PDA

View Full Version : TPI Batch Firing ??



Gator
03-12-2024, 02:18 AM
I'm at it again, Brain won't stop. Mabey someone has the answer.
GM uses batch firing of TPI injectors 1357,2468, the question is, why can't the injectors be batch fired 1843,6572?? which would be more in line with firing order. and more efficient. any thoughts greatly appreciated. :rolleye:

MO LS Noobie
03-12-2024, 03:42 AM
It has to do with left/right bank rather than firing order, methinks

ralmo94
03-12-2024, 03:48 AM
It has to do with left/right bank rather than firing order, methinks

That's what I was thinking too, with each bank firing it sort of mimics what a 2 barrel TBI would do.

You could wire it the way you have proposed and report back to us if you have a TPI to play with?

Gator
03-12-2024, 03:59 AM
Well, I am retired so I will swap them around over the next day or so and post the results

ralmo94
03-12-2024, 04:18 AM
:popcorn:

Gator
03-14-2024, 03:03 AM
ok. I did move injectors around and idle did improve quite a bit, still have tuning to do?? (still learning about that) keep in mind i am running a 7747 ECM. Until i can get my hands on a 7730 ECM.
it is running well enough to get it off the ramps and turn it around and get rear of car up to replace fuel tank (bolts broke off replacing fuel pump). then perhaps get some data logging done.
I guess i should mention i have an 84 C4 am moving from crossfire TBI to TPI and the 7165 ECM StB. So, using what i have available.

ralmo94
03-14-2024, 07:03 AM
Good to hear. Hope it continues to work as smoothly as reported now. :happy::rockon:

Fast355
03-15-2024, 01:31 AM
Good to hear. Hope it continues to work as smoothly as reported now. :happy::rockon:

A 2bbl feeds 2 cylinders on each bank from each bore. Some of the TBI manifolds (Edelbrock 3704, GM performance, stock L31 TBI and marine TBI L31) and carb manifolds used with TBI have the cylinders and TBI bores feeding them swapped in relation to the OE TBI.manifold. I swap the injector outputs at the ECM on engines using those revised manifolds.