Here is a description of the car. Formerly a 305 TPI, this is now a 350, 355 or 383 (we are not sure). It has an adjustable fuel pressure regulator, it may still have the 19lb/hr injectors, edelbrock centerbolt heads milled to 58cc, and a radical cam. I am not sure if there is more yet, she just got the car.

Here is the problem. The car runs rich at idle, but runs lean while driving.

My guess is that the fuel pressure is turned way up, but the stock injectors cannot compensate. I think we should get some Ford SVO injectors. But before we do this I would like to know if anyone knows anything else less expensive to try, first.

Thanks,
Clint Stallard & Darlene Deerfield
1991 Firebird 1991 Trans Am
305 TBI 350+ TPI

 

I would definately find out how many cubes you are dealing w/ first. That would kill me not knowing. I'll agree w/ you on injector size (need bigger ones). Then again, what do I know?

 

Thanks for the reply. Could a severe vaccumm leak be at fault?

 

that vacuum leak would be pretty easy to find.
19# injectors on 350+ and a rad cam...
even with the pressure jacked 50# isnt a good
idea. best idea is to research the CID, match
the size with injectors, and research the cam
(lift/duration) whether the chips been compensated
for the changes. but id get a scanner of some
sort to dechipher the "wuz up" on it.
airdeano

 

Thanks. I am looking into some 36# or 24#
Would Ford Mustang 30# injectors work?

 

I don't actually have my TPI up and running yet, so take this advice as you will:

1) I think the previous posts are good ideas...the best things you can do are find some specs on the displacement (at the very least anyway) and also the cam specs (though I don't know how likely that one will be).

2)If you are dead set on buying injectors, I would stay a little on the conservative side. If the injectors are a little too small, then you could just up the pressure a bit with the AFPR. I am not sure what 24lb/hr. injectors will support, but that would be my best GUESS as to what you should probably be buying WITHOUT knowing anymore than you do.

In closing, I would find out as much about what you have before you buy more stuff. Maybe you could start with taking a look at what the computer is reading (a scanner of some sort perhaps?...someone here can probly give you a recommendation on a good one). Good luck with it.

 

First off, just swapping out injectors isn't going to fix anything without proper tuning. If you go with larger injectors, you'll likely be dumping fuel at the bottom end until you get your initial programming set right. That would be your displacement and injector constant. It's still important to start with the right injectors, too small and there won't be anything you can do about going lean on the top end. That's not real good for the motor. Too big, and you'll have a difficult time getting it to idle properly.

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408cid 1985 Corvette
http://www.mojosgarage.com