HELP! Please Cylinder 2 and 5 not firing
 

I wrote a couple of post about the rough idle on my 88 911 cab. I've performed some of the suggestions from this board to see if I could fix the problem.

Change spark plugs, Cap and Rotor
Change the Oxygen Sensor
and a recent oil change (not a suggestion but was needed)

The last thing that was suggested and I finally had time today to try was checking the spark plug cables. I turned on the car pulled off the cables one at a time to see if there was a noticible engine change. On plug 3, 1, 4, and 6 you could hear kind of a drain of power (as I expected). However, 2 and 5 had no noticible change in the engine sound (no drain of power). My Dad said sometimes you can get bad spark plugs from the stores, is this true. I'm using the bosch cooper plugs. Also, is this just an indication of bad wires? or is there something more serious? If you put your hand near the tail pipe the exhaust feels like puffs and not a consistent flow.

Am I looking at big big dollars? (which I don't have right now and will not go over well with my wife).

Any Help as always is very appreciated...Ron Fitz

Any chance your 2&5 plug wires are switched?

Yep, check the firing order, then try swapping wires to check that it isn't a bad wire. I've had Bosch plugs fail after a couple of starts..only to cause me a week or two of trouble shooting. SoO anythign is possible.

Pull the plugs on 2 and 5. Are you getting fuel in there? Are your injectors healthy and CLEAN?

Yeah..I don't havea 3.2, but combustion is combustion. Air, Fuel and spark..got them? Compression? But that would be a check after you check the easier stuff.

Thanks guys for the reply,
Bob, do you or does any one have a picture of the distributer cap with the order of the wires. I believe I've got the wires in the right order, but when I changed the cap I still had a doubt in my mind if I put them back correctly.

I'm going to the parts store to get a couple more plugs to try the easy fix first.

Thanks Ron Fitz

on 3.2s. the intake gaskets can blow out, usually below the phenolic spacer, against the head. a large enough intake air leak can cause a low rpm dead cylinder.

If the intake gaskets are blown am I look at major expense? I'm not a good enough wrench to fix this and even if I am I would be too afraid.

I removed the spark plug from the number 2 plug and it look almost normal. It was black (no oil or gas on the plug) around the edge and fine on the top. Before I changed my O2 sensor this plug and the others on the drivers side were white. I started the car and it seems to be running even rougher....Argh!

Wow thanks John walker for responding. It almost scares me have the big guns replied to my post....Ron Fitz.

did you swap 2 and 5 wires on the distributor cap yet, just for the hell of it? was the engine always running rough, or just after your tuneup work?

try holding the rpms up to 2500 or so, and then taking the plug connector on and off the plug a few times. do you notice any power drop off then?

I haven't tried the switching two and five yet, but I will. I've got to take my son to his soccer game right now, so in an hour I'll try new plugs for 2 and 5, switch the plugs at the cap for two and five and I'll ask my Dad to keep the rpms up near 2500 to see if there is a change.

Thank you so much for all your help John Walker. I hope you got some sun today since Seattle has been socked in with rain the last few days/weeks.

Ron Fitz

you can hold up the rpms yourself, back in the engine compartment, by pulling on the throttle lever.

You need to determine if you have spark or fuel problems. Try pulling the plug wire from the suspect cylinder. Put a spare plug in the wire. Ground the plug and have a friend crank the engine. If the plug sparks you probally have a fuel problem. Bad injector or computer. If plug does not spark you need to chase the distributor route.

Ok I changed the spark plugs on 2 and 5 and kept the rpms at 2000 to 2500 and pulled the plugs one by one again. 1, 3, 4, 5, and 6 are all responding according. So let me make sure my college degree taught me well, 1,...3, 4, 5, and 6. Yep! number 2 still doesn't seem to have any noticible change. I fixed 5 but 2 is still not responding.

Jeff T. How do I ground the Spark plug as you suggested to test for spark? I've now got an extra plug but I don't want to get fried or do something bad to my engine.

One last thing, if any of you have check my other post I mentioned how I haven't been getting good gas mileage, could what I mentioned in this threat plus my other indicate serious problems. I've been reading about burnt valves, bad injectors, and vacuum leaks just because I'm on the paranoid side. I'm really hoping this is something minor....pleaseeeee.

Thanks again Ron Fitz

Ron, Pull the suspect wire. Put the extra plug into the suspect wire. Put on a very thick glove. Very carefully hold the plug exposed metal to a solid metal engine ground. Do the test while looking for spark. (If you keep the plug grounded you have little chance for shock) If you do get shocked it cannot hurt you. (except for knee jerk) It is very high voltage but very low current.

Thanks Jeff for the help. I'll try your suggestion this afternoon..Ron