Logo
FULL SITE MENU

I think I need new fuel injectors for 5.7 GSI TBi.

S

Shaper79

New member
Ok. This is weird. New carte fuel cell. and ignition system. If cruise at 4200 rpms WOT running the 17 pitch. If I slightly and rapidly pull back and fourth on the throttle I can build her up to 4600 rpms. But as o set the throttle all the Down WOT. It backs its self off the the 4200rpms. I’m totally lost with this one. The only think I can think of is new TBI fuel injectors. Any options would help.
 
Shaper79 said:
Ok. This is weird. New carte fuel cell. and ignition system. If cruise at 4200 rpms WOT running the 17 pitch. If I slightly and rapidly pull back and fourth on the throttle I can build her up to 4600 rpms. But as o set the throttle all the Down WOT. It backs its self off the the 4200rpms. I’m totally lost with this one. The only think I can think of is new TBI fuel injectors. Any options would help.
Click to expand...


First off...... WOT RPM is a test RPM only! It is NOT an RPM that is to be sustained for any longer than the testing requires.

Check with your OEM owners manual...... I'm thinking that your cruising RPM should be around 3,400 rpm to 3,800 rpm.
You may not have a problem.
 
Yea. I know the cruise rpm is somewhere in the 3800-4000 rpm area. But people with the same boat 270hp 5.7l GSI 2000 216 chaparral. With full tank of fuel @58 gallons and 2 people. Can hit the 4600 rpms and it will hold and not back off. If my pumps check out to spec psi. Is there a possibility of a tank vent that me be clogged. It’s like it loads the pumps then bleeds off a bit. I installed a new pressure regulator and injector screens. I was thinking maybe the pressure regulator spring needs to be increased. But I’m not sure what stock spring “psi “ is. And or the injectors are crapping out at that brief high rpm range. I have found a set of new injectors for it. Volvo was penta wants like 500$ per injector. I called a few injector guys. And they confirmed the injectors are the same flow rate of the 94-95 7.4l gmc. 100$ per injector. At Rock auto. Just wanted to see if anyone has experience this with out it being a pump. Problem. .
 
..........................
Shaper79 said:
Yea. I know the cruise rpm is somewhere in the 3800-4000 rpm area. But people with the same boat 270hp 5.7l GSI 2000 216 chaparral. With full tank of fuel @58 gallons and 2 people. Can hit the 4600 rpms and it will hold and not back off.
That is an excellent way to keep the marine shops busy selling replacement engines.

(by the way..... and a friendly gesture only........ revolutions is plural, minute is not!)

If my pumps check out to spec psi. Is there a possibility of a tank vent that me be clogged.
Yes.... but understand that the volume of vapor above the fuel will determine how much fuel depletion would be required in order for a plugged tank vent to have an effect.


It’s like it loads the pumps then bleeds off a bit. I installed a new pressure regulator and injector screens. I was thinking maybe the pressure regulator spring needs to be increased. But I’m not sure what stock spring “psi “ is. And or the injectors are crapping out at that brief high rpm range. I have found a set of new injectors for it. Volvo was penta wants like 500$ per injector. I called a few injector guys. And they confirmed the injectors are the same flow rate of the 94-95 7.4l gmc. 100$ per injector. At Rock auto. Just wanted to see if anyone has experience this with out it being a pump. Problem. .
Click to expand...
 
Back
Top