Accufab Plenum & High Idle

[jayhawk261]

I recently installed an Accufab Plenum & 75mm TB on my 04 GT. As with everyone else that has done this, I wound up with a "floating" idle.

Since this seems to be so common, I have come to the conclusion that Accufab isn't making the plenum correctly. I believe the bolt holes for the TPS are rotated clockwise from the factory plenum some small fraction of a degree. This is enough to raise the voltage into the 1.3 range (at least that's what mine was) which is causing the idle problem.

I solved my problem by using a suggestion I found on another site. I was unable to rotate the switch enough (counterclockwise) to get the difference in voltage that I needed. I then used a 7/32" drill bit chucked into my tap wrench (my dewalt drill bits have a flat spot on the shank which allowed for this) and hand drilled the holes in the TPS. This allowed enough play to rotate the TPS and get the voltage down to .98. My idle is fine now and no longer hangs.

If anyone here has an inside ear at Accufab, you might suggest that they look into their design. Since it is so common, there has to be a difference in bolt hole location.

This is just one engineer's opinion though.

Hopefully this'll help out anyone with the same frustrating issue!

 

[Rocketman]

I didn't need to make any adjustments on my 03 when I put on my Accufab plenum and 70mm TB.

Did you unplug your battery during the install, so your computer would reset?

I did notice there was a very small amount of play to adjust the TPS when the screws were loose, but I didn't need to use any of it.

Good idea on the fix though.

 

[jayhawk261]

I tried re-setting the computer twice. Didn't fix it either time. I'm glad you didn't have any trouble with yours. After alot of searching, I found that many people with this set up have had the problem though. I can't imagine that the plenum woul dbe different for a 75mm TB versus a 70mm, but the posts I have read about people having the issue all mention a 75mm.

Who knows!

 

[Lons2001GT]

I have the accufab tb and also had a hanging idle but the fix was an adjustable screw on the bottom of the tb that had to be screwed in all the way. No problems since and messing with your tps can effect your ecu's ability to know when your at full throttle so be careful.

 

[twogts4us]

It takes about a week for the hanging idle to settle down. I don't think Accufab did anything wrong. And I would not mess with the screw on the TB. That's NOT how to adjust the idle.

 

[csledd]

I had my car tuned the day after I installed mine and it fixed all the problems, that is after the TPS broke on the dyno and was replaced

 

[Lons2001GT]

It takes about a week for the hanging idle to settle down. I don't think Accufab did anything wrong. And I would not mess with the screw on the TB. That's NOT how to adjust the idle.

I waited over a week before I finally called accufab and they told me to screw the adjustment on the bottom of the tb to fix it and it did. You are not supposed to adjust the throttle stop. The computer does not always self adjust to every tb.