maf hesitation issues

[liquidracing]

so, i've been reading about a MAFv issue occuring on n/a model 2.2 and 2.5(seem worse than 2.2).
the issue:
at 1000-1800ish rpm, at wot, the short ram and even simple snorkus deletes have proven to have an adverse reaction to a/f ratios resulting in what i misunderstood to be a "lean" mis-fire. i have since learned that this was exactly dead on!

what happens, from how i understand it, is a resonance created by the micro-pulses of air inside the immediate opening to the maf senser at that low rpm cause the cpu to WAAAAYYYY over-estimate air flow.

how maf works:as you throttle up air passes through the maf senser at an increasing rate, cooling maf "wire", voltage increases, telling cpu to dump more fuel and heats wire back to desired "pre-determined" heat range. the exact opposite happens when you let off throttle.

what happens with snorkus delete and sri(short ram):
the maf is subjucted to MUCH less airflow restriction and thus getting a "cooling" effect as opposed to an air "movement" effect. couple this with less than desirable resonant frequencies and you have this SERIOUS hesitation from the engine.

how to fix it:
unfortunately the easiest/cheapest way is to re-install the snorkus back onto the intake tract, which will yeild a small disadvantage over true cone sri, but, only from about 4000rpm and up.

testing:i am curious about wether or not anyone has ever moved the maf sensor up the intake tract before, and, would that help the cooling/resonance issue described here?

the reason i ask is that i love the sound of my car with my sri and c-bomb exhaust! i would like to keep the cone in operation until i'm finished with wotec and it necessitates changing back to the stock box.

i have almost been hit in intersections at least a dozen times because of this "issue", both with and without my kids in the car. i'm not losing my children because of some damn frequency or quasi-pseudo air flow hiccup that a maf can have! i am amazed nobody has ever reported being hit or almost hit as a result of this. like i said, i love the sound, but, at what cost? life? nope. there are always alternatives, aren't there?

[liquidracing]

anyone ever move their stock maf location?

[99gtlimited]

i have a hybrid intake with short ram piping attached to the stock airbox and noticed the hesitation as well, form what i understand this also puts the engine under very heavy load in this lower RPM range. My car certainly never hesitated so badly to the point where i was almost hit, however i did not like the idea of the car working much harder than it needs to so i reinstalled the snorkus and have been very happy ever since. no noticeable loss of power in the upper RPM's and a small gain in low end torque was created due to larger plenum of available air in the system (since i have no torque box). This is very ideal for me, as i get the benefits of the less turbulent tubing without losing low-end torque.

[liquidracing]

i have a hybrid intake with short ram piping attached to the stock airbox and noticed the hesitation as well, form what i understand this also puts the engine under very heavy load in this lower RPM range. My car certainly never hesitated so badly to the point where i was almost hit, however i did not like the idea of the car working much harder than it needs to so i reinstalled the snorkus and have been very happy ever since. no noticeable loss of power in the upper RPM's and a small gain in low end torque was created due to larger plenum of available air in the system (since i have no torque box). This is very ideal for me, as i get the benefits of the less turbulent tubing without losing low-end torque.

sounds like my situation as i also have no "torque" box. i'll be replacing the snorkus. any knowledge on moving the maf farther back in the air stream closer to the tb?

[ScaryFatKidGT]

??????? I took my snorkus out and i have no more hesetation than i did with out it?????? Theres a little lag from 1000-2000 RPM but that has always been there?

I wouldn't waste ur time with a SRI and just do a CAI that is if your palstic splash protector is still there

[anothernord]

You could possibly try to extend the piping in front of the MAF to extend either into the fender or forward towards the front of the car.

This might give the air more time to stabilize before it reaches the MAF. This is just an idea; no scientific backing to it.

[decke48]

the way to fix the issue is to put a resonator right after the MAF (like the cobb CAI) basicly it a 6inch long 4in diameter pipe with a piece of 3 inch pipe thats 4inchs long inside of it. it help eliminate the turblence before the MAF

[liquidracing]

??????? I took my snorkus out and i have no more hesetation than i did with out it?????? Theres a little lag from 1000-2000 RPM but that has always been there?

I wouldn't waste ur time with a SRI and just do a CAI that is if your palstic splash protector is still there

already "wasted" my time! i love the upper rpm range, but, down low?
i've already done this:
https://sl-i.net/FORUM/images/imported/2008/09/100_2602-1.jpg

so, the question is, again, has anyone ever moved their maf up the intake tract?

decke, i may try that if i can't get an answer on this maf move.

[anothernord]

I'm sure it would work to move it up the intake, but you may have to lengthen the wire and relocate some of the vacuum tubing.

[liquidracing]

I'm sure it would work to move it up the intake, but you may have to lengthen the wire and relocate some of the vacuum tubing.

that'd be alright. i'm still unsure of what i'm gonna do, 'cause it'ss all temporary no matter how you look at it.

[Huffer]

Get another intake pipe, and build an extension harness from an old MAF (I have one here)... that way it's reversible.

Actually, depending on how far you move the MAF, the harness has quite a bit of slack already.

[liquidracing]

Get another intake pipe, and build an extension harness from an old MAF (I have one here)... that way it's reversible.

Actually, depending on how far you move the MAF, the harness has quite a bit of slack already.

do you have a picture? i think i know what it might look like, but can you help?

[Huffer]

My MAF is the same as the MAF you have in your car.

[liquidracing]

My MAF is the same as the MAF you have in your car.

i meant the extension harness....

[Huffer]

I said BUILD an extension harness. But I really doubt you'd need one.

[liquidracing]

oh shit! sorry so stupid....you meant the wire harness extension....i thought you modified the entire maf housing to be an extension somehow. duh! :lol:

[99gtlimited]

just noticed from your photo... you might want to take the breathers off your valve covers and re-route them back to the intake tract like stock. The previous owner of my car had done the same thing and once i re-routed it to flow into the intake my car started running better (smoother idle). Another thing you could do at the same time is incorporate a catch-can on that line.

yeah a little off topic i know, but i thought i'd mention it.

[decke48]

valve cover beather are not reccomended when the pvc valve is used. because of the reason the air in the crank case is not measured by the MAF. so if you like to keep the breathers remove the pvc valve and plug and add a breather crank vent

[liquidracing]

just noticed from your photo... you might want to take the breathers off your valve covers and re-route them back to the intake tract like stock. The previous owner of my car had done the same thing and once i re-routed it to flow into the intake my car started running better (smoother idle). Another thing you could do at the same time is incorporate a catch-can on that line.

yeah a little off topic i know, but i thought i'd mention it.

funny you should mention that! i've been debating with a ricer friend who swears by those breathers. i told him the second we put 'em on it felt a little weird. he said placebo, i said bs......here we are today!

[liquidracing]

valve cover beather are not reccomended when the pvc valve is used. because of the reason the air in the crank case is not measured by the MAF. so if you like to keep the breathers remove the pvc valve and plug and add a breather crank vent

NOPE!!!!!!!! i did that already. i used a moroso breather on the crank side and the car smelled nausious almost immediately. i even welded the pcv valve closed and re-routed the crank through the same breather....same nausious smell! i adamently implore anyone to leave the pcv valve and tubing alone. am actually going to re-route the lines back to the intake.

[99gtlimited]

good luck! i used a PVC T joint to reconnect the valve covers to my intake tubing, look at my members rides thread if you need a visual.

[liquidracing]

good luck! i used a PVC T joint to reconnect the valve covers to my intake tubing, look at my members rides thread if you need a visual.

i'll check it out. thanks for the input.