AAHHHH. I would test it if I had a way. What does the switch put through on this wire?
1978 Camaro Type LT, 383, Dual TBI, '7427, 4L80E
1981 Camaro Z-28 Clone, T-Tops, 350/TH350
1981 Camaro Berlinetta, V-6, 3spd
1974 Chevy/GMC Truck, '90 TBI 350, '7427, TH350, NP203, 6" lift, 35s
Got the new book in today, and F8 is the correct pin for the power steering switch. Also, fount out that B1 is for the DIS system used with the 2.2L. It is called the 1X Signal, and is used for ASDF (Alternate Synchronous Double Fire).
Anyone ever find the VATS pin? I'll trade you the AC High Pressure Switch pin. This was used to raise the idle if the A/C pressure got too high (no bins that I know of with this active).
Last edited by 93V8S10; 02-14-2012 at 06:13 AM.
Sounds like that book has some good info in it. It there anything in there that could make sense of this trans datastream portion of the hac?
I was thinking it might be something used in the diesel engine TCM.Code:L53F3 FDB $0010 ; 11, MALFFLG6, ERROR WD 6 ; ; b7 1 = ERR 57. (not used) ; b6 1 = ERR 58, XMISH TEMP HI ; b5 1 = ERR 59, XMISH TEMP LOW ; b4 1 = ERR 61, TURBO BOOST SENSOR HI ; ; b3 1 = ERR 62, TURBO BOOST SENSOR LOW ; b2 1 = ERR 63, BARO SENSOR HI ; b1 1 = ERR 64, BARO SENSOR LOW ; b0 1 = ERR 65. (not used) ;----------------------------- L53F5 FDB $001B ; 12, CURMALF5, CURRENT ERROR WD 6 ; ; b7 1 = ERR 57. (not used) ; b6 1 = ERR 58, XMISH TEMP HI ; b5 1 = ERR 59, XMISH TEMP LOW ; b4 1 = ERR 61, TURBO BOOST SENSOR HI ; ; b3 1 = ERR 62, TURBO BOOST SENSOR LOW ; b2 1 = ERR 63, BARO SENSOR HI ; b1 1 = ERR 64, BARO SENSOR LOW ; b0 1 = ERR 65. (not used) ;-----------------------------
Can you shed any more info on any unlisted I/O pins?
1978 Camaro Type LT, 383, Dual TBI, '7427, 4L80E
1981 Camaro Z-28 Clone, T-Tops, 350/TH350
1981 Camaro Berlinetta, V-6, 3spd
1974 Chevy/GMC Truck, '90 TBI 350, '7427, TH350, NP203, 6" lift, 35s
Nothing about diesel engines, the new book is the S/T Driveability & Emissions Manual. I've woundered about those too.
Here's what I've got so far:
Looks like that transmission code was also used in a diesel application. Im my LT1 it is simalar to these PCM that it has engine data and transmission data although I have them in same adx, need to change connection and montitor. Transmission data also shows some engine data and all error codes.
1990 Chevy Suburban 5.7L Auto ECM 1227747 $42!
1998 Chevy Silverado 5.7L Vortec 0411 Swap to RoadRunner!
-= =-
79 Jeep Cherokee, AMC 401, T-18 manual trans, hydroboost, 16197427 MPFI system---the toy
93 Jeep YJ Wrangler, 4.0L, 5 speed, 8.8 rear, homebrew hub conversion and big brakes, hydroboost, 2.5in OME lift, 31x10.50's---the daily driver
99 Jeep WJ Grand Cherokee limited, 4.0L, auto, 2wd, leather and power everything, 99% stock---the long distance highway ride.
now the vats deal would be cool. since i have it in a 92 camaro it would be cool to have it wired up as well.
Very interesting that GM found ASDF to produce cleaner emissions in the S10. In some masks ASDF is a function of IPW to prevent commanded on times less than injector is capable of and is implemented without 1X signal. In these cases ASDF is not implemented during most operating conditions. It's noteworthy that GM resorted to hardware solution in 7427. I'd love to have more time to investigate the hardware relationship between the 1X input pin, memcal configuration, and limp mode fueling.
The list of unused pins has been pretty consistent in all of the models I've looked at. A11,A13, B6,B7, B11, B14, E7, F4,F5. Checking multpile vehicles to see if this list can be shortened might be a worthwhile approach.
I am planning on switching from the 7747 to the 7427. Need to the get the PCM itself tho, and since I have a V8, do I need a 7427 from a V8, or will the V6 version work too?
'90 Suburban w/ pretty much stock 350 TBI, 7427 ECM Conversion, sadly sold several years ago
'95 K2500 Suburban w/ soon to be 400HP 454
For those interested I have both the DRAC and VSSB. These little boxes convert a 40 pulse tone ring into the signal to for the PCM or ECM, and speedo. The VSSB has more outputs than the DRAC. Power, ground, and sensor inputs are the same. The PCM 427 with VSSB uses the RWAL singal (anti-lock brake signal), 40 PPR signal, and 2000 PPM signal. The VSSB also converts the 40 pulse tone ring signal to 2000 PPM for the Speedo. The DRAC is missing the 2000 PPM signal to PCM but because i am using a cable driven speedo i can use the 2000 PPM signal from the DRAC as the signal into the PCM by relocating one wire. With the correct diagrams and much research they can be used interchangebly.
As a side note from another question long ago in this thread the VATS pin is pin B7. There is no wire in that location but it is +5 volts and when pulled low at 30Hz the PCM will allow engine start. So enable VATS and use pin B7. I have tested it and activtly using it in my conversion.
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