TWO PCMS:

[racprops]

Dual PCMs

From my latest discovery, I plan on running a 87 Camaro TPI 165 PCM to control my fuel system.

First it is because of Highway Mode (or Lean Burn Cruse) AND I have found a gentleman who can and is willing to fine tune my PCM for my settings for my system. And how there are a large number of setting built into these PCMs.

AND as this is OB1 System with a replaceable chip, I can easily swap in the stock hip to switch back to stock setting at any time. Or run a different tune as well.

Second as this PCM runs a MAF which according to reports is better that the MAP system

I know every hot rodder tuner has said these are slow and dumb old PCMs, and will not handle high RPMs, BUT as my engine is built for under 5K I feel the Camaro PCM will be more than able to handle my needs.

I need a second PCM to handle my 4L80E (electronic, PCM) transmission.

For that I am running a 7427 Stock PCM, plus again there are a large number of transmission control setting already in it.

One is I am planning on a Partial Throttle downshift settings.

So my question of the hour is help in setting up such a system.

Rich

[Piotrsko]

I dont know about slow as the clock runs faster than the control system components response, a good thing.

Stupid, no. The programmers today are so used to having all the memory real estate one could ever want therefore they forgot how to write teensie succinct code . Efficient codng steps around clock speed. They were doing heart pulse monitoring way back in the day where a kilobite was incredibly huge, and assembly programmers were proud to shave milliseconds off the execution of a command on a computer operating at 10khz with th aforementioned kilobyte of memory. C, c++ are incredibly wasteful of computer space, but easy as heck to program in. What do think people program in?

If your guy is good, all he has to do is change parameters inbedded in the running system which probably even you could do with a bit of knowledge.

[racprops]

As I am not needing a 6K plus RPMS and as the 3 Gen Camaros and Corvette's ran find I do not need super computer.

As for what can be done check the pictures....

Here is what I am doing and need help on:

I am building a 93 Custom Van a new drive train.

It is a low RPM Torque Monster SBC 383 that thanks to Roards Veritable roller lifters will produce a torque curve from 1000 to 3000RPMs and power curve from 2500 to 4700 RPMs though a 4L80e and a US Gear Dual Range Overdrive.

It is hoped and believe my special engine will with the 5 gears be able to cruse at around 80MPH and 1600RPMs and get 25+ MPG.

It will not run over 5000RPMs.

I am running 193 Swirl Port heads, stock headers.

All of this will be fed by a 87 Camaro TPI system and controlled by a original 165ECM with its full Lean Burn Cruse custom tuned for best operation.

The 4L80e rebuilt with all the upgrades will be controlled by a 93 7427 PCM acting as the transmission only controller.

This is where I am asking for help: how to set these two controllers up.

My plan so far is to mainly hook both systems up at the same time:

The 165ECM gets all the Camaro sensors, VSS, Knock, IAT, MAF, TPS, Engine Temp, Tach. More of less a full Carmaro set up from a coplet wiring hardness from a 87 Camaro.

The 7427 PCM is the problem, as it will only be controlling the transmission, I am unsure what it needed to operate normally. This is not a drag racer but a RV Cruiser. This will be hooked up using the 93 Stock Van's wring.

So what controls shifting??

I think: VSS, RPMs, TPS(?) and MAP as load sensor. I have read Engine Temp is also need, but why?

I plan on having knock, IAT, and fuel injectors turned off by a programmer.

VSS and RPMs is easy to share being a electronic signal. MAP is also easy to plug into the manifold by its self.

The TPS Throttle Position Sensor is a bug-loo, as it is a sensor managed by the PCM I think I cannot run the PCM and the ECM off the same sensor, so the big question is does the 7427 PCM controlling only the transmission need the TPS??

I am hoping it only needs the MAP to judge load and thus respond to throttle changes requiring a down shift or to do a up shift.

Other wise I will need to figure out a way to add TBI TPS to the Throttle Body of my TPI intake.

Rich

[Piotrsko]

Need temp because it's going to shift into too high a gear cold and then bog horribly. Can be spoofed with fixed resistance value but then you need to monitor block temps manually.

Your tps can be paralled by using a mosfet and a couple resistors. Don't recall the actual circuit, but I built 6 or so when I converted the ranger. Some needed pulse inversion, some needed a voltage change, some needed isolation. One was a frequency to voltage converter but it neded an additional capacitor.