Board diagrams for TI/TII vs TIII SBECs

[RoadWarrior222]

Well it's not just a nand gate it can push more current. read purpose/apps.

[mpgmike]

Typically the ECU has limited inputs/outputs. To add functionality, a bus is used. The ECU streams out data for whatever chip it wants to talk to, but has a "handshake" code it sends first to address the intended target. This way, the same ECU can activate 12 coils and 12 injectors if it needed to; just create an address for each. The Z176 is probably some sort of decoder that only does anything on the output when it is properly addressed. The MOSFETs don't require much current on the gate, so that isn't an issue.

Z174, Z175, and Z176 all have a pin (3 or 7) that leads to Z126. Pin 8 (or 4) is tied to the fill (ground?). Pin 1 or 5 is comm tied to Z126 on all 3 chips (Z174-176).

Z174 controls Q093, Z175 controls Q091, and Z176 controls Q021. Q021 is listed as Coil Driver. Q091 is listed as Injector#8/Coil Driver. Q093 is listed as Injector#7/Coil Driver.

Hopefully this means headway.

Mike

[ShelGame]

In the case of the SMEC, there are 2 Motorola PRU's that do exactly what you describe. But, in the SBEC case, Chrysler had a proprietary chip made that duplicates the effect of the 2 PRU's and also adds some RAM and PWM timer functions. The injectors run off of the PWM outputs in the 'bus' chip. The coils, however, run directly from the PWM outputs on the 6811. So, they don't need to be decoded, there's a dedicated output pin for each coil driver.

[mpgmike]

I'm gonna explore SMECs to see if I can find an easier way, now that you point that out. I have a couple '89 TI A/T, '89 TII, etc I can check out. That might be a little easier. Besides, they are still plentiful.

Mike

[minigts]

The problem is, I don't have an SBECII car to try it in.

The same should be true for other computers as well:

SMEC:
3.0V6 --> Turbo1/Turbo2 (just need to confirm the knock sensor circuit exsists in the 3.0 computer)

SBEC:
3.0V6 --> Turbo1/VNT (just need to confirm the knock sensor circuit exsists in the 3.0 computer)

---------- Post added at 09:22 AM ---------- Previous post was at 09:20 AM ----------



I hadn't thought of that.

I did have the idea of using the logic board form a 3.0 V6 SMEC, with 2 turbo power boards to have 2 coil drivers with a SMEC. You'd have to wire the 3rd injector driver pigtail on the logic baord to the coil input on the 2nd power board.

---------- Post added at 09:24 AM ---------- Previous post was at 09:22 AM ----------

Oh, and if you're really interested in the SBECII, check out this guys site. He reverse engineered the SBECII boards and traces. Too bad he didn't go so far as to make a circuit diagram...

https://sites.google.com/site/mangel...bec-ii-4517652

Rob I have no idea what you just said, but if it's something that will allow creating a new board or using more current electronic components, I'm all for it and will sponsor the effort. At this point my next step is going to a stand alone system and moving away from the stock electronics. I'm sure the issue I have with my car (over charging) is not related to the one frayed wire I have going to my PM, but it doesn't help and eventually those ends that plug to the PM will be worthless. If there is a way to upgrade the stock footprint and connectors to the PM so that it's smaller and uses more common terminals and connectors, I'm all for it.

[mpgmike]

I went out to the garage and found an '87 TI LM & PM, plus an '89 TI SMEC. Since it's supposed to snow about 2' up here this weekend, I should have some time to tear into them and see what I can find. I'm exploring other options & ideas as well.

On a side note, if we used the TIII crank trigger on an older platform, could the code be transfered? The TIII trigger wheel (flywheel) has a unique pattern that I haven't seen on any other applications. What I'm thinking is can we adapt even an ancient LM based platform to multiple coils?

Mike

[ShelGame]

I went out to the garage and found an '87 TI LM & PM, plus an '89 TI SMEC. Since it's supposed to snow about 2' up here this weekend, I should have some time to tear into them and see what I can find. I'm exploring other options & ideas as well.

On a side note, if we used the TIII crank trigger on an older platform, could the code be transfered? The TIII trigger wheel (flywheel) has a unique pattern that I haven't seen on any other applications. What I'm thinking is can we adapt even an ancient LM based platform to multiple coils?

Mike

Adapting the TIII crank trigger: SMEC - probably, with determination; LM maybe not.

The LM runs at half the clock speed of the SMEC, which in turn runs at half the clock resolution of the SBEC. It sould be possible to speed up the SMEC, though, since it uses the same processor as the SBEC. The LM however is a much older 6803 processor with a limited instruction set (comapred to the 6811 in the SMEC/SBEC).

Multiple coils would require a new PM regardless. Also note, that the LM and SMEC use different signals to drive the coils and injectors. The LM is + switched where the SMEC is GND switched (between the LM and PM, that is).

[mpgmike]

I am going to China on the 18th, so not much time to play. I will be opening doors to export US goods to China! New twist, eh?

Mike