I know the spec is 9-12 psi but I'm curious what you guys with TBI cars w/o fuel system modifications are seeing.



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1988 T/A,
9" Ford, 3.50 gears, Auburn posi, 700r4 -w- 2100 converter, 360ci, 9.8:1 cr,
AFR 195 Heads, Weiand #7525 intake, Lunati roller 219/227, .479/.480, 112 LSA
GM big block 2bbl TBI on truck 7747 computer

 

and if you were to replace a fuel pump for a 305, tbi,
what would you get

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91 FireBird 305 V-8
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Hey Dan, how's that 2bbl tuning up? Good I hope! What do you mean fuel system mod's? Different pump? I've been playing with my fuel pressure and it's been anywhere from 10 to 18 psi. Changed the POS holley to a GM pod and modded the regulator to be adjustable. The holley would change psi by itself several times a day and I could not do any justice trying to burn chips while chasing down psi.

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91 RS 350TBI..... Vortec heads..... Holley 670..... Edel. intake .... Lt4 cam 1.6 rollers ..... Edel. TES headers .. 3" exhaust ..... 5spd 3.08

 

I'm trying to figure out a problem and just wanted to see what was going on with other people before I go cuting my return line to check the return side pressure.

I'm seeing 14 psi on the feed line. I'm running a 255l pump.

I was looking for pressures from unmodified systems to check if my pressure is abnormal and possibly a result of the large pump I'm running.

 

Mine has the stock 91 LO3 pump. After changing to the GM pod it's staying at 12 psi. Much better than the holley. Why do you think that you have may have a problem?

 

High pitched screaching noise coming from the TBI unit and the injectors cut out after a minute or two of running. There is nothing wrong with the injectors or the regulator as I've used the stock injectors and regulator with the same results.

 

GM Pod?????\


tell me more,

 

GM 454 tbi unit

 

You can fit the stock GM TBI injector assy on the Holley 670 base. The spray pattern on the 670 was not as smooth as the stock one is and the fuel pressure was up and down by a great amount.

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91 RS 350TBI..... Vortec heads..... Holley 670..... Edel. intake .... Lt4 cam 1.6 rollers ..... Edel. TES headers .. 3" exhaust ..... 5spd 3.08

 

hmm.... on a 305?

A 454 Tbi?

 

yes, it can be done. fuel pressure increase is a must however, ive been working with the idea for a while, on and off the car etc..

results. 454tbi with slight increase in pressure caused the car to still run lean, increasing knock counts, retarding timing, decreasing milage drastically, and causing a lag off idle acceleration, which made my car seem like it had an higher stall converter, spin the tires and seemed to rev faster, but the minute i would get knock, the car would die out as rpm increased, if cruising at 60, the ecm would correct the mixture, acceleration from hwy cruising was increased. all in all, chip changes are probably a necessity if you want a 454tbi on a stock or barely modified l03.

maybe its the iac, trying to move, and something is vibrating badly or somethin. try backin pressure down real low like 9psi.

hard to diagnose stuff like that over the net