hesitation problems after mod

98_mustang_gt · Aug 29, 2004

I did this mod: http://www.corral.net/tech/powerplant/mafgut.htm

i gutted the maf and all replaced it all back together, but now my mustang has a huge hesitation from a stop. It is a 98 gt, automatic. Was running perfect before this, every i talked to said they had now problems doing this mod, i made sure not to touch or damage the sampling tube. Do i need to block up the new hole under the tube where the post was cut? I am disconnecting the battery to reset it and give that a try, But does anyone else have any ideas. I hope the mass air sensor isnt ruined i just replaced it weeks ago.

PG98GT · Aug 29, 2004

That's the first time I've heard of there being a hole in the bottom after removing the post. I've seen a couple that were done and neither of them had that extra hole. Maybe the sensor o-ring fell off or is twisted? It does sounds like an air leak somewhere in the intake tract though. Hope it's not that hole, can't see how it could be, I don't see how it could effect the air passing by the sensor, but these cars can be sensitive. Be careful with what you use to block the hole. If you've removed the screen, it may end up in your valvetrain or on top of a piston. Good luck

Route666 · Aug 30, 2004

The hesitation is most likely caused by a lean idle condition. This could be from the hole, but it is most likely because of the extra breathing space it has.

This mod also alters the amount of air your computer sees versus what the engine actually gets. The sampling tube is now most likely registering (esp. at low rpm) very low throughput of air compared to actual flow because of the reduced vacuum behind the sampling tube caused by the ported MAF. The air is flowing slower now for any given rpm than it was, due to overall volume demand being the same, but cross-sectional area of the inlet being increased. This leads to more air going to the engine because it is free to move, and less air going through the sampling tube as there is less of a restriction elsewhere.

You need to re-calibrate either your MAF, computer or battle the fudged airflow by fudging the fuel-flow as well, by using bigger injectors.

The sampling tube should also have one inlet and one outlet to get most accurate reading, having a hole in it may be accentuating the lean problem.

98_mustang_gt · Aug 30, 2004

hesitation

after i unhooked the battery and rehooked it up, it became worse and just about stalls out, i am going to try and block up that extra hole, i left the screen in, plus im gonna try to rotate the sensor a bit, hope this works. its basically undriveable right now

huesmann · Aug 30, 2004

Have you checked your idle air control valve?

98_mustang_gt · Aug 30, 2004

idle air control valve?

im not really sure how to do that, can you please explain

98_mustang_gt · Aug 30, 2004

problems

i tried blocking the hole, put everything back together, started it up, and it stalled, same over and over. So i removed that plug from the hole( by hole i mean right under the sample tube where i cut away the post, i leaves a hollow hole leading to the sensor tube from the bottom). I put everything back together very carefully and adjusted the sensor a little clockwise and im still leaning out, sputtering and nearly stalling at low rpms.

98_mustang_gt · Aug 30, 2004

does anybody know if this cylinder can be purchased without the mass air sensor on it, i would like to use the sensor i have. Also what is this silver cylinder called? i am trying to find the part

in the attachment, im talking about the part named "housing"

twogts4us · Aug 30, 2004

98_mustang_gt said:
does anybody know if this cylinder can be purchased without the mass air sensor on it, i would like to use the sensor i have. Also what is this silver cylinder called? i am trying to find the part

in the attachment, im talking about the part named "housing"

It is the MAF and can be purchased from FORD, or a boneyard...maybe...

twogts4us · Aug 30, 2004

Route666 said:
The hesitation is most likely caused by a lean idle condition. This could be from the hole, but it is most likely because of the extra breathing space it has.

This mod also alters the amount of air your computer sees versus what the engine actually gets. The sampling tube is now most likely registering (esp. at low rpm) very low throughput of air compared to actual flow because of the reduced vacuum behind the sampling tube caused by the ported MAF. The air is flowing slower now for any given rpm than it was, due to overall volume demand being the same, but cross-sectional area of the inlet being increased. This leads to more air going to the engine because it is free to move, and less air going through the sampling tube as there is less of a restriction elsewhere.

You need to re-calibrate either your MAF, computer or battle the fudged airflow by fudging the fuel-flow as well, by using bigger injectors.

The sampling tube should also have one inlet and one outlet to get most accurate reading, having a hole in it may be accentuating the lean problem.

Excellent Post - "Dead on balls accurate" - The only thing worse than raping your perfectly good MAF is doing like I did and spending money on a C&L MAF.

white99gt · Aug 30, 2004

That article should be taken down..Its been proven 90% of the time it DOESNT work.As you have seen .

The only fix is a new maf..The maf shell can not be had without the electronics unless a junkyard will sell you one..

Route666 · Aug 30, 2004

twogts4us said:
Excellent Post - "Dead on balls accurate" - The only thing worse than raping your perfectly good MAF is doing like I did and spending money on a C&L MAF.

Just trying to help.

I was thinking a fix that might work is upping your fuel pressure if you have an adjustable regulator. That should fix the problem, and give you more power like the mod is supposed to.

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