LOL, no worries Mike

 

I already let 'em know a couple of months back so I think they're on it

 

mine went bad recently,
i replaced it with a boxter maf (looked more sturdy at the
advice of a bosch engeeneer) he said that the wire
is thiker and sturdier then the 996tt version should
hold out with the cone evo filter.

Boris

 

Boris, I heard the only difference you have noticed with your Boxter MAF is a higher idle . . . have you since noticed any other differences? High much higher is the idle?

Thanks,

Craig

 

Upsolute chip, EVO intake, 3.5 years and 25,000 miles. Still hangin' in there with the original MAF.

 

Remember, though, you can log both short and long term fuel trim. The long term should be closer to 0 while the short term (STFT) will vary with your driving conditions (and will change more often than the LTFT).

By the way, I am able to get 15-18 samples per second on my PDA with the pocketlogger software. Basically, you can turn your "timing" settings down to 0 or close to it. I think that mine is 100 and 5 for the two settings.

 

I didn't read all the posts, but the number of stock would greal exceeed modified. Would be nice to know the percentages of those with stock who have had issues and the percentage of those with the modifications have had failures.

 

When you guys say you "have blown the MAF", just what are you talking about? How do you know the MAF is bad or simply needs cleaning or calibrating? Seems like alot of poeple love to blame the MAF (dealers especially) and just replace the part without any sound investigation. I have poured oil on mine, run exptreme boost, run it how, run it without filter, etc, and still have the stock MAF installed and running fine. Obviously it has needed cleaning, but I see no way the MAF can fail unless it is physically broken and I cannot see how the mods you are talking about will break it.

Just curious as to how many here are simply taking the easy way out and replacing the MAF unecessarily? I would be curious to see the sensor readings of the old MAF versus the new one.

 

craig,

the idle seems fine to me. no change



boris

 

How do you clean the MAF. I'll give it a shot.

Mike

 

I haven't found anything that will kill the MAF. For periodic cleaning, I just use an electronic spray cleaner. I have also used GUNK, carb cleaner and rubbing alcohol. Take a reading of the MAF (g/sec) before and after cleaning and you'll see the difference if it was dirty.

 

When I got home from work I plugged in the pocket logger and here's what I got (@ idle)

STFT1 ~ +5% (bouncing around)
LTFT1 = -2%
STFT2 = -2%
LTFT2 = -2%

Assuming the fuel trim 1 & 2 are the same as bank 1 & 2 O2 sensors, this sounds like it confirms the P0130 bank 1 sensor 1 O2 sensor (being replaced Wednesday) CEL.

 

You make an interesting point. I thought this was some kind of electronic sensor (almost like a fuse) that could "burn out". But to be honest I don't know either. Most of what I know comes from here, Rennlist, my mechanic and the dealers (so I am conciously incompetent). Very little science being applied. Perhaps someone can actually tells us what the MAF is. We may then understand its purpose, its design and ultimately figure out a better way. What am I thinking...let's just blame the manufacturer and be done with it!

 

I do not know how a device made up of resisters (thermister and hotwire) can be destroyed by any other means than a physical breakage or an internal short. Either it works or it doesn't. The only variance in operation is the condition of the hotwire. If it is not broken it works the way it was designed. If it becomes dirty, it will not work as designed, but can be cleaned over and over again. Do you get new fuel injectors when they get dirty? Like the throttlebody and injectors, the MAF it is a regular maintenace item and should be cleaned peroidically on cars that have modified intake systems.

 

That is correct. Hosed O2 sensors play a direct roll in the STFT calibration, but it is still an indirect measurement. The device is great, isn't it? Knowledge is power when going to the dealer.

Here is explanation from the pocket logger website:

http://www.pocketlogger.com/index.ph...ams&type=obdii

Range: -100 to +99%
Bank: 1 or 2
Fuel Trims are correction factors applied to the base fuel map. When in closed loop mode, the O2 Sensor is used to adjust the trims based on the sensor's values. A positive trim indicates the ECU is adding fuel (a lean condition), and a negative trim indicates the ECU is taking away fuel (a rich condition) from the base fuel map. Fuel trims are not used in open loop mode.

Short Term fuel trims differ from Long Term trims in that Short Term trims are not stored between starts and they change more frequently. If there is a trend in a short term trim, eventually the long term trim will adjust to move the short term trim back to zero. This allows the ECU to adjust it's fuel map to compensate for variances in sensors or dirty injectors, etc.

The Bank indicates a group of cylinders. Inline motors typically have 1 bank. V motors have two banks. Typically there is an O2 sensor for each Bank and that is the sensor the trims use to adjust themselves. Bank 1 always contains cylinder number 1.