PCM LACKS POWER SCANNER SHOWS NO CODES

1991 GMC SUBURBAN
30 MILES
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SPORT454
  • MEMBER
  • 1 POST
HEY. V2500 5.7 & 4L80E WITH THE "7060" PCM LACKS POWER. SNAP-ON "BRICK" SCANNER SHOWS NO CODES. DATAMASTER ALDL DATALOGGER SHOWS ONLY 11 TO 24 DEGREES OF SPARK ADVANCE. REFERENCING MY '91 454SS W/THE SAME TRANS & PCM SHOWS FROM 22 TO 40 DEG]

Changed engines twice, rebuilt trans, tried high stall & low stall converters. Every component has been changed at least twice. Until I found the data logging software I had no idea what else to do?
Jan 30, 2012 at 11:33 AM
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HMAC300
  • ✓Experienced Mechanic
  • 48,601 POSTS
if this is tbi then check for a blown gasket at bottom of tbi unit. fuel pressure should be 9-11 psi as well. cross A&B on aldlandcount flashes to see if anything other than 12 comes up.
Jan 30, 2012 at 12:44 PM
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