Motor has been together for some time using a custom chip and stock 61# injectors. Just installed EBL Flash for first time and new 74# injectors. K5 Blazer 383ci TBI Sportsman 2 heads Tri-Y headers single exhaust, 2.5" collectors into 3" Y pipe, 3" flowmaster muffler, no cat. Hydraulic roller camshaft, 210 int. 220 exh. @.050, .500 lift with 1.6 roller rockers, 112 lobe separation. Edelbrock TBI intake, 2" enlarged bores. 46mm enlarged throttle body with 1" open plenum spacer. Injector pod spacer, adjustable fuel pressure regulator in factory location. 74# injectors. Factory stock fuel pump set at 10psi (That's all it can do). Fuel pump will be upgraded down the road when time permits. For now I plan to play with the current setup and drive ability of the vehicle. Have completed some VE learns and data log. Idle has improved since first startup but still seems rough. Do any of the experts see anything glaring with my datalog. Just want to make sure I am on the right track.

 

That fuel pump is DONE. It is already in partial-failure. [Edit] ...or the fuel pump wiring harness has problems supplying power to the electric pump...or the fuel filter is plugged. [/Edit]

You will waste a lot of time, money, effort, and enthusiasm trying to tune an engine supplied by a failing fuel system.

 

^^^THIS^^^

 

Yeah, 10 would be sub-optimal for a stock 305 with a driveability issue. For your build...it's fuel pump time!

 

Just completed replacing fuel pump and fuel filter. Fuel pump is ep381 and now has 17psi at the regulator. Have been making adjustments but cannot seem to fix idle surge. Idle surge has improved but cannot eliminate completely. Idle is set in open loop, raised base idle in P/N and drive, timing locked at 23*, played with proportional gains. What else should I look at adjusting? Any advise?

 

Note that the proportional gain is only used during closed loop operation. In open loop they are not used.

The surging is being caused by the engine going lean. In some areas of the VE table the VE% is low, down in the 10% - 15%, not sure why.

As for the pod spacer, with the engine running check where the injector fuel cones strikes the bores. They should hit the bores right above the throttle plates. This provides the best idle and off idle transition. Adjust the pod height to get this correct.

A timing light can be used to freeze frame the injector spray.

RBob.

 

Been working on drive ability and performance. Both have improved. As recommended by RBob I inspected injector spray pattern and one of them needed cleaning. Still need to solve idle surge in park/neutral but this has improved. Surge is not as noticeable in gear. Made a WOT pass to 80mph. Do any of the experts see anything glaring in my data log?

 

Just a small amount of knock being reported. Looks like some of it is from tire spin.

RBob.