OK Short story, building a TPI 383 For LOW RPM torque to put into a 93 Chevy van.

The van has a 4L60E transmission, and I am hoping I can piggy back the PCM for the TPI on top of it so the original PCM can control the transmission and the TPI controls the fuel.

Can it be done??

IF yes any tips of information on how to do it?

Thanks in advance.

Rich

 

It is do-able. Need to share the common stuff such as battery feed, ignition switch feed and grounds.

Then for sensors need to share the distributor ref high and ref low, TPS and VSS.

Move from the stock PCM to the added ECM the engine control terminals/wires. IAC, injectors, MAP, EGR, CTS, O2 gnd and signal, 5V ref and so on.

RBob.

 

Thanks that was what I kind of figured.

Rich

 

I've read frequently that sharing of power, ground, sensor ground and 5V Ref is alright but that sharing a sensors output signal can lead to trouble. You have a different take on this it sounds like?

 

I worried about that as well, as the PCM puts out the 5 volt to run the sensors, and there may not be the right power to be in sync...or the signal might be weak due to supplying to PCMs. One fix might be run two sensors: one set for each PCM, of the ones that are needed by both PCMs.

This is why I asked this question.

Rich

 

It depends upon which sensor you are trying to share. CTS or IAT, no, won't work. MAP can be iffy, just need to try it. For the others it works.

RBob.

 

Thanks, I need to figure out what sensors the transmission PCM will need.

VSS, throttle position, RPMs?? I believe the TBI Computer uses a MAP to adding one along with the fuel PCM’s MAF so each is all by themselves should be easy.

At this time I cannot think I need any more sensors…the Transmission PCM needs...at lease to control the shifting, it might freak out lacking the rest?

Rich

 

It's not a fantastic idea to share sensor outputs when one ECU is providing the vref and another is reading the return voltage, though plenty of people do it and don't have problems.

It's not a fantastic idea to piggy back ECU's in general unless they are communicating over CAN. My attitude is spend a few more bucks and buy a standalone that can do EVERYTHING you need done.

-- Joe

 

If you are trying to save money, there is OE PCM's that will do your port EFI and run your E trans. If you don't mind spending a little money there is aftermarket controllers that will do both and dozens of other things too.

-- Joe

 

I am trying to use the original Camaro PCM both for it controlling the Fuel Injection but also for its hidden feature of High Way Mode to farther improve MPG, and later to buy a add on card to allow flashing the program chip and to allow full control of all settings including High Way Mode.

This should be cheaper than buying a eprom burner and a eprom eraser and a few eproms.

This card runs around $300.00 I do not think any good after market PCM will do cost that little.

And how about running both PCM's 5 volt supplies together, thus provide enough amps to carry the system??

Rich

 

Hrmm.. Well you seem to have a plan laid out and in place. Honestly, most of the people I talk to in regards to builds and tuning is geared towards max performance not fuel economy. So I guess do whatever you think is best.

Don't tie the vrefs together.

-- Joe

 

First why not run the VREFs together, they both are 5 volts and the only problem I can see will be that one may not supply enough current (Modern solid state electronics are more current driven that voltage) to feed two computers.

Or perhaps I need to add a stronger higher AMP 5 volt supply to run both??

As for the Van:

Well the van has plenty of power as she stood. Especially off the line where is counts. This new motor should be a little better at take off. But the darn thing seems to get 14 MPG no matter what. And sadly I lost a oil line to a cooler and then lost the motor, so want to try for a little better MPG.

Everything seems to point to what I plan, a low torque peek so I can gear for it as cruising speed and under 2000 RPMs at the same time.

I think my idea of adding a second old Borg Warner Over Drive will do the trick, I can drop 3rd gear+ OD and have a good gearing at lower speeds and then at higher switch to 4th (OD) + 5th (OD too) and drive at say 75/80MPG and be doing under 2000RPMs. AND by having my torque peek there as well I will not NOT be lugging the engine, rather be running it in its prime.

Then add in the climes of TPI Giving 30% more torque, HP and Mileage...

And then add in the High Way Mode that is on record here for getting 20/25 MPG Camaros to 30/35 MPG, well that should also help.

I have cars that will get 25/30 Highway MPG stock, it is a little hard to take out a Van that at best gets 14 MPG, but get IT to run in the 20s, well it is easier to use it.

Get it to say 25MPG on the highway, even better.

I believe I can reach 20MPG, any thing over that is gravy.

It is a great van, just needs to cure iits drinking problem.

Rich