ok....i have been on a quest for what is wrong with my car for 2 straight weeks now, i have searched...and searched...and searched, and every possible answer has proven wrong.

Car info: 1989 Firebird (originally 305)
355 TBI
305 heads
Automatic Trans
120xxx on the body
1,100 on the motor

It begins-
car began acting up after i installed shorty headers, it would take a while to start (4-6 sec of crank) then when it would start it would run sloppy with minimal throttle response and definite lack of power. Problem was intermittent. Ran diagnostics and pulled code 44 "lean exhaust". Replaced O2 sensor, ran alright

Problem came back but was steady, everytime it started it would have sloppy idle and minimal to zero throttle response. searched foru came up with list of possible culprits.

Problem became worse until finally car had incredibly irradic idle and would die when put into gear.

Now car has gone from that to will run for 2 seconds then die with 4 psi of fuel pressure. ((---edit---- i can keep car alive if i pump gas pedal but if i push and hold it dies----))

i have done/checked the following:
AC/Delco Plugs
Accel 8mm wires
Accel cap and rotor
GP Coil
MSD 6AL box
New fuel injectors (22lbs)
New TPI fuel pump
New ESC module
New fuel filter
New Air Charge Temp sensor
New MAP sensor
New TPS sensor
New IAC
New O2 sensor (unheated)
New MAF sensor
New PCV valve
New ECM
Checked and reset timing (while car was able to run)
checked for spark, air, and fuel
Fuel pump ran at 6-8 psi but now i replaced the pump and it
runs at 2- 4 psi
checked Oil Pressure switch
checked EGR valve
checked P/N switch
strong exhaust from tail pipes

ive searched countless times and i am finally starting to get a lil annoyed, is there anything i am missing? any thoughts/ideas???

 

You have to figure out what's up with the fuel presure...should be closer to 40psi, not 4psi.

Pull the vacuum line off the fuel pressure regulator and sniff for fuel...could be a ruptuerd diaphram sucking fuel into the intake...hence strong exhaust smell.

Too much fuel through the motor washed out the O2 and gives a false lean.


If regulator is okay. block the return line and verify you can actually get 50-60PSI from the pump.

If not, then blow air though the pressure line and veifry it's not obstructed

PS, you did change the "sock" too?

 

yes but it is a TBI motor it should only have 9-13 psi and i don't believe there is a vacuum line that goes into the regulator is there??

 

4psi can not be good. I would fix that first.

 

I see, you threw me off with

New TPI PUMP and
22lb injectors...350 TBI engines came with 65lb/hr injectors

So, still block the return line and see if you can get pressure, should still be in the 50/60 range with the TPI pump.

Did you try and make an adjustable fuel regulator out of the stock one?

 

problem solved...well mostly, a 3 cm slit in the hose connecting pump to the line was draining all pressure, couldn't see with the naked eye!!