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Discussion Starter #1
hey i have a 1989 ford mustang with a 5.0L EFI engine... it has stage 2 computer with K and N airfilter and Shorty headers only... the question i am wondering upon today is if someone has a clue on if i can take the mass airflow sensor off and let the stage 2 computer take over the car completely or if i must keep the MAS on there in order to keep the engine running correctly... i have already tried unplugging the sensor while running and before start up and both times the idling was slightly surging but not too intense however the pick-up on it feels more intense when the mass air is removed... thanks for reading... later
 
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Ok, I'll take this one. Unless your car is carbureted, under no circumstances should you remove your mass air sensor. The End.
 

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Stage 2 computer ? Who sold you that garbage ? Are you referring to a chip that somebody labeled a "stage 2".

As 95.0 stang pointed out, do not under any circumstances remove the MAF sensor.
 

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Discussion Starter #4
i heard that if you unplugged it and it was working correctly that it would turn the car off thats the reason i tried to run the stang without the MAF to see how it would run but only did it temporarily... does anyone have any idea on how to check if the MAF is running correctly because i am thinkng that this one is not working as it should...well get back to me ... later
 

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eclipsehipsi said:
i heard that if you unplugged it and it was working correctly that it would turn the car off thats the reason i tried to run the stang without the MAF to see how it would run but only did it temporarily... does anyone have any idea on how to check if the MAF is running correctly because i am thinkng that this one is not working as it should...well get back to me ... later
Well, you could check the current.

If it's sluggish, with poor idle, it might be dirty. Just spray computer contact cleaner on it, and see if it straightens out.
 
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When you disconnect your maf the computer relies on stored data from the past, so it shouldn't die, but it won't run as good as it should.
 

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eclipsehipsi - To answer your first post - Im going to make the crazy guess you've been around import cars before... :shrug

I have some friends that are into the import scene (eclipses and a supra) and I too have heard the "remove the MAF theory" but mostly the discussions were leaning toward mods on turbo cars. So without getting into it too deep - Yes you can remove the MAF, but be prepared to replace it with some other system(example: MAP) which requires changing other things, which in turn require changing other things, etc.... There are some exceptions - but for the most part the majority of great tuning "ideas" you hear from the import crowd on modifiyng an engine should be flushed down the toilet now that your talking about a naturally aspirated, 90 degree, single cam, pushrod V8 in a mustang. ((Not that it adds anything to the discussion - but I recall 3 or 4 years ago going to a late-night import hangout and listening to these guys debate the Apex N1 muffler is better than the DC sports system cause you gain 40 horsepower while the DC is only a measly 30. OK! :thumbsup ))

As for the MAF, if you think its not working, just unplug it and if it doesnt change how the engine is idling then its broken. Like kscoyote said - Most likely the sensor is just dirty.

And lets leave that stage 2 computer import car marketing propaganda stuff at the door...

Now -- off to tune my stage 14 AEM EMS. :hihi:
 

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Discussion Starter #8
sadly yes i was into the import scene but i now see have seen the light and there is no replacement for displacement...
 
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I would honestly love to hear the logic behind "disconnect your maf," can someone explain to me what this is about.
 

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I got into a debate about Mass Air just the other day. It was with an import guy from my work, one of my buddies. He thought that mass air was an archaeic way of measuring air, and I tried to explain why its not and that our systems use a MAP and MAF in all of the Mass Air cars. He refused to believe anything that i said and went on to claim that I could not turbo my car if i converted it to a MAF system. I tried to explain that you cannot change the cam on our cars much or you will get a rough idle and whatnot, but it was no use. While i have no problem with imports, this irritated me a lot. I find it hard to believe that all imports are essentially speed density system, because it is an inaccurate way of measuring air compared to a MAF system. I would love to know why they dont use MAFs... I did also notice that an F-150 that came into work the other day did not have a MAF either, whats the deal?? Somebody explain...
 

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speed density, or MAP is a great way to monitor engine conditions, imo better than the maf in every way, the logic is that the maf is a restriction to incoming air, especially on a turbo system, a turbo car will definately benefeit from a MAP style system, but ford map sensors are not capable of understanding boost like a lot of the thers are.......


like the sds system, it uses a gm 2-3 bar map with a reprogrammable ford ecu

best of both worlds

and the map on the later cars is not that at all, it is a BAP barometric pressure sensor to adjust the computers output based on altitude
 

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The drawback most people run into with Speed Density is that it relies on a lot of assumtions about the engine's displacement and volumetric efficiency (VE). Those assumtions take the form of tables and formulas programmed into the PCM.

When you change your engine's displacement or VE, those assumtions are no longer valid, so the Speed Density system ends up incorrectly reporting the amount of air coming into the engine.

A MAF-based system actually directly measures the amount of air entering the engine rather than inferring it based on manifold pressure and some tables and formulas. Therefore, on a MAF car, you can change the displacement and/or VE and still get an accurate airflow measurement.

I'm about to convert my '87 GT to MAF myself. After a bunch of mods to increase my VE, I'm getting backfiring and hesitation. The hope is that going to MAF will cure that and clear the way for a cam swap (maybe).
 

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MAF problems?

when I disconnet my MAF sensor the engine die's. I'm assuming it's bad. Can anyone help and yep I get the surging idle also
 

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jayb said:
when I disconnet my MAF sensor the engine die's. I'm assuming it's bad. Can anyone help and yep I get the surging idle also
Your engine will absolutely die if you disconnect the MAF sensor, the computer gets NO readings on the amount of air coming in. THe car won't even start without the MAF.

CLean the MAF with computer contact cleaner, (don't touch it, just spray the stuff on liberally, and reconnect.

Assumin you don't have a vacuum leak. that should fix the surging idle.
 

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kscoyote said:
Your engine will absolutely die if you disconnect the MAF sensor, the computer gets NO readings on the amount of air coming in. THe car won't even start without the MAF.
Actually thats not 100% true. On my '91 5.0 I had just finished installing a C&L 76mm MAF w/intake pipe and 65mm throttle body, and then started it up. It ran like $hit and was sputtering like it was gonna stall out. I then realized the MAF sensor harness wasnt plugged in.
Turned it off, plugged in the harness, then started it again and it ran perfect!

So technically you cant say it wont die. I think the computer goes into a certain mode which I believe allows it to run, just not optimally. I think.... I dont know. All I know is it started without the MAF plugged in......
 

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mccoigk said:
Actually thats not 100% true. On my '91 5.0 I had just finished installing a C&L 76mm MAF w/intake pipe and 65mm throttle body, and then started it up. It ran like $hit and was sputtering like it was gonna stall out. I then realized the MAF sensor harness wasnt plugged in.
Turned it off, plugged in the harness, then started it again and it ran perfect!

So technically you cant say it wont die. I think the computer goes into a certain mode which I believe allows it to run, just not optimally. I think.... I dont know. All I know is it started without the MAF plugged in......
Weren't the 91s running Speed Density?
 

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kscoyote said:
Weren't the 91s running Speed Density?
Actually I think speed density was 87-89 and MAF was 90+ (I could be wrong here)
But I know my Mustang has always been MAF'd since it was driven off the lot by my brother oh so many years ago.... Manufacture date on my VIN is June 1990.
 

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thanks for the replies guys. i appreciate the help. I cleaned it and it still has the surge going on. how do you test the MAF sensor. I have a 90 GT, that I bought from a guy a couple of months ago and have to get the emissions retested. Also when I went to change the plugs i went to the parts store, told them what year it was and everything, got the plugs and they wouldn't fit. went back exchanged them telling them they gave me the wrong plugs. Got another set and same thing. Finally took on out and went back and got the right one's. My best guess that I have aftermarket heads on there. Anyway of telling for sure, and if so what type??????
 

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jayb said:
thanks for the replies guys. i appreciate the help. I cleaned it and it still has the surge going on. how do you test the MAF sensor. I have a 90 GT, that I bought from a guy a couple of months ago and have to get the emissions retested. Also when I went to change the plugs i went to the parts store, told them what year it was and everything, got the plugs and they wouldn't fit. went back exchanged them telling them they gave me the wrong plugs. Got another set and same thing. Finally took on out and went back and got the right one's. My best guess that I have aftermarket heads on there. Anyway of telling for sure, and if so what type??????
ahhhhh!

you need a dyno tune. the OEM program is trying to run an OEM combination. Your computer must've been disconnected and reverted to the OEM tune, or the guy who sold it to you took out the chip and sold it on e-bay.
 

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kscoyote said:
Weren't the 91s running Speed Density?

And I thought KS new everything………. :winks

88 California cars has Mass Air, other 88s were Speed Density. In 89 they all went to Mass Air.
 
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