502 MPI Intake and Injector Question
 

So I am having my 502 worked on and the intake they have has casting number 805233C1. We are replacing it due to corrosion. The injectors that was in it are 861260T and my mechanic said someone put the wrong injectors in it. It was noticed that the injectors are too small size wise and the legs of the intake was cut down to make it fit.

After digging it seems the injectors that are suppose to go with that intake are 805225A1.

We are waiting on getting the injector in but I feel because the injectors are going to be different the fuel rail wont match. Also the spec of the injectors wont match what the computer has.

So my question is this, what is the difference between the 805225A1 and the 861260T injectors? The injector 861260T ran with that motor/computer and everything seemed fine. The issue is the manifold was modified to make fit the injector. The manifold to fit the 861260T injector is very hard to find, while a new fuel rail to fit a 805225A1 is easy to find. Should I not use the bigger 805225A1 injector?

The different injector styles use different electrical connectors and also different ECM (MEFI 1 vs 3) so they are not interchangeable without replacing a lot of other parts too. I'd suggest sticking with what you have if it works.

thanks for the reply. The injector plug looks the same on both.

My mistake. The electrical connectors changed when the 496 came out. Nevertheless, the ECMs are not interchangeable so if your current ECMs are running the mini injectors then that's probably what you should stick with.

I figured. In 1999 was the merceuiser computer smart enough to adjust to the new injectors? Anyone have experience?

The ECM's do not really adjust. They are a fixed fuel and timing map
Being a 1999, it should have an MEFI 3

No the mefi's are not self learning............reach out to Smitty ( Articfriends ) on here he's a wealth of knowledge on the 502 efi plenums and injectors, many dyno sessions

No oxygen sensor = no way at all for the ECM to see a rich or lean condition. Even if the mapping had a way to adjust based on that there is no way for the ECM to obtain that air:fuel info.

I think your mechanic may be mistaken....doing a search on the 805225A1 it looks like those are for 94-96 motors.
I think the ones you have in there now are correct for a 1999 (they fit 1998-2001...

What's your motor serial number?