tks12

otc shows p1238 again, guess its time to try and diagnose that, funny but that never showed up before, perhaps that was the beginning of that failure... who knows, might have to just get it to the shop

tks12

no CEL, still no CEL, but p1238 came back, im going to pull the heat shields and double check all the connnections, but I know they all clicked when pressed on

wish I knew for sure which cyl was missing, I would head right that way. not sure if it is bad to run it with coil disconnected to see which cyl doesn't change the rpm,,,,

Adker

P1238 Fuel Injector, Cylinder 2 - Open Circuit

tks12

well decided to do the hand test real quick, started her up

let her run a sec, pipes got warm to touch, except for CYL 2 and CYL 6

shut her off

pulled cly 2 coil and plug, plug was wet, put old coil back in

fired her up, ran better still a miss

pulled cyl 6 coil, put new coiil back on

runs smooth all pipes warmed instantly......

now let her warm up
change oil and filter (shoot never thought to check if my tool fits this oil filter housing (wonder if same as bmw or mercedes) will find out in a few

then I will replace cyl 2 coil with the new one and see if it has same issue

and I did DOUBLE check the wires to the coils before I did this

if that was cause, these thigns are VERY touchy or I have bad connector

that is if THIS solves issue

but I will say, there is no code now at all,

all in all, this does make me want to go bback into the profession and learn these cars far better.... (watch out Jake, your really close to me, if you start seeing me stop in say hello, close your gates!!! I might just want a job! <big grin>

tks12

I should had ALLCAPS the "IF"

Had my wife drive it down the street and back while I cleaned up, then we took her out.

it did not pull it off, about 25 miles into the second test drive it acted up, CEL came on flashing for a moment, then stayed on, shut her off, started her back up, ran fine for 5 miles or so, then cel flashed and cel stayed on, set p0306 this time. Over the last 12 or so miles back home from that point, it missed a couple quick times, p0306 misfire detected cyl 6 is the only one now, but still it acted just like it was doing before replacing the plugs, coils, MAF, cleaned the throttle plate (really didn't need it to much at all) and changing the oil.

At least it didn't set 5 of the 6 cyl misfires this time <G> Arghhhhhh

My Bride is bummed, she was pretty happy to drive it down the road again.....


Tom

Flat6 Innovations

Remember what I told you about those camshaft deviations a few months back?? You could be seeing the effects of that with these misfires.

tks12

73k miles on it is all now. and yes, I remember, and I could understand variations in performance and setting a code,and misfires even,

but actually loosing a cyl just like you unplugged the coil?

it doesn't act like a cam timing / ignition timing to piston variation where there is some loss of power, like lost compression or intake valve not opening allowing air in properly
or ignition timing being off

it looses a cyl completely and it does not come back unless you shut the car down and restart it, is that the nature of this?

then runs smooth, and has nice smooth power, (by feel mind you) it almost "seems" like a intermittent electrical issue of some sort, complete ignition loss, or fuel loss?

if that is the problem causing this issue, it needs fixed for sure, but I hate to drop that (which is a bunch more) in it to find out something else is still wrong. I just dropped about 600 and it did not solve the issue as we thought it wouldn't, unless it was the MAF.
grant it , it needed plugs regardless so im not complaining, just saying.

ya know I hated buying coils not knowing for sure that was the problem, and the only reason i did was because if I did not pick them up wed, I know I could not have got them till next week when I know I cant work on the car again, I figured my luck, if i didn't get them, i would have a bad coil. honestly though, I really did not think the coils would solve the issue, or the plugs for that matter, chances of so many intermittently not firing was little to none , I just did not know when they had been replaced before.

I was hoping it was the MAF though

Which btw your the only one that I feel would not have just replaced the coils because of the age and miles, at least of the few people I spoke too, which one didn't even get back to me with a estimate (a recommended shop too) the first thing they said was coils....

right now as it stand this car will probably sit another month, and we need the car. Right now i'm at a loss with it. not sure what to try next, tear into it and start replacing stuff that isnt out of spec to "see" if it fixes it?

i sure wouldnt mind getting on your scanner again and see what if anything is worse, I wish I had wrote down those specs that day. car has been sitting for what seems to be months now

thanks again for your help Jake

Flat6 Innovations

With these engines even a sticking lifter can give a solid, dead miss. A flashing CEL is a serious concern, a misfire that heavy can even kill a catalytic converter.

I have even had a bad knock sensor cause this... Too bad it wasn't caught before the engine split a piston in half and was only caught after it was repaired and reassembled only to have the same misfire.

Those cam deviations were hefty, if they have gotten worse it's possible that they can cause this misfire easily and do so without throwing a code for out of range cam deviations.

And of course the #1 cause for misfires today is the bad dual mass flywheel that allows one mass to dance freely and guess what's attached to that mass..... The timing reluctor wheel..

KrazyK

To the OP:
I really hate to say this but never ever depend on a 13 year old 73,000 mile 996 as a DD. Its just too frustrating to trouble shoot the multi problem 996 while in a hurry about what to drive. At 73,000 miles with all the misfire problems and low compression, I would just say screw it and drop the engine. Just replace everything from the IMSB to the water pump and be done with it. Sorry but its just more 996 drama until you do.

I agree with the others that the K&N should go. There are many OEM airboxes out there for sale.

tks12

[QUOTE=Flat6 Innovations;10941695] This is what I don't want to happen, so we are not driving it. car really hadn't been drove much since then, but who knows really,

how busy are you next week? perhaps I can I get it back over there and get it on your scanner again? thing is, only way I really feel ok with moving it, is towed I really do not want to drive it that far after yesterday, can I bring it in my trailer unload the car someplace there while you check it out ill get it back loaded up and out of your way as soon as your done looking at it? my trailer is pretty big 8.5 x 20 V, I know the car fits in it fine, just never strapped her down in there,

didn't know that either....

thanks Jake

extanker

dude take it to a mechanic...sooner or later your poking and hoping with parts is gonna put the car so far into the forest you will sell it not running.you want cheap and easy ? buy a chevy.some sensors require a lab scope AND the experience of knowing what the data means.

tks12

[QUOTE=KrazyK;10941863]To the OP:
.

lately it is all all about time, there just hasn't been any extra time. heck we had all but one vehicle down two weeks ago, hehehe,

the 996 is that bad huh.... is 160-170ish low?

haven't even looked to see what the compression should be on it. To tell the truth, IMO not sure how much I would drop into it, wife loves driving it sure, But she has looked at a few newer ones. (I know it won't be long and she will get another newer one, she really likes the looks of the turbo)

And she is not going to have a car like this and not drive it.
it will be one of the few cars that gets high miles on it.

right now, I just want to find what this problem is. then decide what to do with it. this all started after it sat at the dealership for repair from an attempted breakin, 5 and half weeks at one and the other dealership was 3 weeks.

anyhow, so I started looking to see what might possibly have gotten chewed on by rodents, but do not see any signs of that anywhere that I can see

looking up what the compression should be on a 2000 996 3.4 quickly, I found no hard information, someone had posted a reference to 160 psi. someone else posted 155-175, but that is just someone posting.... anyhow main thing about 160-170 ish, is I did not find a dead cyl. causing this issue.

tks12

uhh did I say anything about cheap and easy? No I did not. just looking for some help with it was all.

sorry I wasted your time...........

Adker

[QUOTE=tks12;10942011]
I guess you did this on a cold engine so the number will be lower. They are all within 10% so you should be good. I was told that the Durametric was all that was needed to check an Engine for a PPI and a compression test wouldn't be necessary. Like you, I found no values in the Bentley but I have seen numbers posted in the 200 + range on a hot engine.

So, this was in a dealer for a repair... what did they do??

Flat6 Innovations

Compression and leak down checks on the engine need to be done with the engine warm. I bet when you did that compression check that you didn't block the throttle plate wide open, did you? If not the intake manifold and its characteristics can easily give a 10% differential between cylinders.

160 on a cold engine is pretty good, but the camshaft deviations can also impact the compression numbers since they are dynamic and are a direct result of chamber filling, which is directly impacted by valve timing events. With those valve timing events occurring with deviations the compression numbers will suffer, too.