cabech984

A friend of mine has a 383 Stroker in a 91 Blazer 4dr. It has an unknown cam and a pair of GM Performance Parts Aluminum heads(Fast burn??). Also has some Hooker swap headers and an open element air cleaner. He bought it the way it sits and has to GM TBI's installed on a dual carb intake with TBI adapters.

It needed a pump when he bought it, so he just bought a cheap autozone one and limped it on down the road. After getting some more money, he installed a factory replacement AC Delco TBI pump. He is currently having leaning out problems, scantool isnt showing sufficient O2 Millivolts. Were suspecting the fuel pump is the cause of the concern, not enough pressure to feed dual TBI's.


What pump shall he wanna run with this setup? It runs fine at idle, less than 1/4 throttle, as well as cruising. In WOT, the O2 Mv drop and truck falls on its face. Were stumped!!! ANy help would be great!

camarorsssss

iTrader: (2)

someone is selling a 255 walbro fuel pump in the "parts for sale" section that will be sufficient for your application, you will need to adjust your fuel pressure as well at the throttle bodies.

cabech984

Around what PSI would I want to set the tbi's at?

camarorsssss

iTrader: (2)

Its a hard question for me to answer you will have to do some tuning of the computer and will have to play around with the pressure to find what the motor likes. If i had to guess i would say around 18-20 psi, but then again it depends on the cam you have as well.

RFmaster

Can you post pictures of his setup - Just increasing Fuel pressure maybe the answer for a single TB on a dual plane manifold. If he has dual TB's then providing fuel volume at all times to both TB's might be tricky. Also, can you find out injector size???

//RF

Ronny

iTrader: (1)

I was of opinion the injector drivers in a stock TBI ECU will soon fail or not function correctly attempting to run 4 injectors. I will suggest the stock ECU may be part of the problem. EBL-ECU may be the best option. Seems a datalog with tuner pro RT showing the duty cycle of injectors will tell the tale. A Walbro fuel pump 190 or 255 will help as stocker wont cut it. 255 series may need a larger return line. GM TPI or LT1 is another alternative..