badabing

I'm about to pull the trigger on a durametric but want to know if it has this capability.

I seem to be limited to .5 bar on the boost.

Anyone have any experience with this?

Texas993

Do we have a "limp" mode? Never heard of one on this car.

ca993twin

That does indeed sound like either 1) "limp" mode, 2) your boost gauge is inaccurate, or 3) you have some boost leakage (hose might be loose). Sorry, I don't know about the Durametric.

AC/911's

My car did that when I put an air intake on, Never again! Filter only, could be your M.A.F?

badabing

I do have an open air box and a k&n filter installed. Although they've been there for a couple years. I just had the MAF out when I was doing some other things and sprayed it down with CRC MAF cleaner.

How would I use the Durametric to test the MAF?

I also read somewhere that our MAF is the same one used in a VW but at a fraction of the price. Anyone heard this?

WingChun

I had boost limited to 0.5 bar and tried to check it out with the durametric but it has no details about "limp mode".
Problem turned out to be loose IC hose clip on the turbo end.
Tightened hose, boost back to 0.8!

Droops83

The Durametric will not say "limp home mode" when you scan it, but if you see MAF sensor and/or IAT sensor codes in the DME control module, that will likely be your clue. The DME is expecting to see certain air mass/intake air temp values at any given load/throttle position/RPM. If these values exceed certain preset parameters, the DME will set plausibility fault codes and limit boost.

Like others have said, check for boost leaks first.

You say that you have an open intake and that your just cleaned your MAF sensor; I personally have no experience with aftermarket intakes on 993TTs, and that is for a reason. Most of them do nothing but draw in hotter air than the factory setup, and do not filter as well, thus requiring oil on the filters to trap dirt which in turn coats the fine wires on the MAF sensor, contaminating them and causing failure. Cleaning them is a band-aid at best, they should be replaced.

As for the VW rumor, don't do it! There were a lot of people on BMW E39 M5 boards ogling about some sort of diesel VW MAF sensor that was supposedly interchangable and a lot cheaper (the E39 has 2 MAF sensors and they are a common failure item, we replace a lot of them). Turns out somebody actually did some empirical testing, and the VW MAF did not have the range to measure the airflow at higher load/RPMs (a race-bred 7,500 RPM V8 vs a VW 4 cyl diesel, go figure!). I would not chance this on a turbocharged Porsche engine.

As for the Durametric, if you are an enthusiast who likes to work on his own car, go for it if you have the money (you should have it if you own a 993TT). It gives you a lot more info than a generic OBDII reader will. It is good enough for code reading and reading actual values and such, but you cannot activate anything via bidirectional controls, and I remember it not having any useful fault code info. My shop bought one back in '05 right when the 987/997 came out, as it could reset the service indicator lights in the dash, and Porsche would not sell the PIWIS scan tool to independents yet. I remember it freezing and crashing a lot, though it may be better now. A few months later we got a PIWIS and never looked back so I honestly never played with the Durametric much, and it collects dust somewhere in a drawer (anybody want it for cheap? ;-)

AC/911's

Disconnect battery overnight, reconnect, get warm, & see if you get .8 bar back, if you do, you might have gunked up Maf? Mine would return & then just go back to .5 again & I'd get passed by sl55's & Subaru's!

badabing

Chris,

Thanks for the advice. A few questions;

Are these codes that would not trigger a CEL as I do not have one and a scan with an OBDII reader yields no current or pending codes.

I do have a Ross-Tech VagCom which is capable of reading, logging, and charting actual values for MAF, RPM, IAT, etc. Is there a way to test it using that info?


Do you mean replace the MAF or the air filter and open airbox? Luckily I retained the original airbox and have a brandy new OEM air filter. What about reinstalling the OEM airbox with the K&N filter in it?

PM sent regarding buying your Durametric.

Thanks!

AC/911's

I don't think its box or filter,from what I understood on mine the MAF was getting wrong readings & telling ECU to reduce boost, you might just need to get MAF cleaner, you spray it all through the inside & directly on the little sensor, don't wipe or rub & let dry

badabing

Did that already with CRC MAF cleaner.

Droops83

The plausibility fault codes in question may or may not set a check engine light. The generic OBDII reader may not be capable of seeing whatever faults may be in there.

I thought that the Ross-Tech only worked for VW/Audi, I have one too and it certainly works on those makes, but I doubt that it would work on Porsche, as the way that it works is totally different from other make's scan tools.

I would not replace anything without a proper diagnosis, but I have seen aftermarket intakes cause MAF fault codes on other cars (996s, BMWs), and of course a faulty MAF sensor could cause your issues. I would expect a faulty MAF to set fault codes, but I can usually tell if they are going south by looking at the air mass readings, fuel trim values, etc.

Don't use a K&N filter or any other that requires oiling on a hot wire MAF sensor engine.

I will check with my boss.

Once again, check for boost/vacuum leaks first and eliminate that variable.

badabing

The majority of the features do not work but I was able to utilize the OBDII, actual values, and readiness monitor status functions successfully.

Is there some infomation available as to what the MAF readings should be at various RPM's so I can see where I'm at. I read on here that there is a TSB that indicates what values should be at idle and 2500 rpm (while standing still) but cant find that TSB.

I was having this problem prior to doing a full tune up and valve cover gaskets in which i removed the turbos and all their plumbing as well as the intake runners. Everything was gone over twice with regards to reconnections and tightness. I'm comfortable that is not the issue.

WingChun

Couple of things to check (if not already):
1. Are the waste gate linkages set correctly from the control boxes and do the gates move freely?
2. Does the boost on the gauge rise, to say .6 or .7 when a WOT is snapped closed, or does it never go above .5?
3. Does the motor seem strong upto .5 boost or struggling?

badabing

The linkages have not be moved or changed since the car left the factory. I did have the turbos out recently for the first time ever but they were taken off as an assembled unit and replaced as such. I don't believe anything was disturbed regarding the linkages or their adjustments. Can I check the gates movement with the turbos installed? How would I do this? Could I just hook up an air supply to the control boxes and see if they move when pressure is applied?


I'll try this test to be sure but i haven't seen it go past .5 bar under any circumstance so far.

The motor seems fine. I bet if someone (not an expert on these cars) drove it and did not know about the .5 boost limitation, they would not suspect something was even wrong.

maybe i should try and video the tach and obc so you can see how fast the boost builds up relative to the rpms. would that give any additional clues?

thanks to everyone for their help so far and keep the info coming.