PCM trouble? In and out of closed loop KPA in the 90s
#1
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This is an LS swap in a 91 Corvette.
specs:
built/forged 5.3 347 iron block with 241 heads
MS3 cam
237/242, .603"/.609", 113 LSA
LS6 Intake
Wiring harness and PCM from a 99 Z28
The veh goes in and out of open loop at idle and the KPA is in the 90s all the time. I have checked the wiring multiple times and its all good. I'm running only 2 02 the front and the others have been deleted in the tune.
specs:
built/forged 5.3 347 iron block with 241 heads
MS3 cam
237/242, .603"/.609", 113 LSA
LS6 Intake
Wiring harness and PCM from a 99 Z28
The veh goes in and out of open loop at idle and the KPA is in the 90s all the time. I have checked the wiring multiple times and its all good. I'm running only 2 02 the front and the others have been deleted in the tune.
Last edited by LSCha0s; 08-09-2012 at 09:11 AM.
#3
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The 02s should be getting good power we had the wideband hooked up to the same fuse block as the 02s and it never failed. I think this may be 2 different problems. Would a vacuum leak also effect the veh staying in closed loop. My brakes are also hard so I could have a Vacuum leak at the booster. There is only a few possibilities here ..intake gasket, cracked intake or brake booster/line. There are not many vacuum lines on the LS. I have not checked for vacuum leaks yet. I need to replace my Valve springs first and will be doing that on Friday. I don't know if you saw my other thread but while we were tuning I broke a spring. It looks like the PO/builder only used one spring of a dual spring kit and I am replacing them all.
#4
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I doubt the MAP/vacuum would affect closed loop, mostly O2 swing and coolant temp. Do you have the coolant sensor hooked up? Have you put a scan tool on the PCM to verify the sensor data? The O2s will function somewhat without heaters and give symptoms like you describe, probably wouldn't hurt to verify the O2 heaters are getting good power and grounds.
Since you replaced the factory brake booster vacuum inlet, have you vacuum tested it?
Since you replaced the factory brake booster vacuum inlet, have you vacuum tested it?
#5
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I doubt the MAP/vacuum would affect closed loop, mostly O2 swing and coolant temp. Do you have the coolant sensor hooked up? Have you put a scan tool on the PCM to verify the sensor data? The O2s will function somewhat without heaters and give symptoms like you describe, probably wouldn't hurt to verify the O2 heaters are getting good power and grounds.
Since you replaced the factory brake booster vacuum inlet, have you vacuum tested it?
Since you replaced the factory brake booster vacuum inlet, have you vacuum tested it?