confusing injector problem

[nismoautoxr]

Ive not messed with the tune in a long time because it is well sorted until now. I am building a 418ci ls motor due to the motor in the car having a rod knock. In anticipation of making more power and since the stock injectors in the car were already at 95% duty cycle....I bought and installed a set of holley 42# injectors in the knocking engine and changed the require fuel and deadtime to match the injector specs. The car will start and then go lean and die. I expected it to go the other direction. I had to substantially richen the tune just to get it to idle. The fuel pressure is the same which is 60psi. I don't understand why this would happen unless the spray pattern is just that much different? They are large body bosch lucas ev1 units. Any ideas?

[Yves]

The bosch EV1 42 have a 4 hole head meaning that they spray in 4 directions. I'm not sure what you used before but more fuel could end up on the wall of the manifold explaining the lean condition.

[nismoautoxr]

That is kind of what I was leaning toward whilst trying to rationalize it I my mind too.

[Yves]

That is kind of what I was leaning toward whilst trying to rationalize it I my mind too.

Does it clear up when thoroughly warmed up ?

[nismoautoxr]

well it turns out that this is not a "confusing injector problem" this is a "stupid mechanic problem". I discounted the fact that I also changed from a very heavy aluminum intake back to a LS6 composite intake at the same time. The ground for the MAF sensor was on the intake . Once I looked at the datalog I saw that the MAF was dead in the water which is why it stopped fueling after I let go of the starter. The only reason I was able to get an idle was because I switched the tune back to SD . I regrounded the MAF this evening and changed the tune back to the way it was before with the rescaled injectors and it ran fairly well aside from the hammering rod . A little tweaking and it should be just fine. I feel like a huge bonehead. NOw to get the new long block in the car. The pistons and the headers arrived today so its just bolts and nuts now. How embarrassing

[Yves]

Not emberassing at all. These things happen. Glad you caught it.

[turbo conversion]

But don't you just love it when it turns out to be user error?

I've done it way to many times.

David