I have new built 355 tpi 26# injectors,alum heads,10:1 ,MILD cam. It idles good at 590rpm. (1990 tpi )it's got alot of pick up ,But my wide band O2 gage in the dash go as high as 17afr and steady 16 at part throtle. The shop that built the engine thinks I might fry my valves before I get the engine broke in. What can i do to the bin to make it rich at part throtle? It goes lean on acceleration also 16 afr.Please help Mike Scott

 

What have you done for tuning so far? Does the ECM go into closed loop? If so, what are the fuel trims?

Note that even the smallest leak in the exhaust will make an O2 sensor report a lean condition.

RBob.

 

ALL I changed was injector size to 26# on stock 350 bin file, and didn't touch fuel or spark. my fuel pressure at the rail gauge is 40#. no egr.

 

Be sure to disable the EGR in the BIN. Set the MAT enable temperature high.

Then see how it is. If still lean, and it may be from the cam change, will need to work on the VE tables to richen it up. Can use the BLM value(s) to see how much to change the VE %.

There is also a possibility that the injector compensation tables need to be tweaked. The stock Multec injectors are a little faster and a little more linear then Bosch injectors. Which is a guess at what you changed them to.

This will mostly affect low PW ranges of the injectors.

RBob.

 

Hi RRob, Just brousing Dynamic EFI and I'm so green with envy. I built my 87 IROCZ in 99, using ACCEL gen 6 as opposed to reprogramming the stock ECM. It works well enough but programming is a chore. Ive added MSD digital 6 and now I have to go in again to fine tune. Seeing whats available today in reprogramming makes me feel a little tinge of pain. Maybe Ill switch to EBL. Its only money. Lol. Thanks for the link

 

I ran datamaster on the way to the header shop and it did get 140 blm. I also found two leaks on each header at the gasket . I'll get the headers back fixed on tuesday and i'll see if I can get it to go closed loop.

 

I got the header leaks fixed, but the WB O2 still said I was running lean. I multiplied the VE table by 1.09 across the table now runs 14-15 AFR AT PART throtle goes to 12 on acc. , but runs 13 afr at idle and when letting off gas at part throtle. DECEL works when no throtle at higher RPM drops to 20 afr.But it never goes into closed loop? I use DATAMASTER it never gets over 192 temp in the datalog,plus error code 13, and 42. I did put in a 4 wire GM O2 from junk yard for the headers. got any ideas? need help!!