My Snap on friend has taken a considerable interest in my project bird, and as a result, he talks to a lot of mechanics on his route - some of them are quite good too. Anyway, after swapping out my bad MAF for a Wells unit, I now get a hard 33 error, and we have not had time to trace it out (just got another 19" of snow here ). So he has been talking to some guys about this pita MAF setup, and one of the GM techies told him to check and see if the car has a MAP as well as the MAF. If it does, he says that you can buy a SD memcal from the dealer, plug it into the ECM and it will (magically?) now be a speed density setup. Furthermore, the MAF can be left in place with no ill effects.

Now, I was always under the impression that
if you wanted to go to a SD setup, you needed a new ECM with memcal, as well as either modifying the engine harness, or outright replacing it. Since I am no TPI guru, I dodn't want to tell him straight out that this is a bunch of baloney, but I would like to hear some knowledgeable replies as to why this would be impossible.

So, anybody care to try...?



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89 Firebird Formula
WS6 package,ZZ4 Crate engine
SLP 58MM TB, Edelbrock TES Headers
Random Tech 3" cat, SLP 3" stainless exhaust
9 bolt rear, Hotchiss swing arms, Lakewood panhard rod
Corvette 2/4 servo, kevlar band, full poly rear.
Centerline 16x8 rims, B.F Goodrich drag radials

 

The GM tech is smoking something. Thirdgens have either a MAF (85-89) or a MAP (90-92). Its the 4th gens (94+) that have both. To convert from MAF to MAP you need a new ECM, a new PROM, and either a new wire harness or re-pin your existing harness. You also need a new knock sensor, and of course the MAP sensor.

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West Coast GM Shootout 2001!
1991 Camaro Z28
5.7L 5-Speed (originally 305)
13.25 @ 107.18 MPH
Southern California
Member: SoCal 3rd Gen F-Bodies
Webmaster: SoCal F-Bodies
-=ICON Motorsports=-

 

On thirdgens, I have always been under the same impression as you; need 730 ecm to read 27C256 eprom used in SD cars.

 

Kevin91Z wrote:
Its the 4th gens (94+)that have both.


OK, that gives me a way to let him save face I will suggest that perhaps he was confused as to the year of my car...
Thanks!



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89 Firebird Formula
WS6 package,ZZ4 Crate engine
SLP 58MM TB, Edelbrock TES Headers
Random Tech 3" cat, SLP 3" stainless exhaust
9 bolt rear, Hotchiss swing arms, Lakewood panhard rod
Corvette 2/4 servo, kevlar band, full poly rear.
Centerline 16x8 rims, B.F Goodrich drag radials