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'88 GMC R3500 DUALLY W/350 TBI and idle closed loop problems.
No it did not. When it drops down to idle speed, it will stay in closed loop for about 10 seconds, meanwhile the O2 sensor is trying to reach zero getting as low as 0.041 volts at 10 seconds. It goes open loop, then the EGR and AIR Injection solenoids are on, idle mixture is actually rich...- GMC dirty glass
- Post #7
- Forum: Engine & Performance
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'88 GMC R3500 DUALLY W/350 TBI and idle closed loop problems.
I replaced the thermostat and checked vacuum at PCV connection this weekend. Temp is up and vacuum is 14 at idle. Checking throttle body to manifold gasket for leaks today. Vacuum should be close to 19 from what I have read. I didnt have my laptop charged, but will check out the closed loop...- GMC dirty glass
- Post #5
- Forum: Engine & Performance
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'88 GMC R3500 DUALLY W/350 TBI and idle closed loop problems.
Hi and thanks for the reply. The o2 sensor and CTS are new, coolant never gets above about 161 degrees F. Coolant is full, reservoir is full also. I also seem to have 0 vacuum at idle?! I have connected smog pump solenoid vac line to egr solenoid vac line at throttle body with new hose, then...- GMC dirty glass
- Post #3
- Forum: Engine & Performance
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'88 GMC R3500 DUALLY W/350 TBI and idle closed loop problems.
I have recently had the heads rebuilt, TBI rebuilt, map and tps sensors replaced, fuel pressure is 11 psi. Idle is rich, it never goes to closed loop at idle, so it turns on the air injection solenoid and the EGR solenoid at idle. Major fumes from idle exhaust, no smoke, just fumes. At normal...- GMC dirty glass
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- 350tbi air injection closed loop fail idle emissions
- Replies: 8
- Forum: Engine & Performance
