tonight I swapped coil pack 1 and 3, and put back in the original 3,000 mile old fr6 LCD plug into cylinder one. I still am getting a p0301 misfire code. I looked at the solenoid bracket and couldn't get a good look to see if it was broken or not. The question is, if this was cracked wouldn't it throw more than just a cylinder 1 misfire? Sounds like everyone was getting multiple misfire codes in the same bank with that issue.

I ordered a new FR6 LDC just in case the one I have now is bad and the NGK was bad as well (or not compatible).

The misfire seems to be coming on quicker as soon as I start building boost. After the misfire code, i smelled the engine bay and smells a bit like fuel but after pulling the airbox can't find a leak.

so what's next, all new plugs? fuel filter? look towards injector? Thanks in advance...

 

if engine bay smells like fuel, look at the manifold to head connection boot..
pressure test

 

per this thread and this image i was under the impression that cylinder one was the cylinder closest to the rear of the car on the drivers side :

https://www.6speedonline.com/forums/...r-numbers.html



the picture of the plug, was the cylinder 1 spark plug, that was pulled out for inspection.

intake manifold or exhaust?

 

correct about the order, just wanted to make sure the wrong plug/coil wasn't being continuously swapped..
Intake manifold, might be that cylinder's intake runner boot has loosen up/out of shape, etc..

 

anyone know how i can test for coil pack connection? Where does the other end go? Is it replaceable?

Anything i should look for on the runner boot Rob?

 

Durametric is on the way... Not sure how i can pinpoint this issue or where to look to point int he right area. Any advice?

 

pressure test at the throttle body, listen for leaking sounds/ feel for air movement
Durametric is a good buy regardless

 

man this is frustrating to read misfires are *usually* spark/fuel in that order..in my limited experience...and 9/10 its plugs and coils!

 

Wouldn't either of these throw a p0300 and not just a p0301 code?

 

I'm running the same injectors as you and I had a similar thread last year. I agree swapping the injectors is a PITA but if you look at all the easy stuff first (coils, plugs, solenoid brackets) and they are not the cause then that is the next logical step. Durametric is a great investment that will come in handy many times in your future and you will wonder how you lived without it once you start using it.
When I swapped injectors (cylinder 1 and 3, stuck to the same bank because going from bank to bank is almost double the work) the misfire disappeared for a while but then came back on cylinder 3 in time. I bought another injector from EPL and the misfire never came back after replacing it.
I'm not saying this is your issue but just relaying my personal experience. Good luck; I know how frustrating this can be. My misfire would occur at light loads and part throttle and it was extremely annoying!

 

The fact that just the P0301 code has been logged is a pretty good indicator the misfire is confined to the #1 cylinder and does not come from other cylinders.

If other cylinders were misfiring then a fault common to the involved cylinders would be what one should be considering.

IIRC you have eliminated the plug and coil for the #1 cylinder as being the source of the misfire.

I do not know if you have eliminated the #1 cylinder's injector. You should probably do this.

You must eliminate all external -- plug, coil, injector, leaks, and even a cracked VarioCam solenoid bracket -- explanations for this misfire at the #1 cylinder.

The reason is if you can't pin this misfire on an external cause, which is easier/cheaper to address, the explanation becomes one that involves an internal engine problem, possibly a burnt valve, a flattened cam lobe (though you would probably hear this as a ticking noise), or a intake valve lifter than doesn't switch from low lift to high lift properly. To address any of these internal causes involves more work and more money.

One test that I think is called for now -- but consult with a trusted professional Porsche engine tech -- is a compression test. Since you have eliminated (or should have eliminated) all external explanations for this misfire an internal explanation becomes more likely and a compression test should find the cylinder is down on compression.

My only concern, which I covered off line with you, is the fact the misfire doesn't occur when the engine is cold. This bothers me some and I don't know the significance of this is if there is any significance. Thus I am a bit reluctant to say unequivocally a compression test is called for at this time. But this is why I advise you to consult with a trusted professional Porsche engine tech.

Usually I point out that at some point someone is going to have to get his hands dirty. Well, you have gotten your hands dirty. But at some point someone is going to have to get his hands dirtier and this could be by performing a compression test.

But consult with the tech first to see if he has any other ideas that don't require a compression test, or if he thinks the compression test is not likely to be of any value because the misfire doesn't occur when the engine is cold and unless he knows of a way to perform a compression test on a hot engine -- one that must remain at a hot and stable temperature during the course of the test -- the compression test is a wast of time and money.

If he does feel this way, though, he should have an alternative course of action, one that hopefully doesn't involve a partial engine tear down. I mean you really want to eliminate this misfire.

 

spark plugs, coils, injector and lastly the wiring are all thats involved. boost leak won't cause a single cylinder to misfire nor will a low compression cylinder. it will be down on power or not fire at all but a misfire when warmed up is unlikely. once the plugs and coils are eliminated then its time to pull the injector and either send it out for testing, replacement or swap it to another cylinder to see if the misfire follows the injector. if the injector proves to be fine than all thats left is the wiring. these cars are getting older. the harness have seen over a decade of weather, intense heat and no telling how much pulling of the plug ends and harness during maintenance, mods and repairs. since i started modding my car the shop i use has replaced 3 complete harnesses on turbo porsches. sadly its a wear item that will eventually fail

 

would the tappet solenoid bracket (if it was cracked) effect multiple cylinders?

 

if you shine a flashlight up from underneath you should be able to see if there is an obvious crack.

 

A cylinder is under performing. That is what the misfire error code means.

The OP has eliminated -- I hope -- the plug, coil, and he should eliminate the injector, he must also eliminate a boost or intake leak along with a cracked solenoid bracket and or the solenoid.

While one would think the boost leak or intake leak or bracket or solenoid would affect more than one cylinder on the bank there is too much at risk to miss a rather easy/low cost explanation for the misfire and instead proceed to other more expensive tests possibly even repairs.

A bad wiring harness is a possibility but in spite of your experience I think an unlikely possibility. Well, check that. IIRC the OP's Turbo is mod'd and during all this the harness might have suffered some damage. The symptoms do not suggest a wiring harness problem to me but a wiring problem can manifest different failure modes. This would require an experienced/skilled tech to know how to approach this.

Thus while one can't rule out the harness, based on my assumption that a replacement harness is expensive and a lot of labor to install I'd have to have conclusive proof the harness was at fault before I gave the OK to replace the harness. There are electrical tests that one could do to perhaps determine the harness was a fault but off hand I do not know what they would be.

Generally a boost leak or intake leak affects more than one cylinder. There could be (there always are) exceptions, which is one reason why I suggested the OP enlist the help of an experienced tech. My thinking is if the intake developed a leak right at where the intake for the misfiring cylinder seals against the head only the one cylinder would be affected. That the misfire doesn't occur when cold but does when hot does lend some weight to a leak very close to the cylinder being a possible explanation.

I have to reinforce this that in diagnosing something like this hands have to get dirty, some times often times in fact very dirty. Just looking at an intake and not spotting an obvious leak -- they seldom are obvious -- is not good enough. The intake system must be checked and positively eliminated as a source of the misfire due to a leak or anything problem associated with the intake system.

The same applies to the VarioCam Plus solenoid bracket. The OP must thoroughly check this that it is intact, secure. Just looking at it is not nearly good enough.

Assuming other explanations have been thoroughly eliminated, a misfire a persistent misfire limited to one cylinder could very well be explained by a cylinder being down on compression. A misfiring cylinder is one that is under performing (ignoring the slim possibility it is over performing) and one reason for this -- after the plug, coil, injector, a very localized intake leak, or something wrong with the VarioCam bracket, or solenoid have been eliminated -- is a cylinder down on compression.

At some point I think the OP is going to have face the possibility a compression test is called for. I generally think compression tests are overused, and they are, but in some cases a compression test is the right thing to do. But as I have mentioned above and before at this stage I think a professional tech should be consulted. He may dismiss the compression test and offer another test or check or look elsewhere and resolve the problem. I hope so.