I was currious. Has anybody ever "hacked" the memcal on a '165 (the two "limp home" proms?) to find out what EXACTLY is on there? I was currious because the only things i have really been able to find is you want to "match" the memcal as close as you can to your application. If i understand they just store enough to MAYBE run your car off of if the 'smarter' prom isn't working.

I have a memcal from a 87 vette I think (ABTS 4767 if anybody wants to refference it) and was planning on using this memcal as maybe a backup or a hotswapper, but not sure what the differences in the memcals are, if there even is any. And further more has anybody ever BURNED to their memcals? or made changes?


Thanks guys

 

They are resistors that set the cylinder select, and the pulse widths generated by the Redundant Fuel Devise. And some info for the knock sensor routine.
There is nothing to burn for limp home mode.

Reverse engineering something like that is months of work, and the return on that info isn't very meaningful.

 

Thanks grumpy

So even if it was hacked... limp home doesn't even store enough to tune it so if you ever do drop into limp it runs somewhat smooth?

So how universal are the different memcals?

 

There was less differences between Vettes and F-bodies with the 165 MAF than with the 7730, if that makes you feel better.

The best thing I could suggest is "test it". Take your Vette Memcal, burn your F-bodies bin on it and remove a sensor like the MAT to have it trigger an SES code and see if it will still "run enough".

The MAT on a 165 may not be "serious enough" of an error so you may want to look at disconnecting the O2 sensor and/or CTS also to get a "good failure" and a test of "limp mode".

 

Yea this is all what I was probably going to end up doing anyways, just wondering if the 'limp' has ever been hacked or is understood enough.

Like the guys moving to 383's or 400's. Just using a 350 limp would seem to leave them high and dry if it ever went into limp.

 

I'm pretty sure on a MAF car removing the MAT won't put it in limp home mode. Unhooking the maf will. I ran mine without the MAT for a long time (I was 16, didn't even know it was under there because my parts car didn't have that little jumper harness on it). It would throw a code but only at idle, after I was moving the light would even go out, and hooking it up made no noticeable difference in car performance. The speed density systems use it for a lot more (can't very well do ideal gas calculations without the T in Pv=nRT). If I unhook my maf it DEFINATELY goes into limp. Maybe the fact I have the b*st*rd 85 computer has something to do with it, but I can't think of any logical reason that would be a critical sensor on a MAF car. The 165 could very well be different and if it is I just made myself look ignorant, all well I have done it before. Have a good one. I have wondered about the memcal donor thing too, and it appears to be not worth the trouble.

 

Yea I had the 85 and when i crossed a cattle gaurd it unplugged the maf, which made driving HELL, "limp" was more like "fall on the floor and twitch" Have yet to drive in limp with the '165, but I doubt it could be any worse