Install large Injectors at same time as DIYPNP, or once I have learnt it?
 

Hello all, probably the first stupid question of many I'm afraid!

The Car: Mk1 1.8 VR-Limited Eunos Roadster (96-97 Spec 3-Connector ECU).

Start of build thread: https://www.miataturbo.net/build-thr...7/#post1017568

Installed so far:
- IAT (Into plastic cross pipe)
- MTX-L (into Decat)
- Plus wires for above and vac line to rear of intake.

This will be my first attempt at MS and I believe my DIYPNP ready to go in. So a pretty basic question...

I also have a set of FIC 650cc injectors ready to support the Turbo once I have got to grips with MS. Is it worth putting them in now, at the same time as the MS? Or would it be a better idea to put them in once I have got to grips with the MS tuning?

Turbo will come later, once step at a time!

Cheers, Dave

You probably want to fire it up on the stock injectors to make sure things work, but you'll want to fit the 650cc ones before you sink a lot of time into perfecting cranking or VE.

If their function is exactly the same (aka they're low impedance, batch injected) then there should be no problem installing them before MS. You want to be absolutely sure they're fully functional (flow tested or new) before installing, however.

But then again, if you're not confident with your wiring it might be worth it to try it on stock injectors, in case you fry them ;). not that i've heard of anybody frying high impedance injectors...

Ok cheers guys.

It does seem sensible to fire up on standard injectors first, check timing, calibration etc. Then fit the injectors before doing any tuning.

The injectors are brand new FIC 650cc high Impedance ones for Miata fitment, and with loom adaptors so no loom chopping. I'm assuming they will be fine as they are new, with test sheets etc.

I haven't looked into what changes I'll need to make to the tune to fit the new injectors. Hopefully that'll be covered in other posts on here already as I believe a few people are running these injectors already.

I need it running well before the last week in June, off to Glastonbury and I don't want to take the laptop!

Dave

All you need to do is change your Req_fuel number under injector characteristics and retune your warmup/afterstart/VE tables, which shouldn't require much changing. You could also play with dead times as well which I hear is helpful.

KISS (keep it simple stupid)

The cool thing about doing MS-only is if something doesn't go right or you're in over your head, getting the car back to driving condition requires all of 5 minutes of un-plugging and re-plugging. It also eliminates variables you'd otherwise have to dial in: req_fuel, injector settings, etc.

Ok, sounds good. I'm getting really excited about getting this conversion going now...

It started first time! :yippee:

It was already warm as I warmed the car up checking the static timing before I swapped over ECUs. Started it again after a few hours once cold and it oscillated on idle (not unexpected I guess, that's with no tuning at all, 96-97 DIYAUTOTUNE basemap.

Time to put the new injectors in and get to grips with TS some more!

One of the car moments that's made me really happy, I'm happy to admit I was bricking it!

'grats dude

650cc FIC Injectors fitted today, all went as you guys suggested.

Req Fuel Scaled from DIYAutoTune Basemap value of 13.0 to 4.6. (13.0x230/650). Started fine once fuel was back in the system, hunted a bit and idled fairly lean. Ran VEAL for 5-10 minutes and the idle settled down smoothly @~1K and on the AFR target.

Maybe I could have put the Req Fuel a little higher as VE is now increasing all the values, but as it's running ok I don't see the point in changing it now.

I know this is boring stuff to you guys but I know how frustrating it can be to find half finished threads with no 'happy ending' :giggle: when searching.

Haven't yet driven it...but I'll leave questions on tuning it from here to other threads as I go :)

Dave

That is frustrating for sure. Glad everything is working OK, now go drive it!