on the aldl you usually ground a and b to read your codes but i stumbled onto this a while back and never asked the question nor needed to.just got my ed wright fast chip the idle leaves a little to be desired during warmup,after that it's fine,so my question is when i connect b with the terminal to the left of it the car's idle jumps to 1200 and is rock steady (compared to normal operation)and runs like a champ absolutely no difference in engine output. what circuit am i grounding out by doing this and has anyone experienced this.i don't know but it feels like either tthe computer ignores all the sensors and just reads the fuel and spark maps or sometthing tto do with the maf sensor.really need help on this one

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87 trans am 350,L98 aluminum heads,LT4 hot cam,slp runners,slp 1 5/8 headers,3in.y-pipe,edelbrock base,hi flo cat,air foil,afpr,as&m ported plenum,t-5 tranny w/centerforce clutch and a 3.27 9bolt(11.9in. brakes),ed wright's fastchip,relocated iat sensor,tb bypass,accel supercoil,hollowed maf,slp 3in. catback,a/c delete.
oh!no!i think my maf is going!!!!!!!!!!!!

14.10@97mph w/2.01 60'

slp catback is finally on!!!
fastchip prom is in.OH!MAN!
FLOWMASTER S.U.C.K.S

 

The ecm has several modes of operation.
The commanded high rpm is part of ALDL mode, for diagnostics. The ecm is not meant to be run long term in that mode.
You can unplug say the MAF sensor and the ecm defaults to a bunch of run home settings. Some calibrations run rather well like that, but there are some gotchas, like the timing is locked, other then what the pickup reluctor generate on their own.

 

grumpy do you know what that terminal is for like a is for diagnostics,i believe d is for the fuel pump,just trying to find what circuit that is

 

Forgive me for interrupting, but I think it goes:

A - Ground
B - Diagnostic Terminal
C - A.I.R. (if used)
D - "Service Engine Soon" light
E - Serial Data
F - TCC (if used)
G - Fuel Pump
M - Serial Data (if used)

Some of my ALDL leads are not used; I don't know what would go there...

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