compression test like seeing if a balloon will fill up with water. A leak down test is checking to see if the balloon has any pin hole leaks once it's full. The compression check will quickly tell you if you have a huge rip in the balloon, but it won't tell you if you have a very tiny pin hole leak.

Ray

 

compression tells you very little. You can have compression and have a very crappy running car. Compression and leakdown go together. doing one without the other is a waste of time. The proper diagnosistc steps have not been done anyway

 

A compression test tells you a lot if you spin a bearing, etc. They both have their place, but neither is better or worse than the other; they simply are used to diagnose different issues.

Ray