ulakovic22

That's really up to you. I personally have one in each side. Make sure you take the TB off before you start.

Kevin Blown 95 TA

Saa

CrystalSS

You should be able to get the Iac below 90 by opening the throttle blades. Slotting the tps is really easy if opening the throttle blades results in the tps over .90 volts. The tps is plastic and super easy to slot..... it does not hurt anything to slot these holes...... range is from .2 to .9 volts, this is a fairly large range so its really hard to screw this up. someone corect me if I am wrong but the IAC will close as the blades open because its trying to keep the idle down.....so you should be able to get the IAC counts lower as you open the blades. Its not like you need to nail the IAC at 40 its not a magical number its a range from 0(shut) to 160(fully open). But you should be able to get them in the 30-50 range. At 120 its almost fully open....thats why I would try the idle screw first....then drill if the idle screw does not work. You need to check where your fully open voltage is, I still say its opening farther than it should which is a different problem but one that should be checked. Unless holley changed its design you will not be at full throttle!

NVetro

Yea i messed around with the throttle stop screw, and i adjusted it as much as i could right BEFORE she hit .8% for the TPS, then backed it off alittle. I got her to the 90-100ish range roughly, drove her around, still had the issue, got back home let her idle and then the IAC position was reading like 80ish give or take at idle, not sure why...so the throttle screw is adjusted all it can go before it starts to show the pcm its opening. Slottnig the tps will not do anything for me according to the posts above, it will only assist me in getting my target voltage for the tps which is something i do not have to worry about since it should be between .65 and .90, and it is about .80 at idle now...i guess I will go ahead and start with a 1/16th hole in the "O" of the holly and if that doesn't lower the iac position to around 50ish then i will make another one in the other "O" and then go from there.

CrystalSS

Slotting the TPS will allow you to put the throttle blades where they need to be, and have the IAC at 40ish. Bottom line if your IAC is at 100 your blades are not open enough. Slotting the TPS will allow you to get 0% throttle opening(in pcm) with your blades open enough for 40ish IAC counts. If you are showing 8% throttle opening when you open the blades, you can get it back to 0 by rotating the tps clockwise.
You really need to use a voltage meter to check your tps voltage, both open and closed.

NVetro

If the car is doing the same thing and the iac counts are at 80ish, dont you think regardless of what i do to the tps sensor that the motor isnt getting enough air to compensate for the rapid lclosing of the throttle blades? From what these posts say it seems the car needs more volume of air at a stop i guess. Also guys i dont get something, im looking at the datamaster log and when the car dips to the 400/500ish rpms when i come to a stop light the iac counts are like 50ish, whats up with that? Doesn't it still have over 100 counts to open up and keep her running good at a stop?

ulakovic22

Your counts are so low because your car is about to die. Have you checked to see if you IAC valve is operating properly?

Injuneer

Nick..... last try, because no matter how many times we have told you what to do.... YOU REFUSE.

Opening the blades admits more air and lowers the IAC counts. Open the blades until the IAC counts come down. At this point IGNORE TPS VOLTAGE. Can't state it any clearer than that. OPEN THE THROTTLE BLADES UNTIL THE IAC COUNTS COME DOWN TO LESS THAN 50..... 40 is better, 30 is best.

Now that you have the IAC counts where they belong, you are at the point where you need to think about the TPS volts. If they are above 1.0V, YOU HAVE TO SLOT THE SENSOR AND ROTATE IT UNTIL IT IS UNDER 1.0V. 1.0V is the upper limit, 0.90V is better because is gives you a little cushion in case the blades are a little sticky closing up. THERE IS NO 0.65V SWEET SPOT. The PCM will work exactly the same, as long at the TPS volts are between 0.20-0.90V. You do not need to get them to 0.65, or any other magic numbere. This is a figment of someone's imagination, or of someone who has only worked on a 3rd Gen engine, where you need 0.50V.

IF.... you can't get the above combination.... IAC counts under 50 and TPS volts under 1.00V, you need to find a way to add supplementary air. You can do that two different ways. One way is to drill holes. This is not the end of the world. If you decide later you don't want the holes, call Holley and buy new blades.

A SECOND way to increase air flow is to use an alternate source. I've seen a writeup posted here, maybe 2-3 years ago, showing a tube than runs from the intake duct to (I think this is what is was) the port in the intake undeer the throttle body, where the 95-97 LT1's connected the PCV vacuum source. On your 94, that hole is not used and has a pipe plug in it. Look into this method further, because I can completely understand your reluctance to start drilling holes in a $400 throttle body.

PLEASE listen to what people are telling you. We are trying to help you.

NVetro

Trying to do everything you guys are saying, just not sure which to do first. OK here is where I stand. I took the TB off, i inspected it and such...it seems on the inside blades (not the part that says holley) there is a light film of oil, not sure if that should be there or not. But w/e, its prob coming from the tube from the passenger side valve cover. Thats another thing ill research. I took the TPS sensor off, and sloted it with my dremel, came out very good. So I put the car back together and rotated the tps sensor, i put it at .67 which seems good. I started the car up and the iac count were in the 120's, they droped to about 100 eventualy i think after open loop. I adjusted the stop screw exactly like you guys said to get the iac position down. I adjusted it to ALL it can go, not tps volt/% wise but literaly cant turn it anymore. The IAC position was in the 90ish range, drove it around and it was in the 80ish range....still not where you guys say it should be which is cool. Injuneer, after atempting everything listed above. The next step would be to drill a hole in the throttle blade to get more airflow and the iac position down correct? I am going to start with a 1/16th hole on the left throttle blade in between the "O" in holley. Sound good? Since i'm pretty far off where your saying i should be would you make (2) 1/16th size holes in the blades, one on each side? Agian sorry for the questions, just dont want to mess anything up. I trust ya guys, dont trust myself sometimes

Gripenfelter

When you drill the holes, start with the smallest hole possible and move up until the counts drop down to an acceptable level.

EDIT: You did the TPS mod correctly. You can crack the TB blades open a bit more. Just keep the TPS voltage under 1.0V

anaik

Bend the tang that the throttle blade adjustment screw rests against. Bend it towards the TB. That will allow more adjustment with the screw.

NVetro

I cant crack the tb blades anymore, the bolt is bottomed out :-) and the idle is at 1500rpms, im sure the pcm will bring her back down but the iac counts are at the lowest they seem to be going, which is 90ish.

Gripenfelter

Ok idle shouldn't be that high. What is your TPS voltage at when you are at 1500 rpm? You only adjust the screw out enough before your TPS voltage goes over 1.0 volt.

If you can't adjust it anymore, you drill the TB.

NVetro

I think when i bottemed the bolt out for the adjustment the tps volt went to .77 or something around that. Looks like I'll be drilling

NVetro

ok well ALL BETTER! Thanks guys! I took the TB off, got a 1/8" drill bit and drilled the "O" in Holley on the left butter fly. I Put her back on, she fired right up, I was looking at the IAC position and it was at 77 now. Still not there, I have the voltage set for about .70 now at idle for the tps sensor and adjusted the stop screw. Last I looked the IAC position was bouncing around between 44 and 50, and then my laptop died I took her out on the road....stoped at a light and she came right back to idle, didn't dip or drop. Thanks alot ALL I'll get a more detailed datamaster and more details tomorrow. Also, took me alittle bit to get this done, I have caps on my heater core ports on my water pump and it decided to explode off for some odd reason, so i had to rectify that :-)