TB Hole size - MS4 Cam, IAC maxxed out

[Kevin Doe]

I measured the stock hole to be a 5/32" diameter size. I tired the method of adjustin the set screw, and it appears as if I'm out of range of the reset. I was able to move it maybe 4-5 degrees, then the TPS failed to reset to 0.0 after that. On cold starts my IAC is maxxed out. After its all warmed up its back down to 65 steps.

Area wise I looked at a few options.

Stock 5/32" hole area is: 0.01917 sq inches.

If I used the next size up in my box, which is 11/64", and drilled the stock hole larger I compared the areas. The new area would be 0.003201 sq inches. That is an increase of 21%, which seems too much.

I was thinking maybe an increase of 10-15% area to start with. To obtain this, I figured it would be necessary to drill a seperate hole, and leave the stock one alone.

If I drill a 1/16" hole seperately, I get an increase of 16% total area. Granted this isn't considering the differences due to effective area, but it gives me an idea.

What does everyone else think?

Thanks,
Kevin

[rosey]

If your using factional drill bits, you'll want to start a second hole, that will give you much more control...it is very easy to go too big and not easy to go backwards.

I had to drill mine out quite a bit, IIRC I went to 7/32 on my original hole, and 5/32 on the second hole. I am at 30-40 steps when warmed up, tps voltage is around .55volts with no throttle, this is with a 232/240 112 cam. Its probably a good idea to drive around a little in between drilling to make sure you don't over do it.

[joecar]

Talk to Jeff before drilling.

[johnv]

Don't drill !
just adjust the throttle stop set screw untill you get the desired IAC, then do a TPS reset so TPS reads zerrow, or close to it when throttle is closed.

[Kevin Doe]

Don't drill !
just adjust the throttle stop set screw untill you get the desired IAC, then do a TPS reset so TPS reads zerrow, or close to it when throttle is closed.

Did you even read my first post? lol. I had to adjust it so far that the TPS is beyond its range of resettin to zero. It would still read 2% even after the reset. I think I may have found the issue wiht my other problems, which I'm sure will have a huge effect on idle.

I'll report back with my findings once I get the computer properly into OLSD mode. Right now I think I'm in some sort of ultra weird backup mode where it uses neither hte MAF or MAP.