bigchief52780

iTrader: (10)

i need help with a fueling or tuning problem. 1970 cutlass with ls3/4l60 combo. all electronics came from psi except ecm. ecm has stock tune setup with nonessential stuff removed.
the car idles fine and drives fine cruising. when i floor it and rpm go up, it dies like its out of fuel. let off the gas and it starts back pulling.
i have swapped tanks to the fuel injected tank for the 70 cutlass and i am running a return style regulator set to 58lbs as recommended from psi instructions. i have -6an line from tank to regulator and -6an from regulator to rail. anybody else had a problem like this.

bczee

iTrader: (12)

Most likely your fuel setup is all and good.. but what you need to do is monitor the fuel pressure at the Fuel Rail..

Also.. connect a scanner and monitor it real time or log the inputs from the sensors.

BC

bigchief52780

iTrader: (10)

i thought about putting a gauge adapter fitting between the rail and regulator. i also ordered a new ecm from psi to make sure that the tune was correct.

LSCha0s

iTrader: (4)

tape a fuel gauge to your hood and watch the fuel pressure when you floor it. You fuel system may not be up to the task. Data-log would also go a long way.

philntx

iTrader: (8)

What fuel pump are you using?

Jimbo1367

What brand EFI tank did you switch to? Hopefully NOT Spectra.

ls1nova71

iTrader: (4)

When he said he had a tank made for the car this was my first thought too.... Classic Spectra symptoms.

oldgoat69

Sounds like you are running out of fuel under load. Carbbed engines show the same symptoms. Backing out of the throttle and things get normal, not enough fuel volume.

bigchief52780

iTrader: (10)

its a spectra but i changed the pump to a 255lph. i am thinking of getting the e85 high flow/pressure pump for 09 and newer chev trucks off ebay. can someone recommend a better one. will the 05 gto pump work better?

ls1nova71

iTrader: (4)

I think the Spectra tank is a baffeling problem, not a fuel pump problem. You'll need to put a gauge on it to see if you're actually loosing pressure when it cuts out. If it is, you don't have a good baffle in the tank and the fuel is running away from the pump.

chuckd71

iTrader: (23)

Well, the fuel pump is garbage as well. Mine died after a few hundred miles, as luck would have it it crapped out just after I paid for a flatbed to take my car to the tuner. Pretty awesome. Anyway, just in case anyone else sees this thread - pull that junk fuel pump out and drop a walbro or better in.
More on topic, you might consider getting a fuel pressure gauge for in the cabin anyway, with a fuel injected car it's nice info to have when troubleshooting.

bigchief52780

iTrader: (10)

i checked the fuel pressure while driving. fuel pressure remain at 58lbs and did the same thing. fuel pressure never dropped or fluttered. could it possibly be the ecm. i did not do the programming.

oldgoat69

At what RPM does it feel like it runs out of fuel? Did your tuner remove the over rev feature in the PCM, I am pretty sure this will cut off fuel at the rev limit.

bigchief52780

iTrader: (10)

is the over rev feature the same as fuel cutoff. if so fuel cutoff is set at 6100 from what i read while looking at the tune with my hptuner. i havent verified it because the ecm is not showing me rpm with the dakota digital dash. i havent drove it with the tuner hooked up yet.

oldgoat69

Put a tach on it and check it out. In my experience these engines rev up so fast that it is easy the hit the cutoff and not even realize it.