SNET Telly

Does anybody know of anybody that sells a MemCal with a ZIF socket already installed?

Is the MemCal diffrent for each engine setup?

Has any tried to use a ribbon cable to extend the chip out of the ECM and under the dash, so you can swap out chips faster and easier?

SNET Telly

I just cut my MemCal in half and cut a 40pin ribbon cable down to 24pin and soldered the socket to the end of the 12" cable. Pushed them into the ECM, and now the check engine light/ computer is going crazy. Could there be a EMI problem with having it out of the ECM case?

John Millican

iTrader: (1)

No one has successfully remote located their memcal to my knowledge. I have tried and failed, poor running and a check engine light. I used twisted sheilded printer cable too. It's not EMI but a loss of signal that is the problem.

JohnL

This is off the Efi Tuning Projects forum. Prom relocated 10ft away from the ECM.


GNJONES said he was "using a DS90C031 and DS90C032 line driver/recvr to make this work".

jeepguy553

I don't know about remote locating your chip, but I am certain that you could get rid of the socket you have now and replace it with a ZIF of some kind.
What ECM are you using?

JPrevost

Nice! Anybody have the circuit handy for said devices?

John Millican

iTrader: (1)

Please more info on the adapter. That's cool stuff.

poncho@home

what's the all the fuss with remote mounting...I simply popped out the chip from a Hypertech memcal, pressed in a ZIF socket, reinstalled the Memcal in the ECU, and now it takes all but 2 seconds to pop out the chip....simply reach under the dash, release ZIF handle and chip falls right out. Reverse procedure to install.

Cobra289

Check by Craig Moates site. You will find several options.
http://moates.net/gmecm/hworder.html

Every engine uses a different MemCal, but the MemCal is based on two parts, one is the resistors part (netres) and the other is the EPROM.
The EPROM contents, you can change but the netres (IC's) are dedicated for the type on engine. This will take care that you engine will run if the processor of the ECM is gone. This is the so call "Lip Home" mode.
If you have problems with accessibility you can also consider getting a PROMinator or an AutoProm.
AutoProm is also at the Craig Moates site and PROMinator is at: http://misterbill.homeip.net/aboutprominator.asp
I hope this will help you.
Regards,
Cobra289

jeepguy553

I think the problem is remote mounting of the PROM or EEPROM.

Grumpy

Yep, since all the wiring to it acts as an antenna.

Might try some 28 conductor cable where the 28 cables are independently spiral wound, and shielded. Less then that and I wouldn't trust it. All it takes is one RFI hit, and it can scramble what the engine is doing. Remote file swiching is an entirely different deal.

RBob

iTrader: (1)

If anyone is thinking of remote mounting the EPROM the GNJones method is about as bullet proof as it gets. It is a tad pricey, but bullet proof. And bullet proof is a good thing.

The DS90C031 and DS90C032 chips are differential line drivers & receivers. The differential part is the key. The signal is transmitted over two wires with the difference in potential between the wires the logic state (on or off).

So they are immune to all kinds of noise. There can be 100 volts of noise on the signal line but the differential signal will not be affected. Many years ago I ran a water injection setup with motor speed control using feedback. The only way I was able to get it to work under the hood was with a differential signal between the under hood controller and the under dash controller.

Anyway, the DS90C031 and DS90C032 are about $3.70 each and have 4 channels per chip. Need a device at each end. With 8 data bits and 15 address lines (32kB EPROM), that is 23 channels. With 4 channels per chip need 6 of each chip. Twelve chips * $3.70 = $44.40US.

But, it is bullet proof. I'd bet that you could run the ECM underhood and have the EPROM in the ashtray with this setup. That is how well a differential signal system operates.

See http://www.national.com/pf/DS/DS90C031.html & http://www.national.com/pf/DS/DS90C032.html for more details on the devices.

RBob.