how to "switch off" a single cylinder?

How can I “switch off” a single cylinder from Bank1? To switch off from Bank2 I can simply disconnect the injector, but the Bank1 is not accessible this way. I don’t want to take off spark cable as this way you can loose your ignition coil. Is there any other way to do it?
edit on 27 June
When I put my hand against exhaust pipe I feel "puffing". This way I wanted to check which cylinder is causing it but I've been told that above won't help me. Any suggestions what could cause such puffing?

Hello Gobowiec,

Please elaborate. (Model year/engine size/#miles, etc)

Turning off a cylinder by pulling the injector cord? How about instead using a long screwdriver with the handle stuck in your ear trick? (Mash the tip of the screwdriver onto the injector and listen for the "click" each time the injector fires)

We can help. And please tell us how you ultimately fix your problem.

Karl

About the car – in my signature: 3.0liter 1997 230k km (150k miles) Europe version, so theres only two O2 sensor, no misfire checking etc. The problem isn't with finding which injector doesn't work but to check which cylinder working might cause puffing. For me it looks like a valve isn't closed so after ignition all goes out the valve. (remember - I'm an ignorant). I was wondering if I disconnect injector would I stop the puffing and find out which cylinder is causing this. But I've been told that this method won't help.
At a garage one told me that this puffing and weak engine might be caused by wrong assemble of camshaft after replacing valves and gasket – done by previous owner. The engine compression is 9,5 so its excellent and I hope that at least this was done correctly.

Normally if a cylinder is running rich the plug for this cylinder will be sooted up.
Inspect all plugs and you should be able to identify the cylinder.

Normally if a cylinder is running rich the plug for this cylinder will be sooted up.
Inspect all plugs and you should be able to identify the cylinder.
All sparks look very nice.
This is what I found on Technical Service Publications - Service Manual. I put in bold what I suspect:
o Insufficient Power

Possible Source(s):
§ Damaged hydraulic valve tappet.

Action(s) to take:
§ REPLACE hydraulic valve tappet.

Possible Source(s):
§ Damaged hydraulic valve tappet guide.

Action(s) to take:
§ REPLACE hydraulic tappet guide.

Possible Source(s):
§ Compression leakage at valve seat.

Action(s) to take:
§ SERVICE or REPLACE valve, valve seat and/or cylinder head.

Possible Source(s):
§ Seized valve stem.

Action(s) to take:
§ REPLACE valve stem.

Possible Source(s):
§ Weak or broken valve spring.

Action(s) to take:
§ REPLACE valve spring.

Possible Source(s):
§ Damaged cylinder head gasket.

Action(s) to take:
§ REPLACE cylinder head gasket.

Possible Source(s):
§ Cracked or distorted cylinder head.

Action(s) to take:
§ REPLACE cylinder head.

Possible Source(s):
§ Damaged, worn or sticking piston ring(s).

Action(s) to take:
§ SERVICE or REPLACE piston ring(s).

Possible Source(s):
§ Worn or damaged piston.

Action(s) to take:
§ REPLACE piston.

Possible Source(s):
§ Damaged fuel system.

Action(s) to take:
§ REFER to the «Powertrain Control/Emissions Diagnosis Manual».

Possible Source(s):
§ Damaged ignition system.

Action(s) to take:
§ REFER to the «Powertrain Control/Emissions Diagnosis Manual».

Possible Source(s):
§ Slipping transaxle.

Action(s) to take:
§ REFER to «Section 07-01».

Possible Source(s):
§ Dragging brakes.

Action(s) to take:
§ REFER to «Section 06-00».

Possible Source(s):
§ Incorrect tire size.

Action(s) to take:
§ REFER to «Section 04-04».

Possible Source(s):
§ Restricted exhaust system.

Action(s) to take:
§ REFER to «Section 09-00».

By removing the valve cover and using a hose from a compression gage put air pressure in the cylinder. A leaking valve you can hear. Move the valve spring by hand you will feel a worn valve guide. By watching watching it run a bad lifter or cracked spring will be noticeable.
You can change a spring or install a new valve seal by holding the valves closed with air pressure. If you need to do this ask?

Specs for the car in you signature. I'll pay attention from now on, and do the same.
Puffing.
My 3.8 ran compatatively ragged, until I had the heads removed, milled and rebuilt. This was due to a head gasket coolant leak that I could not fix myself.
I removed the heads myself, had a pro do the valve job and milling, and put the heads back on myself. The engine at that time had about 150K mi. on it.

The car behaved world's better after that. Clean bright always up to the mark oil, great gas mileage, and no coolant leaks.

The pro's said that in my car, the heads were warped do to a major coolant failure. (True) But the compression/mileage was off due to valve guide failure.

IMO, Pull the heads and rebuild them, or have the best guy in town do it. It's pretty cheap here to do it ($320 for blasting, milling, a valve job and . . . new gaskets & head bolts) Head shops are pretty rare, usually only one or two in any sizeable town, but, any of the garages in town will use the same outfit. Ask your favorite mechanic who he prefers (to rebuild heads) and why he does.

Let us know how this all turns out .

Karl

Have you had a mechanic corroborated your suspected condition based on the "puffing" is not normal? Or is this something new?

Does it run rough at idle or trying to accelerate? Is there a possibility that you have a faulty injector or other lean creating condition? It's not clear to me why wouldn't a bad injector cause puffing. Puffing can be created by an absence of exhaust. Isn't that your logic to disconnecting the injector?

Have the egr and its passages, etc been cleaned recently? The valve stuck?

I made a short mpeg film of the engine and exhaust pipe. http://rapidshare.com/files/125852462/MOV07037.MPG.html
http://rapidshare.com/files/125852463/MOV07038.MPG.html
You can see the engine shaking. The mechanic who replaced two lifters says that it looks like they are the cause, but he doesn't want to replace all of them and then find out that this wasn't the problem. Never worked on V6 (or doesn't want to), so he send me to specialist. I visited three mechanics specializing in american cars. They told me is:
1.lifters are stuck because of LiquidMoly added by previous owner, replace all of them...
2.camshaft wrongly assembled. Much cheaper job, probably no parts will be needed.
3.this engine is not worth doing the job, drive as long as you can and then to the junk yard...
I just want to know which job to chose (except third one :) ) The heads were done at about 130K mi. I believe the valves, gasket etc was replaced and done correctly. Compression is between 9 to 10kg/cm2. No oil in coolant, no coolant in oil. No disappearing coolant or loosing/burning oil. Oil clear even when time to change and done by me 3 times before 10Kmi limit. Between changes I add maybe 0,5liter of oil (thats ½ quarter). Exhaust is clear, catalyst replaced at 145K mi. I even told my local mechanic to do a engine flush with kerosene hopping that this will clean oil valleys and lifters. Kerosene was dark but there wasn't much washed out.
Trying to put off injector I was expecting to get rid off puffing and then I'll know which cylinder/valves/lifters... cause problems. Why I don't expect injectors? My car runs also on LPG (liquid petrol gas) and then injectors don't work. The engine works poorly on gasoline and LPG.

I would suggest doing a cool engine compression test. Obtain an "Actron" (http://www.actron.com/product_detail.php?pid=16171) compression tester. In North America, these cost about $30 at such places as AutoZone.

1. Remove the windschield cowling so that bank #1 is more accessible.
2. Remove all spark plugs.
3. Loosen and separate the throttle body from the upper intake manifold ...or ...open the throttle and wedge throttle wide-open ...or... have assistant keep throttle open using floor pedal.
4. Pull fuse or relay to shut down fuel pump.
5. Install compression tester one-at-a-time in each spark plug hole. Crank engine several revolutions. Record gauge readings.

This should quickly show which cylinder is suspect. I would guess that you have an intake valve not correctly seated. I've just spent some time re-doing a cyl head on D's Mercury Tracer. I had sent the head originally to a trustworthy shop ... but they just made a mistake on one cylinder. I disassembled the head and returned it to the shop. The error was obvious. They reworked the cylinder head at no charge. But, of course, it still cost me time and money ... but I'm happy to get the engine running smoothly.

If it would be intake valve, shouldn't I have puffing backward - into the intake manifold?
If I already had once done the head (gasket, milling...) can I do it again? Wondering how many times such a job could be done. There's no blowing out the oil bagnet or oil cap - could this be a "measure of quality" together with the compression on all cylinders between 9 and 10kg/cm2? Or should I check compression again - somewhere else than last time? I'm thinking about buying a secondhand engine (car taken for parts after collision) with 60k mi, but again no warranty and I have to believe that it's OK and with that milleage.

A used engine with 60,000 miles would be a good deal if the price is right.
Otherwise put compressed air in cylinders you suspect it shows a lot more than a compression test.
I was working on a 350 chevy engine that was rebuilt. A valve job was done on the engine. No.1 cylinder wouldn't work. I pulled the plug wire no change.
I put air in the cylinder it blew so hard back through the valve the compressor wouldn't shut off. I took the head back to the machine shop. He turned it over and put kerosene on the valve it leaked out. He said it would be ready in a day.

It's true that a leaking inlet valve leaks "backwards" up toward the intake manifold ... but you would never sense it coming out of the inlet. It usually amounts to a slow, over time, build-up of carbon on the back side of the valve and the valve stem as well as the inside of the inlet vent in the cylinder head. The build-up continues until all air flow going into that particular cyl is all but snuffed out.

Of course it could just as well be an exhaust valve ... it's just my experience that shops usually do the worst jobs on inlets. (I now let the shop do the machine work but return to me the head, with parts marked, but not yet assembled. That way I can give it a good inspection ... even do some hand-lapping if I wish before assembly.)

Cyl heads can be rebuilt several times. The valves, valve seats, valve guides are all replaceable. So if the shop isn't overly aggressive on the surfacing procedure .. it can be redone many, many times.

I have used both the air compressor and compression tester to test engine conditions. I find the compression tester handier and quicker.... but, granted, it won't detect all the faults that a compressor will. Even if you don't consider yourself a mechanic (?), I would suggest buying a compression tester ... it is not that expensive or that difficult to use. That way you can reach your own self-informed conclusions.