People who had probrem with Mac 75MM TB, check this out

[mity2]

So i'm one of many who had an issue with 75mm TB, you know bad idle, and such. So for the past 2.5 month, my Mac TB just sat ont he garage, and i was just happened to looking at it(infact, i was playing with it, by blowing in to it and crop. lol)
then i noticed there was considerable amount of air leak. So i taped up Idle air hole with tape, and tested again. And again, there is alot of air going through. so i got looking around, and come to realise that there are considerable amount of leak from 2 bolts that secure TB brade to the shaft. I mean i was just blowing, but when engine is running, there is quite bit of vacume created behind the blade, and surely enough to suck sufficient air through the leak. If enough air is passing through there, that would surely cause bad idle(high idle), right? so i sealed up the area(see pic) with some paint(didn't know that to use), and i'm going to try it again. lets hope this cures the age old Mac TB issue huh?

View attachment 500967
View attachment 500969

 

[helty]

hmmmm.....interesting. i dont have mac tb, cuz i dont think i'd ever buy anything made by mac (maybe a pro chamber), but let us know your results. good find man

 

[tomustang]

i never had a prob with the my mac 75mm tb


hope what you did works

 

[mity2]

i never had a prob with the my mac 75mm tb


hope what you did works

ur lucky one then....

i've had every known probrem with our car so far

BBK X-pipe don't seal - Check
IAC going bad - Check
Mac TB bein' POS -Check
strip manihold stud -Check
gettingpulled over for racin' -Check

 

[03MGT]

Hey its my old TB that I gave you lol .. Remember before you put it back on that it likes to stick shut so try to sand the edge of the butterfly a lil bit..

 

[mity2]

Hey its my old TB that I gave you lol .. Remember before you put it back on that it likes to stick shut so try to sand the edge of the butterfly a lil bit..

ya its your old one.lol i see why you sold it to me cheap but i'll get it to work somehow..

ya i've noticed it sticks little. Not noticeble at all while its on the car tho

 

[mity2]

so i reinstalled it. I guess its working! my Mac made my car idle at like 1200~1500RPM the last time, and nasty hang up. Now her idle is at around 900~1000RPM. Still has little idle hang up, but I had Batt. disconnected for almost 2 days, so its still learning...

we shall see!!!!

 

[urban96]

i would use some epoxy or RTV to seal up the TB

 

[GDawg]

I had one that would stick real bad. I didn't feel like grinding a brand new piece of crap so I sold it to someone for real cheap. (The person knew of the problems). I bought an Accufab and it's like butter.

 

[03MGT]

mity2, I hope you know your selling it back to me for 60 bucks If you get it to work...
























J\K... LOL

 

[mity2]

mity2, I hope you know your selling it back to me for 60 bucks If you get it to work...


J\K... LOL

ya its working. so far. its still hanging up bit, but only for few sec. Idle is prettymuch down to 800RPM+-few. One PCM gets its ass in gear and lean some new tings, I'm certain there will be no more hang up.


03MGT, i'll sell it back to ya for $75!!!!!

 

[Gearbanger 101]

Remember before you put it back on that it likes to stick shut so try to sand the edge of the butterfly a lil bit..

Before he goes breaking out the sandpaper, I would first recommend loosening off the bolts that hold the T/B blade itself and move it around in the bore a little. Sometimes all it takes is a little adjustment to smooth it all out. Better that, that to sand off an area of the blade, just to find out that it now no longer sticks, but has created a big leak at idle.