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ECM Replacement Procedure - 91 Cutlass Supreme - 3.1 V6


2Tired

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Hello..,

 

I would appreciate it if someone could let me know if there are any special procedures when replacing an ECM in a '91 Olds Cutlass Supreme 3.1 V6..?

 

Do you just need to exchange the MemCal from the Old ECM into the New ECM..??

 

I picked up an ECM from the wreckers out of an '88 Cutlass Supreme International.., I just want to make sure I am doing this correctly before proceeding with the replacement.

 

Please advise.., thank-you.

 

2Tired

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Thanks for your reply...,

 

So all of the vehicle specific information.., such as the vehicle's Mileage for the Digital Dash Cluster.., etc.., is all contained on the MemCal..., is this correct..?

 

Replacing the MemCal is essentially 'Re-Programming' or 'Flashing' the ECM to the vehicle..?

 

 

Also.., is there then a need to perform an ECM "Re-Learn"...??

Edited by 2Tired
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vehicle mileage is stored in the instrument cluster. it has it's own processing and storage.

 

replacing the MEMCAL does accomplish the same procedure that flashing/reprogamming does on newer cars: it updates the calibration. the 91 and 88 2.8/3.1 ECM is identical(part number 1227727), the only differences between them are the MEMCALs, so be sure to use the 91's MEMCAL in the 88 ECM, otherwise you'll have some interesting issues.

 

about the only "relearning" needed would be for the IAC Minimum position updating. couple of different methods for this, the simplest being to just drive the car until it's completely warmed up(10 minutes should be more than enough time even when just idling), then before parking and shutting the car off, just sit in one spot with your foot on the brake and the shifter in 4th gear for a good minute or so. then shift into park and shut it off. the IAC minimum learned value will update any time the engine gets warm enough and is in an idle condition for a long enough time.

 

if you can't drive it around without stalling issues, you may just have to let it idle until the value gets updated enough to where it is driveable.

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Ok.., that sounds good.., I greatly appreciate this information.

 

Thank-you..!! :thumbsup:

 

 

Regarding the Digital Instrument Cluster.., do you know what the main cause(s) are.., for the displays on the cluster to either not light up at all.., or everything lights up really bright.., then 5 to 15 minutes of driving.., the cluster suddenly goes back to normal display..., any ideas..??

 

Also.., it seems to always be different.., the speed is not on one time, then the mileage.., or both.., or everything at once., it's very strange.., then 'poof'.., everything comes back on to normal again.

 

Could this be related to the ECM..??

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no, not ECM related. sounds like your cluster is the problem. either it's not getting a good source of power or it's worn out or if you're lucky it's something as simple as the PCB needing resoldered.

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Right.., I did find a link for specific issues to look for regarding the circuit board of the cluster.., will have to take a close look.., hopefully it is just reheating the solder of the main plug pins to the board.

 

Thanks for your input.., time to get to work.

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  • 10 months later...

... missed the last post.., but..., for informational purposes....

 

 

1991 Olds Cutlass Supreme 3.1

 

I have the base digital cluster.., Fuel on Left.., Speed - Center.., Mileage on Right...

 

My cluster would go nuts at times.., work fine.., or not at all...., hit a bump on the road.., everything comes on.

 

What I did.., was to remove the cluster.., take it apart.., then re-soldered the 14-Pin IC chip.., it is @ 3/4" long x 5/16" wide.., and black in color.

 

 

I heated each pin with a soldering iron.., just until the solder melted.., and that's all I did.., put it back together.., and it works 'perfectly' since. __:thumbsup:

Edited by 2Tired
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