Mark #2
11-12-2003, 06:29 PM
Posted on 150 online,
I have a 90MAF and a 4 lb pulley that I have run on the stock program a few times. I know a couple of others that have run down the track this way.
Do NOT drive a '99 or '00 L with a 90mm Ford MAF on there and a pulley on the stock factory program - you *will* run lean (from the MAF), and you *will* run out of MAF voltage in the stock program at heavy throttle, too.
The stock program only gives you 4.78 volts of the total 5.0 volt MAF range - and while that sounds like a very small difference, the actual difference in CFM & additional load that having the full 5.0 volt range allows the PCM to continue responding properly to is significant.
Here's the kicker - all it takes to run out of MAF voltage in the stock program in any year Lightning is a 4 PSI pulley - with a 4 PSI pulley, this happens anywhere from as low as 3900 to as high as 4400 rpm in 3rd gear @ WOT for example, and can happen even sooner (in terms of both rpm and load via which gear) depending on atmospheric conditions & terrain.
If you have the stock 80mm MAF, as someone else suggested, please put that back on and *then* you could drive it *gently* and carefully with that pulley on there until you got the chip back - but *NO* heavy-throttle usage of any kind during this time. If you do not have that original 80mm MAF that you can swap out temporarily, then don't drive it at all - those 90mm Ford MAF's found on 2001 & newer Lightnings will lean out the A/F on the 1999 & 2000 Lightnings (and other FoMoCo vehicles) by as much as more than 2 full points (say, 12.0:1 to 14.0:1), and that's with a *stock* pulley!
Even though most of us know many of the '99 & '00 bolts are pig-rich A/F from the factory, some are 10.3:1 and some are 11.4:1 in those 2 model years- thus you could easily end up significantly leaner than 13.0:1 A/F.
Yes, some people seem to "get away with" doing things like that for a period of time, but that doesn't change the facts or lessen the risk in any way. Many times you won't get a SES light warning you of the lean condition at all, or not until you are either at or slightly beyond meltdown range - thus we can't depend on a SES (or check engine) light to warn us.
Certainly there is variance in all these L's, and if those variances stack up "in your favor" with a particular mod combination, yes, you could get lucky and have it last for a while - maybe even a good while, depending - but our advice is to *never* run a 90mm MAF on the stock program on a 1999 or 2000 Lightning (even with *stock* boost levels) due to the gross leanout - there is no way to know exactly how lean you will go without actually testing the A/F's - or how long you can run like that before hurting something - and it's not worth taking a risk. The combination of a 90mm Ford MAF & a 4 PSI pulley on a 99 or 00 L running on the stock factory program is a recipe for potential disaster.
The age-old question of why do you need a chip to run a pulley is answered right here - it's due to the limited MAF voltage allowed in the stock program on these Fords, that will cause you to run out of MAF voltage - no 2 ways about it, that *will* happen - and when you reach *that* point, the PCM can no longer properly respond to load. Then you're just begging for trouble. It doesn't matter if someone claims they did that or are doing that, all that says if they are taking a big chance, and that perhaps nobody has ever explained this to them.
If you're still not sure about this, please call whatever tuner you are dealing with and ask them to explain this to you in detail and give you advice.
I'm sorry, I really don't mean to rain on anyone's parade, so to speak - it's just important that you know the facts, what really happens & what risks you are taking by running that mechanical configuration on the stock program.
Remember, even on lighter throttle and in closed loop, the PCM only has so much effective "compensation range" for lack of a better term, meaning the % of fuel it can add to correct/combat a detected lean condition. The pulley by itself you could get away with **as long as you drive it easy and NEVER use heavy throttle** - very hard for us Lightning owners to do. http://www.f150online.com/forums/images/smilies/smile.gif But that 90mm MAF is a gross leanout, so the total combination is not "safe" to operate on the factory tune, we do not consider that an acceptable risk.
Best of luck whatever you decide,
I have a 90MAF and a 4 lb pulley that I have run on the stock program a few times. I know a couple of others that have run down the track this way.
Do NOT drive a '99 or '00 L with a 90mm Ford MAF on there and a pulley on the stock factory program - you *will* run lean (from the MAF), and you *will* run out of MAF voltage in the stock program at heavy throttle, too.
The stock program only gives you 4.78 volts of the total 5.0 volt MAF range - and while that sounds like a very small difference, the actual difference in CFM & additional load that having the full 5.0 volt range allows the PCM to continue responding properly to is significant.
Here's the kicker - all it takes to run out of MAF voltage in the stock program in any year Lightning is a 4 PSI pulley - with a 4 PSI pulley, this happens anywhere from as low as 3900 to as high as 4400 rpm in 3rd gear @ WOT for example, and can happen even sooner (in terms of both rpm and load via which gear) depending on atmospheric conditions & terrain.
If you have the stock 80mm MAF, as someone else suggested, please put that back on and *then* you could drive it *gently* and carefully with that pulley on there until you got the chip back - but *NO* heavy-throttle usage of any kind during this time. If you do not have that original 80mm MAF that you can swap out temporarily, then don't drive it at all - those 90mm Ford MAF's found on 2001 & newer Lightnings will lean out the A/F on the 1999 & 2000 Lightnings (and other FoMoCo vehicles) by as much as more than 2 full points (say, 12.0:1 to 14.0:1), and that's with a *stock* pulley!
Even though most of us know many of the '99 & '00 bolts are pig-rich A/F from the factory, some are 10.3:1 and some are 11.4:1 in those 2 model years- thus you could easily end up significantly leaner than 13.0:1 A/F.
Yes, some people seem to "get away with" doing things like that for a period of time, but that doesn't change the facts or lessen the risk in any way. Many times you won't get a SES light warning you of the lean condition at all, or not until you are either at or slightly beyond meltdown range - thus we can't depend on a SES (or check engine) light to warn us.
Certainly there is variance in all these L's, and if those variances stack up "in your favor" with a particular mod combination, yes, you could get lucky and have it last for a while - maybe even a good while, depending - but our advice is to *never* run a 90mm MAF on the stock program on a 1999 or 2000 Lightning (even with *stock* boost levels) due to the gross leanout - there is no way to know exactly how lean you will go without actually testing the A/F's - or how long you can run like that before hurting something - and it's not worth taking a risk. The combination of a 90mm Ford MAF & a 4 PSI pulley on a 99 or 00 L running on the stock factory program is a recipe for potential disaster.
The age-old question of why do you need a chip to run a pulley is answered right here - it's due to the limited MAF voltage allowed in the stock program on these Fords, that will cause you to run out of MAF voltage - no 2 ways about it, that *will* happen - and when you reach *that* point, the PCM can no longer properly respond to load. Then you're just begging for trouble. It doesn't matter if someone claims they did that or are doing that, all that says if they are taking a big chance, and that perhaps nobody has ever explained this to them.
If you're still not sure about this, please call whatever tuner you are dealing with and ask them to explain this to you in detail and give you advice.
I'm sorry, I really don't mean to rain on anyone's parade, so to speak - it's just important that you know the facts, what really happens & what risks you are taking by running that mechanical configuration on the stock program.
Remember, even on lighter throttle and in closed loop, the PCM only has so much effective "compensation range" for lack of a better term, meaning the % of fuel it can add to correct/combat a detected lean condition. The pulley by itself you could get away with **as long as you drive it easy and NEVER use heavy throttle** - very hard for us Lightning owners to do. http://www.f150online.com/forums/images/smilies/smile.gif But that 90mm MAF is a gross leanout, so the total combination is not "safe" to operate on the factory tune, we do not consider that an acceptable risk.
Best of luck whatever you decide,