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75mm mac tb

  • Thread starter Thread starter FoxRod87
  • Start date Start date Nov 24, 2006

FoxRod87

Active Member
Feb 1, 2006
243
1
27
Carolina
Nov 24, 2006
#1
  • Nov 24, 2006
  • #1
I just bought a c&l upper intake and a 75mm tb. I installed them but I couldn't get the tps off the stock tb, so I went and bought a cheap one and put on. I went and set the tps at 1.04 volts with the ignition on. But it wont idle right. I can barely push the throttle and it will rev up to about 1500 to 2200 and hang there for a few seconds and then slowly come back down to idle about 900 or a 1000. It just feels like it is sticking. I unhooked the batt cable for about 10 min to reset the computer but it still does it. When I come up to a red light and stop it will hang at 1500 for about 6 or 7 seconds until it will come back down to an idle. It gets on my nerves. So I put the stock tb back on and its fine. By the way the tb is a used one and the guy I got it from said it didn't do it on his. So do I need to get an accufab tb? Thats what I was going to do before I come across this one. Is an accufab a better quality? What do you think is wrong? Is the tps set right? Thanks!
 

jstreet0204

Active Member
Jun 26, 2003
939
0
36
Winston Salem, NC
Nov 24, 2006
#2
  • Nov 24, 2006
  • #2
Make sure the TB is closing all the way. If it is, try to get the TPS down to around 0.98 volts. If it isn't closing all the way, check the stop screw to make sure it hasn't been adjusted out too far.
 

FoxRod87

Active Member
Feb 1, 2006
243
1
27
Carolina
Nov 24, 2006
#3
  • Nov 24, 2006
  • #3
I took the adusting screw out completly and it didn't help any. the lower I set the tps the lower it will idle? Or should I not go any lower than .98.
 

jstreet0204

Active Member
Jun 26, 2003
939
0
36
Winston Salem, NC
Nov 24, 2006
#4
  • Nov 24, 2006
  • #4
.98 is about where you want to be, not much under or over, but as close as you cant get it. Physically look inside the TB and make sure it is closing all the way. Aslo make sure is opens and closes freely without sticking or hanging.
 

94GTStang

Founding Member
Oct 26, 2001
1,631
0
36
Oklahoma City
Nov 25, 2006
#5
  • Nov 25, 2006
  • #5
Why couldn't you get the old one off?

I did a swap on a friend's car and really had to work to get hers off. I ended up having to put the plenum between my feet to counter act my electric drill. Sucked but it came off.
 

jivepepper

Founding Member
Jun 19, 2002
776
5
18
Under a Sombrero. in WV.
Nov 25, 2006
#6
  • Nov 25, 2006
  • #6
I had a mac tb a good while back damn thing never idled right and would kind of stick.
 

sgarlic

Founding Member
Apr 21, 2001
3,085
1
56
Nov 26, 2006
#7
  • Nov 26, 2006
  • #7
1st, read the TPS sticky.

Second, Use a speed handle with an apex phillips bit, or vice grips to get the old TPS screws and TPS off the old plenum. They are simple to get off. I can't believe how many people consider those difficult.

It may take a few days for the idle to settle down. Took mine a few days before it returned to normal. Also check for leaks. Those plenum to intake bolts need to be 89 inch pounds. If there is a vac leak, the idle will be screwy.
 
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