Fuel Injector Questions

[cpk]

Have an '89 Allante with the 4.5.

I discovered I had three leaking fuel injectors. Ordered some new OEM ones (actually NOS off ebay) but they took awhile to arrive.

Last weekend, I really needed the car, so I went up to Summit Racing (their store is near my house) and got a set of MSD injectors, manufactured by Rochester, which had the identical specs to the rochester injectors that were stock on the Allante (based on some injector comparison charts I found online).

Put them in and they worked great.

Today, the NOS parts arrived.

I'm wondering if I should leave the MSD ones in, or swap them out with the OEMS.

Is there anything I can monitor to determine if the injectors are working as the ECM expects them to?

Aside from not wanting to mess with anything that's working, having the intake and injectors off always introduces the risk of dropping something into the intake. If I can somehow objectively verify my "seat of the pants" feeling that they are working OK, then I'd be inclined to leave them in.

The original injectors were labelled Rochester P/N 5235451.

Here's the comparison chart(s) I used:

http://users.erols.com/srweiss/tableifc.htm

http://www.juscuzmotorsports.com/injector.html

The 5235451s are rated at 22lb/hr, 43.5psi, high impedence

The MSD 2017s are rated the same and are identical in outward appearance, down to the Rochester insignia cast into the case.

[cpk]

Would monitoring the O2 sensors be worthwhile?

I didn't get any codes due to the leaking injectors, I just smelled gas in the exhaust and oil.

[KevinW]

Is there anything I can monitor to determine if the injectors are working as the ECM expects them to?

Monitor the Block Learn (B/L) values under different operating conditions. You may notice that there's a difference at low pulsewidths due to slower opening characteristics. If the driveability is acceptable and the fuel trims are not pegged near one of the limits, they should be fine.