hello everybody,
can anyone decipher some winaldl raw data for me. i have a 90 c1500 1/2 ton light duty 2wd, with a 350 and a 5 spd. with overdrive, it originally had a 4.3 but was changed by the previous owner. i just installed a new 350 with flowtech headers, 2" inch bored gm tbi intake and a holley 502-9 tbi. when the truck first starts and idles up you can give it gas and it revs right up, but once it warms up if you try and give it a quick rev it stumbles bad and then catches up. installed a 3 wire o2 sensor, and just installed a a/f meter and it always stays rich, if youre givin it gas it goes to stoich in first thru third and then stays rich but in fourth and fifth any slight acceleration after youre up to cruising speed sends it all the way lean until you let off the least little bit or going up a hill that requires even a little gas and the only way to get out of lean is to let off slightly or floor it to stop reading the o2 sensor and just dump fuel. thanks for listening.

What computer and prom are you using?
Hello from St. Fancisville!

Welcome to the board and sorry I can't help you with specifics to your porblem, but I think edman87 may have hit on the problem.

hey edman,
im using a 1227747, and i went to graves chevrolet and told the parts department all about the truck and told them i needed a new prom and calpak for that truck with a 350 instead of a 4.3, i have tried a computer out of a 93 witha 350and 5 speed, and i bought one from a junkyard and brought it to graves and they said it was for a 90 350 5 spd. both idle perfect but as soon as you go to pull off thats when the trouble starts, they throw all kinds of codes . the ecm i have in the truck is an autozone 747 and it only shows -
drp ocurred, idle/cool flag, and a rich flag that is constantly on and off, but no error codes.

OK, sounds like your computer knowledge is farther along than mine. I have never used winaldl and such, but plan to start trying them out soon. I am familair with using a scanner to pinpoint problems and will try the winaldl and laptop route for my camaro and blazer.
I was asking about the computer and prom, but it looks like you are using what would have been in there from the factory.
Sounds like you definately have a fuel problem. How did it act with a factory tbi unit?
I would start with the basics; fuel pressure and timing for starters.
Also check the distributor thoroughly, false timing readings can play bad tricks on computers, my 98 puzzled me for a long time until I relized the distributor gear was worn.

Good luck.

hey edmund,
im lost even with the winaldl, believe ive tried just about everything, this a new engine top to bottom, i mean everything. only old parts are the wiring and a few sensors like the esc, egr, and starter. i cant find a shop to work on it that doesnt turn me away because of the holley tbi. thanks for the help and drop me a line if you need a computer and cable to use for the winaldl. itll do wonders if you understand what youre looking at, cause im lost.

Do you have a stock tbi to drop on it and see how it works? I would try that and see how it acts. I am not real familiar with the holley unit you have, I do knoe that they can be a nightmare in general. A buddy had the holley setup on a 6 cyl jeep and it never failed completely, but was bad about stalling out and running strange.
I plan to buy an aldl cable and try some datalogging on my camaro pretty soon, but mostly just using it as a scanner to see what is going on.
If you want to know about anything specific with the computer and such, try www.thirdgen.org , some of those guys know their stuff when it comes to gm computers.