T1 and T2 computers, what's the difference?

[Force Fed Mopar]

Is it just a software difference, or is the different hardware in each? If you have a T1 computer, can you socket it and burn a T2 chip for it and use it as a T2?

[sdac guy]

Is it just a software difference, or is the different hardware in each? If you have a T1 computer, can you socket it and burn a T2 chip for it and use it as a T2? For the most part the answer is yes. Some LM's that are for log intake based T1, may not control T2 AIS motors, or may not have Charge Temp Sensor provisions, but that is about the only limitation I can think of.

I'm pretty sure all SMEC or SBEC T1 ecu's can run T2 calibrations and are good to go.

Barry

[black86glhs]

Some of the LMs have 2 chips. The T-II LMs (daytona, CSX) have the higher capacity chip.

[turbovanman²]

All turbo SMEC's can be converted, LM's, only some.

[black86glhs]

Am I right about the later LMs having the 256Kb chips and the earlier ones having 2 128Kb chips?

[chilort]

Let's limit down "only some."

Can any '87, external MAP TI LM be converted to TII with software?

http://www.thedodgegarage.com/turbo_pfi.html
"All 85-87 are the same except for the software burned into the prom chip! In short there is just 2 basic logic modules- internal or external map sensor units. This means you can take a Turbo I 86-87 internal map sensor LM and have GLHS Turbo II programming "burned" to the chips or you can take a Turbo I 87 external map sensor LM and have 87 Turbo II or 87 CSX programming burned to it. The 85-86 LM used 2 Motorola chips and the 87 and up used a single chip."

I like how he says the only difference is the software burned on the chip and then points out that some have an external MAP versus and internal MAP and some use two chips and some use one chip....

[Force Fed Mopar]

Am I right about the later LMs having the 256Kb chips and the earlier ones having 2 128Kb chips?

Yeah, the '86 LM's (and '87 L-body LM's) have 2 chips. Not sure about '84 and '85.

[black86glhs]

Yay, I got something right!!!:thumb::D

[ShelGame]

Is it just a software difference, or is the different hardware in each? If you have a T1 computer, can you socket it and burn a T2 chip for it and use it as a T2?

LM or SMEC?

[chilort]

I am mostly curious about the LM. Rob may be interested in the SMEC. It is my understanding that TI SMECs lack the charge temp compared to TIIs. Not sure if the charge temp is different on the 1987 LMs. I know the '86 log cars all have charge temp but that computer is no good for a TII upgrade especially if you go 2.5L.

Edit: answered my own question. An '87 TI LM will have charge temp since it is a log setup. There should be no differences between an '87 log LM and an '87 TII LM other than the code.

[chilort]

Crickets?

[Force Fed Mopar]

LM or SMEC?

Either one. Actually I want to know the answer to this for all the computer types, LM, SMEC and SBEC. Seems like it would be good information to know.

[csomni]

ive got a 86 log lm stage 2. will this lm work on the 4 wire ais, as long as i stay t1

[ShelGame]

Either one. Actually I want to know the answer to this for all the computer types, LM, SMEC and SBEC. Seems like it would be good information to know.

Hardware-wise:

'87 LM's, as far as I know, T1 and T2 are the same and can be converted back and forth except for the L-Body LM's, they were the same as the '86 LM's. I don't really know much about the '86 and earlier LM's myself.

The SMEC, T1 and T2 are the same. The only difference being that some of the '88 SMEC's did not have all of the hardware for cruise installed. I'm not sure if that's a logic boad or power board issue. Also, the 3.0 SMEC can run a turbo cal and engine. It simply has an extra injector driver that the turbo SMEC's don't have. Though, that extra injector uses the same ouput port as the wastegate on the turbo cals. So, I don't know about computer controlled boost with the 3.0 SMEC using a turbo cal. TBI (logic board or power board) can NOT be used for turbo. It's missing too many components.

The T1 and VNT SBEC's are the same. The T3 uses the same board but has more hardware (drivers). Just for reference, a T3 SBEC is 'universal' - it has all 4 injector drivers and both coil drivers loaded. So, it should actually run any cal for any engine (90/91). In the SBEC case, the 3.0 computer will not work for the turbo cals. The 3.0 only has 3 injector drivers. Should be obvious, but the TBI computer cannot be used for turbo applications.

The SBECII is slightly different. Comparitavely, it has a ton of more outputs available. Though I have not tested this myself, I beleive the 3.0 SBECII will run turbo I code fine. And the 3.3/3.8 SBECII will run T3 code fine. The 3.0 SBECII has 6 injector drivers and 1 coil driver, so 2 injector drivers would be redundant. On the 3.3/3.8, they have 6 injector drivers and 3 coil drivers. So, on a T3 you have 2 unused injector drivers and 1 unused coil driver. I have not yet tore into a V8 computer to see what they have, but I assume they have 8 injectors and 1 coil driver. So, I assume they could be used for a turbo application as well. The real question is the 'other' outputs - WG, Cruise, A/C, etc.

Software wise, the '87 T2 LM is different from the T1 code, and it's different from the earlier code by quite a bit.

The SMEC, '88T1 is unique, '88/89 T2 code is basically the same, '89 T1 is totally new. Too many differences to get into detail. But, essentially the code all does the same things with basically the same (or at least very similar) tables. The T1 just has more tables for spark and fuel.

SBEC is actaully very similar to the '89 T1 code-wise - except for the T3 which is totally unique for the SBEC. The Mexican cals, on the other hand, are totally different from the US cals in terms of code and calibration. I have yet yo really understand the Mexican cals.

SBECII, I am not into enough yet to comment on the differences. But, the code is very similar to the '91 T3. In fact, the cal data from '91 to '92 T3 is basically the same. The code differences are mainly due to the hardware changes.

[chilort]

Great info Rob. Thanks.

[Force Fed Mopar]

Awesome, thanks Rob. I'm gonna quote this in a FAQ on BM, if you don't mind :thumb: I'm sure someone here will add this into the KC here also.

[sdac guy]

Let's limit down "only some."

Can any '87, external MAP TI LM be converted to TII with software?

http://www.thedodgegarage.com/turbo_pfi.html
"All 85-87 are the same except for the software burned into the prom chip! In short there is just 2 basic logic modules- internal or external map sensor units. This means you can take a Turbo I 86-87 internal map sensor LM and have GLHS Turbo II programming "burned" to the chips or you can take a Turbo I 87 external map sensor LM and have 87 Turbo II or 87 CSX programming burned to it. The 85-86 LM used 2 Motorola chips and the 87 and up used a single chip."

I like how he says the only difference is the software burned on the chip and then points out that some have an external MAP versus and internal MAP and some use two chips and some use one chip....What is listed above is not entirely accurate. And since Rob did a great job on the SMEC/SBEC ecu's, I'll expound what I know about the LM's.

Where the MAP is located doesn't make any difference on the LM's except the earlier LM's will not have the pins in the connector for the external MAP. Any LM can have an external MAP if the leads from the internal connector are extended. Starting with the 1987 T2, the MAPs were all external. There may have been some 1987 T1 cars made with external MAP, but I am not certain.

The T1 log manifold through 1987 used the pull through TB with the older style AIS motor. The 86 GLHS and the 87 T2 used the blow through TB with the newer style AIS motor which was used in everything starting in 1988.

The LM's needed a slight hardware change to control the different motors. The older AIS motors were of a servo style operation and the newer ones of a stepper motor operation. The earlier LM's will not correctly control the later AIS motors, but otherwise they can be used.

So none of those earlier LM's could be used to control an AIS motor in a T2 application. That is true with the exception of the 86 GLHS LM.

As far as chip capacity, the earlier LM's with the cal spread over 2 chips, used two 27C64 chips (8K each), while the 87 T2 used a single 27C128 (16K). I have never seen a factory 87 T2 LM with a chip of larger capacity. I am not sure about the 87 T1 LM as I have never taken one apart.

1985 LM's are essentially the same as the 86 (with the exception of changes for the different HEP in the different distributors). The 1984 LM is very different as boost was not electronically controlled.

In summary, the 1986 & 87 GLHS LM's can be used for T2 application as long as you have knowledge to spread the cal properly over the two chips. Of course all 87 T2 LM's should work for any T2 app. But all the other LM's may or may not work correctly (regarding the AIS).


Barry

[chilort]

Drat. I forgot about the difference in the AIS. I'm going to have to look into that.

[black86glhs]

Thanks Barry. I figured my numbers on the chips were off a little.

[Aries_Turbo]

i have a 87 t1 harness setup with the external map. it was in a 87 lebaron h body. i socketed the ecu and used 87t2 code on it. its in my k car.

barry, are you saying that 87 code could be ran on the GLHS LM's if the table data and the operating system are separated?

Brian

[ShelGame]

i have a 87 t1 harness setup with the external map. it was in a 87 lebaron h body. i socketed the ecu and used 87t2 code on it. its in my k car.

barry, are you saying that 87 code could be ran on the GLHS LM's if the table data and the operating system are separated?

Brian

I thought I read somewhere that if the 2nd chip was left off, that the L-Body LM could run a single chip. However, without the timer chip, I don't know how well the PWM stuff would work. It certainly wouldn't be as accurate with respect to timing as the '87 non l-body LM's.

[chilort]

While I'm not going to say the AIS motor driver is working properly, I get the feeling there are a lot of cars out there running '87 TI LMs with TII setups.

[sdac guy]

While I'm not going to say the AIS motor driver is working properly, I get the feeling there are a lot of cars out there running '87 TI LMs with TII setups.I would not doubt that at all.

Barry

[chilort]

Info on these links say the '87 TI LMs have the electronics to control a 4-wire AIS already installed:
1) http://minimopar.knizefamily.net/ecu/lm-1987-t1.html

2) http://www.turbo-mopar.com/forums/showthread.php?51148-87-TI-LM-vs-TII-LM&p=690471&viewfull=1#post690471

Best news I've read all day.

[sdac guy]

Info on these links say the '87 TI LMs have the electronics to control a 4-wire AIS already installed:
1) http://minimopar.knizefamily.net/ecu/lm-1987-t1.html

2) http://www.turbo-mopar.com/forums/showthread.php?51148-87-TI-LM-vs-TII-LM&p=690471&viewfull=1#post690471

Best news I've read all day.Here is what The Instructors Guide says.


1985, '86 & '87 Turbo I AIS motor and circuit.
This is the same AIS motor as in 1984 and a similar circuit. In 1984 there were four H drivers to handle the current flow. The extra current flow capabilities was not needed and therefore eliminated. There are only two H drivers in this circuit.
These H drivers work the same as in 1984, however: the transistors are internal and not shown in the schematic. When the microprocessor wants to to drive the AIS motor, it tells the CPI to output a command voltage to the H drivers. One of the H drivers will output 12 volts while the other one outputs a ground. this is reversed to get the AIS motor to move in the opposite direction.


1987 Turbo II AIS Stepper Motor and Circuit
The Turbo II AIS stepper motor is the same style as what's used on the 1986 & '87 low pressure EFI. This style of motor has two electromagnets (windings) and one permanent magnet. The permanent magnet is the "nut" with threads on the inside. The AIS motor pintle is attached to a shaft with threads on it (the "bolt"). When one electromagnet is energized, it causes the permanent magnet to be attracted to it. The permanent magnet now rotates to line up with the opposite poles. Now the other winding is energized making a new set of magnetic poles that the permanent magnet is attracted to. The permanent magnet then rotates to line up with the opposite poles again. As the permanent magnet rotates, the pintle is driven in or out.

The AIS stepper motor circuit is the same as the 1985 - '87 with one exception. Since there are two windings and four connections, there are four H drivers in the logic module. When the microprocessor wants to drive the AIS stepper motor, it tells the CPI to output a command voltage to H drivers 1 and 4. This provides 12 volts on one wire and a ground on the other wire. The AIS moves one step and stops. The microprocessor now tells the CPI to turn off H drivers 1 & 4 and to turn on H drivers 2 & 3. This causes the AIS motor to move one more step. This oscillating back and forth from winding to winding happens so fast, (How fast does it move?) so fast that the AIS stepper motor appears to be running continuously.

When looking at the schematic supplied for each style, the T1 motor has two leads that go from the motor's single coil to the LM on pins 1-18 & 1-22.

The T2 stepper motor has 4 leads one coil is connected between 1-18 & 1-16, and the other coil is connected to 1-22 & 1-20.

I don't see any way that a T1 style LM can control a stepper style AIS as the two pins go to two different coils on the motor, with no provision for terminating or controlling the other end of the coils.

With regards to the link for Russ's site, even though he makes the statement that the necessary electronics are there, in the pinout shown, the other pins needed for the 4-wire AIS are shown as vacant (1-16 & 1-22).

The other thread you list does raise some questions because clearly some 87 T1 LM's came on cars equipped with 4 wire AIS while some did not.

So it is not safe to say ALL 87 LM's came with the necessary electronics to control the 4 wire AIS. Certainly all the T2 and all the EFI did, but it appears only some of the T1 cars came so equipped.

Barry

[GLHNSLHT2]

Every 87 T1 car I've seen has an external MAP EXCEPT The Lbodies. Hell that's how I tell when I lift the hood at the j-yard between 87 T1 or 86 and earlier. Log manifold check, External MAP=87 T1.

[cordes]

Every 87 T1 car I've seen has an external MAP EXCEPT The Lbodies. Hell that's how I tell when I lift the hood at the j-yard between 87 T1 or 86 and earlier. Log manifold check, External MAP=87 T1.

Agreed.

[Aries_Turbo]

my 87 t1 LM did indeed have the T2 transistors to drive the 4 wire ais. there may be some early 87 t1's that dont have the drivers but all the 87 t1 LM's that i got from the JY had the transistors.

Brian

[cordes]

my 87 t1 LM did indeed have the T2 transistors to drive the 4 wire ais. there may be some early 87 t1's that dont have the drivers but all the 87 t1 LM's that i got from the JY had the transistors.

Brian

I have seen many guys write that the late 86' boards would be compatible with an 87' TII setup. I too have never seen an 87' LM which won't work with 87' TII cals.

[GLHNSLHT2]

http://www.pnw-sdac.org/gallery/v/Members+Rides/Jay+Jochec/Parts+For+Sale/100_1626.jpg.html

87 T1 board (Note 366 # on blue plug) socketed, Have run an 87 T2 chip in this board.

[csomni]

how can i tell if my 86 mp stage 2 will drive a 4 wire ais.

[Aries_Turbo]

if the pins that connect to the T2 wires for a 4 wire ais trace back to transistors on the board. i dont have any 86 lms to see what spots arent populated on a 2 wire ais lm.

Brian

[csomni]

thanks for the imfo, ill check and hopfully it its all there , if not ill be looking for another lm.

[chilort]

if the pins that connect to the T2 wires for a 4 wire ais trace back to transistors on the board. i dont have any 86 lms to see what spots arent populated on a 2 wire ais lm.

Brian

I did a little tracing and a little comparison last night between an '86 LM and an '87 TI LM. Granted, that might not be the best set of options but I don't have an '87 TII LM to verify any differences. :(

If you are looking at the board with the component side facing you and the red connector in the upper right hand corner, then all of the action is basically in the upper right and corner. Without looking at a schematic I don't know exactly what they are doing with the design (I was an electrical engineer before going in another direction after a few years getting screwed by industry ... I mean working) but there are some resistors and even a cap or two that are missing on the '86 LM compared to the '87. More then likely that is output protection circuitry but without the schematic I don't know.

Then I only found one transistor missing on the '86 compared to the '87, at least on a quick look. An H-bridge setup needs 4 transistors to operate. 2-windings, each controlled with an H-bridge would need 8 total transistors. That is not what I found on a very quick review (may have missed something). Chrysler may be doing something different than a true H-Bridge. Without a schematic I couldn't tell you without pinning out the entire board and I simply don't have time for it.

So, long post to essentially say, I don't know (not that uncommon on TM.com). Based on the similarities between the '86 LM and '87 TI LM there would have to be a substantial board layout difference between an '87 TI and TII LM if there is any difference. If The area I am looking at is correct then it is just he population of one transistor and a couple resistors. I'd be happy to look at the schematic and verify my thoughts if anyone has one.

The only pin I had trouble tracing out at all was 1-16 and that's because it goes under an IC. I'm relatively uncomfortable about that one since it is not common between the 2-wire and 4-wire setup.