PDA

View Full Version : Experts Only ! :) 1987 GMC High Sierra 4X4 EFI rich exhaust


jnettrecker
08-11-2004, 08:05 AM
Ok guys I have a small dilemma. The problem is with a 1987 GMC High Sierra Short bed 4X4 with a 350 Fuel Injected Small Block. I just purchased the truck and a list of what was replaced before I got it will follow. Motor has 2000 miles on a quality rebuild.
Problem: I have rich exhaust (slightly black and smelly) doesn’t matter if it is cold or warm. Engine Starts after 4 to 5 revolutions when cold and after 1 revolution when warm. At an idle if you put it in gear engine stays running just fine but turn the steering wheel and put a load on the engine and it dies. Motor seems to run fairly strong except low end could use a little help but not bad. Timing is set at 4 BTDC. Electronic advance is set by the ECM as well as the idle so I cannot adjust them. Both injectors are working correctly. Strangest thing is the ECM is not throwing a code. No check engine light and no Codes are stored in the ECM. Engine does not leak or burn any oil whatsoever.

New Parts:
• EGR Valve
• PVC Valve
• EGR Vacuum Control (tested fine)
• MAP Sensor (tested fine)
• New exhaust and muffler w/o a catalytic Converter
• 0/2 Sensor
• Plugs
• Pick up coil
• Idle control motor
• Air Filter


Any help is appreciated.

Josh in Indiana

www.Go4Synthetic.com