Cleaned 440s or new 550cc injectors?

[Dan88t]

So I've resumed work on my Supra after having it torn apart and sitting untouched for almost 3 years and now I've arrived at my first real decision. Eventually I'm going to have to upgrade to 550cc injectors when I start upgrading but for now I just want the car running stock to get the engine broken in and make it easier to track down problems and all that.
Would I be better off installing 550cc injectors now or spending the $150+ to get 440s cleaned/flow-tested?
Can the stock ECU handle having the 550s in there with all else being stock or will it run pig rich?
I assume just throwing a Lexus AFM in the mix without the accompanying AFPR wouldn't be a good idea?
My worry is that installing the whole Lexus AFM/Walboro mod before I even start the car will lead to issues trying to troubleshoot whatever problems I know the motor will have on first start

{As for other mods right now, none... The block and head have been machined, I installed forged pistons, Eagle rods, HKS MHG, all new bearings, valve springs, the usual stuff...}

Thanks!

 

[radiod]

You need to do something with the electronics to be able to run the 550's properly otherwise it will run very rich. Understandable that you don't want to add much to "go wrong" on the first turn key, but if you're getting new injectors and you're using known good AFM electronics (you can still use your old one, just put it in the new housing), then it shouldn't really be too much of a problem. You can set the fuel pressure even before you try to start the car by jumpering the fuel pump on, and keeping it to an already known working pressure, you shouldn't have problems with your first start of the engine. I wouldn't try to wire in an SAFC or MAFT quite yet, but doing a lexus AFM, pump, injectors, AFPR shouldn't be bad. Once you do have it up and running you can either go the SAFC route or MAFT route to tune the fuel better than the rough but working tune that the Lexus AFM will give you. Just be sure to have a wideband hooked up

On the other hand, if the 440's aren't flowing bad, I'd just soak the tips in injector cleaner and call it a day until you're sure of the route you want to go for upgraded fuel.

 

[Nick M]

You will be running rich in open loop as mentioned above. In closed loop when the car is at operating temps and you don't punch it, the ECU will shorten the injector on time by the oxygen sensor. It is responding to its own control, that is what closed loop is. The lean out will show in Vf, but that is just letting you know the ECU did a correction.

 

[Poodles]

No way in hell the TCCS has enough control to trim 25% more fuel out...

 

[Nick M]

That is certainly on the outer fringe, which is why it will show on Vf, when in closed loop.

 

[Dan88t]

No way in hell the TCCS has enough control to trim 25% more fuel out...

Thanks! That's exactly what I should have asked, "can the stock ECU trim enough out to run the bigger injectors?"
Now I've just gotta decide what to do - I'm leaning towards the Lex AFM/550s/AFPR/Wideband right now and hoping for the best... If it won't start I'll just be back at Supramania begging for help

 

[radiod]

If you're not being a complete retard then you'll always find lots of people willing to help you out with the tech side of things here . Good luck with the shopping and keep us updated as to how it goes!