I checked my TPS today, at closed its sitting at .60 - > is that enough to cause it run off? Or is that close enough to be ok? I check the curve and it tops out around 4.6ish and is quite steady.

TIA!

 

its a hair high, ideal is .54 i don't think i would worry about that too much.

 

I'm still surging a bit at idle and running a bit rich. Likely the IAC not handling the new cam I think. But now that its not 20* retarded its waay better lol. Amazing that!

 

amazing eh

what cam are you running, if you still have the stock chip, you are likely going to run rich at idle no matter what.

what did you set your timing to? i would guess that somwhere between 4* and 6* advanced with the ESC disconnected, is going to give you the best results.

 

Comp Grind 266HR
Gross lift .500/.500 gross
Duration 266/270 advertised - 210/215@0.50
Lobe Seperation 112*

yeah timing is about 5* Advanced now.

 

well, that isnt' all that big for a 4.3, since it basicly a 350, minus a couple of cyls.

i would say 5* is about where you should be set, you really should look into prom burning, really that motor is never going to run as good as it could, without you tuning it right.

 

yeah I've got a guy in town that does ODB1 Tuning but I want it "finished" before I get that done -meaning getting the holley TBI on and working, and getting the headers/exhaust redone so that I only need it chipped once.

Also looking into scooping an ALDL cable off ebay to do some datalogging and see whats going on.

I believe the gross lift on the stock cam is about .357 as opposed to .500 for the comp so its a bit of a difference

 

yeah, just knowing the spec diffrences, i can tell you it is going to need less fuel, and more timing at idle, and alot more fuel up high. without a chip there is no real good way to do that.

 

With the logger what kind of values should I be looking at to see if my a/f mixture is good all the way through the run to WOT? I dont need it leaning out at higher RPMS.. I think the Holley 670 should help out with that.

 

no it will not help out, because the computer contorls how much fuel is added. if anything, it will make it worse, since more air will be going into the engine.

read the tunning intros. basicly, start at idle and part throttle, look at the BLM data. once you have BLMs sorted out, the work your way up to WOT runs, once you go into PE mode, you will only have the o2 values to go off of, shoot for around 900mv here, but the stock o2 is VERY inacurate. once you get them all around 900mv, i would try to get on a dyno with a wideband, and then you can really tune WOT.

there is alot involved, and a very steep learning curve, i would suggest reading all you can in the DIY-PROM board, read all the tuning intro's at the top of the page.

 

thanks, I've been doing some reading on the DIY Eproms, very complicated stuff lol. But I'm willing to learn. Man this internal modding is fun stuff

 

when my fuel curves were in line(data logged/burned 20 chips) the WOT or PE was spot on at WB02/dyno run. commanded 12/1 and dyno run showed 11.9/1 and 12.1/1. i might add i disabled PE (not recommended) to get higher rpms in line(fuel table) and ones that did not populate i kinda guessed and enrichened on safe side. also i swapped out injectors and went to the biggest 90's. started tuning 6/2003.