I have an '89 Formula Firebird with TBI L03. I took my car to the track in March and It ran 3 16.2's. I took my bird to the track yesterday after changing the fuel pump (gm replacement) and now my car runs 16.8's. I think maybe my injectors are maybe going bad or my regularor isnt working correctly at full throttle??? My brother has a totaled '85 Motecarlo with 4.3 TBI. Would has Injecters be the same as mine?? Would his regularor etc be the same??? If so I might change them over. Is is possible to get my injectors flow tested??? Thanks
Ben

 

If you changed the fuel pump, the volume and psi settings are now different (increased) than before, what you want to do is tune your TBI using your O2 sensor readings at WOT under load to get the right fuel pressure for your setup.

 

But my Fuel pressure before the swap was 9, and now its 11psi... still within the factory 9-13psi settings. Plus my Fuel pressure regulator will make up for this 2 psi difference.
The Volume is the same as before... Its a stock replacement pump. Everythings electronic, I cant "tune" anything. My electric regulor does this for me... inless its shot.
That is why I ASK, Is my brothers TBI the same as mine???
I wanna swap his parts for mine, without spending 1Billion dollars, which might not even cure the problem.
Ben

 

As pumps age/break the volume of fuel they transfer goes down.

With a volume change there is a pressure change, this is why you should adjust your fuel pressure regulator (FPR) in the TBI to work in conjunction with the difference in pressure/PSI.

Besides, this is a good thing in general that way you will run good at WOT, which is exactly your concern, at part throttle, its all goverened by the ecm, the injectors will be pulsed for fuel whenever needed.

 

probably also a good idea to take a look at the blms. Those will give you some idea if the computer is trying to compensate for too much or too little pressure.

 

Well, if the guy at "Zim's Carberator Shop" said my psi was 9, and now its 11, should I adjust it to 9, when I get a new regulator of course. What kind of regularor shold I get. If I get the one that mounts on the throttle body (turbo city), how will I know my psi. My gauge is before the regularor, my gauge tells me my pump psi, not what my regularor is letting through.

Also I just realized Maybe my car needs a common tune up, over the summer is it possible that my coil and cap could be slowly getting weaker??? 103,000miles.
Ben

 

I hadn't done a tuneup for 4 years.. changed coil, wires, cap and rotor.. noticed one hell of an improvement from that alone from the seat of my pants. Funny how my ac delcos looked good still.. tan/brown with a slight increase in gap to 0.036-0.037 darn good plugs for the money.

Prior to the coil, I couldn't get my 16's kdws to peel, now I have to feather it to not peel when driving normally.

 

If its been awhile since your last tune-up id defiently do that anyways and just see how that helps. Man when I first got my car it WOULDN'T peel out at all..couldnt even force it. Now it just about burns my poor 150$ a piece dunlops to shreds. Notice the singular MY lol damn peg leg.

 

Hey, what kind of coil did you guys get. I was thinking of going with
Hypertech Coil/Cap/Rotor
AC Delco Plugs
Taylor Spiro-core Wires

What tune up parts did you guys get
Thanks for the help, Ben
Also a peg-leg...that wont spin-em (it)