350 Vortec wi th 454 TBI running pig rich

[rsicard]

As a relative newbie, need some advice. Converted '98 350 Vortec to TBI using 454 throttle body, 4 barrel intake and adapter. Have several injectors from 305, 350 and 454 TBIs. Purchased Cop Car injectors that are NOT marked supposedly 65 pph. Keep running into the same situation wherein the engine runs pig rich at idle. Fuel pressure at present is 14 psi. Just switched to 350 injectors and still runs pig rich. Installed adjustable pressure regulator and have it at lowest pressure setting. Still runs rich.

Found that Oring sizes and fit are critical in the fuel portion of the TBI. Got the wrong size, wrong fit and it hydraulically LOCKED the engine. Pulled all the spark plugs and rotated with starter. Got a gasoline bath. Tried to dry out plugs and reinstalled. Still misfiring and running pig rich. Went to the auto parts store for new spark plugs. Need to get these installed and try again.

Advise needed for this situation.

[Chewy1576]

I just put 454 injectors (80 lb/hr) over my TBI 383. Had to update the BPW/BPC for the displacement, injector flow, and fuel pressure from 135 to 96. I also deleted the EGR. After a few datalogs and updates to the VE table it is running very well.

[rsicard]

I just put 454 injectors (80 lb/hr) over my TBI 383. Had to update the BPW/BPC for the displacement, injector flow, and fuel pressure from 135 to 96. I also deleted the EGR. After a few datalogs and updates to the VE table it is running very well.

Did you replace the electric fuel pump with one that could achieve higher pressure? What was the fuel pressure set at? Don't understand fuel pressure 135 to 96. How was the EGR deleted. Did you emulate to update the VE tables? Was a wideband O2 sensor/display hooked up when modifying the VE tables? Please advise. Thanks.

[BLG355]

It sounds like you have too much fuel. Your VE tables will need updated, but you need to get something close for it to work off of. Are you sure you don't have a pinched return line or something? Does it lean out when it warms up and gets into closed loop? Can you post a datalog?

BLG

[rsicard]

It sounds like you have too much fuel. Your VE tables will need updated, but you need to get something close for it to work off of. Are you sure you don't have a pinched return line or something? Does it lean out when it warms up and gets into closed loop? Can you post a datalog?

BLG

Would be pleased to attach a datalog. As a relative newbie, learning how to tune the hard way. Get little bits and pieces. Yet it may all add up in the end. The engine is a 1998 350 Vortec with a 4 barrel manifold on top of which is a 454 throttle body on an adapter. It is on a run-in stand right now. Will check to see if the fuel return line is clear. Using export Vortec 5.7L TBI binary file. Fuel Pressure is at 12-14 psi. Purchased supposed 65 pph injectors off of Ebay. Came unmarked look refurbished. Hooked up Innovate LM-1 Wide Band AFR. Runs 10 AFR at idle. Occasionally, leans out to 17 AFR and almost quits at idle then goes back to rich AFR. Installed used 350 (slightly smaller) injectors, same rich AFR results.

Thinks maybe it is the MemCal. Will pull the MemCal from the 1995 Chev C1500 pickup, and try, that the Vortec on the engine stand is to be installed in to replace the oil burner in the pickup now.

Seems as though it is in Limp Home Mode (LHM) all the time??? Please advise. Thanks.

[Chewy1576]

Did you replace the electric fuel pump with one that could achieve higher pressure? What was the fuel pressure set at? Don't understand fuel pressure 135 to 96. How was the EGR deleted. Did you emulate to update the VE tables? Was a wideband O2 sensor/display hooked up when modifying the VE tables? Please advise. Thanks.

Yes I installed an EP381 fuel pump and 18 psi spring in the regulator to achieve a higher pressure. It was the Base Pulse Width that I changed from 135 to 96. 135 was the value from the factory with 350 cubic inch engine, 56 #/hr injectors, and 13 psi fuel pressure. I'm now at 383 cubic inches, 80 #/hr injectors, and 18 psi fuel pressure. There is a spreadsheet Dave W created in another post that will do this calculation for you. To delete the EGR I sandwiched an aluminum plate between the valve and the intake to seal the port, then increased the EGR enable RPM to its maximum value. Dave W's spreadsheet will also update VE tables if you can input your current table and average BLM values from a datalog. Update and log a few times and it gets very close to running efficiently. I don't have a wideband O2, just a new Bosch replacement sensor.

[rsicard]

Yes I installed an EP381 fuel pump and 18 psi spring in the regulator to achieve a higher pressure. It was the Base Pulse Width that I changed from 135 to 96. 135 was the value from the factory with 350 cubic inch engine, 56 #/hr injectors, and 13 psi fuel pressure. I'm now at 383 cubic inches, 80 #/hr injectors, and 18 psi fuel pressure. There is a spreadsheet Dave W created in another post that will do this calculation for you. To delete the EGR I sandwiched an aluminum plate between the valve and the intake to seal the port, then increased the EGR enable RPM to its maximum value. Dave W's spreadsheet will also update VE tables if you can input your current table and average BLM values from a datalog. Update and log a few times and it gets very close to running efficiently. I don't have a wideband O2, just a new Bosch replacement sensor.

Thanks much for the reply. You have a 747 ECM, I have a 7427 ECM. Was the base pulse width setting item in the Scalars, Flags or Tables? Guessing the Scalars. Trying to interpret which item should be changed for base pulse width in the long list of TunerPro for 7427 ECM which I have. Understand what Dave W. has done with the spreadsheets. Just trying to lean out the fuel some as a first step.

[Chewy1576]

I'm not 100% sure but I think it's call Base Pulse Constant in the 7427 ECM. For me, the Base Pulse Width was one of the first scalar values in the parameter list.