Hi guys,

I am alex from germany. I posted the same thread over at P9, too.


I have a 987.2 Boxster S with the 3.4 DFI engine an dits modded by TPC

racing's low pressure turbo kit.


it runs fine and i can actually compete with R8's (the V8's of course only)

I have this problem though that the durametric logs show a much too lean

value I just logged lambda today and its freaking me out honestly.


I just emailed TPC:

hi mike,

when I went to my garage i did that throttle body thing

and brought it to 14V - all good


now - something that still gives me headache - even that the car runs better

now - it is still incredibly lean!


what do your DFI boxster or cayman S cars with the low pressure turbo kit

have in actual lambda value before cats?

mine is regularly above 1,0 - at times even up to 3,03!


check attached durametric log column F and G are lambda actual values

running too lean can easily bring your engine to blow

you know that more than i do

please have a look and let me know your feedback

thanks

alex

-----------------

so the car is running better than before now - but its still incredibly lean.

can anybody else on this forum, like the recent cayman R build

duramtric log his lambda values - if all DFI cars are driving these

I foresee a dark future for our engine - a very recent dark one indeed

-----------------


tpc's (mike's) response:

your using durametric you have no idea what those values are its unreliable
-----

thanks - but how does this help exactly?

so I replied:


so what should i do then to get peace of mind on this too lean angst

that i have? who can log or better what system can log real a

head cat values for me correctly?


...so lets see

the guys on the german tuning forum

they drive driving porsche factory turbos modded up to 600-1000 hp
are telling me do NOT drive the car with this kind of lamda values

-----

I have attached two durametric logs

I have to admit the support from tpc is at times very difficult

so you got to figure things out on your own i am afraid. What do you guys

say about the durametric's values reliability?

I understand all around the world it used even for ECU mappings - so that

would be strange if its values were not usable - would it not?


I really wish I could get a straight answer from TPC with their facts

it just is impossible...

what is normal according to their mapping?

what should I use to log?

porsche tester?

get a separate lambda tool
(what if the values remain the same more $$ down the drain)

what values should show in duramteric?
(thats why I asked for other DFI low pressure turbo kit cars here
like the cayman R who has the intercooler kit already installed)


thinking about this again.

it appears to be pure nonesense to me that the durametric values are wrong

i mean what does the durametric do other than reading out what the ECU

supplies in terms of data?


based on those lambda values the ECU is regulating the amount of fuel

that is injected. which is obviously too little

thanks for constructive participation

 

are the o2 sensors working and can you monitor them with a good scan tool ? does your CEL work and is it on ? i could not open your posted data file [my fault i,m not putor smart]did this problem just start or was it after some work?

 

Side note, my stock cayman s with an exhaust kept up with the V8 R8's on track without any problem. You should be eating the V10's mate

 

Well, if the engine were really running lean I doubt it would be running as good as you report. A boosted engine running lean doesn't run lean for long before it lets you know it is too lean. Blobs of molten piston material generally leak from the exhaust tips.

Thus I question your diagnosis the engine's running lean. Which kind of agrees with what TPC says.

I'm unfamiliar with the Durametric system so I can't help you sort that out. I have used other OBD2 data readers/data loggers but my experience with them is of no help at this time.

Couple of things, some probably obvious.

You have to be sure all air the engine is getting is monitored air.

Check for intake air leaks. This includes a cracked/split oil filler tube and possibly a bad AOS.

Be sure the intake is getting fresh cool air. The turbo compressor heats it up enough as it is. If for some reason the stock air box or aftermarket air box is allowing hot engine compartment air to get into the engine this can upset the MAF.

Be sure the fuel system is in good working order. The DME assumes a pretty constant fuel pressure when it calculates how long to leave the injector on. The DME can only vary the amount of time the injector is open (well that and when to open the injector). If fuel pressure is low...The fuel pressure may not be consistent either. You have to consider an intermittent problem.

(But with no misfires I lean -- oh, no pun -- towards agreeing with what TPC strongly hinted at: The engine is not running lean. To put it another way: The problem is with your test tool, not the engine.)

Anyhow, moving on: Check for exhaust system leaks. This can upset the O2 sensor readings.

Be sure you have the right sensors. Some models -- I do not know if the engine/DME you have is one -- use narrow band sensors, others (996 Turbo for one) uses wide band sensors. I would think the DME would flip out if these were wrong but you never know. Also, who is to say that extremely lean lamba is not the DME flipping out?

Don't change anything or fix anything unless you are sure you have found a smoking gun. Even then be careful. There may be 2 problems, unless I like to add there are 3 or more problems or just one problem.

But before you delve too far into this I think you need to be really really sure of the engine's lean. It doesn't read like it is.

Sincerely,

Macster.

 

Hi,

thanks for the input

I should have mentioned that I did change

the Air/oil Separator as it was leakin goil

The fuel pump sitting in the gas tank

the DFI fuel pump (was changed by dealer last year as basically all early DFI models had a service call from porsche and theirs changed)

I checked all seals on the engine

I made sure there are no leaks in neither air intake system

nor exhaust


before the turbo mod my car would have black residue on the exhaust tips
(like all DFI engines do) - that is just not the case, either ever since the mod (that I have been driving for almost 5thousand KM)

i am afraid adding new sensors - will bring the same results - and eventually what the DME reads is the basis for its fuel supply regulating - is it not?


I thought of trying to replace the injectors to the ones from the 997.2 turbo (the part number at porsche is another - if they are bigger/deliver more fuel - I have no idea - but again if the DME/ECU is just not giving more fuel from its mapping then changing injectors may be a lost cause, too)

How about chances its the actual mapping? I mean softronic does ALL its work ONLY with durametric logs - isn't that right?

 

here is a log from before changing the AOS and fuel pump n the gas tank

back in July.


at this time the airbox may have had a slight leak btw - possibly this was the

reason for the extreme ho tair intake temperature (column N)- but it

was really tiny


column G shows correction up to 30% - that seems enormous too

if it had to regulate/correct the fuel trim up ton one third!


what strikes me is column M - that has a max value of 120 Bar

afaik 120 bar is the stock max setting - now from the logic

if an engine gets more air through a turbo system but the fuel pressure

remains at its max similar to the stock setup = too little fuel delivery

does this make sense?


I will log those again to see if this changed

 

Since the exhaust passes through 2 converters what you see at the exhaust tips is probably more a reflection of what the converters are doing rather than the engine.

Absence any signs of a badly running engine, check engine light, the exhaust tips could be covered with pink polka dots for all that's worth.

I can't help but ask what is it your are seeking to fix?

If you suspect the engine is not being fueled properly you need hard proof of this. Just thrashing about acting upon what the exhaust tips look like or don't look like is not going to make things any better (they may be ok) and could make things much worse.

I am not familiar with the TPC system but if it requires higher flow injectors I think this would be clearly stated in the installation instructions.

My WAG is it doesn't. The DME has considerable adjustment to add more fuel when more air is brought into the engine courtesy of the super charger.

Now the DME might reach its enriching limits and turn on the CEL and log error codes to this effect.

A remap of the DME could raise set the adaptation points higher to avoid triggering the CEL. Does TPC suggest a remap?

If there are no O2 sensor related error codes I'd leave sensors alone, provided you are sure they are the right ones for the car, are installed in the right locations. (Some sensors can't be swapped from the #1 to the #2 position because they are quite different sensors even if they mechanically fit in the threaded hole).

O2 sensors are critical to proper engine fueling and just as importantly to the the converters health and proper operation and the DME checks them 6 ways to Sunday every time you start the engine and run the engine for any length of time. If there was any problem with the sensors, either because they were bad, or were not up to the task, I think you'd have a CEL and error codes pointing to the sensors.

Not sure about your question about the actual mapping and Durametric logs. But if you are implying that because of what you see using Durametric that the mapping may be wrong somehow, that could be -- given the limitations of my knowledge about the TPC and any remapping and how Softronic works, etc.

Sincerely,

Macster.

 

Generally fueling is based upon a known and fairly tightly constrained fuel pressure and of course adequate flow to allow the engine to make full power with no risk of being short of fuel.

I'm not sure about a DFI engine but I am operating on the assumption is is the same as non-DFI engines. Fuel pressure at the injector is while high (quite a bit higher than non-DFI engines) the pressure from idle to max rpm is the same. If I'm wrong then what comes after is wrong too.

Fueling is based on a regulated supply of fuel supplied at a consistent pressure.

To avoid extra complexity the DME is built with the assumption operates on the assumption, calculates fueling fuel requirements and satisfies those based on a constant fuel pressure.

The DME supplies more fuel to the engine by extending the time the fuel injector is open.

There can be problems. First the fuel system must be in tip top shape. If for any reason the fuel pressure is not within spec or if under extremely high loads the fuel system simply can't deliver sufficient fuel, well, these are problems.

Generally aftermarket engine add ons rely upon the considerable margin in this case the stock fuel system has and it has considerable margin, provided it is working right 100% of the time.

Under lighter loads the fuel system can keep up, but if for instance the fuel pump can't keep up at high fuel demands the DME will at some point flag a problem when it reaches the limit of how long it can keep the injectors on.

AFAIK there has been nothing flagged. I still haven't seen any posts from you reporting a CEL and error codes that clearly point to a problem.

Now on a related note the fuel injectors need to be in tip top shape too. They are on more and as such they run hotter. If one or more are weak the higher cycle times can send marginal injectors over the edge. Injectors that may have been quite capable of supplying a stock engine with fuel for years and years with nary a problem.

Another area of possible issues. Air mass used to be measured by a mass air flow sensor (hot film). At some point -- I do not know when -- Porsche switched to using an air pressure (barometric) pressure sensor in the intake. Somehow this sensor's output with some other data at the DME can be used to determine air mass and thus how much fuel to add to produce the proper fueling.

Now obviously a supercharger changes the pressure in the intake system. The sensor -- if this is used in your car's engine -- could be confused by the big increase in pressure (and intake air temperature). Or it could be confused by the pulsing or non-laminar flow over/past/through the pressure sensor. Even if there is a MAF this can also be affected by these things.

However, TPC should have this covered, even if covertly by describing the proper installation steps. The result is that if the system is installed correctly proper operation is ensured, no abnormal air flow occurs that can upset the measurement of the mass of air the engine is ingesting.

In short, if the install is not right the system will not run right, the engine will not fuel right, and various sensor and derived readings will be wrong, worse that wrong, all over the map and having you chasing your tail following one phantom problem after another when all along it is a simple installation problem (well, relatively simple problem) that is the root cause of the behavior.

Sincerely,

Macster.

 

Here is lambda1 logged

appears not too lean - but I will have someone

with experience give me a feedback and I will re-confirm those

values with the porsche tester tomorrow


here is another concern

http://www.youtube.com/watch?v=cSJWU...3&feature=plcp

are those 6MT vs 6MT?

or PDK vs PDK?

at least same type vs same type?

because in all reality my car would NEVER EVER beat a GTS modded 987

here is a fact - my 100-200 km/h time is a flat 11sec

sometimes a tiny bit lower - and my car is a PDK!


to compare - a friend in germany has a gen1 car with a 911

3.6 engine conversion that delivers at 355 crank hp

he is driving an 11.7 (2 shifts 2-3 and 3-4)


so again people - i do NOT intend to bash TPC or anything

but I want people to know the TRUTH about the REALITY of the mod

they intend to do - and we, the customers, the people,

should put our results together to create a reliable feedback

on what those cars and mods really deliver

:thanks: for sharing your durametric and/or 100-200 runs with another


I would also ask TPC - since troubleshooting over the net is difficult,

why would you not try to create data that is of helo, as a benchmark

why would TPC not have duramteric logs

only

b1 actual and nominal lambda before cats and rpm

only

b2 actual and nominal lambda before cats and rpm


only

fuel delivery relevant values and rpm


only

mass air flow, load and rpm



see what i mean - it would take them a 3 hour of work to create those logs and then if a customer has a problem - tell him to compare his log runs with theirs - right now anything i sent them if looked at, at all - would never get a straight answer or solution - that if you got mike on the phone - it a little like
Never Get A Straight Answer and I thought Nasa was hiding the exisitence of aliens from us

anyhow I hope we as users - can help each other with creating logs and
benchmark data - or if all may have the same "problem" as I am facing

one thing is a fact THIS: http://www.youtube.com/watch?v=cSJWU...3&feature=plcp

is NOT my car's reality, and I checked and replaced so many things
and I do NOT have any fault codes either

thanks everyone

 

at idle ,closed loop you should see the o2 sensors mil volt around .450 varying, the more active they are [over 450 under 450 the better]. a data line called o2 cross counts will tell you their health,again the more the counts the better. o2 mil voltage below a certain number will pop a cel as will voltage over. unless you have the sensors tuned out. at WOT on the road you should see .800/.900,s mil voltage

 

sorry extanker - what exactly are you referring to?

what health do you mean? pls clrify and I will look for o2 something in durametric

if the sensors are tuned out its part of the ECU programming from TPC

 

take it to a repair shop that has a scan tool

 

and then scan what?

I am at porsche tomorrow morning

thats why I am trying to make more sense of your posting

to really understand what you are saying , you know

 

k went to porsche today and logged with piwis

lambda ahead of cat looks fine at full load and top rpm around 0.79

and when you go off the gas it always goes around 1.0

so basically this looks ok


what the porsche technician spottet though was the values AFTER cat

he said those were moving quite a lot - and they should be rather

constant values


based on that the porsche technician said he would check the kats

possibly they may be stuck.


I emailed TPC:

so what is the course of action now mike?

should I take them out and empty them for a test?

would this interfere with the ECU programming?

or should I get other possibly sport cats?

if so which ones would you give an ok for?

please advise - thank you

-------

so lets see...