I took the TBI off my motor a while ago and replaced it with a holley, cause rats chewed on the wiring and I didn't have the time to troubleshoot.
Of course the carb out performed the TBI and the drivability was MUCH improved.
Unfortunately I'm going to have to reinstall the TBI cause this is Cal. and if I get caught it's bad news.
Is there ANYthing that can be done to a TBI to make it work even kinda as well as the carb worked? The TBI takes SO much pedal to make it go, that the trans was constantly downshifting. The carb uses about 1/8 the pedal that the TBI does to get the same response, and it always stays in hi gear like it ought to.
Can I hear from someone who's tried both TBI and carb and knows if there's a fix for this problem. I hated having to give it 3/4 throttle just to accelerate or climb a grade.
Thanks

 

I donno man, maybe you could try an aftermarket TBI throttle body, or port yours a bit.. other than that I wouldn't know! Maybe you could put a CCQ-Jet and distrubutor on? Would be kind of a PITA but better power than TBI.

 

i hate cali and all these emissions BS. I agree that beaters shouldnt be allowed to drive around if theyre pumping out black smoke but when did we lose our right to build powerful cars?!?!? I live in Ontario and i think i heard once that theres a law that your not allowed over like 700 hp or something...WTF IS THAT??? i hate emissions and all this other crap. sorry im not much help just venting....really wish you were able to stay with your carb ****ty deal having to go back. best of luck

 

Thanks. At least here up north we don't have to re-certify every 2 yrs. but that doesn't mean you won't get in trouble if you get caught.

 

Well i really dont care about getting caught with it thats not my big concern. its funny because you say up north but im pretty far north of you. Yeah every two years i have to get it emissions tested but luckily some places do a pretty half assed job so its either that or getting someone to lie on it for you.

Dont mean to change the purpose of this post. SOMEONE HELP THIS MAN FOR HEAVENS SAKE!!!

 

*cough cough hint* TPI *cough* maybe (if the smog commies say its ok) you can swap a TPI induction on

 

That would be an elegant solution for sure, but kind of like getting from LA to SD via NY.

Couple of things you can do.... there are aftermarket TBI units of course. First thing though is chip programming!! You can usually make an amazing difference that way. You'd probably have to put your stock chip in for inspection, but you might be able to more nearly approach carb performance if you had a decent fuel curve in it, for the other 729 days out of every 2 years.

 

Where are you located?

 

Located in Eureka.
The TPI idea has definitely crossed my mind, as well as aftermarket kits like the Edelbrock MPFI. But I'm interested in hearing about chip tuning also, cause it seems like no matter what I end up with, I'll have to burn a custom chip for it before I'll really be happy with it.
TPI is smog legal for my year, and it's a realistic option. But if it's possible to get the TBI dialed in, it's money saved.
By taking up chip burning for my TBI could I apply the same program or software or however that works, to a TPI if I decided that I wanted to upgrade to that?
I guess my real question is this. Is learning to burn custom chips the next step?
I'm kind of an ignoramus when it comes to computers.
I've tried all the ultimate TBI stuff, and that woke it up some, but not the way I like it.

Thanks for the replys

 

Well yeah burning a chip will help you a bit but you really dont need to start worrying about doing a new chip until you start doing engine internals. youve gotta think its not like gm is going to make a bad chip for their cars so if its stock i wouldnt dedicate your time too much if you think its going to net you a big gain. Going to tpi would work but it sucks that you have to waste your time with a tpi and cant just slap on a mini ram or something because its doing the same amount of work and only netting you half of the gains. Anyways so much for building fast cars....Id start seriously thinking about the tpi

 

It's not that GM makes a "bad" chip; it's just that their priorities aren't necessarily the same as yours. I could be wrong, but as far as I can tell, most people's priorities on this board are different from GM's in the first place, otherwise they wouldn't be here at all.

It's just like tuning anything else as far as that goes. All that the chip is, is the values for ignition timing, fuel feed, and a few other things, that the computer uses to tell it what to do under whatever conditions of temp, load, throttle position, etc. that it sees. No different really from tuning a carb; you just go about it with different tools. If it surges under certain conditions yougive it more fuel; if it pings you back the timing off; if it's lazy you crank some more fuel and timing in; etc. etc.

Changing internals (especially the cam) will usually require tuning changes via the "chip", just like it does with anything else. But often, drastic changes in how the engine behaves can be accomplished that way, even without internal mods.

 

Internal mods or not... mine is near stock... I just did a side by side comparison, TBI to Holley 600vs. There's a world of difference between the two. It's obvious that the fuel delivery/ spark curve is responsible for the performance difference. If a custom chip could remedy that I'd be all over it.
I think the GM chip is designed to pass emissions and other EPA regs. for starters. I can't say a whole lot else about the subject, cause I've never driven a TBI car or truck that was modded to perform.
Still hoping to find out more.
I AM thinking seriously about TPI, but now the question is: Can I get started at chip burning for a TBI and use the same stuff to burn a chip for a TPI later?
I really do believe that a custom chip for the TBI would at least get me part of the way there, and if I'm still not satisfied, upgrade later.

 

I assume you still have the 305? If so, and you installed a carb and magically found some serious Butt-Dyno-Torque and HP, I'd jsut reinstall the TBI, then figure out why it's not running correctly.

Not that a 305 TBI is a neck slapper, but you shouldn't see more than 10-15HP (my guess) up top (where the butt dyno doesn't work as well) from just installing a carb...unless something is whacked with the original setup.

 

It wasn't so much WOT, it was part throttle.
Just terrible driveability.
BTW it's a 350.

 

You can use the same hardware and I guess software for burning a TPI chip, they just have different code, there are all kinds of codes out there (check the prom board) and you could also mess around with the baseline tpi code. I'm sure you can't use the same TBI computer on the TPI setup; the best thing would be to hit up the junkyards and pull: manifold, fuel rails, ECM, Wiring harness, fuel pump (probably should buy a new one), and get some new fuel lines

 

Well...I'm 99.99% sure you have a problem with the original unit that needs to be fixed...tell ya why.

A few years ago I helped with a 305 to 350 TBI swap (90 or 91 RS) and all we did was install larger injectors (from a truck, IIRC, 350) ran it.

The engine was a Caprice crate 350, totally stock, and ran very well, the Camaro had 2.73's and 700R4. I drove the car myself, and noticed no drivabilty issues at all. Part throttle and WOT were acceptable for what it was...again, we used the stock PROM for the 305 with no mods.

Soooo, in summary, since you live in Ca., I'd suggest reinstalling the TBI and working out whatever died.

 

Maybe the tps was bad???
I'll look into that.
Thanks ... Everyone