Feels like a misfire under load 🤷****♂️

[colacharlie]

Originally Posted by blue62

Colacharlie.

Your vacuum readings are low. Ideal would be 17-21 in.hg
I see lots of oil dirt residue on the AOS tubes and other parts of the engine.
So that tells me that you have minor vacuum leaks at the connections and or tubes themselves.
Another common place for a vacuum leak is the oil fill tube that runs from the trunk to the engine. It can rub the edge of the body where it passes into the engine bay. (hope that makes sense).
These are closed system engines with crankcase vacuum rather then pressure.
So anytime you see oil or oil dirt residue on the upper engine area, around the intake, or the AOS you have vacuum leaks.

If your vacuum gauge needle is rock steady when you test then there is most likely no valve train issues. I think your low vacuum is all down to minor vacuum leaks.

With the way your car acts in the video and that fact that it is smooth at any RPM until you give it more gas. Vacuum leaks don't typically act that way once your at around 2000-3000 RPM so I think it may be more of a fuel delivery problem rather then an air metering problem. Low fuel pressure or low volume. Once you step on the throttle there is a momentary lag in the fuel systems ability to meet demand. thats the theory anyway.
Although a faulty MAF (which you have changed out so it is most likely good) or a faulty Throttle position sensor (which has not been tested) could have the same affect.

A confusing thing to me is that you have no misfire codes and your Durametric shows no misfires. Are you certain it is misfiring????

I would do a fuel pressure test at the rail (which I see your preparing to do) next.
There is a spec. for key on engine off. and a spec. for engine running.
If you need those spec. let me know I will look them up.

Sorry I do not know the thread size for the fuel rail test valve.
unbelievable that the sent you a fuel test kit without correct fittings.

Hi blue and thank you for your reply, and also thank you to everyone else who has replied so far.

When I say misfiring- I mean that’s what it feels like, but yes the computer shows no misfires. I had a very similar feeling recently on my motorbike and it turned out to be a coil pack but I thought the best way to describe it at the start of all this was like a misfire. I am also thinking it is probably a fuel issue.

Just to clarify- do you mean that I probably have some small vacuum leaks to address but this will not cause the present problem? Or the small vacuum leaks are the problem? Or are you thinking it is probably the fuel pump, or the regulator, or a injector O ring maybe?

…. And yes please do provide the measurements for the fuel Pressure test if you can buddy Tia ��

Pps- sorry IDK but my pic converter on my iPhone is only letting me compress and not letting me resize unfortunately

[Stl-986]

2002 is when they moved the fuel filter as part of the fuel sender.

Blue - Why do you keep calling the air induction system the evap system? The black/white check valve connects to the air induction which includes the vacuum canister, flapper in the resonance tube and even the valve on tiptronic cars to the tiptronic cooler. EVAP system is for the fuel system like the carbon canister.

[blue62]

Originally Posted by Stl-986

2002 is when they moved the fuel filter as part of the fuel sender.

Blue - Why do you keep calling the air induction system the evap system? The black/white check valve connects to the air induction which includes the vacuum canister, flapper in the resonance tube and even the valve on tiptronic cars to the tiptronic cooler. EVAP system is for the fuel system like the carbon canister.

As I said in an earlier post "It appears to be" connected to the EVAP system.
Perhaps I am incorrect
Which vacuum canister are you referring too???
Where is the EVAP system drawing it's vacuum from on his car??
Vacuum hose layout for European spec. cars would be helpful.

[Stl-986]

the vacuum lines, change over, cannister, check valve, sai are all part of the air induction system, same as ours. EVAP is for the fuel system. Only thing different on his car would be the secondary O2 sensors not being present and a ROW tune, otherwise it is the same as us spec. On RHD the location of a couple parts will just be different, but they will still be there such as the vacuum line to the fuel damper (on the right side of engine instead of left). The intake & vacuum system are all the same as US cars. EVAP is going to be at the front of the car like ours in the right wheel well.

You can get the row PET from here: https://www.porsche.com/central-eastern-europe/en/accessoriesandservice/classic/genuineparts/originalpartscatalogue/

The vacuum cannister is circled in blue:

[blue62]

Originally Posted by Stl-986

the vacuum lines, change over, cannister, check valve, sai are all part of the air induction system, same as ours. EVAP is for the fuel system. Only thing different on his car would be the secondary O2 sensors not being present and a ROW tune, otherwise it is the same as us spec. On RHD the location of a couple parts will just be different, but they will still be there such as the vacuum line to the fuel damper (on the right side of engine instead of left). The intake & vacuum system are all the same as US cars. EVAP is going to be at the front of the car like ours in the right wheel well.

You can get the row PET from here: https://www.porsche.com/central-eastern-europe/en/accessoriesandservice/classic/genuineparts/originalpartscatalogue/

The vacuum cannister is circled in blue:

I did not realize that Euro spec. cars had SAI. thanks for pointing that out.
Even thou the components for the EVAP. system are in the wheel well. The system is still put under vacuum for leak testing by the DME/ECU. So it is connect to a manifold vacuum source somehow.

If you have things like changeover valves, check valves, charcoal cannisters, vacuum cannisters, included as part of various vacuum test you run a high risk of inaccurate and misleading readings.
If a valve energizes and opens to something like a vacuum cannister while your doing a exhaust restriction test. The needle on the gauge is going to drop slowly just like it would if the exhaust is restricted. That is why you isolate as many vacuum operated systems as possible from those types of tests.

That is why I tell the OP to run his test either without the check valve connected or to run two test one with it connected and one without it connected.

What the system is called downstream of the check valve I couldn't care less.
I know it has a vacuum component that can skew the test.
When I tell the OP to include or don't include check valve in the test. he knows what I mean.

[Stl-986]

Just wanted to make sure. You had me very confused when you were calling it the evap system. You have educated me enough so it's all good.

[blue62]

Originally Posted by Stl-986

Just wanted to make sure. You had me very confused when you were calling it the evap system. You have educated me enough so it's all good.

It's all good.
Actually I am not very familiar with Porsche's of any model.
My 2000S is the only one I have ever had "hands on".
But I never have any issues with it so I don't have to dig very deep into it.
But an internal combustion engine is just an air pump. No matter what make of car it is in.
But I do know at least the basics of most systems on older cars like our Boxsters.
Things like EVAP, SAI, they are very similar from one make to the next.
So if you have good knowledge of the basic's of a system it's like a good foundation to a house. You can use and build on that knowledge no matter what make of car they are on.
Things like vacuum testing for diagnostics, using a vacuum gauge to set timing, or carbs on old school cars, compression testing, and general diagnostics I have been doing that for 50+ years.
Now electrics that's my weak spot
I know nothing, not a damn thing about turbo's, except they push air and are more or less free horse power.

[ike84]

The evap system hooks to the plenum just beyond the TB, it runs into the same connector that the AOS breather connects to. It has nothing to do with any of the vac lines that he has pictured so far.

STL is right, some euro cars (Germany and GB) have the SAI system just like ours. There are several different versions of emissions tunes for Europe. Only true ROW cars (sold in middle east for example) did not have the SAI system.

ColaCharlie - do yourself a favor here. There is a diagram of your vac system in the trunk. The line that comes off of one of the bank 1 (passenger side) boots either on the plenum or resonance tube, has become dislodged. As I said earlier, it is the tubing that goes to the SAI and resonance flapper actuator, along with the vac reservoir. Study the diagram, find pics of how everything should be connected (Stl has a nice pic on the post he suggested you read) and hook your stuff up properly. Then see what happens.

This isn't rocket science. You have a vac leak on bank 1. You are leaning out and detonating (not misfiring, big difference) on bank 1. It is happening at WOT because your fuel trims can adjust for the leak while under closed loop operations. When it goes open loop (i.e. WOT) you lean out and throw the code. If you don't believe me, buy a $15 elm327 tester and download your long term fuel trim data. $5 says that your bank 1 is going to be positive and much higher than bank 2 which should be close to zero or at least very low positive single digits.

Sent from my SM-G970U1 using Tapatalk

[blue62]

Originally Posted by ike84

The evap system hooks to the plenum just beyond the TB, it runs into the same connector that the AOS breather connects to. It has nothing to do with any of the vac lines that he has pictured so far.

STL is right, some euro cars (Germany and GB) have the SAI system just like ours. There are several different versions of emissions tunes for Europe. Only true ROW cars (sold in middle east for example) did not have the SAI system.

ColaCharlie - do yourself a favor here. There is a diagram of your vac system in the trunk. The line that comes off of one of the bank 1 (passenger side) boots either on the plenum or resonance tube, has become dislodged. As I said earlier, it is the tubing that goes to the SAI and resonance flapper actuator, along with the vac reservoir. Study the diagram, find pics of how everything should be connected (Stl has a nice pic on the post he suggested you read) and hook your stuff up properly. Then see what happens.

This isn't rocket science. You have a vac leak on bank 1. You are leaning out and detonating (not misfiring, big difference) on bank 1. It is happening at WOT because your fuel trims can adjust for the leak while under closed loop operations. When it goes open loop (i.e. WOT) you lean out and throw the code. If you don't believe me, buy a $15 elm327 tester and download your long term fuel trim data. $5 says that your bank 1 is going to be positive and much higher than bank 2 which should be close to zero or at least very low positive single digits.

Sent from my SM-G970U1 using Tapatalk

Ike
I keep looking at the picture in "Car dies" thread that your referring to and also Colacharlies picture.

In both pictures the white end of the check valve is plugged into a three way connector.
In the picture in "Car dies" thread one of the other two legs of the connector , connect to a four way connector. The vacuum canister is just to the right.
The third leg is connected to the electric /over vacuum switch that lets the resonance flapper move.
So if I understand you correctly your saying either the resonance flapper leg is disconnected or the vacuum canister leg is disconnected???
Or am I misunderstanding??

Thanks for the clarification on where the EVAP hooks in. I will check it out on my Boxster tomorrow so I have a visual.

[ike84]

Blue, no worries dude, it has literally taken me 2 years to piece together my understanding of this cars vac system, and there's still more to learn!

In post 21 of this thread he is pointing at the check valve, the black end of which is not connected to anything, and says "not sure where this goes". Check out stls pic - that end should connect to a hose that runs to one of the intake boots. On most it's the bank 1 plenum boot, on mine is the bank 1 resonance tube boot.

Sent from my SM-G970U1 using Tapatalk

[ike84]

Fwiw, bank 1 vac leaks have been the bane of existence for many forum members over the years. That circuit is complicated, there are a bunch of parts, ALL of them are nearly impossible to access without removing the intakes (at the very least the plenum and resonance tubes), and all can fail. I was recently having a sidebar with Stl about deleting that whole circuit if possible, and when he asked me why I said to prevent vac leaks down the road lol.

Sent from my SM-G970U1 using Tapatalk

[blue62]

Ike no sweat.
I got what your saying now.
yes there is a hose missing from the check valve to the vacuum port in the OP picture.

My thought has been that the black end of the check valve had be inserted directly into the vacuum port by a previous owner.
And as Colacharlie was trying to find a vacuum port to connect a vacuum gauge to he pulled it loose because the port was turned down so the check valve was under the collar.
He saw the check valve first then latter found the vacuum port to the side.
The reason I thought this was because in the pictures you can see Charlie has hose clams loose, a AOS hose disconnected and what looks like a screwdriver handle in the picture.
Also there were no codes for anything.
except for the no codes everything above was a guess at best.

[Stl-986]

There is a code though. He showed an O2 code earlier

[colacharlie]

Hi all. Vacuum test complete plus a smoke test and small leaks found and O rings renewed, plus fuel pressure test complete and all in range and spot on. Car runs a bit better but still judders and is still horrible. I’m going to buy a set of injectors (second hand) for my 2.7 2002 and wonder if someone might know the product code of the injectors? Ps I have no access to the car Atm

[blue62]

Originally Posted by colacharlie

Hi all. Vacuum test complete plus a smoke test and small leaks found and O rings renewed, plus fuel pressure test complete and all in range and spot on. Car runs a bit better but still judders and is still horrible. I’m going to buy a set of injectors (second hand) for my 2.7 2002 and wonder if someone might know the product code of the injectors? Ps I have no access to the car Atm

Sorry don't know the product codes for injectors.
Ike84 or STL-986 will probably know

I take it your test for exhaust restriction tested ok?
Did you see if your CEL works??
I can also be tested with your Durametric.

Did you do another vacuum test after you found the small vacuum leaks
to see if it brought the vacuum readings up??

[gabedrummin]

For original injectors Porsche 2000 3.2 motor its a 996 606 120 01 .... There is a post for a 987 injector swap but you have to modify it .You have to add the groove for the injector clamp . Its a steel keeper that clamps the injector to to he rail .

[colacharlie]

Originally Posted by gabedrummin

For original injectors Porsche 2000 3.2 motor its a 996 606 120 01 .... There is a post for a 987 injector swap but you have to modify it .You have to add the groove for the injector clamp . Its a steel keeper that clamps the injector to to he rail .

It’s a 2.7 2002 buddy so it appears to be
0280156053

[blue62]

Originally Posted by Stl-986

There is a code though. He showed an O2 code earlier

Yes I saw that but he said no check engine light.
So was it a pending code????
Don't remember if Durametric shows pending codes.

Or Did it throw the code because he started it while working on it with somethig disconnected.????
Knowing when a code was thrown and under what conditions is kinda important.

Amazes me that Duarametric does not show freeze frame data. Bull **************** for the price of the thing. Some units even provide a time stamp in the freeze frame data.

[Stl-986]

yea. Durametric isnt all that it is hyped up to be.

For codes it shows pending & set codes all as just "Codes"

I'm also disapointed it wont do custom pids either. Besides the limited coding it can do, all it is doing is ready PID's. If we could ever get a list of all of the PID's it reads then we can just create them in Torquefor and not really need to buy the durametric.

[ike84]

the injectors for the 2.7, 3.2, and 3.4 are all the same from 00 - 02. the dme just runs them on different duty cycles to adjust for different fueling needs.

these injectors are no longer being made. they were a special part made by bosch specifcally for porsche. you can remove yours and send them out for cleaning and testing (which costs about $30 per injector plus shipping), buy a remanufactured set from a company called reman, or do the 986.2 injector swap. If youre worried about the injectors, I recommend the latter - you can get them for $25 a piece and the modification takes less than 5 min per injector with a dremmel.

before you do this though, do as blue says - repeat your vac test. if your vac is still low then you haven't fixed your problem. bad injectors dont cause low vac pressure.