hyperzone

I got the new motor in last weekend and it runs like a champ. I changed from the stock throttle body to A holley 52mm on friday and have had issues since.

Had to switch over the TPS sensor, and the bottom plate which houses the IAC as well. So, I start it up and it idles great and runs great. I go for a drive and everytime I come to a stop and the RPMs come down to idle it starts to stumble and dies. I crank it back up and it idles fine until I go and then come to another stop, and dies. Its throwing TPS codes also. So, I hooked up autotap and see that my TPS voltage is at .8v when the blades are shut so, I did some dremel'ing so that I could rotate the TPS sensor a bit more to make that voltage 0v when the blades are shut. NO CHANGE. I did mess a little with the set screw and am not sure that I put it back to the original spot but, now when I start up the car and let it idle it keeps fluctuating up and down between 750rpm and 1050rpm and wont stop. I spent all evening tinkering and taking it for tests drives and then tinkering somemore and I feel like I've made absolutely no progress. Any ideas? I didn't remember to write down the codes but I will will post them tomorrow.

sleeperMULLET

iTrader: (4)

http://www.golenengineservice.com/html/tps.html
thats for the TPS

the problem your having is mostly like something with the IAC, there are a ton of threads about adjusting the blades to get the right IAC counts

hyperzone

hmm... That TPS info says it should be .67v so maybe I over-did-it going to 0v. I'm going to be messing with that first and then the set screw tomorrow.

As for the IAC, I dont know that its good or not but, it had absolutely no problems with the stock TB. All I did was switch over the whole plate that houses the IAC. The idling thing bouncing around only started after I messed with the set screw. at least, I think. Grrr.. sucks that the car is so loud or I'd be out there still messing around. I need to give the neighbors a break after 10pm though so, I'll hit it up again tomorrow. Thanks for the info.

STILL LOOKING FOR ANY OTHER INPUT!

Chaotic Firebird

I think there are issues with the throttle blades sticking with the Holly peices. Might want to search for that. Not sure if it effects your problem though.

-PEPE-

iTrader: (10)

Chaotic Firebird hit it on the head, your IAC is fine, your TPS is fine, not that either never fail because they do on occasion, but I would bet you lunch it's your shiny new Holley. Dude trust me I've been threw TWO BRAND NEW Holley's and still same faking problem both times, idles fine in the garage, take her out for a spin, get to a light and there she sticks at 1900 rpm taking a good 20 seconds or longer to idle down. It's the poor design Holley came up with, they claim the original TBs had a poor bushing design for the blade shaft, sent me a new design one week off the assembly line, same damn thing. I've heard some people having good luck but have read tons of threads where Holley folks are going through hell getting the idle to come down. Your TPS voltage is fine, I've been through all that with a multitester to find out it was dead on, tried slotting the TPS for further tuning, helped with throttle response but not with idling down.

My personal opinion is Holley needs to totally redesign their product, although they stood by it though, I'll give them that, both occasions they sent me a new replacement in at least a week, but bottom line is it's a poor design still. I put a mono AZM TB on mine and not a bit of hiccup, idles down fine, no TPS issues and the throttle response (more related to PCM tuning) is ridiculously responsive!

foggedz

iTrader: (1)

HMMM, I have had a 58mm Holley TB for about 4 years, and have never had any idle issues. I have noticed the butterflys sticking closed from the throtle snaping back too fast, but just taping the gas petal will free them.

-PEPE-

iTrader: (10)

like I said, some have no issues which is rare, most I've talked to hate them, I've had three 58mm Holley's, all brand new...all not woth the fancy box they came in.

Fire67

iTrader: (3)

I had some issues with mine as well. And its not the design of the TB that caused it, well sort of.

The problem lies in the size of the IAC passage in the front of the TB... With anything other than a stock motor, its not big enough...

Dont mess with the throttle blades other than to adjust the set screw enough so that the blades will not stick. From there, you adjust the TPS sensor clocking to be within spec. After that you need some sort of ability to see what the pcm sees and commands for IAC counts.
When you see that the counts are too high, you'll see my argument. I drilled my IAC passage out 3/32 larger and completely solved my problem. No more hanging idle, no more erratic idle speeds, nothing.

I followed the instructions of someone on the LT1edit mailing list to do this, after making him dumb his explanation down to my kinda terms (From his engineer talk).

Let me go through the notes I made from his instructions and I'll post a writeup on exactly how to do this and why it should be done this way...

96silverram

iTrader: (12)

If your IAC counts are right, then the TPS should be set somewhere around .025 to .050 in that range with the key on in the energized position. I believe my 52mm Holley is set at .043 at the bottom. I can't remember the max you can go, but I'm pretty sure anything over .070 will throw a TPS code # 23.

Fire67

iTrader: (3)

I thought I had all my notes here at work with me, best guess now is they're home in the garage. I'll try for tomorrow.

hyperzone

Okay, the codes were :

P0122 - Throttle position sensor circuit low voltage
P1122 - Throttle position sensor circuit intermittant low voltage

Tonight I adjusted my TPS voltage to be .7v (according to autotap readings) closed. The blades were NOT sticking but, were shut totally so I adjusted the set screw just slightly to where I could see light coming through around the edges.

Also, I fould that my rubber intake elbow had a tear in it. It was such that I dont think it was leaking air yet but, I'm not 100% sure. I rigged it with electric tape for now until I get a replacement. I'm not sure if I'll get a 1LE elbow or a metal one with rubber couplings. Any suggestions?

After tinkering like I said above, I drove it and the car doesn't die when I come to a stop now. It does try and idle down a bit to far but, it catches itself and goes back to where it should be. Might need a bit more tinkering but, I'm happy if it will stay like this at least. Oh, and the codes are gone too.

Oh, and my IAC count was 66 at idle according to autotap. Not sure what is good or bad in that respect.

-PEPE-

iTrader: (10)

Dude that's one mean looking LT1, looks sharp, buddy of mine here had a badass Z28 that color that was totaled.

hyperzone

Thanks. You cant tell in that picture but, it needs some cosmetic attention and will get it eventually.

PunishedU

iTrader: (1)

This is the problem that I had with my Holley 52. Needless to say it isn't on the car now. Once I get some extra time Im gonna try and fix it.

hyperzone

Well, the Holley 52mm I got is part number 112508. I dont know if there's another version or revisions were made or what but, there's no pinhole for it to breath with the throttle blades completely shut. While I was playing with the set screw on mine I found that it would stick shut a little if I adjusted it to much that way. Anyway, I'm not about to drill holes in it so I just set the screw so that the blades were just BARELY cracked open, enough that you can see light shine through around the edges. Set like that, the blades dont shut enough for it to stick or catch and it gets that little bit of air it needs. I'm not sure if mine is different or these other ones you guys are talking about are catching on something else but, this worked great for me.