Misfires '97 2.5

[casi]

Hello everybody,

I've been reading here for a few days now and it seems to me that you got some really experts here.

I was searching but did not find the right answer for my probleme.

It's a '97 2.5 boxster with 150tkm and it was working without problems.

From now to then it started with misfires and the cel went on and sometimes blinking.

I know - with blinking cel you should'nt drive...

With OBD2 I got the codes 300, 306, 304, 305 the meaning is multiple misfire, mf zyl6, mf zyl4, mf zyl 5

The sparkplugs are in for about 10tkm.

Because of what I was reading, the age and the mileage of the car I decided to buy a set of coilpacks and oxygen-sensors.

I cleaned the maf sensor and changed with another - the same!

I started changing the coilpacks on this bank - 4/5/6 - tested - the same!

Then I changed the oxygen-sensor - tested - the same!

I can delete the errors but they come back after maybe 30seconds or driving about 100 to 200 meters.

Meanwhile I got Durametric on it and it told me the same errors and in addition:

P1316

P1317

P1318

P1319

and P1585 - something with misfire with emty fuel tank

The fuel lamp was on so I filled in about 15 liters - after that this error did not come up again but all the others.

I get no other errors displayed!

Sorry for writing a book and my sometimes bad english but I want to give as much information as possible and sometimes miss some words...

Thanks in advance

Carsten

Edited June 25, 2012 by casi

[JFP in PA]

OK, 1385 is the knock sensor on bank 4-6; not surprising as all the other codes are all cylinder misfires. Could be bad fuel, but I would pull the plugs and have a look at them as something is not right.

That said, I would also recheck the 1385 code and make sure it isn't a 1585, which could be a fuel starvation issue and time to check fuel pressure and delivery for a bad fuel filter or failing fuel pump, which would also cause misfire codes.....

Edited June 24, 2012 by JFP in PA

[casi]

• I´m sorry - it was P1585 and not P1385 - I had it wrong in my mind - that´s for sure. I did edit it up there.
  
• It didn`t come back after filling some fuel in.
  

I´ll check the sparkplugs - I should have done with the coilpacks...

What does anybody think about a malfunktion of the variocam - usually I think it should be displayed as an error?

[JFP in PA]

If the VarioCam was acting up, it would throw specific codes, which you do not have. I would still look at the fuel system and run a pressure and delivery rate check.

[casi]

I did check the sparkplugs yesterday - I changed them with others - the same than before.

I'll try to check the fuel pressure and the delivery rate.

The manual says "special tool 9559 and P378a" can someone please tell me how it looks like and where to connect exactly?

In my manual the picture is so bad that it's nothing to see...

If there's a thread - which size is it? I've got some possibilities to make an adapter by myself and some gauges I have, too.

[wvicary]

I'm not sure on the boxster but the coil packs might be fused so I would also verify none have failed.

[JFP in PA]

I did check the sparkplugs yesterday - I changed them with others - the same than before.

I'll try to check the fuel pressure and the delivery rate.

The manual says "special tool 9559 and P378a" can someone please tell me how it looks like and where to connect exactly?

In my manual the picture is so bad that it's nothing to see...

If there's a thread - which size is it? I've got some possibilities to make an adapter by myself and some gauges I have, too.

It is a pressure gauge with an adaptor. Actron has a similar system for about $50 or so.

[casi]

I did check the fuel delivery rate today.

After 30 seconds it was about 500cc maybe little less.

The manual says it should be 850cc.

I think I should try a new fuel filter...

Is it possible that this causes my problem? - Well I think the right side with zylinder 1-3 is getting the fuel first so it might be.

[JFP in PA]

That is significant, to the tune of about 41% below what it should be. Try the filter first, but it may be the pump itself.

[casi]

I'll try the filter!

The car got a new pump years ago - after the pump they did change the relay in addition, what had been the fault,

anyway had to pay everything. At that time the car didn't even want to start of course - without activation.

What do you think - it should be possible to check the fuel pressure at the same point where you usually check the delivery rate,

because when everything is closed the pressure is the same in all the system - am I right?

[JFP in PA]

Both the delivery rate and pressure are measured at the fuel rail port where the guage attaches.

[casi]

I did check the delivery rate at the return line at the rear underside like it's written in my manual.

In my manual the picture where to connect the gauge is bad so I can't see where to connect.

[JFP in PA]

There is a schrader style port (looks like a tire air valve stem with a brass cap) on the fuel rail by the intake manifold that is used for fuel system testing, very neat and clean way to do it.

Edited June 28, 2012 by JFP in PA

[casi]

I know which one you mean - I have already sean it - thanks a lot.

[casi]

Only little progress here...

I changed the fuel filter and to make it complete the coil packs from cylinder 1-3.

Afterwards I wanted to check the fuel delivery rate again, but with durametric I could not get on the option "drive links"

everything other is possible but at drive links I only get an empty window.

OK - this I think I can do directly on the relay...

When I had a look at the engin from the top I just decided to check the hose from the AOS to the TB.

Removed the hose and there was a bit oil coming out. That made me check the TB and the T-tube after it.

Well what can I say - never seen something like this - it's everywhere oily inside and the TB was dry and dirty on the front and muddy-oily everywhere on the back.

Even the T-tube was very oily and with muddy dirt (very fine stuck togehther like a paste) on the lower part.

I should say that there is a K&N filter in the stock housing.

This I immediately changed with a stock one thinking the filter is not working right.

What do you think is it possible that the oil in the pipes can cause the misfires?

[casi]

which amount of oil in this area is normal?

My thaught is that the hose from the AOS comes in to the t-pipe on the left side where my misfires are.

What makes me thinking all the time is that the misfires are in idle and with very low throttle - when it is more throttle it seems like no misfires.

The car was used the last months only for short distances most about 5-10 km - can this give problems with the AOS - I think maybe

in wintertime but not in summer...

I'm going to clean all the pipes and hoses even want to clean the pipes down to the cylinders hoping maybe this caused the misfires

[JFP in PA]

Have you tried removing the oil cap while the car is running? If the AOS is in good shape, you should be able to remove it without much force, if it takes a lot, the AOS is failing.

There is ususally a slight oil film in the connections you mentioned, but not a lot.

[casi]

I missed to check this,

now I already took the TB and the T-pipe out for cleaning and I want to take the manifolds of, too.

Which sort of sealing is between manifold and cylinderhead?

Do I need new ones or is it possible with the old ones to mount again?

Right after building everything together I will check with the oil cap, but what I did is that I removed the hose from the AOS to the T-pipe,

put a plug in the T-pipe and turned the engine on what happened was that some dust was coming out of the AOS.

[JFP in PA]

They look somewhat like greenish rubber bands. I would not reuse these gaskets; fortunately, they are relatively inexpensive.

Edited July 1, 2012 by JFP in PA

[casi]

To keep you up to date...

I cleaned the TB and the T-pipe and cleaned the "idle regulation valve".

With the intake manifold I gave up then - I think it wouldn't be a problem on the right side, but for the left side where my problem seems to be

I thaught if I really get it out I'm not sure to damage something.

So narrow inside there ...

My additional problem is that I have not a garage to leave the car as it is.

It's standing on my carpark in front of my house so that I have to close it everytime I finished working.

Well after cleaning the intake manifold with a cloth, trying that nothing falls inside and getting all the dirt out, what I think I could manage good,

because there's a step inside the manifold, I buildt everything togehther again.

I tested with the oil cap while the engine running but there's no problem to take it off.

In my opinion it was a liitle bit better with the misfires, but they're still there.

I took the car for a ride to test it out when exactly the misfires appear.

It's really only on idle or when the throttle is opened very little - maybe about 5%,

when the engine is kept working, there's no problem at all.

Tomorrow I'll give the car to the shop hoping they know what they do better than me.

[casi]

I got a probleme with the keyboard on my android tablet so I can't get the cursor at the right point to continue sometimes - that's why I sometimes write

two times for my reply...

Sorry therefor!

I did another test with the durametric checked some live values but there was nothing what made no sense to me.

I tryed and shut off the injection valves piece by piece and where I got the less difference was no4 but all the bank (4- 5 - 6) did not make so much difference like bank 1.

I did this on idle.

I'll give the car to "techart" a german tuner - they tuned the car right after production to 238hp.

In my opinion there must be one sensor somewhere, that doesn't give the right measure but me I can't find it.

Or maybe all this three injection valves have together one mistake in the "blackbox"

Anyway I'll keep you updated

[casi]

Back here after long time now...

well the car is still in the shop - they couldn't find the mistake with any diagnostic programm but then figured out that the timing of the camshaft on row 2 isn't right.

They took the engine out and checked piece by piece.

What seems to be happened:

A piece from the sliding bracket from the tensioner bank 2 broke away and got through the chain and the sprocket of the camshaft.

The timing was one tooth wrong and they told me with two teeth it would be crashed.

As they checked everything now I know that cylinders and pistons are in good shape and a pressure test and pressure loss test showed

[casi]

They also checked all the bearings - the IMS is ok but the rods and the crank bearings are very used.

Because of that they checked the crank housing and it is bend and can't be reworked.

Now my probleme is to find a crank housing in good shape what seems to be a hard job as this is a common fail on these engines as they told me.

Also need the cams replaced as all the sprockets are a bit round at the edges.

Next possibility if I don't find these parts is another engine in reliable condition.

Now my next question:

When we swap to a 2.7 engine what needs to be changed?

I already searched but did not find anything - only that it is possible.

The additional hp from 204 to 238 was made by a larger throttle body, other blackbox, airfilter and exhaust manifold.

Thanks for your answers...