SPFI Injector Differences

[SuspiciousPizza]

I've been searching for a new SPFI injector to have on hand when the the pearly gates come calling for my limited stock of used injectors. MPFI injectors are a dime a dozen but new SPFI injectors are more difficult to track down.

The only actual new parts I can find are compatible with the Subaru P/N 16637AA000. However this only seems to be compatible with 1986 and maybe 1987 models. My car is an '89 model which calls for the P/N 16637AA010.

Is there really any difference between the two? It doesn't list 16637AA010 as a supersession part number. But I'd have a hard time believing that Subaru would have one injector only work with a 1-2 year model range. That doesn't sound cost effective.

Why would they change the injector? Different flow rate? Updated spray pattern? Maybe a different throttle body casting? The latter seems very cost ineffective. New molds, tooling, jigs, etc.

The kicker is that 16637AA010 shows it's compatible through the entire SPFI production ('86-'94 here in the States). 

:]

[el_freddo]

With Subaru part numbers, if the second last digit is different by one digit value it usually indicates a compatible part number. 

Some times you can find this occurs up to for our five digit number values as updated but compatible parts become available. 

I’d put money on those two part numbers you give there as being the same. 

What do you do for that unique O ring setup between the TBI and the intake manifold? 

Asking as I have a SPFI setup to go on an ea81 over here (we didn’t get them in Oz) and that gasket is a little worse for wear - not that it’s going into a vehicle anytime soon, it’s in waiting. 

[SuspiciousPizza]

I bought the injector and once I got it I compared it side-by-side with a Loyale injector. They're the exact same. 

I vacuum sealed the injectors with desiccant packets. Hopefully they'll last until I need them. I've heard it's the moisture that'll corrode the coils and kill them. 

Are you asking about that weird horseshoe gasket? For installation I use a few dabs of silicone grease to hold the gasket into the throttle body then quickly flip the throttle body onto the intake. 

There's Walker brand throttle body gasket kits, I'd recommend those. You get every seal you'd need for a throttle body rebuild. 

I'd recommend a coolant system pressure test after you install a new gasket. I've learned my lesson on that one the hard way. 

:]