350 TBI fuel delivery problem (1 Viewer)

[COLOCRUISER]

I have a fj60 that I put a tbi in and it has a hesitation problem. When you get on the gas it has about a second hesitation before you can feel the power kick in. It feels like the motor is starving for gas initially but after it finds its tune it takes off like a bat out of hell. I used all the stock fuel lines except for about 7 feet of rubber fuel line I used to connect the fuel pump to the fuel filter and part of the return lines when I did the swap.

Also another problem I had when I was in moab was when I got on any kind of incline it would act like a carberator and stall out. This was after the motor (runs about 190 degrees) and weather outside was pretty warm.
Do rubber fuel lines swell when they are hot so it starves the motor for fuel?

 

[TemboTusk]

Sounds like timing. Timing needs to be 0 degrees TDC with the computer out of the loop.

 

[39sandaV8]

I have had the same hesitation issues with my TBI powered 40.
Chasing the problem on mine revealed that my static timing was
retarded by a few degrees....this helped a little....but didn't get
rid of the hesitation entirely. Unfortunately, I haven't had the time
to further diagnose things on my rig, but here are some things to
check out on yours:

1) Fuel pressure. GM TBI systems need at least 13-15 psi to work
properly. This may be what is causing your stalling issue as well.

2) Timing. Recheck the static timing setting. (I forget what the
recommended setting is for a TBI 350....but thats what manuals are
for...right?)

3) Check the vacuum line going to the MAP sensor. Make sure it is
in good condition. Also test the operation of the MAP sensor by
backprobing the output wire with a digital VOM. Since the MAP
sensor works similar to the accelerator pump on a carb, this could
be the cause of the hesitation.

That should be a good starting point. For some VERY good reading
on TBI tuning and such, check out:
http://www.cfm-tech.com/GM_tbi_tuning_tips.htm
Lots of good info on this site!

Hope that helps and please share your results here
Good luck

~Jack~

 

[blackandbluefj]

http://www.cfm-tech.com/GM_tbi_tuning_tips.htm

great website not to hijack but abyine use there hop up with the spacer and fuel pressure regulator

 

[Gumby]

The fuel hose should be kept short as possible and it should be high pressure fuel line. It's spendy. Regular fuel line is built for 4-8 psi.

You can bump your fuel pressure regulator up pretty easily.

How's your vacuum?

 

[Tinker]

Does it set any codes?

 

[COLOCRUISER]

I replaced the fuel line to high pressure fuel lines and it seems to be running a little better, but I am going to by a pressure gauge and see how many psi my pump is putting out. so far it has not thrown any codes and vaccum is good

 

[Elbert]

I would also say to check the timing. Those engines are very senstitive to timing. ON my 92K1500 the base timing is 0 degrees. You have to be right on the tming or it runs like crap. I would also suggest you change the fuel filter.