natronathon

When logging with my hptuners I am getting MAF values at WOT of only 26-28 lbs per min. I have heard that this is low, and I think it is causing the computer to make me run lean and therefore get high LTFT numbers... Is this the case, or are these values normal MAF readings for a 98. I took the MAF off today and cleaned it with some electronics cleaner, but it didnt make much of a difference. Any thoughts?

Thanks,
Nathan

technical

Yes that does seem low. What was the MAF frequency and RPM at 20lbs? Have you modified your MAF calibration table?

RedHardSupra

iTrader: (1)

that is low, most stockish cars do 35-36. i'd guess you have a leak somewhere, take it apart, put it back together, make sure that everything fits without any spaces.

how much air you can 'eat' is a good ballpark measurement of how healthy/strong your car is. the really fast cars with big head/cam/intake can get 48+lb/min. my car even though has a tiny cam goes as fast as another guy's with a bigger cam, but his is 'eating' 5-6 lb/min less air than mine. that practical power difference can also be seen in injector duty.

natronathon

i havent done anything to the maf tables at all. the only things ive changed are transmission settings. The rpm at 20 lbs was 4000, how do i check the MAF frequency?

edit: I checked the the mass airflow vs output frequency in vcm editor, and I see that the MAF should be outputing somewhere around ~8050 hz. but i wasnt recording the frequency on the scanner, so i dont know if thats what the output was or not...

SmokingWS6

iTrader: (1)

I just checked a customers 98 lid only car. It looks like the most he hit was 33 at wot. Average was around the mid/upper 20's.

technical

For comparison, my heads/cam/headers car peaks at ~45 lbs at 6500 rpms and MAF freq of 10500hz. No MAF calibration changes.

SmokingWS6

iTrader: (1)

Same here. Peak of 47 though

natronathon

hmmm. well im gonna go do some logging on it again, and ill let ya know what the maf frequency is at 20 lbs. also Im gonna check to make sure everything between the lid and throttle body is sealed up well.... it should be.... is there any possibility that I just have a bad MAF???

natronathon

well, i checked the hose running between the maf and the throttle body and it is very secure and sealed. also, I am not able to make my vcm scanner monitor the MAF frequency using hptuners. I added the measurement to my chart display, but it simply duplicates the item being measured above it(Manifold air pressure).... why is this? how do I make it display the MAF frequency correctly? Also, when i went out today the MAF reading was still around 28. Would a frequency of 95 hz be close to correct, because at one point thats what it was saying, when the maf was regeristering 20lb/min. I thought that sounded to high to be a value copied from the MAP item....

any help would be greatly appreciated, this is all still a bit new to me...

thanks
Nathan

SmokingWS6

iTrader: (1)

in HPT go under engine<airflow<Mass Air Flow (HZ)

If you've ran an K&N for a long time your maf might have some reseidu on the diodes, a gentle touch with a qtip and rubbing alcohol might help. Also in most cars I have tuned with a lid, the maf table is as much as 15% off on average after ve tuning causing trim to run up to +15.

If you can send me your scans and bin file I might be able to help you out.

natronathon

well, i have a lid, but thats all. I dont use a K&N, and I actually cleaned the maf already as well.

When you say go under engine>airflow>mass air flow hz, are you talking about when selecting another item to show on the graph, because thats exactly what i did, and it simply duplicates the map reading, or whatever reading is directly above it...

SmokingWS6

iTrader: (1)

Thats odd. Email Support@hptuners.com

If you can get me some scans and your file I can probalby get the fueling taken care of.

natronathon

sure thing thanks...
pm sent

technical

Yeah, but my freq is higher...