MAF Sensor - a maintenance item?
#16
Nordschleife Master
http://www.durametric.com/
This is what I have for the Audi
http://www.ross-tech.com/
#17
Rennlist Member
Thread Starter
This is all I have found for the 993
http://www.durametric.com/
This is what I have for the Audi
http://www.ross-tech.com/
http://www.durametric.com/
This is what I have for the Audi
http://www.ross-tech.com/
http://p-car.com/obd-2/
It's around $122. I'm told it will work on my 96 993 and my M5 which would be great. I just spoke with the company and was told MAF flow in lbs/hr is available to view. This is the value I want to see rather than the actual MAF voltage output. It would be nice to plug in a laptop, go for a drive, and record all the measurements. A main point will be determining what values the sensors should be producing at wide open throttle so I have comparison points.
If I can line up a laptop, I plan to give it a try. Right now I just have a company laptop with no administrative priviledges to add software.
I recognize that if I'm going to continue working on these cars in the future, having OBD software will be a requirement, unless I just want to do trial and error; so I might as well get the setup now rather than waiting for a problem to crop up.
#18
Nordschleife Master
Here's another option on P-Car.com.
http://p-car.com/obd-2/
It's around $122. I'm told it will work on my 96 993 and my M5 which would be great. I just spoke with the company and was told MAF flow in lbs/hr is available to view. This is the value I want to see rather than the actual MAF voltage output. It would be nice to plug in a laptop, go for a drive, and record all the measurements. A main point will be determining what values the sensors should be producing at wide open throttle so I have comparison points.
I recognize that if I'm going to continue working on these cars in the future, having OBD software will be a requirement, unless I just want to do trial and error; so I might as well get the setup now rather than waiting for a problem to crop up.
http://p-car.com/obd-2/
It's around $122. I'm told it will work on my 96 993 and my M5 which would be great. I just spoke with the company and was told MAF flow in lbs/hr is available to view. This is the value I want to see rather than the actual MAF voltage output. It would be nice to plug in a laptop, go for a drive, and record all the measurements. A main point will be determining what values the sensors should be producing at wide open throttle so I have comparison points.
I recognize that if I'm going to continue working on these cars in the future, having OBD software will be a requirement, unless I just want to do trial and error; so I might as well get the setup now rather than waiting for a problem to crop up.
This is a log that I graphed with my Vag-com
I use a older Dell laptop, that is super small, is only a p800, it's like $150 used! Runs XP fine, the only downside is it doesn't have a internal CD, but it's like 3lbs & fits in my lap when I drive.
#19
Drifting
[QUOTE=Stealth 993;4995629]This is all I have found for the 993
http://www.durametric.com/
Don't have have a laptop so the Durametric isn't under consideration. The two handhelds I've seen that have "live scan" are the Actron 9145 and Equus 3130. I wonder if these more sophisticated type of hand-helds can check the function of the MAF and specific sensors?
http://www.durametric.com/
Don't have have a laptop so the Durametric isn't under consideration. The two handhelds I've seen that have "live scan" are the Actron 9145 and Equus 3130. I wonder if these more sophisticated type of hand-helds can check the function of the MAF and specific sensors?
#20
Rennlist Member
Hi:
I don't consider a MAF a regular replacement item unless its failed or been contaminated.
I do clean them with a special solvent made specifically for MAF's (CRC) and I clean the throttle assembly every 50K for best idle & performance. The latter item gets coated with oil from the oil tank breather over time and that affects idle and off-idle therottle response. Carb cleaner works best for that application.
I don't consider a MAF a regular replacement item unless its failed or been contaminated.
I do clean them with a special solvent made specifically for MAF's (CRC) and I clean the throttle assembly every 50K for best idle & performance. The latter item gets coated with oil from the oil tank breather over time and that affects idle and off-idle therottle response. Carb cleaner works best for that application.
#21
Technical Guru
Rennlist Member
Rennlist Member
Many M5 owners who were not achieving full fuel flow rate under full throttle saw the fuel flow and also power increase after the MAFs were replaced.
If anyone is interested in the tech discussion, it's in the attached link.
http://www.m5board.com/vbulletin/showthread.php?t=54788
If anyone is interested in the tech discussion, it's in the attached link.
http://www.m5board.com/vbulletin/showthread.php?t=54788
#22
RL Technical Advisor
As Jason wrote, the 993 hot-wire MAF's are pretty trouble free and I've not seen many outright failures unless they became contaminated by something like an over-oiled K&N.
#23
Rennlist Member
#24
Rennlist Member
Thread Starter
Even on the M5, there are few if any outright failures of the MAF despite the difference in technologies you mention. The entire purpose of my question was around MAFs that had not failed outright.
The issue is how to tell if the 993 MAF reading is inaccurate. What I understand is that the deviations from factory accuracies will occur over time regardless of the robustness of the sensor. I understand that the same deviations occur with the O2 sensors over time so they do have a recommended replacement interval.
I'll do a little more digging into the issue later this year to see what I find out.
#25
Do you have a DIY to clean the MAF? I used the search engine and nobody have one.. I clean my ISV yesterday but it was not to bad. And now I want to clean the MAF... Anybody can help me...
#26
Burning Brakes
This is a guide for the BMW E39 M5 but it applies just the same to any MAF. Since you cleaned the ISV you know where the MAF is. Just remove it and follow this guide. This guide is a bit overkill though.
http://www.louv.tv/cars/m5/MAF/
In simple terms, remove the MAF cylinder(you don't have to take out the MAF sensor from the cylinder unless you want to inspect it) and give it a few lengthy shots of CRC MAF sensor cleaner from autozone/pepboys etc. I've used this on both MAFs in my M5 and the single MAF in my 993 Turbo. I have NOT used simple green on it.
http://www.louv.tv/cars/m5/MAF/
In simple terms, remove the MAF cylinder(you don't have to take out the MAF sensor from the cylinder unless you want to inspect it) and give it a few lengthy shots of CRC MAF sensor cleaner from autozone/pepboys etc. I've used this on both MAFs in my M5 and the single MAF in my 993 Turbo. I have NOT used simple green on it.
Last edited by Jenner; 03-30-2008 at 06:41 PM. Reason: typo
#27
Nordschleife Master
In simple terms, remove the MAF cylinder(you don't have to take out the MAF sensor from the cylinder unless you want to inspect it) and give it a few lengthy shots of CRC MAF sensor cleaner from autozone/pepboys etc. I've used this on both MAFs in my M5 and the single MAF in my 993 Turbo. I have NOT used simple green on it.
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#28
Addict
Rennlist Member
Rennlist Member
The MAF used in the M5 is based on newer hot-film technology (the writeup on the M5 BBS has the terminology wrong) like the type 996 and unlike the type 993 that uses an older and more robust hot-wire based sensor. Two different technologies that shouldn't be compared. At most you should clean the 993 MAF sensor and only replace if the sensor readings starting biasing in one direction or get all wacky.
Is that correct re the 993 sensor ??
I have checked in Porsche 911 Story .. Paul Frere says on p 96 (7th Ed), when discussing M64 05/06 engines (first 993 motors), that the hot wire system of the M64 /01 (964 engine) is replaced with the 'latest' Bosch hot film system .. likewise Tobias Achele's 911 Engine History & Development p 74 ..
Definitively, Workshop Manual Vol VIII p 24-13 "Hot-film mass air flow sensor" ..
cheers, Maurice
Last edited by maurice97C2S; 03-31-2008 at 02:05 PM.
#29
Rennlist Member
This is a guide for the BMW E39 M5 but it applies just the same to any MAF. Since you cleaned the ISV you know where the MAF is. Just remove it and follow this guide. This guide is a bit overkill though.
http://www.louv.tv/cars/m5/MAF/...
http://www.louv.tv/cars/m5/MAF/...
#30
Technical Guru
Rennlist Member
Rennlist Member
I have checked in Porsche 911 Story .. Paul Frere says on p 96 (7th Ed), when discussing M64 05/06 engines (first 993 motors), that the hot wire system of the M64 /01 (964 engine) is replaced with the 'latest' Bosch hot film system .. likewise Tobias Achele's 911 Engine History & Development p 74 ..
Definitively, Workshop Manual Vol VIII p 24-13 "Hot-film mass air flow sensor" ..
Definitively, Workshop Manual Vol VIII p 24-13 "Hot-film mass air flow sensor" ..
996 MAF HotFilm Sensor
964 AFM Sensor