LM7 With Weird idle issues
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Teching In
Joined: Jun 2012
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LM7 With Weird idle issues 1997 Jeep Wrangler with a 5.3l vortec (lm7 gen3) Manual trans
Recently did a different cam swap in the engine, did a remote mail order tune from black bear performance. Needless to say the jeep runs very strong. My only issue , and its driving me nuts is erratic idle issues. I installed the cam for more lower end torque along with an aggressive sound so I know I was going to end up with a choppy idle. The jeep will idle around 850rpms but on some occasion it would drop all the way down to literally 100rpm and I would hurry up and try to rev it so it doesn't stall out on me. After that happens I usually receive a check engine light with 2 codes. P0106 (Manifold Air Pressure (MAP) Barometric Pressure Sensor Electric Circuit Output Range and Performance Problem) and p0500 (general OBD-II code that indicates a malfunction has been detected in the vehicle speed sensor circuit)
I went ahead and replaced both the MAP sensor and PCV valve and it didn't fix anything. I only get that CEL when the idle goes way down like that.
The guys from black bear performance think I had a vacuum leak since the MAP would read anywhere from 2-9psi on average. Anyone experience this issue?
I can almost certainly stall the engine by pushing the clutch in at the last second when approaching a stop.
The specs for the cam are :
Comp Cams 54-601-11
Dur at .050 227 IN 241 EX
LSA 109
Installed at 103 which is what the ICL was on the cam card
Recently did a different cam swap in the engine, did a remote mail order tune from black bear performance. Needless to say the jeep runs very strong. My only issue , and its driving me nuts is erratic idle issues. I installed the cam for more lower end torque along with an aggressive sound so I know I was going to end up with a choppy idle. The jeep will idle around 850rpms but on some occasion it would drop all the way down to literally 100rpm and I would hurry up and try to rev it so it doesn't stall out on me. After that happens I usually receive a check engine light with 2 codes. P0106 (Manifold Air Pressure (MAP) Barometric Pressure Sensor Electric Circuit Output Range and Performance Problem) and p0500 (general OBD-II code that indicates a malfunction has been detected in the vehicle speed sensor circuit)
I went ahead and replaced both the MAP sensor and PCV valve and it didn't fix anything. I only get that CEL when the idle goes way down like that.
The guys from black bear performance think I had a vacuum leak since the MAP would read anywhere from 2-9psi on average. Anyone experience this issue?
I can almost certainly stall the engine by pushing the clutch in at the last second when approaching a stop.
The specs for the cam are :
Comp Cams 54-601-11
Dur at .050 227 IN 241 EX
LSA 109
Installed at 103 which is what the ICL was on the cam card
Thread Starter
Teching In
Joined: Jun 2012
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When I did the tube, they sent me the efi live cable. I had to drive around through all types of daily driving conditions and it recorded the engines data log. From there they were able to design a tune to fit specific for my jeep. So i though it's the closest thing besides an actual dyno tune
Thread Starter
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I'm not sure to what extent they made the tune. I was shipped a completely different pcm as well. I still have the efi live wire that I can still grab engine data from. I also messaged comp cams to see what they recommend the idle be at and manifold psi should be at.
Other than this issue the jeep runs awesome. Very strong response and able able to chirp 3rd gear with 35" tires
Other than this issue the jeep runs awesome. Very strong response and able able to chirp 3rd gear with 35" tires
You might need idle speed around 950 to stabilize it. That and increased base idle air. If you have a mechanical throttle you might need to open the set screw also
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Not sure that would be my choice of cam in an LM7 in a heavy vehicle. With that being said. Did you check for vacuum leaks?? If you have access to a tuner locally with a dyno I would take it there and have them check the tune out.
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