EProdRx7

Just finished a bunch of work on my 87 TII. Here is what was done:

Complete rebuild with light/mild porting. Compression tested great.
Waste gate ported on stock turbo
Duel scroll removed
3" down pipe
No emissions stuff
TB stripped down to the basics, no wax or dashpot
BAC, acv, etc. removed
All vac line that I didn't think I would need were capped. Including the Primary and secondary injector air bleed lines (didn't use them on my n/a race car?)
Stock intercooler
Racing Beat FCD
The car is a manual steering model and the AC hasn't worked in years.

The problem I'm having is that the idle is very low but steady. It does drop too low as TB shuts but rebounds quick so I can live with that. More of a problem is that "off idle" from a stop the car stumbles and I need to feather the clutch and work the throttle to get moving. It acts sort of like my old carbed truck when the accelerator pump was bad. After that it's great and very smooth, although I haven't really gotten into it yet as the motor is not broken in. I'm also getting a lot of mini backfiring. Research has told me that one cure might be to reinstall the BAC but in my infinite wisdom I welded over the mounting point, so without replacing the UIM that is not an option. I know that I kind of screwed myself by removing more then I should have but I'm stuck with what I have left. So if you have some ideas as to how to make this a happy daily driver again I would greatly appreciate it.
Thanks

iceblue

The BACV will have nothing to do with it, if removed the car will function just fine. If you had AC and stuff it would be more ideal to bump the idle up to 900 to 1k. The BACV is only to uphold the AWS and compensate loads that you have eliminated.

I would start by using the injector bleeds. Unless you are referring to the oil injector bleeds and you removed them and running premix, then that’s fine.

Other then that sounds like a fuel delivery issue or ECU, possibly grounds.

EProdRx7

Almost forgot to mention that I changed the secondary injectors for 720cc ones from a 85 gsl-se.

iceblue

An 85GSL-SE had 680cc injectors.

EProdRx7

Ok so here's the story. Most of my Mazda work is on n/a race cars (EP and ITS) and this is the first turbo I've done start to finish. When I pulled the motor and started to disassemble it the harness disintegrated in my hands. The plugs for the injectors where in pieces, it was a total mess. I bought a new harness for the reinstall and when it came to installing the harness I had nothing to go by. Now on the n/a car's harness the primary and the secondary injectors are paired. On the TII the front injectors and the rear injectors are paired. So my brain said to pair the P's and the secondaries and the end result was that I was running on one P and one secondary. Straightened that out made a new ground from the motor to the chassis, bumped the idle, changed a leaky oil injector seal and a few other small details and the car seems to run well. Can't wait to finish breaking in the motor so I can get on it. It feels almost as strong with no boost as the old motor did at 10psi!