Fairly new to TPI here. I installed it with a custom wiring setup. I'm working on getting it to idle here. To get it to idle, I have the blades cracked open so much as to make the TPS read .70. Then the IAC valve is showing max open.. and this is to get it to idle!!

Are these blades twisted part way open from the factory?

Anyone ever drilled holes in the throttle blades? I have a second body thats damaged with blades. I am willing to remove the blades from it, drill, then install. But it looks like the screws have been melted on the back side to prevent removal. Has anyone successfully removed them screws/blades?

 

Yes, I've drilled the screws out to over bore to 58mm.
You need to give more info.
There's no reason to drill holes in the blades.

 

Far as I know, I have no parts making it need to drill the blades. 350, 810 TBI heads, crate cam, TPI intake.

Scanning shows the IAC opening to 310(limit the ecm has), but it wont idle. I have to have the blades cracked open for it to idle. To put the blades in propper position, I would need holes in the blades.


What size screws did you go back with?

 

ss 6-32 Allen Hex head (socket)

It's up to you if you think you need holes in the blades, but unless it's a really radical build or with a carb I'd diagnose it for the root cause.

Have you tried setting the minimum air rate and then the TPS minimum voltage?

 

TPS wont set right because of the blades being titled (non-adjustable TPS).


Thanks for info about screws.

min air rate is set thru ecm? Ive played with it, but when tps is maxed out at 310 already, adjusting it wont do me any good.

 

The blades are adjustable. If you will look where the idle screw would be on a carb you will find a plug covering the head of the screw. You can drill it out to uncover the screw head.

I assume the car will not stay running. If the IAC is all the way open maybe the air passage that feeds it is clogged.

 

No, not thru the ECM.
use The tech article, but skip the TPS instructions. https://www.thirdgen.org/tpimod2

Disconnect the set timing connector as step #1, but be sure to reconnected when you're done.
Basically the IAC passage must be completely closed before the minimum air rate can be set.

 

DSmith, already got that. Blades are already cracked open to make the car idle. If they are closed, it wont idle.

Garcia, thanks for link, but I cant do that. I dont have an OBD1 computer anymore. I have done the 411 swap at the top of the board. The people I have talked to have not had this problem. Makes me wonder if my IAC is bad? But I dont have 200bux to go make that purchase and not beable to return it if thats not the problem.

 

Anyone know how different the IAC is between a TBI and TPI? I have a TBI sensor I can use for testing if its close enough.

 

[QUOTE=Dale;3558948]DSmith, already got that. Blades are already cracked open to make the car idle. If they are closed, it wont idle.

If you can't get the TPS set correctly with the blades open that far you will have to close them some. Your problem with the car not wanting to run at idle is your IAC. If a passage is blocked or if the plunger is not opening the engine will not idle unless you open the blades.

Ask yourself what you want to do, solve the problem the right way or just make the engine run.

The IAC from a TPI and a TBI should be the same, if you have one try it. but you need to get the TPS set correctly for the ecm to manage the engine efficiently. The blades can be open some if need be but you need to be able to set the TPS to the correct setting. If .07 is as low as you can get it close the blades just enough to .054(I think).

I know all this is a pain in the *** if your not sure what your doing. I had the same problems when I swaped from TBI to TPI. When I did my swap I didn't know TGO existed. www.chevythunder.com is where I got all my information.
At least you can come here and get some input from others who have been there.

Good Luck,
Dewayne

 

I know the TPS needs to be at .50-.55. But right now we cant get there at all and it still run.

Passage is not blocked, throttle body was so clean in and out, I would eat off it. Now if the pluger on the IAC is broken and blocking, thats possible.

Parts places list TPI and TBI IAC as different. But if it will work for testing reasons, thats all I care(I have one). Cause if I can point that as my problem, I will buy correct part. 200 is alot to spend to "test" something.

 

WHere are you getting a price of $200 for an IAC? Thats rediculous.

Are you sure its wired up correctly? That may be why its not working as planned.

 

I can check wires again. But IIRC 3 of the 4 colors matched. Scanning shows it moving.

Most of the parts stores here want 160+ uncle sam cut. Might as well say 200.

 

http://www.partsamerica.com/ProductD...pe=506&PTSet=A

$47
Tell those that want 160 to get lost.

 

Wonder what the difference is between the neihoff, BWDs that make it 1/3 of the cost?

Ohm checked my wires and checked against wire diagrams.

Installed TBI IAC and it fired right off, reved high for a bit, then hunt n pecked for idle, that calmed down. So its is bad, guess I know what I'm buying next payday.

Thanks for help.

 

If anything, you can get the AC Delco version. gmpartsdirect has it for ~70, plus their $hipping fee. Still less than 160.

 

Now you can set your TPS to where it needs to be.

I don't know what the difference is between the TPI IAC and the TBI IAC but if I remember correctly I am still using the one from my TBI on my TPI.

 

Great, I was hoping you wouldn't settle for having to feather the pedal to get it to stay running.

 

forgot about gmdirect, 70 huh?

I'll run this TBI one in it tell payday. Dunno what difference is, but I'll put the propper one in it.

Lunch today will be setting blades/tps correct. Tonight will commence tuning time. WOOT