anvil8679

I was hoping someone could please help me out and give some advice. I just did a 5.3 swap into my 79 Malibu with a s475 turbo. I just got it tuned and it did great on the dyno. Got it home and went for a ride and I blew the maf in half. Changed that and the car was running pretty good. Went for another ride with no issues. Jumped in the car today and it idled great and the first mile was fine. After that it started running very rough. It barely wants to run at part throttle. If I jump on it it still runs rough til about 4000rpm or 5 psi then it seems to wake up and take off. I have about 56psi of fuel pressure. Car was at about 180 degrees. I'm using the stock truck maf, a 2 bar cobalt map sensor, 80 pound injectors and had the car tuned by a shop. If someone could give some advice I'd appreciate it. This is my first efi and my first turbo build so I am at a bit of a loss as where to start. Thank you

JoeNova

Bothered calling the shop?

Why did you stick with a MAF and not convert to SD?

anvil8679

Haven't had a chance to call them yet. I wanted call them as a last resort just so I don't bother them if it's something stupid I've over looked or my fault. And honestly I only stuck with maf because it seemed simpler and really didn't know why I should go 1 way or another. I still have a carb on my daily haha

Budget LS Guy

Maybe the new maf is bad?

anvil8679

It's a possibility is there anyway to test that? Anyone think it might be a throttle position sensor?

forcd ind

iTrader: (7)

How did it run when the orig MAF went bad, same as now-it might have killed your 02 sensor-everything is a guess now
if you messed with your throttle screw it could mess things up unless a reset was done

ls3fox

Unplug the maf and see how it runs it sounds like you have a bad maf and its running rich until you make some boost then it can use the fuel

carguy662000

Id drive it with the maf unplugged but don't get into boost, see how it runs this will force it to use the ve tables. if its smooth the new maf is bad

Fat Jesus 808

iTrader: (5)

Maybe a a post maf leak?

nodrok

Put a wide band on it so you have a clue as to whats going on. Your working in the blind if you don't have one.

anvil8679

It wound up being a combination of a bad tps and not a heavy enough blow off valve spring. Air fuel gauge is def on the list to buy. Any preference where it should go?

JoeNova

AEM is my personal favorite.