Mass Airflow Sensor readings

[speedosack]

Anyone know why my MAF will not peg on a WOT blast? Tried two different MAF sensors and both max out at ~225-240 according to directscan. These are both stock sensors.

I've attached a link to the directscan file if someone wants to take a look. I have more.
http://home.nc.rr.com/weinstein/RUN2.DAT

Mods:
1) turbotweak street chip
2)adjustable wastegate actuator set to 17psi.
3)32 lb injectors
4)adjustable fuel pressure regulator set to 43.5 psi
5)walbro 307 pump
6)cold air intake
7)pypesperformance exhaust

 

[turbojd]

Are the stock mafs rebuilt ones, it so most of them are not calibrated properly, thats why I went with the translator and 3" LT 1 maf, your just rolling the dice trying to get a properly calibrated rebuilt stock maf.

 

[speedosack]

I have a completely stock original MAF and a rebuilt one. Any other explanations that may be offered?

For the sake of clarity let's not talk about the translator option in this post.

 

[salvageV6]

I'll go out on a limb here and say it's possible to not max. out the stocker at around that boost.

If your boost gauge was off/high a pound or two it's also possible for sure.

What kind of cold air kit do you have and how is it plumbed in there?

What boost level is the chip burnt for?

 

[speedosack]

I'll test the boost gauge. This is the CAI system (Performance Systems Manufacturing, LLC). It makes this awful whooosh sound when I let off full throttle- I guess going from boost to vacuum suddenly.

The chip is burned for 15-17 psi. I guess you are saying it's possible that nothing is wrong at all?

 

[TurboMonte 2]

It makes this awful whooosh sound when I let off full throttle- I guess going from boost to vacuum suddenly.

The horst-fart/ whoosh is when the system is pressurized under boost, then when the throttle plate slams shut, the added pressure rapidly relieves from the IC/ turbo system out thru the MAF/ CAI system/ & finally the inlet filter==BIG WHOOSH No vacuum involved...

 

[GRAY86T-TYPE]

With a Turbo Tweak chip the MAF should be locking onto 255 grams per seconds under WOT. This is a feature of the TT chip....it should do this no matter what. I just changed my stock one out for an LT1 last week(just because I got a good deal). Mine would lock on to 255 at 1/2 to full throttle, and was very consistant. Car does run better with LT1, if you are looking to upgrade. I thought it wouldn't make much of a difference, but the car has more power at less boost. Why it does what its doing? Could be going bad.....could be dirty......try MAF cleaner. I know when my pipe pops off the turbo, the sensor would go a couple of grams up at idles 8 or 9 but would fix itself. They are very tempremental, but I have no complaints with a stock one....hope this helps

 

[GRAY86T-TYPE]

Have another questions for you.....sorry to go off topic, but how do you like your pypes exhaust...I'm going to try and get a race pro one soon....any likes or dislikes.....Thanks....

 

[speedosack]

So when you say performance gain with the LT1 setup how much are we talking here. A few HP ain't worth it for my application. My MAF sensor is clean as they get so that's not the problem.

My pypesperformance comments:
www.turbobuick.com/forums/pypes.html

 

[WS6]

With a Turbo Tweak chip the MAF should be locking onto 255 grams per seconds under WOT. This is a feature of the TT chip....it should do this no matter what.

Help! I was starting from scratch on a tune and I set the boost at 12 PSI. As I was collecting data I decided to watch the AF on the scanmaster and it wouldn't go over 176-178 under WOT clear up to 100 MPH. The idle numbers are consistent at 5-6.

This is with a translator and a used 3" LT1 maf. I thought the car was running better with this set up, but maybe not? I guess I never really looked at WOT air flow numbers before. I just assumed if the idle numbers were correct they would be correct all the way up.

I have a TT chip so I'm a bit confused by your statement.

 

[johnnyttype]

Help! I was starting from scratch on a tune and I set the boost at 12 PSI. As I was collecting data I decided to watch the AF on the scanmaster and it wouldn't go over 176-178 under WOT clear up to 100 MPH. The idle numbers are consistent at 5-6.

This is with a translator and a used 3" LT1 maf. I thought the car was running better with this set up, but maybe not? I guess I never really looked at WOT air flow numbers before. I just assumed if the idle numbers were correct they would be correct all the way up.

I have a TT chip so I'm a bit confused by your statement.

Straight off the TT website: "-MAF/LV8 locks on to 255 under wide open throttle conditions for consistency."

it says its supposed to lock but maybe your not meeting certain criteria or something

 

[TurboMonte 2]

Help! I was starting from scratch on a tune and I set the boost at 12 PSI. As I was collecting data I decided to watch the AF on the scanmaster and it wouldn't go over 176-178 under WOT clear up to 100 MPH. The idle numbers are consistent at 5-6.

This is with a translator and a used 3" LT1 maf. I thought the car was running better with this set up, but maybe not? I guess I never really looked at WOT air flow numbers before. I just assumed if the idle numbers were correct they would be correct all the way up.

I have a TT chip so I'm a bit confused by your statement.

At 12# boost it's not necessary true that you'd do a 255/max. And, you don't need WOT @ 100 mph to test any more than just a max in 1st or 2nd. Air flow is about engine rpm--not vehicle speed...

 

[A2000RICH]

Anyone know why my MAF will not peg on a WOT blast? Tried two different MAF sensors and both max out at ~225-240 according to directscan. These are both stock sensors.

I've attached a link to the directscan file if someone wants to take a look. I have more.
http://home.nc.rr.com/weinstein/RUN2.DAT

Mods:
1) turbotweak street chip
2)adjustable wastegate actuator set to 17psi.
3)32 lb injectors
4)adjustable fuel pressure regulator set to 43.5 psi
5)walbro 307 pump
6)cold air intake
7)pypesperformance exhaust

i have a flowbench set up just to test MAFs----its possible the you arent meeting all the conditions to max the thing out-----especially with a small turbo and not enough room to really tax the engine------if you want to clear up all doubts i would be glad to test it for you-----i can supply you with a calibration curve------all it will cost you is shipping..........RC

 

[Eric Stage I]

MAF/LV8 locks on to 255 under wide open throttle conditions for consistency.

Airflow has to get up close to 255 before it will lock on.

 

[WS6]

At 12# boost it's not necessary true that you'd do a 255/max. And, you don't need WOT @ 100 mph to test any more than just a max in 1st or 2nd. Air flow is about engine rpm--not vehicle speed...

Yes, I hadn't thought of that. I was testing 3rd 4th gear O2's and I thought I'd switch over to AF's.

Anyway...with no changes from yesterday except for taking the LT1 and translator out and putting in the original OEM maf the car went 215-235 and then locked on 255. I tried it back to back to back runs and it went to 255 each time and locked there.

Looks like I may have a bad LT1 MAF? I thought those things were reliable.

Strange enough too...my idle BLM's are now lower than the 130 they were before with the LT1 maf. They are now 126 and sometimes 123. I don't get that??